RECALLS 3 Flashcards

Question

Which of the following is most associated with gastric ulcer formation? A. Helicobacter pylori B. Gluten sensitivity C. Giardia lamblia D. Salmonella typhi E. Vibrio cholerae

Answer 1

Correct Answer: A. Helicobacter pylori Explanation: ✅ Helicobacter pylori infection is the most strongly associated factor in the development of gastric ulcers. • It damages the mucosal barrier and increases gastric acid secretion. • Also linked to duodenal ulcers and gastric carcinoma. Diagnosis: • Urea breath test • Stool antigen test • Biopsy during endoscopy Treatment: • Triple therapy: PPI + clarithromycin + amoxicillin/metronidazole ⸻ Why not: • B. Gluten sensitivity: causes celiac disease, not ulcers • C. Giardia lamblia: causes small bowel malabsorption • D. Salmonella typhi: causes typhoid fever, may ulcerate Peyer’s patches • E. Vibrio cholerae: causes watery diarrhea, not ulcers

Answer 2

Correct Answer: C. Bloody discharge Explanation: ✅ Bloody nipple discharge is the most concerning for malignancy, especially if: • Unilateral • Spontaneous • From a single duct Possible causes: • Ductal carcinoma in situ (DCIS) • Intraductal papilloma (benign, but must be ruled out histologically) ⸻ Why not: • A. Milky discharge: commonly galactorrhea, often benign • B. Green/D. Yellow/E. Thick white: more suggestive of infection or fibrocystic changes, usually benign

Answer 3

Correct Answer: A. Vitamin A Explanation: ✅ Steatorrhea in chronic pancreatitis is due to fat malabsorption, which leads to deficiency of fat-soluble vitamins: • Vitamin A • Vitamin D • Vitamin E • Vitamin K Vitamin A deficiency can cause: • Night blindness • Dry eyes (xerophthalmia) • Increased risk of infections ⸻ Why not: • B. B12: absorbed in the terminal ileum; deficiency more common in pernicious anemia or ileal disease • C. Vitamin C: water-soluble; deficiency causes scurvy • D. B1 (thiamine): more related to alcoholism or beriberi • E. B6: water-soluble; deficiency seen in isoniazid use

Answer 4

Correct Answer: B. Superior mesenteric vein Explanation: ✅ The superior mesenteric vein (SMV) runs posterior to the neck of the pancreas, where it joins the splenic vein to form the portal vein. This is a key surgical landmark during: • Pancreaticoduodenectomy (Whipple procedure) • Portal hypertension evaluation ⸻ Why not: • A. Portal vein: formed posterior to the pancreas neck but slightly more superior • C. IVC / E. Aorta: more posterior and central, not directly behind the pancreas neck • D. Common bile duct: courses posterior to the first part of the duodenum and then into the pancreas head, not the neck

Answer 5

Correct Answer: D. Inferior surface of the liver Explanation: ✅ Calot’s triangle (originally described by Jean-François Calot) is an anatomical space used to identify and safely ligate the cystic artery during cholecystectomy. Modern borders of Calot’s triangle: • Medial: common hepatic duct • Lateral: cystic duct • Superior: inferior surface of the liver However, in surgical practice, the triangle of Calot refers to this region bounded by structures, not including the liver as one of its formal boundaries. • Cystic artery and Lymph node of Lund (also called the cystic lymph node) are within the triangle. ⸻ Why not: • A. Cystic duct, B. Common hepatic duct, C. Cystic artery, and E. Lymph node of Lund: all are directly involved in or contained within Calot’s triangle.

Answer 6

Correct Answer: A. Transfer the patient to theatre and perform decompression Explanation: ✅ This scenario is highly suggestive of compartment syndrome, a surgical emergency. Classic signs: • Pain out of proportion to injury • Pain worsened by passive stretch • Anterior interosseous nerve palsy (inability to flex the distal phalanx of the thumb and index finger) • Can lead to ischemia and necrosis if not promptly managed Management: • Immediate fasciotomy (surgical decompression) • Do not delay for reassessment or conservative measures ⸻ Why not: • B. Physiotherapy: dangerous; delays urgent treatment • C. Remove slab & reassess in 4 hrs: may worsen delay; compartment syndrome needs immediate action • D. Analgesia and follow-up: inappropriate for suspected compartment syndrome

Answer 7

Correct Answer: D. Sepsis and multi-organ failure Explanation: ✅ In acute pancreatitis, especially severe cases, the main cause of death is: • Sepsis • Multi-organ failure (MOF) This usually results from: • Infected pancreatic necrosis • Systemic inflammatory response syndrome (SIRS) Mortality timeline: • Early death: SIRS → MOF • Late death: infection/sepsis of necrotic tissue ⸻ Why not: • A. Hypovolemia: can contribute early but is manageable • B. Pulmonary embolism: less common cause • C. Arrhythmias: not typical unless due to severe electrolyte imbalance • E. Hemorrhage: rare but can occur in necrotizing pancreatitis

Answer 8

Correct Answer: C. Aortic transection Explanation: ✅ A widened mediastinum on chest X-ray in the context of trauma is highly suspicious for aortic injury, particularly aortic transection. Most common cause: • Deceleration injury (e.g. car crash) • Occurs at the aortic isthmus (just distal to the origin of the left subclavian artery) Next step: • CT angiography to confirm diagnosis • Urgent vascular surgery or endovascular repair ⸻ Why not: • A. Tension pneumothorax: causes mediastinal shift, not widening • B. Flail chest: rib fractures with paradoxical movement, not widening • D. Pericardial tamponade: causes enlarged cardiac silhouette, not mediastinum • E. Hemothorax: fluid in pleural space, not mediastinal widening

Answer 9

Correct Answer: D. Recurrent laryngeal nerve Explanation: ✅ The recurrent laryngeal nerve is the most commonly injured nerve during thyroid surgery, and its injury results in: • Hoarseness of voice • Unilateral vocal cord paralysis If bilateral injury occurs, it can lead to: • Airway obstruction • Stridor ⸻ Why not: • A. Hypoglossal nerve: affects tongue movement • B. External branch of superior laryngeal nerve: affects pitch (inability to produce high-pitched sounds), not hoarseness • C. Vagus nerve: higher up injury; rare in isolated thyroid surgery • E. Glossopharyngeal nerve: involved in swallowing, not hoarseness

Answer 10

Correct Answer: B. Upper outer quadrant Explanation: ✅ The upper outer quadrant (UOQ) is the most common site for breast cancer — accounting for approximately 50% of all cases. Reasons: • UOQ has the highest density of glandular tissue • Closest to the axillary tail (of Spence), where breast tissue extends ⸻ Why not: • A. Upper inner quadrant / C. Lower inner quadrant / D. Lower outer quadrant: much less common • E. Central region: includes the nipple-areolar complex, less frequently involved

Answer 11

Correct Answer: D. Oxygen and pain control Explanation: ✅ The initial management of flail chest focuses on: • Adequate oxygenation • Effective pain relief (e.g., opioids, nerve blocks) These improve ventilation and prevent hypoxia, atelectasis, and respiratory failure. Flail chest = fracture of two or more ribs in two or more places, causing a segment to move paradoxically during respiration. ⸻ Why not: • A. Chest physiotherapy: useful in later stages, not initial • B. Surgical fixation: considered for severe or persistent cases • C. Chest drain: only if pneumothorax/hemothorax present • E. High PEEP: reserved for ventilated patients with respiratory failure

Answer 12

Correct Answer: A. Tail of pancreas Explanation: ✅ The tail of the pancreas lies in close proximity to the hilum of the spleen and is often within the splenorenal (lienorenal) ligament, along with the splenic vessels. During splenectomy: • Ligation of the splenic artery and dissection near the splenic hilum can inadvertently injure the pancreatic tail, risking: • Pancreatic leak • Fistula • Postoperative pancreatitis ⸻ Why not: • B. Fundus of stomach: nearby, but less likely to be directly injured during splenic artery ligation • C. Pancreatic duct: runs centrally in the pancreas, not near the splenic hilum • D. Phrenico-colic ligament: supports the splenic flexure, not closely involved in splenic artery ligation • E. Lienorenal ligament: contains the splenic artery and vein, but it is not the injured structure — the tail of pancreas inside it is

Answer 13

Correct Answer: A. Gastroduodenal artery Explanation: ✅ A posterior penetrating gastric ulcer, especially one in the first part of the duodenum, is most likely to erode into the gastroduodenal artery, causing massive upper GI bleeding. Clinical clues: • Sudden hematemesis or melena • Hypotension • Ulcer located on posterior duodenal wall or gastric antrum ⸻ Why not: • B. Left gastric artery: involved in lesser curvature ulcers, not posterior wall • C. Right gastric artery: supplies lesser curvature, not commonly eroded • D. Splenic artery: related to posterior stomach and pancreas, but less commonly eroded than GDA • E. Inferior pancreaticoduodenal artery: deeper in retroperitoneum, not a direct target of typical ulcers

Answer 14

Correct Answer: B. Meckel’s diverticulum Explanation: ✅ A positive technetium-99m pertechnetate scan (also called a Meckel scan) in a child with painless rectal bleeding is classic for Meckel’s diverticulum. • It arises from a persistent vitelline duct • Contains ectopic gastric mucosa, which secretes acid and causes ulceration of adjacent ileal mucosa → bleeding Rule of 2s: • Occurs in ~2% of population • 2 feet from ileocecal valve • 2 inches long • Presents before age 2 • May contain 2 types of ectopic mucosa (gastric and pancreatic) ⸻ Why not: • A. Crohn’s disease: presents with pain, diarrhea, and inflammation • C. Juvenile polyp: painless bleeding but scan wouldn’t be positive • D. Hirschsprung’s disease: chronic constipation, not bleeding • E. Intussusception: causes pain and red “currant jelly” stools, not painless bleeding

Answer 15

Correct Answer: D. Adenocarcinoma Explanation: ✅ Adenocarcinoma of the esophagus is the most common type in the distal esophagus and gastroesophageal junction, especially in: • Patients with long-standing GERD • Those with Barrett’s esophagus (a precursor condition) Key clues: • Dysphagia (especially progressive) • Weight loss • Ulcerated mass on endoscopy • Background of reflux disease ⸻ Why not: • A. Esophageal stricture: causes dysphagia but not ulcerated mass or weight loss • B. Achalasia: functional motility disorder, not an ulcerated mass • C. Barrett’s esophagus: a premalignant condition, but not ulcerative mass itself • E. Squamous cell carcinoma: more common in upper/mid-esophagus, linked to smoking and alcohol

Answer 16

Correct Answer: C. Carcinoma of the head of pancreas Explanation: ✅ Painless obstructive jaundice, weight loss, and pale stools are hallmark signs of a pancreatic head tumor. Mechanism: • Tumor compresses the common bile duct, leading to: • Bile flow obstruction • Conjugated hyperbilirubinemia • Acholic (pale) stools • Dark urine Other features: • Courvoisier’s sign: palpable, non-tender gallbladder • Often presents late with poor prognosis ⸻ Why not: • A. Hepatitis: causes painful jaundice, systemic symptoms (e.g. fever, malaise) • B. Gallstones: usually cause painful jaundice and biliary colic • D. PSC: more common in younger males with IBD; presents with cholestatic liver profile • E. Cholangiocarcinoma: similar presentation but rarer than pancreatic head cancer

Answer 17

Correct Answer: C. Median nerve Explanation: ✅ The median nerve is responsible for: • Thumb opposition (via the opponens pollicis muscle) • Sensation over the lateral 3½ fingers • Flexion of the wrist and fingers Injury to the median nerve at the wrist (e.g., deep laceration): • Loss of opposition • Weakness of thumb abduction and flexion • Sensory loss over thumb, index, middle, and lateral ring fingers ⸻ Why not: • A. Radial nerve: affects wrist and finger extension, not opposition • B. Ulnar nerve: affects fine motor control, especially the intrinsic hand muscles, but not opposition • D. Posterior interosseous: a branch of radial nerve, controls extension, not thumb opposition • E. Musculocutaneous nerve: supplies biceps and forearm flexors, not hand muscles

Answer 18

Correct Answer: B. Squamous cell carcinoma Explanation: ✅ A non-healing ulcer on the lower lip in an elderly person with sun exposure history is most suggestive of squamous cell carcinoma (SCC). Key features: • Commonly occurs on sun-exposed areas (face, lips, ears, hands) • Lower lip is a high-risk area for SCC • Presents as a non-healing ulcer, nodule, or crusted lesion • May be painful or painless Risk factors: • UV radiation • Smoking • Chronic irritation ⸻ Why not: • A. Basal cell carcinoma: more common on upper lip/face; pearly papule, rarely ulcerates deeply • C. Actinic keratosis: pre-malignant, scaly lesion, not typically ulcerated • D. Melanoma: pigmented lesion, often not ulcerated initially • E. Keratoacanthoma: dome-shaped, rapidly growing, may regress spontaneously

Answer 19

Correct Answer: C. Remove the nail, repair nail bed and apply buddy splint Explanation: ✅ In cases of nail bed injury with an undisplaced distal phalanx fracture, the recommended approach is: • Remove the damaged nail • Repair the nail bed under magnification • Apply a buddy splint (or protective dressing) to stabilize the fingertip This allows for: • Proper healing of the nail matrix • Prevention of nail deformity • Preservation of function and appearance ⸻ Why not: • A. Excision of the distal phalanx: unnecessarily aggressive; not indicated for undisplaced fractures • B. Microvascular reattachment: used for amputations, not partial nail bed injuries • D. Delayed repair: increases infection and deformity risk • E. K wire pinning: only if fracture is unstable or displaced

Answer 20

Correct Answer: C. Orbital floor fracture Explanation: ✅ A blowout (orbital floor) fracture typically results from blunt trauma to the orbit and presents with: • Diplopia, especially on upward gaze (due to inferior rectus entrapment) • Infraorbital numbness (due to injury of the infraorbital nerve) • Possible enophthalmos (sunken eye) Mechanism: Fracture of the thin orbital floor, allowing orbital contents to herniate into the maxillary sinus. ⸻ Why not: • A. Globe rupture: more severe, usually obvious signs like loss of vision, teardrop pupil • B. Retro-orbital hematoma: rapid painful proptosis, vision loss risk, surgical emergency • D. Blow-in fracture: rare, opposite of blowout — pushes contents in, less common • E. Optic neuritis: associated with pain on eye movement and visual loss, not diplopia or numbness

Answer 21

Correct Answer: B. Mohs micrographic surgery Explanation: ✅ Mohs micrographic surgery is the gold standard treatment for basal cell carcinoma (BCC), particularly when: • Located in cosmetically or functionally sensitive areas (like the face, nose, eyelids, ears) • The lesion has ill-defined borders • There have been recurrences or aggressive subtypes Mohs technique advantages: • Highest cure rate • Tissue-sparing • Immediate microscopic margin control ⸻ Why not: • A. Radiotherapy: reserved for non-surgical candidates • C. Wide excision with 5 cm margin: excessive; BCC typically requires 3–5 mm, not cm • D. Chemotherapy: not first-line for localized BCC • E. Laser ablation: not suitable for BCC

Answer 22

Correct Answer: B. Thyroglossal duct cyst Explanation: ✅ A thyroglossal duct cyst is a midline neck mass that: • Moves with swallowing and tongue protrusion • Is typically painless unless infected • Results from persistent thyroglossal duct (embryologic remnant) Common in: • Children and young adults • Often presents after an upper respiratory infection Treatment: • Sistrunk procedure (removal of cyst, tract, and central portion of hyoid bone) ⸻ Why not: • A. Branchial cleft cyst: lateral neck, near sternocleidomastoid • C. Thyroid nodule: also moves with swallowing but is deeper and part of thyroid gland • D. Lymphadenopathy: may be tender, often related to infection or malignancy • E. Carotid body tumor: pulsatile, located at carotid bifurcation, doesn’t move with swallowing

Answer 23

Correct Answer: C. Oral antibiotics Explanation: ✅ This presentation is classic for acute mastitis, most commonly caused by Staphylococcus aureus, especially in lactating women. Key features: • Localised breast pain, swelling, redness, and fever • Most often affects one quadrant • Can develop into breast abscess if untreated Initial management: • Oral antibiotics (e.g. flucloxacillin) • Continue breastfeeding or expressing milk • Reassess in 48–72 hours ⸻ Why not: • A. Immediate surgery: only indicated for abscess drainage, not uncomplicated mastitis • B. Mammogram: not useful in acute infection; painful and low diagnostic yield here • D. Fine needle aspiration: used if abscess is suspected • E. Reassurance: insufficient — infection requires treatment

Answer 24

Correct Answer: B. Pelvic binder Explanation: ✅ In a hemodynamically unstable patient with a pelvic fracture, the first step is to apply a pelvic binder. Purpose: • Reduces pelvic volume • Stabilizes the fracture • Helps control venous bleeding (the most common source in pelvic trauma) Binder should be applied: • Over the greater trochanters, not the iliac crests ⸻ Why not: • A. External fixation: helpful later, especially if binder ineffective • C. Laparotomy: only if intra-abdominal bleeding suspected; not first step in isolated pelvic injury • D. Angioembolisation: effective for arterial bleeding but takes time and requires imaging • E. Tranexamic acid: used adjunctively but not the immediate mechanical stabilisation step

Answer 25

Correct Answer: E. Non-seminomatous germ cell tumor (NSGCT) Explanation: ✅ A testicular mass with elevated AFP and β-hCG points to a non-seminomatous germ cell tumor (NSGCT). These tumors are typically: • Aggressive • Occur in younger men, but can affect those >50 • Present as a painless testicular mass Types of NSGCT include: • Embryonal carcinoma • Yolk sac tumor (↑ AFP) • Choriocarcinoma (↑ β-hCG) • Teratoma (may or may not elevate markers) Seminomas may have elevated β-hCG but never elevate AFP. ⸻ Why not: • A. Seminoma: typically only β-hCG raised, AFP remains normal • B. Leydig cell tumor: usually hormonally active (e.g., estrogen/testosterone) • C. Sertoli cell tumor: rare, often hormonally active, normal markers • D. Teratoma: part of NSGCT, but on its own doesn’t always raise both markers

Answer 26

Correct Answer: C. IV fluids and blood products Explanation: ✅ In a patient with cirrhosis and massive upper GI bleeding (e.g., from varices), the first step is resuscitation with: • IV fluids • Blood transfusion (with target hemoglobin ~7–8 g/dL) • Monitoring vitals and urine output Stabilizing the patient is essential before any intervention like endoscopy. ⸻ Next steps after initial resuscitation: • IV terlipressin or octreotide • IV antibiotics • Urgent endoscopy (after stabilization) • Balloon tamponade or TIPS if bleeding uncontrolled ⸻ Why not: • A. Emergency endoscopy: required, but only after resuscitation • B. IV omeprazole: useful for ulcer bleeding, not variceal bleeding • D. Sengstaken-Blakemore: used if massive bleeding continues, temporary measure • E. TIPS: a later intervention if endoscopic and medical treatments fail

Answer 27

Correct Answer: C. Most are found incidentally Explanation: ✅ Appendiceal neuroendocrine tumors (NETs), formerly called carcinoid tumors, are: • Often found incidentally during histological analysis after appendicectomy • Most are <2 cm, located at the tip of the appendix • Rarely symptomatic ⸻ Key points: • <2 cm: simple appendectomy is usually sufficient • >2 cm, mesoappendiceal invasion, or base involvement: consider right hemicolectomy • Carcinoid syndrome (flushing, diarrhea, wheeze) is rare, usually requires hepatic metastasis ⸻ Why not: • A. Aggressive and early metastasis: false; most are indolent • B. Hemicolectomy always: false; only for larger/high-risk tumors • D. Carcinoid syndrome: rare with appendiceal origin • E. Squamous cells: NETs arise from neuroendocrine cells, not squamous cells

Answer 28

Correct Answer: E. Emergency laparotomy Explanation: ✅ The presence of free air under the diaphragm on X-ray in a patient with peptic ulcer disease indicates a perforated viscus — most likely a perforated gastric or duodenal ulcer. This is a surgical emergency. ⸻ Management: • Immediate resuscitation • Broad-spectrum IV antibiotics • Nasogastric decompression • Emergency laparotomy to identify and repair the perforation ⸻ Why not: • A. Endoscopy: contraindicated in perforation due to risk of further air insufflation • B. IV antibiotics and NG: part of initial management, but not definitive • C. PPI: helpful adjunct, not sufficient • D. CT abdomen: can be done if diagnosis is uncertain, but X-ray is already diagnostic

Answer 29

Correct answer: C) Clostridium difficile infection Explanation: The clinical scenario described is characteristic of a Clostridium difficile infection (CDI), particularly following antibiotic use associated with surgical procedures such as cholecystectomy. CDI typically presents within days to weeks after surgery or antibiotic therapy, causing significant watery diarrhea, abdominal pain, and fever. • Minor bile spillage during cholecystectomy would not typically cause infectious diarrhea, but could lead to local complications such as abscess or bile leakage. • Giardia lamblia typically causes prolonged, greasy diarrhea following exposure to contaminated water or food, not commonly associated with postoperative complications. • Escherichia coli infections (particularly pathogenic strains causing severe diarrhea) are less likely postoperatively unless explicitly contaminated or exposed to a known source. • Salmonella infections generally result from ingestion of contaminated food, causing diarrhea, fever, and abdominal cramps, not typically related to surgical procedures. Given the postoperative setting and diarrhea onset after surgery with antibiotic use, Clostridium difficile infection is the most likely diagnosis.

Answer 30

Correct answer: ✅ C) Absence of HER2 amplification Explanation: In breast cancer, absence of HER2 (Human Epidermal growth factor Receptor 2) amplification is associated with a better prognosis. HER2-positive cancers tend to be more aggressive, with a higher likelihood of recurrence and poorer outcomes unless treated specifically with anti-HER2 therapies like trastuzumab. Let’s briefly review the other options: • A) Presence of lymphovascular invasion: ❌ This suggests tumor cells have entered lymphatic or blood vessels, increasing the risk of spread — a poor prognostic factor. • B) Bloom and Richardson Grade III: ❌ This denotes high-grade tumors with poor differentiation — worse prognosis. • D) More than three positive axillary nodes: ❌ Greater nodal involvement is a strong predictor of worse outcomes and higher recurrence risk. Hence, Option C is correct and indicates a more favorable prognosis histologically.

Answer 31

Correct answer: ✅ B) Cemented total hip replacement Explanation: In fit and independent elderly patients (typically under 80 years) with displaced subcapital (intracapsular) fractures, cemented total hip replacement (THR) is preferred over hemiarthroplasty. It offers better functional outcomes, less long-term pain, and reduces the risk of revision surgery. • A) Cemented hemiarthroplasty: ❌ Suitable for frail or immobile patients or those with significant comorbidities. • C) Intramedullary nailing: ❌ Generally reserved for intertrochanteric or subtrochanteric fractures, not intracapsular fractures. • D) ORIF (Open Reduction and Internal Fixation): ❌ Often used in younger patients with good bone quality or nondisplaced fractures. Your choice is spot on — THR is ideal in this scenario.

Answer 32

Correct answer: ✅ C) Hypertrophic pyloric stenosis Explanation: This is a classic presentation of hypertrophic pyloric stenosis, which typically occurs between 2–6 weeks of life. Key features include: • Projectile, non-bilious vomiting (since the obstruction is proximal to the duodenum), • Palpable olive-shaped mass in the right upper quadrant (the hypertrophied pyloric muscle), • Failure to thrive and signs of dehydration over time. Let’s look at the distractors: • A) Oesophageal atresia: ❌ Usually presents in the first few days of life with drooling, choking, cyanosis after feeding. • B) Malrotation: ❌ Can cause bilious vomiting, often in the first week, and may present with volvulus. • D) GERD: ❌ Common in infants but doesn’t cause projectile vomiting or a palpable mass. • E) Duodenal atresia: ❌ Presents with bilious vomiting, and classic “double bubble” sign on X-ray.

Answer 33

Correct answer: ✅ C) Simmonds’ squeeze test Explanation: This is a classic presentation of an Achilles tendon rupture. The key clues include: • Sudden sharp pain in the posterior ankle during activity (like tennis), • Sensation of being “kicked” or “hit” from behind, • Gap in the Achilles tendon, • Weakness or loss of plantar flexion. The Simmonds’ squeeze test (also called Thompson test) is the most appropriate and sensitive initial bedside test: • The examiner squeezes the calf — normal response: plantar flexion. • In a ruptured tendon: no movement of the foot. Let’s review the other options: • Apley’s grinding test: ❌ Used for meniscal injury in the knee. • Phalen’s manoeuvre: ❌ For diagnosing carpal tunnel syndrome. • Thomas test: ❌ Assesses fixed flexion deformity of the hip. • Impingement sign: ❌ Used for shoulder impingement.

Answer 34

Correct answer: ✅ B) Refeeding syndrome Explanation: This is a classic scenario of refeeding syndrome, which occurs when nutrition is reintroduced too rapidly after a period of starvation or undernutrition — in this case, 10 days after a gastrectomy without TPN. Key features include: • Hypophosphatemia: hallmark biochemical abnormality due to insulin surge driving phosphate into cells during refeeding. • Other electrolyte disturbances: hypokalemia, hypomagnesemia. • Can lead to: confusion, muscle weakness, arrhythmias, and even death. Let’s review the distractors: • A) Dumping syndrome: ❌ Typically causes hypoglycemia or GI symptoms after meals, not isolated hypophosphatemia. • C) Short bowel syndrome: ❌ Malabsorption-related, more chronic in nature. • D) Electrolyte dilution: ❌ Would affect multiple electrolytes, but usually seen with overhydration or SIADH. • E) Thiamine deficiency: ❌ May contribute neurologically (e.g. Wernicke’s), but not the primary issue here. Well done! This is a high-yield, often tested metabolic complication.

Answer 35

Correct answer: ✅ D) Complete heart block Explanation: This scenario strongly suggests complete (third-degree) heart block, a recognized complication after aortic valve replacement, especially in the context of heavy aortic annulus calcification which may extend into the conduction system. Clues: • Bradycardia (HR 40 bpm) with hypotension postoperatively, • Rising right atrial pressure indicating impaired cardiac output and backup pressure, • Commonly occurs due to AV node disruption during valve surgery. Let’s examine the other options: • A) Atrial fibrillation: ❌ Typically presents with irregularly irregular rhythm, and not associated with bradycardia. • B) Cardiac tamponade: ❌ Would cause equalization of pressures, muffled heart sounds, and pulsus paradoxus — not isolated bradycardia. • C) Digoxin toxicity: ❌ No digoxin use was mentioned, and toxicity typically also involves visual changes and ectopic arrhythmias, not just bradycardia.

Answer 36

Correct answer: ✅ D) Sarcoidosis Explanation: This patient has: • Hypercalcemia (Ca 3.45 mmol/L) • Low PTH • Bilateral hilar lymphadenopathy • History of a self-resolving rash These findings are most consistent with sarcoidosis, a granulomatous disease that increases vitamin D activation by macrophages, leading to hypercalcemia and suppressed PTH. Let’s break down the options: • A) Carcinoma of the lung: ❌ May cause hypercalcemia via PTHrP but doesn’t typically present with hilar lymphadenopathy and resolved rash. • B) Familial hypocalciuric hypercalcemia: ❌ Generally mild hypercalcemia with normal or high PTH. • C) Primary hyperparathyroidism: ❌ Would cause high PTH, not low. • D) Sarcoidosis: ✅ Granulomas produce 1-alpha-hydroxylase, increasing calcitriol, which raises calcium and lowers PTH. • E) Secondary hyperparathyroidism: ❌ Occurs in chronic hypocalcemia, not hypercalcemia. This is a textbook presentation of sarcoidosis with hypercalcemia.

Answer 37

Correct answer: ✅ D) Conservative management Explanation: In a hemodynamically stable patient with a grade 3 liver injury and no active bleeding, the most appropriate and evidence-based approach is non-operative (conservative) management. This includes: • Close monitoring of vitals • Serial hemoglobin measurements • Imaging as needed • Bed rest and observation in a high-dependency setting Washout and drainage (Option B) is only considered if there is active intra-abdominal bleeding, bile leak, or infection, none of which are present in this scenario. Let’s review the options: • A) Laparotomy and packing: ❌ Reserved for unstable patients with ongoing hemorrhage. • B) Washout and drain monitoring: ❌ Unnecessary in a stable, non-bleeding patient. • C) Refer to hepatobiliary center: ❌ Not needed unless there are complications or very high-grade injuries. • D) Conservative management: ✅ First-line for most stable liver injuries. • E) Transfer to HDU: ❌ May be part of conservative management, but not the definitive plan.

Answer 38

Correct answer: ✅ D) Increase steroid on day of operation and continue for three days post-op Explanation: Patients on long-term corticosteroids are at risk of adrenal insufficiency due to suppression of the hypothalamic-pituitary-adrenal (HPA) axis. During surgical stress, the body requires higher cortisol levels. Therefore, the appropriate management is: • Administer a stress-dose of steroids (e.g. hydrocortisone 100 mg IV) on the day of surgery. • Continue higher dosing for 1–3 days postoperatively, then taper back to maintenance. Let’s break down the options: • A) Continue normal dose of steroid: ❌ Insufficient to meet stress demands. • B) Decrease dose: ❌ Dangerous — increases risk of adrenal crisis. • C) Stop steroid pre-op: ❌ Contraindicated and unsafe. • D) ✅ Increase steroid on day of op + continue 3 days: Correct. • E) Continue for a month: ❌ Unnecessary, could cause complications like hyperglycemia or infection.

Answer 39

Correct answer: ✅ B) IV fluid rehydration and electrolyte correction Explanation: Although pyloromyotomy (Ramstedt’s procedure) is the definitive treatment for hypertrophic pyloric stenosis, initial management must focus on correcting dehydration and electrolyte imbalances caused by persistent vomiting. These infants often present with: • Hypochloremic, hypokalemic metabolic alkalosis • Dehydration and weight loss Why B is correct: • Fluids (typically 0.9% NaCl with potassium) are given until the child is hemodynamically stable and labs normalize. • Only then is surgery safe. Let’s look at the distractors: • A) Pyloromyotomy: ❌ Not until fluids/electrolytes are corrected. • C) Fluoroscopic reduction: ❌ Used for intussusception, not pyloric stenosis. • D) Upper GI contrast study: ❌ Not first-line if US already confirmed diagnosis. • E) NG tube and NPO: ❌ May be done, but not sufficient on its own.

Answer 40

Correct answer: ✅ C) Orthopantomogram (OPG) Explanation: An orthopantomogram (OPG) is the most appropriate initial imaging for suspected mandibular fractures, particularly in patients presenting with: • Trismus (inability to open the jaw), • Facial trauma, • Malocclusion or tenderness along the mandible. Why OPG? • It provides a panoramic view of the mandible including the condyles, rami, and body in a single film. • Non-invasive, quick, and low radiation. Let’s go through the distractors: • A & B) Occipitomental (OM) views (0°/30°): ❌ Best for midface/maxillary fractures. • D) CT scan of the head: ❌ Useful if intracranial injury is suspected or in complex midface trauma. • E) Lateral skull X-ray: ❌ Not detailed enough for mandible fractures.

Answer 41

Correct answer: ✅ C) Ulcerative colitis Explanation: Crypt abscesses are a classic histopathological hallmark of ulcerative colitis (UC). They result from the accumulation of neutrophils in the colonic crypts, leading to: • Destruction of crypt architecture • Chronic mucosal inflammation • Bloody diarrhea and urgency Let’s review the other options: • A) Rectal ulcer: ❌ May show non-specific inflammation, not crypt abscesses. • B) Crohn’s disease: ❌ Characterized more by transmural inflammation, granulomas, and skip lesions. Crypt abscesses are not typical. • D) AVM: ❌ Vascular malformation — not inflammatory. • E) Rheumatoid arthritis: ❌ An extraintestinal disease, may have bowel symptoms from medications but not crypt abscesses.

Answer 42

Correct answer: ✅ D) Percutaneous drainage Explanation: A 5×5 cm fluid collection in the right upper quadrant after cholecystectomy is most likely a biloma or abscess. In a stable patient, the best initial management is image-guided percutaneous drainage, especially when the collection is localized and accessible. Let’s break down the options: • A) ERCP with stenting: ❌ Appropriate if there is evidence of ongoing bile leak from the common bile duct or cystic duct stump. It’s not the first step if no leak is confirmed. • B) MRCP: ❌ Useful for detailed biliary anatomy, but not therapeutic. Use after drainage if needed. • C) Conservative management: ❌ Not sufficient for a 5 cm symptomatic collection. • D) Percutaneous drainage: ✅ Minimally invasive, effective, and often resolves the issue. • E) Diagnostic laparoscopy: ❌ More invasive, reserved for unclear diagnosis or failed percutaneous management.

Answer 43

Correct answer: ❌ C) Duct ectasia Explanation: The most likely diagnosis in this scenario is duct ectasia (also known as periductal mastitis), especially given the combination of: • Intermittent discharge, • History of nipple piercing, • No palpable lump, • Normal ultrasound. Duct ectasia involves dilation and inflammation of the milk ducts, often presenting with: • Greenish or brownish nipple discharge, • Possible nipple retraction, • Chronic inflammation without malignancy. Why not mammary fistula (B)? • A mammary fistula is a chronic complication, usually of periductal mastitis, where a tract forms between the duct and skin. It’s typically associated with recurrent infections or visible external openings, which are not mentioned in the scenario. Let’s review the other options: • A) Breast abscess: ❌ Usually presents with pain, redness, and swelling. • B) Mammary fistula: ❌ Requires signs of chronic tract/fistula formation. • C) Duct ectasia: ✅ Fits best with painless, intermittent discharge and prior trauma (piercing). • D) Fibroadenoma: ❌ Painless, mobile lump — no discharge. • E) Inflammatory breast cancer: ❌ Would present with skin changes, swelling, and systemic signs.

Answer 44

Correct answer: ✅ A) Ischemic colitis Explanation: This is a classic case of ischemic colitis, especially in an older patient with sudden-onset: • Severe abdominal pain, • Bloody (plum-colored) stools, • Elevated lactate, indicating tissue hypoperfusion, • No signs of obstruction, and • CT showing segmental colonic thickening or edema, often in the left colon. Key pointers: • Common in elderly, especially with vascular risk factors. • Left colon (especially splenic flexure and descending colon) is more susceptible due to watershed blood supply. Let’s briefly dismiss the other options: • B) Toxic megacolon: ❌ Associated with inflammatory bowel disease, typically with systemic signs, colonic dilation, and chronic diarrheal history. • C) Diverticulitis: ❌ Often localized LLQ pain, fever, not usually with bloody stools or acute systemic features. • D) UC flare: ❌ UC can cause blood in stool but is more chronic and gradual. • E) Acute mesenteric ischemia: ❌ Typically affects small bowel, presents with pain out of proportion to exam, not isolated left colon findings.

Answer 45

Correct answer: ✅ E) X-ray frog-leg lateral view Explanation: In a 14-year-old with knee pain and a normal knee X-ray, the concern should shift to the hip, as referred pain from a slipped upper femoral epiphysis (SUFE) is a common cause. Key clues: • Age: adolescent (typically 11–16 years) • Knee pain is a referred symptom from hip pathology • Normal knee X-ray The frog-leg lateral view is the most sensitive plain radiograph to diagnose SUFE, showing: • Posterior and inferior slippage of the femoral head, • The classic “ice cream slipping off the cone” appearance. Let’s examine the alternatives: • A) X-ray pelvis AP and lateral: ❌ Can be useful but frog-leg is more sensitive. • B) X-ray hip AP: ❌ Might miss subtle slippage. • C) CT scan: ❌ Not first-line in pediatric cases due to radiation. • D) MRI knee: ❌ Irrelevant if knee is not the source.

Answer 46

Correct answer: ✅ D) Hypophosphatemia Explanation: This is a classic presentation of refeeding syndrome, and the hallmark electrolyte abnormality is hypophosphatemia. Key features: • Occurs in malnourished patients started on nutrition (e.g., TPN or enteral feeding), • Insulin secretion shifts phosphate (and potassium, magnesium) into cells, depleting serum levels, • Phosphate is essential for ATP production — depletion causes weakness, arrhythmias, confusion, even death. Let’s clarify the options: • A) Hypokalemia: ⚠️ Common, but not the hallmark. • B) Hypoglycemia: ❌ Rare in refeeding — more likely hyperglycemia. • C) Hyperphosphatemia: ❌ Opposite of what’s seen. • D) ✅ Hypophosphatemia: Correct. • E) Hypermagnesemia: ❌ Typically not seen — hypomagnesemia is more common.

Answer 47

Correct answer: ✅ D) Class IV Explanation: This patient is exhibiting severe hypovolemic shock based on: • BP = 70/30 mmHg (marked hypotension) • HR = 145 bpm (severe tachycardia) • RR = 30 (marked tachypnea) These signs meet the criteria for Class IV hypovolemic shock, which is defined as: • >40% blood loss • Profound hypotension • Marked tachycardia and tachypnea • Mental status: confused or unconscious • Minimal to no urine output Let’s break down the shock classes: • Class I: Up to 15% blood loss, normal vitals • Class II: 15–30%, HR ↑, slight BP drop • Class III: 30–40%, marked HR ↑, BP ↓, anxious/confused • Class IV: ✅ >40%, severe signs, unconsciousness likely • Neurogenic shock: ❌ Typically presents with bradycardia and hypotension (not tachycardia)

Answer 48

Correct answer: ✅ B) Inferior vena cava Explanation: The epiploic (Winslow’s) foramen connects the greater sac and lesser sac in the abdomen. Understanding the anatomical boundaries is key for interpreting the Pringle maneuver and its relationships: Anatomical borders of the epiploic foramen: • Anterior: Hepatoduodenal ligament (containing the portal triad – portal vein, hepatic artery, common bile duct) • Posterior: Inferior vena cava • Superior: Caudate lobe of liver • Inferior: First part of duodenum During the Pringle maneuver, the portal triad is clamped to temporarily stop hepatic inflow. If bleeding persists, it suggests injury to structures behind the foramen, such as the inferior vena cava or hepatic veins. Let’s clarify the options: • A) Hepatic artery: ❌ In front (in portal triad). • B) ✅ Inferior vena cava: Correct – posterior to the foramen. • C) Portal vein: ❌ Anterior, within the hepatoduodenal ligament. • D) SMA: ❌ Deeper in retroperitoneum, not related here. • E) Common bile duct: ❌ Also part of the portal triad, anterior.

Answer 49

Correct answer: ✅ D) Diaphragmatic irritation via phrenic nerve (C3–5) Explanation: Shoulder tip pain following abdominal or laparoscopic procedures — especially when CO₂ is insufflated into the peritoneum — is a classic example of referred pain due to phrenic nerve irritation. The phrenic nerve arises from the C3, C4, and C5 spinal nerve roots and innervates the diaphragm. Irritation (e.g., by peritoneal gas or inflammation) causes referred pain to the shoulder tip, particularly the right side. Let’s go through the other options: • A) C3–C6 nerve root irritation: ❌ Close, but C6 is not part of the phrenic nerve. • B) C5–C6: ❌ Would affect deltoid/suprascapular region, not shoulder tip via diaphragm. • C) C8–T1: ❌ Associated with ulnar side of forearm and hand, not shoulder. • **D) ✅ Correct — phrenic nerve (C3–C5) explains the referred pain. • E) Peritonitis involving pelvic nerves: ❌ Would cause lower abdominal or pelvic pain, not shoulder tip pain.

Answer 50

Correct answer: ✅ D) Simple thyroid cyst Explanation: Although the scenario is somewhat vague, this question was included in the MRCS May 2023 recalls with insufficient information provided in the stem. However, based on diagnosis of exclusion and lack of defining malignant features, Simple thyroid cyst was considered the best fit. The presence of: • Defective epithelial cells • Siderophages (macrophages that ingest iron/hemosiderin, often after hemorrhage) …suggests a benign cystic lesion, possibly with prior hemorrhage. Why not the others? • A) Medullary thyroid carcinoma: ❌ Arises from parafollicular (C cells), not associated with siderophages or defective epithelial cells. • B) Papillary carcinoma: ❌ Would show Orphan Annie nuclei, psammoma bodies — not siderophages. • C) Follicular carcinoma: ❌ Defined by capsular or vascular invasion, not relevant here. • E) Hashimoto thyroiditis: ❌ Associated with lymphocytic infiltration and Hurthle cells, not siderophages. In exams, when data is limited, always opt for the safest diagnosis by exclusion.

Answer 51

Correct answer: ✅ D) Posterior cricoarytenoid Explanation: The posterior cricoarytenoid is the only muscle that abducts the vocal cords, meaning it is the only muscle that opens the glottis. Injury to both of these muscles (or their nerve supply) can result in airway obstruction due to unopposed vocal cord adduction. Let’s go over the roles of each: • A) Cricothyroid: ❌ Tenses the vocal cords to increase pitch, not an abductor. • B) Lateral cricoarytenoid: ❌ Adducts the vocal cords — it closes the glottis. • C) Thyroarytenoid: ❌ Relaxes the vocal cords. • D) ✅ Posterior cricoarytenoid: Only abductor, opens the rima glottidis. • E) Aryepiglottic: ❌ Involved in closing the laryngeal inlet during swallowing. Mnemonic: “Posterior cricoarytenoid Pulls cords apart” — the only abductor.

Answer 52

Correct answer: ✅ B) Hypokalemic metabolic alkalosis Explanation: Hypertrophic pyloric stenosis leads to persistent projectile vomiting of non-bilious gastric contents (rich in hydrogen, chloride, and potassium ions). This results in: • Loss of H⁺ and Cl⁻ → Metabolic alkalosis • Loss of K⁺ → Hypokalemia • Dehydration and contraction alkalosis may also elevate bicarbonate Summary of classic findings: • Hypokalemia • Hypochloremia • Metabolic alkalosis Let’s rule out the distractors: • A) Hyperchloremic metabolic acidosis: ❌ Seen in diarrhea, not vomiting. • C) Hyperkalemic metabolic acidosis: ❌ Often seen in renal failure or Addison’s. • D) Hypocalcemic respiratory alkalosis: ❌ Not a feature of this condition. • E) Hypernatremic metabolic alkalosis: ❌ Sodium can vary, but this combo isn’t classic. Mnemonic: “Vomiting = volume loss + acid loss = metabolic alkalosis.”

Answer 53

Correct answer: ✅ D) Metronidazole Explanation: Bacteroides species are anaerobic gram-negative bacilli, commonly found in gut flora and often implicated in intra-abdominal, pelvic, and dental infections. The drug of choice is: ✅ Metronidazole, which has excellent anaerobic coverage. Let’s go through the options: • A) Ciprofloxacin: ❌ Good gram-negative coverage, but poor against anaerobes like Bacteroides. • B) Clindamycin: ⚠️ Has some anaerobic activity, but resistance among Bacteroides is increasing. • C) Penicillin: ❌ Poor anaerobic coverage; many Bacteroides species produce β-lactamase. • D) ✅ Metronidazole: Best choice, highly effective against Bacteroides. • E) Amoxicillin: ❌ Only works if combined with clavulanic acid (co-amoxiclav) to cover anaerobes. Clinical tip: Metronidazole is often used in combination with other agents (e.g. ceftriaxone) for mixed intra-abdominal infections.

Answer 54

Correct answer: ✅ D) Local flap Explanation: When there is exposed bone (tibia) following trauma, especially with a deep laceration, soft tissue coverage becomes essential to prevent infection, necrosis, and non-healing. In such cases: • Local flap reconstruction is the most appropriate method to cover the exposed bone, • It provides vascularized tissue, promoting healing and reducing infection risk. Let’s evaluate the options: • A) Conservative dressing: ❌ Inappropriate when bone is exposed — won’t granulate over bone. • B) STSG (Split-Thickness Skin Graft): ❌ Requires a vascularized bed — not effective over bare bone. • C) Debridement and primary closure: ❌ Often not possible due to tissue loss. • D) ✅ Local flap: Correct — supplies blood and tissue bulk to cover exposed tibia. • E) Full-thickness graft: ❌ Like STSG, requires vascularized base — not suitable for bare bone.

Answer 55

Correct answer: ✅ B) Sphenopalatine artery Explanation: While Little’s area (also called Kiesselbach’s plexus) is a common site of anterior epistaxis, the most significant artery involved — especially in severe cases — is the sphenopalatine artery, which is a terminal branch of the maxillary artery. Little’s area is an anastomotic network of several arteries: • Anterior ethmoidal artery (from ophthalmic) • Superior labial artery (from facial) • Greater palatine artery (from maxillary) • Sphenopalatine artery (from maxillary) ← most significant source So even though the anterior ethmoidal artery contributes to the area, the most important and often responsible vessel in severe cases is the sphenopalatine artery. Let’s clarify the distractors: • A) Anterior ethmoidal artery: ❌ Part of the plexus but not usually the source in profuse bleeds. • B) ✅ Sphenopalatine artery: Main source, especially in posterior or significant bleeds. • C) Middle meningeal artery: ❌ Associated with extradural hematomas. • D) Infraorbital artery: ❌ Supplies the face, not nasal cavity. • E) Supratrochlear artery: ❌ Supplies forehead/scalp.

Answer 56

Correct answer: ✅ C) Ulcerative colitis Explanation: This is a textbook presentation of ulcerative colitis (UC), characterized by: • Crypt abscesses on histology (neutrophil infiltration into colonic crypts), • Diarrhea and extraintestinal manifestations, such as arthritis, • Continuous colonic involvement, typically starting from the rectum. Key features of UC: • Colon only (no small bowel involvement), • Continuous lesions (no skip areas), • Extraintestinal manifestations: arthritis, uveitis, erythema nodosum. Let’s rule out the distractors: • A) Rectal ulcer: ❌ Would not present with systemic features or crypt abscesses. • B) Crohn’s disease: ❌ Transmural inflammation, skip lesions, and granulomas — not crypt abscesses. • D) AVM: ❌ Vascular cause of bleeding, not inflammatory or linked to crypt pathology. • E) Rheumatoid arthritis: ❌ Can have GI symptoms due to medications, but not crypt abscesses.

Answer 57

Correct answer: ✅ E) 0.9% Normal Saline Explanation: In cases of severe hypercalcemia (corrected calcium >3.5 mmol/L), the first-line and most urgent step is aggressive IV hydration with 0.9% normal saline. This addresses volume depletion caused by hypercalcemia-induced polyuria and vomiting, and enhances renal calcium excretion. Subsequent treatments, like bisphosphonates, may follow once the patient is rehydrated. Let’s break down the options: • A) IV Pamidronate: ⚠️ Used for definitive management, especially in malignancy-associated hypercalcemia, but not first-line. • B) Oral Alendronate: ❌ Too slow-acting and inappropriate in acute settings. • C) Dexamethasone: ❌ Used in granulomatous diseases like sarcoidosis. • D) Calcitonin: ⚠️ Acts quickly but is short-acting and typically used after fluids. • E) ✅ 0.9% Normal Saline: Correct — immediate and crucial in acute management. Clinical tip: Rehydration should be followed by loop diuretics if needed, to prevent fluid overload and promote calciuresis.

Answer 58

Correct answer: ✅ A) Embryonal carcinoma Explanation: Embryonal carcinoma is a non-seminomatous germ cell tumor (NSGCT) that can produce beta-hCG, particularly in children and young adults. It is highly malignant and may present as a painful, rapidly enlarging testicular mass. Key features: • Often part of a mixed germ cell tumor, • Can produce beta-hCG (sometimes AFP), • More aggressive than seminoma. Let’s look at the other options: • B) Seminoma: ❌ Rare in children, typically in adults; may secrete beta-hCG, but not common. • C) Differentiated teratoma: ❌ Generally does not secrete tumor markers. • D) Leydig cell tumor: ❌ Hormone-secreting (androgens/estrogens), not beta-hCG. • E) Yolk sac tumor: ⚠️ Common in young children, but classically raises AFP, not beta-hCG. Mnemonic tip: • AFP ↑ → Yolk sac • β-hCG ↑ → Embryonal carcinoma or choriocarcinoma

Answer 59

Correct answer: ✅ A) Ipsilateral side Explanation: In the presence of a dilated pupil, especially with bilateral epidural hematomas, the side of pupil dilation indicates transtentorial herniation due to ipsilateral mass effect — this is a surgical emergency. ➡️ The first burr hole should always be placed on the ipsilateral side of the dilated pupil (i.e., same side) to rapidly relieve pressure and prevent irreversible brainstem herniation. Let’s clarify: • A) ✅ Ipsilateral side: Correct – decompress the side with signs of herniation (dilated pupil). • B) Contralateral side: ❌ Would delay decompression and risk fatal herniation. • C) Vertex: ❌ Not appropriate. • D & E) Frontal/Occipital bone: ❌ Not primary sites for burr holes in epidural bleeds. Clinical reasoning tip: In trauma with a lucid interval followed by pupil changes, always think epidural hematoma → middle meningeal artery bleed → urgent burr hole on side of herniation.

Answer 60

Correct answer: ✅ D) IgM Explanation: Immunoglobulin M (IgM) is the first antibody produced in response to an infection and is found predominantly in the intravascular compartment. It is pentameric, which gives it high avidity but makes it too large to cross the placenta. Let’s break down the options: • A) IgG: ❌ Monomer — the only antibody that crosses the placenta, providing passive immunity to the fetus. • B) IgA: ❌ Dimer — found in secretions like saliva, tears, and breast milk. • C) IgD: ❌ Function not well understood; acts as a B-cell receptor, not significant in circulation. • D) ✅ IgM: Pentamer, does not cross the placenta. • E) IgE: ❌ Involved in allergic reactions and parasitic infections, does not cross placenta either, but not a pentamer. Mnemonic: “M = Massive = pentamer = doesn’t Move across placenta.”

Answer 61

Correct answer: ✅ B) Metaplasia Explanation: The described scenario — bone formation in dense fibrous tissue under a scar — is classic for metaplasia, which is: ➡️ The reversible change of one differentiated cell type to another mature cell type not normal for that location, often in response to chronic irritation or inflammation. In this case: • Fibrous tissue is converting into bone or cartilage (often referred to as osseous metaplasia), • Common in scar tissue, long-term inflammation, or areas of trauma. Let’s review the other options: • A) Neoplasia: ❌ Abnormal and uncontrolled cell growth — not described here. • B) ✅ Metaplasia: Correct – mature tissue type replacing another, often benign. • C) Hyperplasia: ❌ Increase in number of normal cells, not type change. • D) Dysplasia: ❌ Disordered cellular growth, often premalignant — not mature tissue change. • E) Anaplasia: ❌ Loss of cellular differentiation — seen in malignancy. Clinical tip: Chronic metaplasia can progress to dysplasia and then neoplasia if the irritant persists (e.g., Barrett’s esophagus).

Answer 62

Correct answer: ✅ E) Conservative with compression stockings Explanation: In the initial management of varicose veins, especially if symptoms are not severe or if no complications (like ulcers, bleeding, or thrombophlebitis) are present, the first-line treatment is always: ➡️ Conservative management with graduated compression stockings This is in line with NICE guidelines, which recommend: 1. Compression therapy initially (unless contraindicated), 2. If symptoms persist or complications occur, then consider: • Endovenous ablation (radiofrequency or laser), • Foam sclerotherapy, • Surgical ligation/stripping as last resort. Let’s assess the other options: • A) High ligation and stripping: ❌ More invasive, reserved for failed non-operative management. • B) Foam sclerotherapy: ❌ Appropriate in certain cases, but not first-line. • C & D) RFA or EVLA: ❌ Minimally invasive but only after conservative treatment fails. Mnemonic: “Stockings before surgery.”

Answer 63

Correct answer: ✅ B) Strangulated hernia Explanation: The patient’s presentation — sudden pain, erythema, vomiting, and a history of a longstanding umbilical hernia — points to a strangulated hernia, which is a surgical emergency. Key signs of strangulation: • Severe, constant pain, • Tenderness and redness over the hernia site, • Signs of bowel obstruction (e.g., vomiting, distension), • Risk of bowel ischemia and necrosis. Let’s differentiate the options: • A) Obstructed hernia: ❌ Involves bowel obstruction without vascular compromise. • B) ✅ Strangulated hernia: Correct – obstruction + compromised blood flow. • C) Incarcerated hernia: ❌ Trapped but not necessarily ischemic. • D) Richter’s hernia: ❌ Only part of bowel wall is entrapped — often no obstruction. • E) Sliding hernia: ❌ Involves retroperitoneal organs like bladder or colon; not acutely painful.

Answer 64

Correct answer: ✅ C) Preformed antibodies Explanation: Hyperacute transplant rejection occurs within minutes to hours after transplantation and is mediated by preformed recipient antibodies directed against donor antigens, typically ABO or HLA antigens. These antibodies immediately bind to the graft vasculature, triggering: • Complement activation, • Thrombosis, • Graft necrosis, • And rapid graft loss. Key concepts: • Occurs in sensitized recipients (e.g., prior transplants, pregnancies, or transfusions), • Prevented with crossmatching and compatibility screening. Let’s look at the distractors: • A) CD4+ T cells: ❌ Mediate delayed (chronic) rejection. • B) CD8+ T cells: ❌ Responsible for acute cellular rejection, not hyperacute. • D) Memory B cells: ❌ May contribute to chronic rejection, but not hyperacute. • E) NK cells: ❌ Involved in immune surveillance, not the main players here. Mnemonic: “Hyperacute = H = preformed antibodies = Happens Immediately.”

Answer 65

Correct answer: ✅ E) Immediate fasciotomy Explanation: This scenario is classic for acute compartment syndrome, which is a surgical emergency. The hallmark features include: • Pain out of proportion to the injury • Pain on passive stretch • Tense, swollen compartment • Possible paresthesia, pallor, pulselessness, and paralysis (late signs) Once clinical suspicion is high, do not delay — proceed directly to fasciotomy to relieve pressure and preserve tissue viability. Let’s dismiss the other options: • A) Elevate and observe: ❌ Elevation can reduce perfusion further. • B) IV morphine and monitor: ❌ Delays definitive treatment, risks permanent damage. • C) Doppler ultrasound: ❌ Useful for vascular injury, but not diagnostic for compartment syndrome. • D) Compartment pressure measurement: ⚠️ Can be used if diagnosis is uncertain, but clinical signs are usually enough for action. • E) ✅ Immediate fasciotomy: Correct — time-critical limb-saving intervention. Mnemonic: “6 Ps” of compartment syndrome: Pain, Pallor, Pulselessness, Paresthesia, Paralysis, Poikilothermia.

Answer 66

Correct answer: ✅ C) Recent surgery or trauma Explanation: The most common cause of colonic pseudo-obstruction (Ogilvie’s syndrome) is recent surgery or trauma, particularly in elderly or hospitalized patients. It often occurs within a few days postoperatively, especially after: • Orthopedic surgery (e.g., hip or spinal), • Abdominal/pelvic procedures, • Severe infections or trauma. Key features of Ogilvie’s syndrome: • Massive colonic dilation (usually the caecum), • No mechanical obstruction, • Risk of perforation if not treated promptly. Let’s review the other options: • A) Hypokalemia: ❌ Can contribute, but not the most common cause. • B) Diabetes mellitus: ❌ May lead to autonomic dysfunction, but not a primary cause. • C) ✅ Recent surgery or trauma: Correct – most frequent trigger. • D) Neuromuscular disease: ❌ Possible association (e.g., Parkinson’s), but less common. • E) Hypothyroidism: ❌ May cause ileus, but not the main cause of Ogilvie’s. Management: Supportive care, correction of electrolytes, sometimes neostigmin

Answer 67

Correct answer: ✅ C) Recurrent laryngeal nerve Explanation: The recurrent laryngeal nerve (RLN) is the most commonly injured nerve during thyroidectomy. It runs in close proximity to the inferior thyroid artery and enters the larynx just behind the cricothyroid joint. Injury to the RLN can result in: • Unilateral palsy → hoarseness, weak voice • Bilateral palsy → airway obstruction, stridor (requires emergency airway management) Key anatomical tip: • The left RLN loops under the aortic arch, • The right RLN loops under the subclavian artery, Both ascend in the tracheoesophageal groove to enter the larynx. Let’s consider the distractors: • A) Glossopharyngeal nerve: ❌ Not in the surgical field of thyroidectomy. • B) Hypoglossal nerve: ❌ Higher up, not typically at risk. • D) External branch of superior laryngeal nerve: ⚠️ Can be injured, especially during superior pole ligation → affects pitch (cricothyroid muscle), but less common than RLN. • E) Phrenic nerve: ❌ Not at risk in neck surgery — runs along anterior scalene. Mnemonic: “Recurrent gets wrecked.”

Answer 68

Correct answer: ✅ C) Medullary carcinoma Explanation: Medullary thyroid carcinoma (MTC) arises from the parafollicular C cells of the thyroid and is the only thyroid cancer that produces calcitonin, making it a biochemical hallmark for diagnosis and follow-up. Key features: • Elevated calcitonin levels, • Associated with MEN 2A and 2B syndromes, • May secrete other peptides (e.g., CEA, ACTH), • Does not arise from follicular cells, so doesn’t uptake iodine. Let’s review the other options: • A) Papillary carcinoma: ❌ Most common, but doesn’t raise calcitonin. • B) Follicular carcinoma: ❌ May uptake iodine, not calcitonin-producing. • D) Anaplastic carcinoma: ❌ Very aggressive, undifferentiated, not calcitonin-secreting. • E) Thyroid adenoma: ❌ Benign, non-secretory. Clinical tip: All patients with MTC should be screened for pheochromocytoma and hyperparathyroidism (MEN 2A workup).

Answer 69

Correct answer: ✅ C) Barium swallow Explanation: In a patient with suspected achalasia (dysphagia to both solids and liquids, regurgitation, weight loss), the most appropriate initial investigation is a barium swallow. It typically shows: • A bird-beak appearance at the gastroesophageal junction, • Dilated esophagus with poor emptying. This is a non-invasive, quick, and informative first step. Let’s evaluate the alternatives: • A) Oesophageal manometry: ⚠️ Most definitive test, but not first-line. It’s used to confirm the diagnosis after radiologic suspicion. • B) Upper GI endoscopy: ⚠️ Used to rule out malignancy (pseudoachalasia), especially in older patients — but not the first investigation. • D) CT chest: ❌ May help rule out malignancy but doesn’t directly assess motility. • E) Chest X-ray: ❌ May show non-specific findings or air-fluid level — not diagnostic. Clinical sequence: 1. Barium swallow 2. Endoscopy (to exclude malignancy) 3. Manometry (to confirm)

Answer 70

Correct answer: ✅ B) Perforated duodenal ulcer Explanation: Air under the right hemidiaphragm (pneumoperitoneum) on a chest X-ray is a hallmark sign of hollow viscus perforation, most classically due to a perforated duodenal ulcer. Why the right side? • Free intraperitoneal air collects under the right hemidiaphragm because the liver doesn’t block air accumulation (unlike the stomach on the left). Clinical features often include: • Sudden-onset severe epigastric pain • Signs of peritonitis • Sepsis in later stages Let’s rule out the other choices: • A) Pneumothorax: ❌ Air in the pleural space, not under the diaphragm. • C) Splenic rupture: ❌ Causes intra-abdominal bleeding, not free air. • D) Liver laceration: ❌ Causes bleeding, not air. • E) Retroperitoneal hematoma: ❌ No air, confined to retroperitoneum. Clinical tip: Always consider a perforated ulcer in trauma or acute abdomen when free air is seen under the diaphragm.

Answer 71

Correct answer: ✅ B) Testicular torsion Explanation: The key features — high-riding, non-palpable, and acute onset after trauma — strongly point toward testicular torsion, which is a surgical emergency. Although torsion can occur spontaneously, trauma can precipitate it, especially in adolescents and young men. Classic signs of testicular torsion: • Sudden onset of severe scrotal or lower abdominal pain, • High-riding testis, often horizontally oriented, • Absent cremasteric reflex, • Nausea/vomiting, • Swelling and tenderness. Let’s rule out the alternatives: • A) Epididymitis: ❌ Usually gradual onset, painful but not high-riding or non-palpable. • B) ✅ Testicular torsion: Correct – urgent detorsion needed within 6 hours. • C) Testicular rupture: ❌ May follow trauma, but testis is usually still palpable and swollen. • D) Retractile testis: ❌ More common in children; can be manually moved to scrotum and isn’t acute or painful. • E) Testicular cancer: ❌ Presents as a painless lump, not acutely painful or displaced. Clinical tip: Any testicular abnormality post-trauma should be treated as torsion until proven otherwise.

Answer 72

Correct answer: ✅ E) Venography Explanation: Although duplex ultrasound is the most commonly used first-line test for suspected DVT, the gold standard investigation — meaning the most definitive and historically accurate — is contrast venography. Venography: • Involves injecting contrast dye into a vein and taking X-rays to visualize the venous system, • Provides detailed anatomic images, especially for pelvic or upper limb DVTs, • Rarely used due to its invasiveness, contrast use, and discomfort. In clinical practice: • Duplex ultrasound is preferred due to its non-invasive nature and high accuracy for proximal DVTs. • D-dimer helps rule out DVT in low-risk patients, but is non-specific. Let’s review the options: • A) CT pulmonary angiography: ❌ Used to diagnose PE, not DVT. • B) D-dimer: ❌ A rule-out tool, not diagnostic. • C) Duplex ultrasound: ⚠️ Most commonly used, but not gold standard. • D) MRI venogram: ❌ Rarely used due to cost and availability. • E) ✅ Venography: Correct — historical gold standard.

Answer 73

Correct answer: ✅ A) Duration of surgery Explanation: While prophylactic antibiotics are important in reducing surgical site infections (SSIs), the single most predictive factor for developing an SSI is the duration of the operation. Longer surgeries increase the risk of: • Bacterial contamination, • Tissue trauma, • Hypothermia, • Compromised immunity. Key evidence shows: • Risk of SSI rises proportionally with each additional hour of surgery, especially beyond 2 hours. Let’s assess the options: • A) ✅ Duration of surgery: Correct – strongest independent predictor. • B) Use of prophylactic antibiotics: ❌ Reduces risk, but is not a predictor. • C) BMI: ⚠️ Obesity is a known risk factor but not the most predictive. • D) Type of suture used: ❌ Minor contributor. • E) Number of assistants scrubbed in: ❌ Not strongly linked unless linked to breaches in sterility. Clinical tip: Keep procedures as efficient as possible — prolonged duration equals increased infection risk.

Answer 74

Correct answer: ✅ A) Perforated peptic ulcer Explanation: A perforated peptic ulcer typically presents with: • Sudden severe abdominal pain, • Signs of peritonitis, • And free air under the diaphragm, often seen as tympanic resonance over the liver on examination. The tympanic note arises due to pneumoperitoneum, which is caused by air leaking from a perforated hollow viscus — classically the anterior wall of the duodenum in peptic ulcer disease. Let’s break down the alternatives: • B) Pneumothorax: ❌ Would affect chest exam findings, not give tympanic abdomen or liver resonance. • C) Chilaiditi syndrome: ❌ A rare cause — colon interposes between liver and diaphragm, mimicking free air but usually asymptomatic. • D) Bowel obstruction: ❌ Presents with distension and vomiting, but tympanic liver is not typical. • E) Hepatic encephalopathy: ❌ Affects mental status, not abdominal resonance. Mnemonic: “Tympany over the liver = think perforation.”

Answer 75

Correct answer: ✅ C) Endoscopic therapy with adrenaline and clips Explanation: The primary treatment for a bleeding duodenal ulcer with active spurting (Forrest Ia classification) is urgent endoscopic hemostasis. This typically involves: • Adrenaline injection to induce local vasoconstriction, • Followed by mechanical therapy such as clips, • Or thermal coagulation to secure hemostasis. Key management principles: • Endoscopy is first-line, • PPIs are started after for acid suppression, • Surgery or embolization is reserved for failed endoscopic management. Let’s go through the options: • A) IV antibiotics: ❌ Not first-line; used in perforation/infection. • B) PPI infusion: ⚠️ Useful post-endoscopy, but won’t stop active arterial bleeding. • C) ✅ Endoscopic therapy with adrenaline and clips: Correct – gold standard. • D) Emergency laparotomy: ❌ Reserved for refractory cases. • E) Transarterial embolization: ❌ Second-line if endoscopy fails or patient is unfit for surgery. Mnemonic: “Spurting = scope first.”

Answer 76

Correct answer: ✅ C) Acute respiratory distress syndrome (ARDS) Explanation: ARDS is a severe complication of acute pancreatitis, especially in severe or necrotizing cases, due to the release of inflammatory mediators that increase pulmonary capillary permeability. It typically presents with: • Acute onset hypoxia, • Bilateral pulmonary infiltrates on chest X-ray, • No evidence of cardiogenic pulmonary edema, • Rapidly increasing oxygen requirement. Key diagnostic criteria (Berlin Definition): • Onset within 1 week of known insult (e.g. pancreatitis), • Bilateral opacities on imaging, • Respiratory failure not fully explained by cardiac failure or fluid overload, • Impaired oxygenation (PaO₂/FiO₂ ratio ≤300 mmHg). Let’s assess the other options: • A) Pneumonia: ❌ May cause infiltrates but less likely bilateral so acutely in this context. • B) Pulmonary embolism: ❌ Usually causes focal findings or clear lungs; not bilateral infiltrates. • D) Atelectasis: ❌ Typically unilateral or basal, not causing diffuse infiltrates. • E) Pleural effusion: ❌ May occur in pancreatitis but shows blunting of costophrenic angle, not infiltrates. Mnemonic: “Pancreatitis + PaO₂ drop + infiltrates = ARDS.” Reference: MRCS May 2023 Recalls – Q73.

Answer 77

Correct answer: ✅ A) Wide local excision Explanation: Ductal carcinoma in situ (DCIS) is a non-invasive breast cancer where malignant cells are confined to the ducts and have not invaded surrounding tissue. The standard management for small, localized DCIS (e.g., 2 cm lesion) is: ➡️ Wide local excision (also known as breast-conserving surgery or lumpectomy) This involves removing the tumor with clear margins, often followed by adjuvant radiotherapy to reduce recurrence. Let’s examine the other options: • B) Mastectomy: ❌ Reserved for extensive/multifocal or recurrent DCIS. • C) Sentinel lymph node biopsy: ❌ Not routinely indicated in pure DCIS unless there’s suspicion of invasive disease or mastectomy is planned. • D) Chemotherapy: ❌ Not used in non-invasive disease like DCIS. • E) Radiotherapy: ⚠️ Commonly used after WLE, but not the initial step. Clinical tip: DCIS is a pre-invasive lesion but requires definitive surgical management to prevent progression to invasive carcinoma.

Answer 78

Correct answer: ✅ B) Popliteal artery Explanation: In posterior knee dislocations, the popliteal artery is the vessel most at risk of injury due to its fixed position behind the knee joint, particularly as it passes through the adductor hiatus and the soleal arch. These injuries are limb-threatening, and vascular injury can occur even if the pulse is palpable — hence, immediate vascular assessment is critical. Key points: • Posterior dislocations = highest risk for vascular compromise • Popliteal artery has limited mobility, making it vulnerable to stretching or tearing Let’s review the other choices: • A) Femoral artery: ❌ Too proximal — not typically involved. • B) ✅ Popliteal artery: Correct – lies directly behind the knee joint. • C) Anterior tibial artery: ❌ More distal. • D) Posterior tibial artery: ❌ Also more distal. • E) Genicular artery: ❌ Small branches – not the major vessel compromised. Mnemonic: “Posterior dislocation = Popliteal danger.”

Answer 79

Correct answer: ✅ D) Laparotomy Explanation: In a hemodynamically unstable trauma patient with positive FAST scan (i.e., free intra-abdominal fluid), the next immediate step is emergency laparotomy. This is because: • The patient is unstable, indicating likely active intra-abdominal bleeding, • Time is critical — no further diagnostics should delay surgical control of hemorrhage. Let’s clarify the other options: • A) Diagnostic peritoneal lavage: ❌ Outdated; FAST has replaced it in most settings. • B) CT abdomen with contrast: ❌ Only for hemodynamically stable patients. • C) Laparoscopy: ❌ Inappropriate in unstable patients; takes longer and doesn’t control bleeding quickly. • E) Repeat FAST in 15 minutes: ❌ Delays definitive management in an unstable patient. Clinical tip: FAST positive + unstable = straight to the OR.

Answer 80

Correct answer: ✅ C) Pancreatic adenocarcinoma Explanation: Pancreatic adenocarcinoma is notoriously associated with a dense desmoplastic reaction, which refers to the fibrotic stromal response surrounding the tumor. This fibrotic tissue can: • Make the tumor firm and infiltrative, • Complicate surgical resection, • Impede chemotherapy delivery due to poor vascularity. Desmoplasia is driven by tumor-secreted factors that activate fibroblasts and inflammatory cells, forming a fibrous capsule. Let’s eliminate the distractors: • A) Renal cell carcinoma: ❌ Often highly vascular with necrosis, not fibrotic. • B) Hepatocellular carcinoma: ❌ Tends to invade vessels, not cause desmoplasia. • C) ✅ Pancreatic adenocarcinoma: Correct – classic for desmoplasia. • D) Testicular seminoma: ❌ Soft, fleshy tumors with lymphocytic infiltrates — not desmoplastic. • E) Gastric lymphoma: ❌ Lymphoid tumors don’t stimulate desmoplasia. Clinical tip: The firm consistency of pancreatic tumors on imaging/surgery is often due to desmoplasia, not just tumor mass.

Answer 81

Correct answer: ✅ B) Topical glyceryl trinitrate (GTN) Explanation: Acute anal fissure is a small tear in the anoderm, often causing sharp pain during defecation and rectal bleeding. The first-line treatment is topical glyceryl trinitrate (GTN) 0.2% ointment, which: • Relaxes the internal anal sphincter, • Increases local blood flow, • Promotes healing within 6–8 weeks. Let’s assess the other options: • A) Lateral internal sphincterotomy: ❌ Gold standard for chronic fissure, not first-line for acute. • B) ✅ GTN ointment: Correct – proven efficacy in acute cases. • C) Botox injection: ❌ Alternative for chronic fissure or when GTN fails. • D) Diltiazem ointment: ⚠️ Effective and used as an alternative to GTN, but GTN is more commonly recommended first. • E) Hydrocortisone cream: ❌ Addresses inflammation, not sphincter spasm or healing. Tip: Headaches are a common side effect of GTN, so patients should be advised accordingly.

Answer 82

Correct answer: ✅ D) Perforated duodenal ulcer Explanation: The scenario describes: • Sudden severe abdominal pain, • Vomiting, • Rigid (board-like) abdomen, • Free air under the diaphragm on X-ray —all of which are classic signs of a perforated duodenal ulcer, typically from peptic ulcer disease. This is a surgical emergency due to risk of peritonitis and sepsis. Prompt diagnosis and intervention (often laparoscopic repair) are critical. Let’s break down the alternatives: • A) Acute pancreatitis: ❌ Pain is typically epigastric, radiates to the back, and doesn’t cause free air under diaphragm. • B) Small bowel obstruction: ❌ Usually causes colicky pain and distension; may show air-fluid levels, not free air. • C) Ischemic bowel: ❌ Causes severe pain but not typically associated with pneumoperitoneum early on. • D) ✅ Perforated duodenal ulcer: Correct – hallmark cause of free intraperitoneal air. • E) Appendicitis: ❌ May progress to perforation, but less likely to present with widespread peritonitis and free air this early. Mnemonic: “Sudden pain + free air = perforation = duodenal ulcer until proven otherwise.”

Answer 83

Correct answer: ✅ C) Sarcoidosis Explanation: In sarcoidosis, macrophages in granulomas produce excess 1-alpha hydroxylase, leading to increased conversion of vitamin D to its active form (calcitriol). This causes hypercalcemia, but suppresses PTH via negative feedback, resulting in low PTH levels. Let’s go over the options: • A) Primary hyperparathyroidism: ❌ High PTH — the primary driver of hypercalcemia. • B) Familial hypocalciuric hypercalcemia: ❌ Normal or slightly elevated PTH due to altered calcium sensing. • C) ✅ Sarcoidosis: Correct – PTH is low due to extra-renal calcitriol production. • D) Lithium therapy: ❌ Increases PTH secretion by altering calcium sensing. • E) Tertiary hyperparathyroidism: ❌ Seen in chronic renal failure, PTH remains high even after calcium correction. Clinical tip: Always suspect granulomatous disease (sarcoidosis, TB) in PTH-independent hypercalcemia.

Answer 84

Correct answer: ✅ D) Villous adenoma Explanation: Villous adenomas are colonic polyps with the highest risk of malignant transformation. They: • Tend to be larger, sessile (flat), and occur more commonly in the rectosigmoid region, • Have a higher grade of dysplasia than tubular adenomas, • May secrete mucus, leading to hypokalemia and secretory diarrhea in some cases. Malignancy risk increases with: • Villous histology, • Size >1 cm, • High-grade dysplasia. Let’s review the others: • A) Hyperplastic polyp: ❌ Benign, with no malignant potential. • B) Inflammatory polyp: ❌ Seen in IBD; not neoplastic. • C) Tubular adenoma: ⚠️ Premalignant but lower risk than villous. • E) Hamartomatous polyp: ❌ Typically benign; seen in conditions like Peutz-Jeghers. Mnemonic: “Villous is villainous.”

Answer 85

Correct answer: ✅ B) Appendectomy alone Explanation: A well-differentiated, low-grade neuroendocrine tumor (NET) of the appendix that is <1 cm and located at the tip is considered low risk. In such cases: ➡️ Simple appendectomy is curative, with no need for further surgery or adjuvant therapy. When is right hemicolectomy indicated? • Tumor size ≥2 cm, • Invasion into mesoappendix >3 mm, • Lymphovascular invasion, • Tumor at the base of the appendix, • High mitotic index or grade. Other options: • C) Chemotherapy: ❌ Not indicated for low-grade NETs. • D) Radiotherapy: ❌ NETs are not radiosensitive. • E) Observation only: ❌ Surgery is still required to remove the lesion. Mnemonic: “Small NET at the tip? Just snip!”

Answer 86

Correct answer: ✅ D) Ultrasound abdomen Explanation: The most sensitive and first-line investigation for detecting gallbladder stones (cholelithiasis) is abdominal ultrasound. It can: • Accurately detect stones ≥2 mm, • Show acoustic shadowing behind stones, • Assess for gallbladder wall thickening, pericholecystic fluid, and Murphy’s sign. CT may be used for complications like abscess, perforation, or gas in the biliary tree, but is less sensitive for gallstones, especially if they are radiolucent (non-calcified). Let’s break down the other options: • A) Plain X-ray: ❌ Only 10–15% of stones are radiopaque. • B) MRI (MRCP): ⚠️ Excellent for bile duct stones, but not as sensitive for gallbladder stones. • C) CT abdomen: ❌ Misses non-calcified stones. • D) ✅ Ultrasound abdomen: Correct – gold standard. • E) ERCP: ⚠️ Diagnostic and therapeutic for CBD stones, but invasive and not first-line for gallbladder stones.

Answer 87

Correct answer: ✅ C) Esophageal varices Explanation: In a patient with chronic liver disease, the most common cause of hematemesis (vomiting blood) is bleeding from esophageal varices. These develop due to portal hypertension, which causes collateral vessels to dilate and become fragile. Clinical signs pointing to variceal bleeding: • History of cirrhosis, • Splenomegaly, ascites, caput medusae, • Sudden-onset large-volume hematemesis, • Often associated with hemodynamic instability. Other options: • A) Gastric ulcer: ❌ Common, but not the leading cause in cirrhosis. • B) Mallory-Weiss tear: ❌ Typically post-vomiting; causes mild bleeding. • D) Duodenal ulcer: ❌ Can bleed, but less likely in this context. • E) Gastric cancer: ❌ Unlikely to present acutely like this. Management: 1. Resuscitation (ABC) 2. Vasoactive drugs (e.g. terlipressin) 3. Endoscopy with banding 4. Antibiotics and PPI

Answer 88

Correct answer: ✅ C) Terminal ileum Explanation: Crohn’s disease is a transmural, segmental inflammatory condition that can affect any part of the gastrointestinal tract — from mouth to anus — but the terminal ileum is the most commonly affected site. Key features of Crohn’s involving the terminal ileum: • Right lower quadrant abdominal pain • Diarrhea (often non-bloody) • Weight loss • Risk of B12 deficiency due to malabsorption Imaging clues: • “Skip lesions” (normal segments between inflamed areas) • Cobblestoning, strictures, and fistulas on imaging Let’s assess the options: • A) Stomach: ❌ Rarely involved. • B) Jejunum: ❌ May be involved but less commonly. • C) ✅ Terminal ileum: Correct – most commonly affected. • D) Sigmoid colon: ❌ More often involved in ulcerative colitis. • E) Rectum: ❌ Often spared in Crohn’s but commonly involved in UC. Mnemonic: “Crohn skips but loves the end – terminal ileum.”

Answer 89

Correct answer: ✅ B) Hypokalemia Explanation: Hypokalemia is the electrolyte abnormality most strongly associated with paralytic ileus, a condition where bowel motility ceases without mechanical obstruction. Why? • Potassium is critical for smooth muscle function and neuromuscular excitability. • Low potassium levels impair peristalsis, leading to abdominal distension, pain, and absent bowel sounds. Other symptoms of hypokalemia: • Weakness • Muscle cramps • ECG changes (e.g., U waves) Let’s examine the alternatives: • A) Hypernatremia: ❌ May cause CNS symptoms but not ileus. • C) Hypermagnesemia: ❌ Causes hypotonia and lethargy; not a typical ileus cause. • D) Hypocalcemia: ❌ Associated with tetany, not ileus. • E) Hyperchloremia: ❌ Nonspecific; rarely causes clinical symptoms on its own. Clinical tip: Always check K+ levels in patients with unexplained post-op ileus or distension.

Answer 90

Correct answer: ✅ C) AFP (Alpha-fetoprotein) Explanation: AFP (Alpha-fetoprotein) is the most commonly elevated tumor marker in hepatocellular carcinoma (HCC). Elevated AFP levels are used for: • Diagnosis (especially when imaging is equivocal), • Surveillance in high-risk patients (e.g., cirrhosis, hepatitis B/C), • Monitoring treatment response and recurrence. However, note that: • Not all HCCs produce AFP, • Mildly elevated AFP can occur in chronic hepatitis or cirrhosis. Let’s review the other markers: • A) CA 19-9: ❌ Marker for pancreatic and biliary tract cancers. • B) CEA: ❌ Marker for colorectal cancer, sometimes gastric or pancreatic. • D) CA-125: ❌ Mainly used for ovarian cancer. • E) Chromogranin A: ❌ Marker for neuroendocrine tumors. Clinical tip: If a cirrhotic patient develops a mass and raised AFP → HCC until proven otherwise.

Answer 91

Correct answer: C) Surgical excision under local anesthesia Explanation: In the case of a thrombosed external hemorrhoid, surgical excision is the most appropriate treatment if the patient presents within 48–72 hours of symptom onset. This provides rapid pain relief and prevents further complications. Key points: • The procedure is simple, usually done under local anesthesia, • Involves removing the thrombosed clot, • Patients feel significantly better within 24 hours. Why not the others? • A) Oral antibiotics: ❌ Not indicated unless there’s surrounding cellulitis. • B) High-fiber diet and sitz baths: ⚠️ Supportive, but not enough for acute, painful thrombosis. • D) Rubber band ligation: ❌ Used for internal hemorrhoids, not thrombosed external ones. • E) Topical steroid cream: ❌ May help itching but not appropriate for acute thrombosis. Mnemonic: “Thrombosed and timed right? Excise with a local bite.”

Answer 92

Correct answer: ✅ C) Atelectasis Explanation: Atelectasis — the collapse or incomplete expansion of alveoli — is the most common cause of post-operative fever within the first 48 hours. It’s especially common after abdominal or thoracic surgery due to: • Shallow breathing, • Impaired cough reflex, • Effects of anesthesia and pain medications. Key features: • Low-grade fever, • Mild hypoxia or increased respiratory rate, • Often resolves with incentive spirometry, chest physiotherapy, and early mobilization. Let’s review the alternatives: • A) UTI: ❌ More common after day 3, especially with catheters. • B) DVT: ❌ Tends to occur after day 3–5. • D) Surgical site infection: ❌ Typically occurs after 3–5 days. • E) C. difficile colitis: ❌ Usually seen after antibiotic use, days to weeks later. Mnemonic: “Wind (atelectasis) is the first of the 5 Ws of post-op fever.”

Answer 93

Correct answer: ✅ B) Intravenous steroids Explanation: The first-line treatment for toxic megacolon — especially when related to inflammatory bowel disease (IBD) — is IV corticosteroids, typically hydrocortisone. This helps reduce the massive colonic inflammation and edema. Toxic megacolon is a life-threatening condition characterized by: • Severe colitis, • Colonic dilation >6 cm, • Systemic toxicity (fever, tachycardia, hypotension), • Risk of perforation and sepsis. Treatment escalation path: 1. IV steroids 2. If no improvement → biologics (e.g. infliximab) or colectomy depending on response and severity Let’s review the other options: • A) Oral vancomycin: ❌ Used in C. difficile colitis, but not first-line in IBD-related toxic megacolon. • B) ✅ IV steroids: Correct – first-line in IBD-related cases. • C) Subtotal colectomy: ❌ Indicated if medical therapy fails or in perforation. • D) Infliximab: ⚠️ Effective as rescue therapy, but not first-line. • E) Oral mesalazine: ❌ Not useful in acute severe disease. Mnemonic: “Toxic megacolon? Start with steroids, then reassess.”

Answer 94

Correct answer: ✅ B) Ileocolic artery Explanation: The appendix is primarily supplied by the appendicular artery, which is a branch of the ileocolic artery, itself a terminal branch of the superior mesenteric artery (SMA). • The appendicular artery runs in the mesoappendix, • It is an end-artery, meaning no collateral supply — hence, it’s highly susceptible to ischemia during appendicitis. Option breakdown: • A) Superior mesenteric artery: ❌ Main trunk that gives rise to ileocolic, but not directly supplying appendix. • B) ✅ Ileocolic artery: Correct – direct parent artery of appendicular artery. • C) Right colic artery: ❌ Supplies ascending colon. • D) Inferior mesenteric artery: ❌ Supplies distal transverse colon, descending, sigmoid, and rectum. • E) Middle colic artery: ❌ Supplies transverse colon. Mnemonic: “IleoColic supplies the Culprit.”

Answer 95

Correct answer: ✅ D) Sigmoid colon Explanation: The sigmoid colon is the most common site for colorectal cancer, followed closely by the rectum. This is largely due to the long transit time and concentrated fecal matter, increasing mucosal exposure to carcinogens. Typical features of sigmoid colon cancer: • Change in bowel habits (e.g., constipation alternating with diarrhea), • Left-sided abdominal pain, • Rectal bleeding or mucus, • May present with obstruction, due to narrow lumen. Breakdown of other options: • A) Ascending colon: ❌ Right-sided cancers tend to present later with anemia due to occult bleeding. • B) Transverse colon: ❌ Less commonly affected. • C) Descending colon: ❌ Affected, but not as frequently as sigmoid. • E) Rectum: ⚠️ Very common too, but sigmoid colon slightly edges it in incidence in many series. Clinical tip: Left-sided (sigmoid) tumors are more likely to cause obstruction, while right-sided tumors cause anemia.

Answer 96

Correct answer: ✅ D) Urine microalbumin Explanation: Urine microalbumin (also known as albumin-to-creatinine ratio) is the most sensitive test for detecting early diabetic nephropathy, even before overt proteinuria or changes in creatinine levels. • Detects 30–300 mg/day of albumin, classified as microalbuminuria, • Allows for early intervention with ACE inhibitors/ARBs to delay progression. Other options: • A) Serum creatinine: ❌ Rises late in the disease. • B) Urinalysis for protein: ❌ Detects macroproteinuria; not sensitive to early changes. • C) 24-hour urine protein: ⚠️ Accurate but less practical and not as sensitive as microalbumin testing. • E) Estimated GFR (eGFR): ❌ May remain normal until moderate kidney damage. Clinical tip: Screen all diabetic patients annually for microalbuminuria. Mnemonic: “Microalbumin = micro damage warning.”

Answer 97

Correct answer: ✅ B) Non-contrast CT KUB Explanation: Non-contrast CT of the kidneys, ureters, and bladder (CT KUB) is the gold standard and most appropriate initial imaging for suspected renal colic. It is: • Highly sensitive and specific for detecting urinary calculi, • Can detect stones as small as 1–2 mm, • Also identifies other potential abdominal causes of pain. Advantages: • Rapid, • No contrast needed, • Excellent for emergency evaluation Option review: • A) Abdominal ultrasound: ❌ First-line in pregnancy, but limited for ureteric stones. • C) Intravenous urogram (IVU): ❌ Largely outdated by CT. • D) MRI abdomen: ❌ Not practical for acute stone detection. • E) X-ray KUB: ❌ Only ~50% of stones are radiopaque — not reliable alone. Clinical tip: Always check renal function before giving contrast, but no contrast is needed for stone detection.

Answer 98

Correct answer: ✅ C) Femoral hernia Explanation: Femoral hernias have the highest risk of strangulation among all hernia types due to: • Their narrow neck, • Passage through the rigid femoral canal, • Often being diagnosed late, especially in elderly women. Classic features: • More common in females, • Appears as a lump inferolateral to the pubic tubercle, • Often irreducible and tender if strangulated. Comparison with others: • A) Indirect inguinal hernia: ⚠️ Common but less likely to strangulate. • B) Direct inguinal hernia: ❌ Rarely strangulates due to wide neck. • D) Umbilical hernia: ❌ May strangulate, but less frequently. • E) Incisional hernia: ❌ Risk depends on size and contents but generally lower than femoral. Mnemonic: “Femoral = Fatal first” (most likely to strangulate).

Answer 99

Correct answer: ✅ D) CT scan with oral contrast Explanation: The best investigation for suspected esophageal perforation is a CT scan with oral (water-soluble) contrast, typically Gastrografin. This allows for: • Accurate localization of the perforation, • Identification of contrast leak, • Assessment of associated mediastinitis, pneumomediastinum, or fluid collections. Other options: • A) Barium swallow: ❌ Barium can cause mediastinal irritation if leaked — contraindicated. • B) Upper GI endoscopy: ❌ Can worsen the perforation; not diagnostic in emergencies. • C) Chest X-ray: ⚠️ May show signs like subcutaneous emphysema or pleural effusion, but is not definitive. • E) Abdominal ultrasound: ❌ Not useful for thoracic or esophageal evaluation. Clinical tip: Always suspect esophageal perforation in cases of sudden chest pain after vomiting or endoscopy (e.g., Boerhaave’s syndrome).

Answer 100

Correct answer: ❌ B) Warm, dry skin Explanation: In neurogenic shock, typically caused by spinal cord injury above T6, there is loss of sympathetic tone. This results in: • Vasodilation, • Bradycardia (due to unopposed vagal tone), • Hypotension, • And warm, dry skin due to lack of vasoconstriction and sweating. It is unique among shock types in that: • The skin is warm (not cold and clammy), • The heart rate is often slow, not fast. Let’s evaluate the options: • A) Hypertension: ❌ False — hypotension is typical. • B) ✅ Warm, dry skin: Correct – hallmark feature. • C) Tachycardia: ❌ Opposite – bradycardia is more typical. • D) Increased systemic vascular resistance: ❌ It’s actually decreased. • E) Cold, clammy skin: ❌ Seen in hypovolemic or cardiogenic shock, not neurogenic. Mnemonic: “Neurogenic = no tone = warm, floppy, slow.”

Answer 101

Correct answer: ✅ C) Calcitonin Explanation: Calcitonin is the most sensitive marker for detecting recurrence of medullary thyroid carcinoma (MTC). It is secreted by parafollicular C cells, which are the origin of MTC. • Rising calcitonin levels after surgery suggest residual or recurrent disease, • Often monitored serially post-operatively, • Carcinoembryonic antigen (CEA) is also used as a secondary marker. Let’s review the other markers: • A) TSH: ❌ Not useful in MTC — more relevant to papillary/follicular thyroid cancers. • B) Thyroglobulin: ❌ Used for differentiated thyroid cancers, not MTC. • D) Free T3: ❌ Not tumor-specific. • E) Anti-thyroglobulin antibodies: ❌ Interfere with thyroglobulin measurement but irrelevant to MTC. Mnemonic: “MTC = Measure The Calcitonin.”

Answer 102

Correct answer: ✅ A) Colonic diverticulosis Explanation: The most common cause of massive lower gastrointestinal (GI) bleeding in adults is colonic diverticulosis. Though often asymptomatic, diverticula can erode into vessels, particularly in the descending and sigmoid colon, causing sudden, painless, and profuse bleeding. Features of diverticular bleeding: • Bright red or maroon blood per rectum • Often large volume • Usually painless • Common in elderly patients Let’s assess the alternatives: • A) ✅ Colonic diverticulosis: Correct – #1 cause of significant lower GI bleeding • B) Angiodysplasia: ⚠️ Common in elderly, but less frequent than diverticulosis • C) Ischemic colitis: ❌ Usually causes bloody diarrhea and pain, not massive bleeding • D) Colorectal cancer: ❌ May bleed, but rarely causes massive hemorrhage • E) Hemorrhoids: ❌ Cause minor bleeding, not massive or hemodynamically significant Mnemonic: “Diverticulosis = Downpour.”

Answer 103

Correct answer: ✅ D) Coagulopathy Explanation: Coagulopathy is a contraindication to laparoscopic surgery, including laparoscopic cholecystectomy, unless it is corrected preoperatively. The use of pneumoperitoneum and sharp dissection in a vascular organ like the liver increases the risk of uncontrollable bleeding in coagulopathic patients. Let’s assess the other options: • A) Obesity: ❌ Not a contraindication — in fact, laparoscopy is often preferred in obese patients for faster recovery. • B) Acute cholecystitis: ❌ Can still be done laparoscopically by experienced surgeons, ideally within 72 hours. • C) Previous abdominal surgery: ❌ May pose challenges due to adhesions, but not an absolute contraindication. • D) ✅ Coagulopathy: Correct – must be corrected prior to surgery. • E) Symptomatic gallstones: ❌ An indication, not a contraindication. Mnemonic: “Correct clotting before cutting.”

Answer 104

Correct answer: ✅ B) Parietal lobe Explanation: Subdural hematomas commonly affect the parietal region, especially over the cerebral convexities, because this is where bridging veins (between the cortex and dural sinuses) are most vulnerable to tearing — particularly in older adults and trauma cases. Key features of subdural hematoma: • Crescent-shaped hemorrhage on CT • Slow onset of symptoms (e.g. confusion, headache, focal deficits) • Risk factors: age, alcohol use, anticoagulation Option analysis: • A) Frontal lobe: ❌ May be affected but less commonly than parietal. • B) ✅ Parietal lobe: Correct – most commonly involved. • C) Temporal lobe: ❌ More common in epidural hematomas. • D) Occipital lobe: ❌ Less commonly involved in subdural bleeds. • E) Cerebellum: ❌ More relevant in posterior fossa bleeds or strokes. Mnemonic: “Parietal for the pull — bridging veins fall.”

Answer 105

Correct answer: ✅ C) Diagnostic laparoscopy Explanation: In a hemodynamically stable patient with a penetrating injury to the left lower chest (below the nipple line), there is a high suspicion for diaphragmatic injury — especially without signs of peritonism. Since small diaphragmatic tears can be missed on imaging and may present later with herniation or strangulation, diagnostic laparoscopy is the most appropriate next step. Why not the others? • A) Immediate laparotomy: ❌ Not indicated without signs of peritonitis or hemodynamic instability. • B) Chest X-ray only: ❌ Useful initial test, but insufficient for ruling out diaphragm injury. • C) ✅ Diagnostic laparoscopy: Correct – safe, effective, and allows direct inspection. • D) Observation: ❌ Risks missed diaphragm injury → delayed hernia/complications. • E) Exploratory thoracotomy: ❌ Unnecessary unless chest trauma is the main concern (e.g., massive hemothorax). Mnemonic: “Left chest stab? Look for the gap — lap it.”

Answer 106

Correct answer: ✅ C) Hypophosphatemia Explanation: The hallmark biochemical abnormality of refeeding syndrome is hypophosphatemia. It occurs when a malnourished patient is rapidly refed — especially with carbohydrates — leading to: • Sudden insulin surge, • Intracellular shift of phosphate, potassium, and magnesium, • Resulting in critically low serum phosphate, which can cause: • Respiratory failure (due to muscle weakness), • Cardiac arrhythmias, • Neurological symptoms. Breakdown of options: • A) Hyperkalemia: ❌ Potassium drops due to insulin shift → hypokalemia more common. • B) Hypoglycemia: ❌ Hyperglycemia is more typical during refeeding. • C) ✅ Hypophosphatemia: Correct – most characteristic and dangerous. • D) Hypermagnesemia: ❌ Usually hypomagnesemia occurs. • E) Hypercalcemia: ❌ Not typically seen. Clinical tip: Start refeeding slowly and monitor electrolytes closely — especially phosphate.

Answer 107

Correct answer: ✅ B) Long thoracic nerve Explanation: The long thoracic nerve is the most commonly injured nerve during axillary lymph node dissection, particularly in breast cancer surgery. It innervates the serratus anterior muscle, and injury leads to: • Winging of the scapula, • Inability to raise the arm above shoulder level, • Medial border of the scapula protrudes when pushing against a wall. Breakdown of other options: • A) Axillary nerve: ❌ At risk during shoulder dislocation or humeral fracture, not axillary dissection. • C) Radial nerve: ❌ At risk with humeral shaft fractures. • D) Median nerve: ❌ Runs through the cubital fossa and carpal tunnel — not affected during axillary dissection. • E) Musculocutaneous nerve: ❌ Runs through the coracobrachialis, not typically endangered here. Mnemonic: “Long thoracic nerve – lifts the wing, loses the wing.”

Answer 108

Correct answer: ✅ C) CT pulmonary angiography (CTPA) Explanation: CT pulmonary angiography (CTPA) is the gold standard investigation for diagnosing pulmonary embolism (PE) because it: • Directly visualizes the pulmonary arteries, • Identifies filling defects (clots) within the arterial tree, • Is quick and widely available, • Can also detect alternative diagnoses (e.g., pneumonia, pleural effusion). Let’s break down the other options: • A) Chest X-ray: ❌ May be normal or show nonspecific findings — not diagnostic. • B) V/Q scan: ⚠️ Useful in pregnancy or contrast allergy; less specific than CTPA. • D) Echocardiography: ❌ Helpful in massive PE to assess right heart strain, but not diagnostic. • E) D-dimer test: ⚠️ High sensitivity, low specificity — useful for ruling out PE in low-risk patients. Clinical tip: Always assess renal function before contrast-enhanced CT. Mnemonic: “Suspect a PE? CTPA is key.”

Answer 109

Correct answer: ✅ A) Diabetes mellitus Explanation: The most significant risk factor for wound dehiscence after abdominal surgery is diabetes mellitus, due to: • Impaired wound healing, • Microvascular disease, • Immune dysfunction, • Higher infection rates. Wound dehiscence refers to the partial or complete separation of the wound layers, which can lead to evisceration, sepsis, and increased mortality. Option breakdown: • A) ✅ Diabetes mellitus: Correct – major risk factor. • B) Early oral feeding: ❌ No proven link to increased wound dehiscence. • C) Use of absorbable sutures: ⚠️ Only increases risk if used incorrectly or in high-tension closures. • D) Laparoscopic technique: ❌ Associated with lower risk of wound complications. • E) Antibiotic use: ❌ Prevents infections, which otherwise increase dehiscence risk. Clinical tip: Always optimize blood glucose levels in perioperative patients to reduce surgical site complications.

Answer 110

Correct answer: ✅ B) Gonorrhea Explanation: Sterile pyuria refers to the presence of white blood cells in urine without bacterial growth on standard culture. Neisseria gonorrhoeae is a classic cause, as it requires special culture media (e.g. Thayer-Martin agar) and does not grow on routine urine cultures. Other causes of sterile pyuria include: • Chlamydia trachomatis, • Tuberculosis, • Recent antibiotic use, • Interstitial nephritis Option breakdown: • A) Escherichia coli: ❌ Common UTI pathogen — not sterile. • B) ✅ Gonorrhea: Correct – causes urethritis with sterile pyuria. • C) Enterococcus: ❌ Cultured easily on standard media. • D) Klebsiella pneumoniae: ❌ Cultured normally. • E) Proteus mirabilis: ❌ Cultured readily; associated with struvite stones. Mnemonic: “Sterile pyuria = Think STIs or TB.”

Answer 111

Correct answer: ✅ C) Intramuscular adrenaline Explanation: The first-line treatment for anaphylactic shock is intramuscular (IM) adrenaline (epinephrine), typically: • 0.5 mg IM in adults, • Administered into the mid-anterolateral thigh, • Repeat every 5 minutes if necessary. Adrenaline: • Reverses bronchospasm, • Raises blood pressure via vasoconstriction, • Reduces mucosal edema, • Stabilizes mast cells. Supporting treatments include: • D) IV fluids – to support circulation. • A) Hydrocortisone – reduces late-phase response. • B) Chlorpheniramine – H1 blocker for symptom control. • E) Oxygen – for hypoxia, but not definitive treatment. Mnemonic: “IM Adrenaline First – Everything else supports.”

Answer 112

Correct answer: ✅ D) Anaphylactic shock Explanation: Among the shock types listed, anaphylactic shock is the one most commonly associated with increased cardiac output (at least initially). This occurs due to: • Massive vasodilation, • Reduced systemic vascular resistance (SVR), • Compensatory tachycardia, • Resulting in a hyperdynamic circulation. Let’s go over the options: • A) Hypovolemic shock: ❌ ↓ Preload → ↓ cardiac output. • B) Cardiogenic shock: ❌ ↓ Pump function → ↓ cardiac output. • C) Obstructive shock: ❌ ↓ Venous return or outflow → ↓ cardiac output. • D) ✅ Anaphylactic shock: Correct – may show increased cardiac output early on. • E) Neurogenic shock: ❌ ↓ Sympathetic tone → ↓ SVR and bradycardia → ↓ cardiac output. Mnemonic: “Anaphylaxis amps up the pump (at first).”

Answer 113

Correct answer: ✅ B) Scrotal ultrasound with Doppler Explanation: The best initial investigation for suspected testicular torsion is scrotal ultrasound with Doppler flow studies. This allows rapid assessment of: • Blood flow to the testis — which is typically absent or reduced in torsion • Testicular position, size, and echotexture However, clinical suspicion overrides imaging — if torsion is strongly suspected, surgical exploration should not be delayed for imaging. Option breakdown: • A) Urinalysis: ❌ Useful in epididymitis, but not diagnostic for torsion. • B) ✅ Scrotal ultrasound with Doppler: Correct – best non-invasive test. • C) MRI pelvis: ❌ Not practical or necessary for acute scrotal pain. • D) Testicular biopsy: ❌ Never indicated in acute testicular pain. • E) Abdominal X-ray: ❌ Irrelevant for scrotal pathologies. Mnemonic: “Doppler decides, but don’t delay the knife.”

Answer 114

Correct answer: ✅ A) Portal vein Explanation: The hepatoduodenal ligament is part of the lesser omentum and contains the portal triad, which includes: • Portal vein • Proper hepatic artery • Common bile duct These structures are enclosed within the ligament and travel toward the liver at the porta hepatis. Option review: • A) ✅ Portal vein: Correct – part of the portal triad. • B) Inferior vena cava: ❌ Located posterior to the liver, not within this ligament. • C) Left hepatic vein: ❌ Drains directly into the IVC — not in the hepatoduodenal ligament. • D) Hepatic flexure of colon: ❌ Anatomically close but not part of the ligament. • E) Gastrosplenic ligament: ❌ A different ligament, contains short gastric and left gastroepiploic vessels. Mnemonic: “Duct, Artery, Vein — in the hepatoduodenal train (anterior to posterior).”

Answer 115

Correct answer: ✅ C) Peptic ulcers refractory to treatment Explanation: Zollinger–Ellison syndrome (ZES) is a condition characterized by gastrin-secreting tumors (gastrinomas), most commonly located in the pancreas or duodenum. These tumors cause excessive gastric acid secretion, leading to: • Refractory peptic ulcers (multiple, large, or in unusual locations like jejunum), • Abdominal pain, diarrhea, and GERD-like symptoms, • Elevated gastrin levels with low gastric pH (acidic). Option breakdown: • A) Hypercalcemia: ⚠️ May be present in MEN1, but not diagnostic for ZES alone. • B) Elevated gastrin with high gastric pH: ❌ This occurs in atrophic gastritis, not ZES. • C) ✅ Peptic ulcers refractory to treatment: Correct – hallmark of ZES. • D) Low serum chromogranin A: ❌ It is usually elevated in neuroendocrine tumors. • E) Associated with hyperaldosteronism: ❌ That’s Conn’s syndrome, not ZES. Mnemonic: “ZES = Zapped ulcers from Zany Gastrin.”

Answer 116

Correct answer: ✅ D) Streptococcus pneumoniae Explanation: Streptococcus pneumoniae is the most common organism associated with overwhelming post-splenectomy infection (OPSI). The spleen plays a critical role in clearing encapsulated organisms, and its absence significantly raises the risk of rapid, life-threatening sepsis. Key encapsulated organisms in OPSI: • Streptococcus pneumoniae (most common) • Haemophilus influenzae type B • Neisseria meningitidis Post-splenectomy care includes: • Vaccination against pneumococcus, meningococcus, and Hib • Long-term or standby antibiotics • Patient education (e.g., seek medical care urgently if febrile) Other options: • A) Escherichia coli: ❌ Common in UTIs and abdominal infections, not typical in OPSI. • B) Klebsiella pneumoniae: ❌ Rarely causes post-splenectomy sepsis. • C) Staphylococcus aureus: ❌ More often skin/soft tissue or device-related infections. • E) Pseudomonas aeruginosa: ❌ Seen in immunocompromised or nosocomial infections. Mnemonic: “Post-spleen? Beware the capsule queen — Strep pneumo!”

Answer 117

Correct answer: ✅ C) Propylthiouracil Explanation: Thyroid storm is a life-threatening exacerbation of hyperthyroidism, often triggered by surgery, infection, or trauma. Propylthiouracil (PTU) is the preferred antithyroid drug in this emergency because: • It inhibits thyroid hormone synthesis, • Also blocks peripheral conversion of T4 to T3 (unlike carbimazole), • Works rapidly and reduces circulating thyroid hormone levels. Management of thyroid storm typically includes: 1. Propylthiouracil (high dose, oral or via NG tube), 2. Beta-blockers (e.g., propranolol) for symptom control, 3. Steroids (reduce T4 to T3 conversion and adrenal support), 4. Iodine (Lugol’s iodine) given after PTU to inhibit hormone release, 5. Supportive care (cooling, IV fluids, treatment of precipitating cause). Other options: • A) Levothyroxine: ❌ Treats hypothyroidism — contraindicated here. • B) Radioiodine therapy: ❌ Not for acute settings — delayed effect. • D) Beta-blockers only: ❌ Important adjunct, but not sufficient alone. • E) Total thyroidectomy: ❌ Can be curative but not first-line in storm. Mnemonic: “PTU for the storm that breaks the T4.”

Answer 118

Correct answer: ✅ D) Endoscopic ultrasound with biopsy Explanation: In a patient with painless jaundice and a pancreatic head mass, the most appropriate next step is endoscopic ultrasound (EUS) with biopsy. This provides: • Tissue diagnosis to confirm pancreatic adenocarcinoma, • High-resolution imaging of the pancreas, • Guidance for FNA (fine needle aspiration) to avoid unnecessary surgery. Key steps in workup: 1. Confirm presence and location of the mass (CT/MRI) 2. EUS-guided biopsy to get histology 3. Then decide on resectability and management (surgery, chemo, or palliative) Why not the others yet? • A) ERCP with stent placement: ❌ Done after diagnosis, mainly for biliary decompression if jaundice is severe or cholangitis is present. • B) Chemotherapy: ❌ Needs confirmed diagnosis first. • C) Laparotomy: ❌ Too invasive without tissue confirmation or staging. • E) MRI liver: ⚠️ Can help in staging but not first unless liver lesions are unclear. Mnemonic: “Pancreas? Prove it with a poke — EUS is bespoke.”

Answer 119

Correct answer: ✅ A) Fracture at the base of the odontoid process Explanation: A Type II odontoid fracture occurs at the base of the odontoid process, where it joins the body of the axis (C2 vertebra). It is the most common type and has the highest risk of non-union due to poor vascularity at this junction. Anderson and D’Alonzo classification: • Type I: Avulsion of the tip of the odontoid – rare and stable • Type II: Fracture at the base of the odontoid – unstable, poor healing • Type III: Fracture extends into the body of C2 – better healing potential Option breakdown: • A) ✅ Fracture at the base of the odontoid process: Correct – Type II • B) Avulsion of the odontoid tip: ❌ Type I • C) Fracture through the body of C2: ❌ Type III • D) Fracture extending into lateral masses: ❌ Not part of odontoid classification • E) Fracture at the base of the skull: ❌ Unrelated – that’s a basilar skull fracture Mnemonic: “Type II — Two parts at the base break through.”

Answer 120

Correct answer: ✅ C) Ischemic colitis Explanation: Ischemic colitis is the most likely diagnosis in this case, especially given: • Older age and atherosclerosis, • Acute onset abdominal pain, • Bloody diarrhea, • CT findings of colonic wall thickening, particularly in watershed areas like the splenic flexure. Splenic flexure is a classic location because it lies at the junction of supply from the superior and inferior mesenteric arteries, making it vulnerable during hypoperfusion or thromboembolism. Option breakdown: • A) Ulcerative colitis: ❌ Typically starts in the rectum and progresses proximally. • B) Crohn’s disease: ❌ Can involve any GI part; usually has skip lesions, not isolated splenic flexure. • C) ✅ Ischemic colitis: Correct • D) Diverticulitis: ❌ Usually localized to the sigmoid, presents with LLQ pain and systemic signs. • E) Infectious colitis: ❌ Possible, but less likely in this vascular-risk setting and age group. Mnemonic: “Ischemia loves the flex — splenic is its reflex.”

Answer 121

Correct answer: ✅ A) Pelvic binder Explanation: In a hemodynamically unstable trauma patient with suspected pelvic fracture, the first step is application of a pelvic binder. This: • Reduces pelvic volume, • Stabilizes fracture fragments, • Tamps venous bleeding, which is the most common source in pelvic trauma. Pelvic fractures can lead to life-threatening hemorrhage, even without external bleeding. Option breakdown: • A) ✅ Pelvic binder: Correct – best immediate step. • B) Laparotomy: ❌ Only if intraperitoneal source suspected. • C) External fixation: ❌ Definitive step after initial stabilization. • D) Foley catheter insertion: ❌ Contraindicated until urethral injury is excluded. • E) CT angiography: ⚠️ Useful for definitive bleeding localization, but not first if unstable. Mnemonic: “Binder before blood loss blinds you.”

Answer 122

Correct answer: ✅ D) Ileostomy Explanation: A high-output stoma is most commonly associated with an ileostomy, especially in the early postoperative period or in patients with short bowel syndrome. Output can exceed 1.5–2 liters/day, leading to: • Dehydration, • Electrolyte imbalances (particularly sodium and magnesium), • Risk of renal impairment. Why ileostomy? • It diverts contents from the small bowel, which are more liquid and continuous, • No time for significant fluid reabsorption, unlike in colostomies. Option breakdown: • A) Parastomal hernia: ❌ Can cause obstruction, not high output. • B) Electrolyte imbalance: ❌ Effect, not cause. • C) Distal obstruction: ❌ Would cause low output or overflow symptoms. • D) ✅ Ileostomy: Correct • E) Colostomy: ❌ Typically produces formed stool, low output. Mnemonic: “Ileostomy = Irrigation-like output.”

Answer 123

Correct answer: ✅ B) Vitamin B1 Explanation: The triad of confusion, visual disturbances (nystagmus, ophthalmoplegia), and ataxia is classic for Wernicke’s encephalopathy, caused by thiamine (vitamin B1) deficiency. This condition is especially common in: • Malnourished patients, • Alcoholics, • Patients undergoing major surgery or TPN without proper supplementation. If untreated, it can progress to Korsakoff syndrome, which includes permanent memory impairment and confabulation. Option breakdown: • A) Vitamin A: ❌ Deficiency causes night blindness, not confusion. • B) ✅ Vitamin B1: Correct – Wernicke’s encephalopathy. • C) Vitamin B12: ❌ Causes subacute combined degeneration – slower onset, not acute confusion. • D) Vitamin C: ❌ Deficiency causes scurvy – bleeding gums, poor wound healing. • E) Vitamin D: ❌ Affects bone metabolism, not CNS function. Mnemonic: “Wacky Wernicke: B1 for the brain.”

Answer 124

Correct answer: ✅ B) Core needle biopsy Explanation: In a case of a suspicious breast mass (BIRADS 5) confirmed on ultrasound, the appropriate next step is a core needle biopsy. This: • Provides histological diagnosis, • Allows for tumor grading, hormone receptor testing, and planning of treatment, • Is standard after triple assessment indicates malignancy. Why not the others? • A) Fine needle aspiration (FNA): ❌ Only gives cytology, not tissue architecture — inadequate in suspected cancer. • C) MRI breast: ❌ Used for staging or evaluating extent, not first-line diagnostic. • D) Excisional biopsy: ❌ More invasive, not necessary when a core biopsy suffices. • E) Mastectomy: ❌ Requires confirmed malignancy and staging — not the next step in diagnosis. Mnemonic: “Core for cancer certainty.”

Answer 125

Correct answer: ✅ C) CRP 220 mg/L Explanation: In acute pancreatitis, a CRP >150 mg/L at 48 hours is a strong indicator of severe disease and worse prognosis. It reflects systemic inflammation and correlates with risk of complications such as necrosis or organ failure. Let’s review the other values: • A) Serum calcium 2.4 mmol/L: ❌ This is within normal range (2.2–2.6 mmol/L). Hypocalcaemia, not normocalcaemia, indicates poor prognosis. • B) AST 35 U/L: ❌ Mild elevation, not prognostic. • C) ✅ CRP 220 mg/L: Correct – a strong marker of severity. • D) Blood glucose 5.2 mmol/L: ❌ Normal – hyperglycaemia would indicate poor outcome. • E) Serum albumin 45 g/L: ❌ Normal – hypoalbuminemia may suggest poor nutrition or worse prognosis. Mnemonic: “CRP climbs in catastrophe.”

Answer 126

Correct answer: ✅ C) Diverticular stricture Explanation: In a patient with a history of multiple episodes of diverticulitis, the most likely cause of a sigmoid obstruction is a diverticular stricture. Repeated inflammation leads to fibrosis, narrowing the lumen and causing chronic obstruction. CT findings typically show: • Thickened sigmoid wall, • Luminal narrowing, • No discrete mass (helps differentiate from cancer). Option breakdown: • A) Sigmoid volvulus: ❌ More common in older, immobile patients and has a distinct coffee-bean appearance on imaging. • B) Colorectal cancer: ❌ Always a differential but less likely if imaging lacks mass and history suggests chronic inflammation. • C) ✅ Diverticular stricture: Correct • D) Adhesions: ❌ More common in small bowel obstruction, especially post-op. • E) Hernia: ❌ Would usually show herniation and be more common in small bowel obstruction. Mnemonic: “Diverticulitis leads to narrowing — stricture’s the sequel.”

Answer 127

Correct answer: ✅ D) Fat embolism syndrome Explanation: This classic triad of: • Respiratory distress (tachypnea), • Neurological symptoms (confusion), • Petechial rash (typically chest, axilla, conjunctiva) — strongly points to fat embolism syndrome (FES), a complication seen after long bone fractures, especially the femur. Why does it happen? Fat globules from the bone marrow enter the bloodstream and lodge in pulmonary and systemic microvasculature, leading to inflammation and capillary leakage. Other options explained: • A) Pulmonary embolism: ❌ Can cause dyspnea and tachypnea, but rarely causes confusion and rash. • B) Tension pneumothorax: ❌ Causes respiratory distress but also hypotension and tracheal deviation — not this picture. • C) Head injury: ❌ Wouldn’t explain rash or isolated hypoxia. • E) Sepsis: ❌ Possible, but petechial rash and the context of long bone fracture are key differentiators. Mnemonic: “Fat embolism = Fracture, Foggy brain, Freckles (rash).”

Answer 128

Correct answer: ✅ C) Urgent surgical exploration Explanation: This patient presents with signs of a strangulated inguinal hernia: • Irreducible and tender, • Overlying skin erythema, • Systemic sepsis (fever, tachycardia, possible hypotension). These findings indicate compromised bowel viability, requiring emergency surgery to prevent necrosis, perforation, or death. Option breakdown: • A) Attempt manual reduction: ❌ Dangerous in strangulation — can reduce non-viable bowel into the abdomen → peritonitis. • B) Oral antibiotics and observation: ❌ Delays definitive treatment. • C) ✅ Urgent surgical exploration: Correct – definitive and time-critical. • D) Ultrasound-guided drainage: ❌ Not appropriate for a hernia. • E) CT abdomen and pelvis: ⚠️ Helpful in diagnostic doubt, but not needed here — clinical picture is clear. Mnemonic: “Red, raw, and rigid hernias go to theatre.”

Answer 129

Correct answer: ✅ D) No involvement of the superior mesenteric vessels Explanation: The most critical factor in determining whether a pancreatic head tumor is resectable is whether there is vascular involvement, especially: • Superior mesenteric artery (SMA) • Superior mesenteric vein (SMV) • Celiac axis Tumors involving these major vessels are often deemed unresectable due to technical challenges and poor prognosis. Option breakdown: • A) No evidence of liver metastases: ⚠️ Important for staging, but not sufficient alone to define resectability. • B) Absence of ascites: ⚠️ Suggests no peritoneal disease, but again not the defining factor. • C) Normal CA 19-9: ❌ Useful for monitoring, but not diagnostic or staging. • D) ✅ No involvement of the superior mesenteric vessels: Correct – key anatomic criterion. • E) Absence of biliary duct dilatation: ❌ The opposite is usually seen and not related to resectability. Mnemonic: “Surgery skips SMA squeeze.”

Answer 130

Correct answer: ✅ B) Gallstone ileus Explanation: This is a classic textbook presentation of gallstone ileus, a rare form of mechanical small bowel obstruction caused by a gallstone that enters the bowel through a cholecystoenteric fistula and lodges (often in the terminal ileum). Key triad (Rigler’s triad) on CT: • Pneumobilia (air in biliary tree) • Small bowel obstruction • Ectopic gallstone, often at the ileocecal valve Option breakdown: • A) Acute cholecystitis: ❌ No bowel obstruction, no pneumobilia. • B) ✅ Gallstone ileus: Correct • C) Bowel perforation: ❌ Would present with free air, not pneumobilia. • D) Cholangiocarcinoma: ❌ Doesn’t cause mechanical SBO. • E) Ascending cholangitis: ❌ Causes sepsis, not bowel obstruction. Mnemonic: “Gallstone in the ileum? Ileus it is.”

Answer 131

Correct answer: ✅ D) Colorectal cancer Explanation: In an elderly patient with iron deficiency anaemia and weight loss, a stenosing lesion in the proximal colon is highly suspicious for right-sided colorectal cancer. Right-sided colon cancers: • Often present late, • Can cause chronic occult bleeding, • Lead to iron deficiency anaemia, fatigue, and weight loss, • Less likely to present with obstruction compared to left-sided lesions. Option breakdown: • A) Diverticular disease: ❌ Typically involves sigmoid colon, not proximal. • B) Ischaemic colitis: ❌ Sudden onset pain, bloody diarrhoea — not anaemia. • C) Colonic tuberculosis: ❌ Rare in high-income settings; mimics IBD. • D) ✅ Colorectal cancer: Correct • E) Angiodysplasia: ⚠️ Can cause anaemia, but would not cause stenosing lesion. Mnemonic: “Iron deficiency in an older man? Rule out cancer with a scan.”

Answer 132

Correct answer: ✅ C) Intravenous heparin and vascular surgery referral Explanation: The clinical picture suggests acute mesenteric ischaemia (AMI) due to arterial embolism from atrial fibrillation — one of the most common causes. Classic features include: • Sudden severe abdominal pain, • Pain out of proportion to physical findings, • Elevated lactate, • Confirmed SMA occlusion on CT angiography. Initial management should include: • IV heparin to prevent clot propagation, • Urgent vascular surgery referral for potential embolectomy or revascularization, • Surgery only if there are signs of peritonitis or bowel necrosis. ⸻ Why not D (emergency laparotomy)? That would be appropriate if the patient had signs of peritonitis, sepsis, or confirmed necrotic bowel — but in this case, the clinical data points to ischemia without infarction. Option breakdown: • A) Antibiotics and observation: ❌ Delay in treatment worsens prognosis. • B) Oral anticoagulation: ❌ Too slow, not for acute management. • C) ✅ IV heparin and vascular referral: Correct • D) Emergency laparotomy: ❌ Not yet indicated unless peritoneal signs develop. • E) CT-guided thrombolysis: ❌ Not first-line and less effective than surgical intervention. Mnemonic: “SMA clot? Heparin hot — then call the surgeon.”

Answer 133

Correct answer: ✅ B) Carotid artery aneurysm Explanation: A pulsatile neck mass with a bruit is highly suggestive of a carotid artery aneurysm, especially when accompanied by: • Headaches, • Transient visual disturbances (suggesting embolic events or reduced cerebral perfusion), • Location along the anterior border of sternocleidomastoid. This is a rare but dangerous vascular anomaly that carries risks of: • Embolic stroke, • Thrombosis, • Rupture, • Compression of cranial nerves (especially IX–XII). ⸻ Option breakdown: • A) Carotid body tumour: ❌ Also presents as a pulsatile neck mass, but usually non-tender, mobile side-to-side, and doesn’t cause bruit. • B) ✅ Carotid artery aneurysm: Correct • C) Subclavian steal syndrome: ❌ Affects upper limbs and vertebrobasilar flow — no neck mass. • D) Cervical lymphadenopathy: ❌ Non-pulsatile, no bruit. • E) Internal jugular vein thrombosis: ❌ Causes neck pain, swelling, but not pulsatility or bruit. Mnemonic: “Pulsatile mass with pulse and pain? Aneurysm’s to blame.”

Answer 134

Correct answer: ✅ D) Immediate transfer to theatre Explanation: This scenario is a classic presentation of a ruptured abdominal aortic aneurysm (AAA): • Elderly male, • Sudden back/abdominal pain, • Hypotension, • Pulsatile abdominal mass. This is a surgical emergency. Delays for imaging (CT or US) may cost the patient their life if they are hemodynamically unstable. The only appropriate next step is urgent surgical repair — either open or endovascular depending on stability and local protocols. ⸻ Option breakdown: • A) CT angiogram: ❌ Appropriate only if stable and diagnosis unclear. Not for unstable patients. • B) IV antibiotics and observation: ❌ AAA is not an infection. • C) Ultrasound scan: ❌ May be used for screening or in stable patients — not for unstable rupture. • D) ✅ Immediate transfer to theatre: Correct • E) Endovascular embolisation: ❌ Not standard for AAA rupture; EVAR (not embolisation) may be done in theatre. Mnemonic: “Pain + Pulse + Pressure drop = Push to theatre!”

Answer 135

Correct answer: ✅ C) Left chest drain insertion Explanation: This patient has clinical signs highly suggestive of a hemothorax or pneumothorax following a penetrating chest injury: • Stab wound to 5th intercostal space (mid-clavicular = near heart and lung apex), • Tachycardia + hypotension, • Unilateral reduced breath sounds. The most appropriate immediate management is insertion of a chest drain (i.e. intercostal tube thoracostomy) to relieve pressure from air or blood in the pleural space. ⸻ Why not E (Emergency thoracotomy)? • This is reserved for patients with massive hemorrhage (>1500 mL immediate or >200 mL/hr) or cardiac arrest after trauma. • The patient is unstable but not in extremis or arrest, and there’s no info suggesting massive output. ⸻ Option breakdown: • A) Chest X-ray: ❌ Delays urgent intervention. • B) High-flow oxygen: ❌ Helpful but not sufficient alone. • C) ✅ Left chest drain insertion: Correct • D) Needle decompression: ❌ First step for tension pneumothorax, but this case suggests open pneumo or hemothorax. • E) Emergency thoracotomy: ❌ Only if cardiac arrest or massive hemorrhage. Mnemonic: “Stabbed and short of breath? Drain before death.” Reference: MRCS May 2023 – Q174

Answer 136

Correct answer: ✅ C) Zenker’s diverticulum Explanation: This is a classic presentation of Zenker’s diverticulum, a pharyngoesophageal outpouching that occurs through a weak spot (Killian’s dehiscence) between the inferior constrictor and cricopharyngeus muscle. Key features: • Dysphagia (especially to solids), • Halitosis (food retention and fermentation), • Regurgitation, gurgling noises, • Palpable neck mass that gurgles or empties on pressure. ⸻ Option breakdown: • A) Oesophageal carcinoma: ❌ Causes progressive dysphagia and weight loss, not a gurgling neck mass. • B) Thyroglossal cyst: ❌ Midline, moves with swallowing, doesn’t cause dysphagia or halitosis. • C) ✅ Zenker’s diverticulum: Correct • D) Pharyngeal pouch carcinoma: ❌ Possible complication but much rarer, not first diagnosis. • E) Retropharyngeal abscess: ❌ Typically painful, febrile, and not chronic with halitosis. Mnemonic: “Zenker’s: Zipper pouch in the neck with stink.”

Answer 137

Correct answer: ✅ C) Atelectasis Explanation: This patient has developed acute hypoxia on post-op day 3 — a very common timeframe for postoperative atelectasis, particularly after abdominal or thoracic surgery. It results from: • Reduced ventilation (due to pain, sedation, shallow breathing), • Mucus plugging, • Poor mobilization post-op. ⸻ Classic clues for atelectasis: • Day 1–3 post-op, • Tachypnea, • Hypoxia, • Often no fever or sputum, • No chest pain, and signs may resolve with deep breathing, physio, or incentive spirometry. ⸻ Option breakdown: • A) Pneumonia: ❌ Would usually present with fever, productive cough, and take longer to develop. • B) Pulmonary embolism: ⚠️ Always a possibility, but day 3 without chest pain or risk factors makes it less likely. • C) ✅ Atelectasis: Correct • D) Pleural effusion: ❌ Wouldn’t typically cause sudden hypoxia and tachypnea unless massive. • E) Aspiration pneumonitis: ❌ Needs history of vomiting or known aspiration event. Mnemonic: “Day 1–3? Collapsed alveoli = hypoxic me.”

Answer 138

Correct answer: ✅ D) Flexible cystoscopy Explanation: In a 65-year-old male with painless visible haematuria, especially with a history of smoking, the primary concern is urothelial carcinoma, particularly bladder cancer. The most appropriate initial investigation is: 👉 Flexible cystoscopy, to directly visualize the bladder mucosa and look for: • Transitional cell carcinoma (most common), • Other structural abnormalities (stones, strictures, inflammation). ⸻ Why not the others yet? • A) Urine microscopy and culture: ❌ May help rule out infection, but not sufficient alone. • B) Serum PSA: ❌ PSA is for prostate evaluation, not primary haematuria workup. • C) CT urogram: ⚠️ Excellent for upper tract evaluation, usually done in parallel or after cystoscopy. • D) ✅ Flexible cystoscopy: Correct • E) Ultrasound kidney and bladder: ❌ May miss small lesions, not diagnostic for bladder tumours. ⸻ Mnemonic: “Blood in the pee? Scope the sea (bladder) first.”

Answer 139

Correct answer: ✅ C) Intravenous antibiotics and urgent laparoscopic cholecystectomy Explanation: This is a classic case of acute calculous cholecystitis: • Fever, • Right upper quadrant pain, • Murphy’s sign, • Ultrasound findings: gallstones, thickened wall, pericholecystic fluid. The gold-standard treatment: • IV antibiotics to treat infection, and • Urgent laparoscopic cholecystectomy (ideally within 72 hours of symptom onset). ⸻ Option breakdown: • A) Oral antibiotics and outpatient follow-up: ❌ Inadequate for acute/severe cholecystitis. • B) Elective cholecystectomy: ❌ Delays treatment — risk of perforation or sepsis. • C) ✅ IV antibiotics + urgent surgery: Correct • D) ERCP: ❌ Only indicated if there’s choledocholithiasis (CBD stones), not shown here. • E) Percutaneous cholecystostomy: ❌ Reserved for unfit or septic patients who can’t undergo surgery. ⸻ Mnemonic: “Cholecystitis? Cut it out within 72!” Reference: MRCS May 2023 – Q184

Answer 140

Correct answer: ✅ C) Incision and drainage Explanation: This patient has a perianal abscess, a surgical emergency marked by: • Pain, • Fever, • Erythema + fluctuation (pus under pressure). The definitive management is prompt incision and drainage (I&D) — ideally in theatre under local or general anaesthetic. ⸻ Option breakdown: • A) Oral antibiotics: ❌ Alone are not effective; drainage is essential. • B) MRI pelvis: ❌ Useful for complex fistulas, not for obvious abscess. • C) ✅ Incision and drainage: Correct • D) Colonoscopy: ❌ Not indicated unless IBD suspected and stable. • E) CT: ❌ Might help in deep/complicated collections but not needed here. ⸻ Mnemonic: “If it’s red, hot, and full of pus — cut, don’t fuss.”

Answer 141

Correct answer: ✅ C) Hypocalcaemia Explanation: This patient has classic signs of hypocalcaemia: • Perioral tingling, • Carpopedal spasm (Trousseau’s sign). Most likely cause post-thyroidectomy: accidental removal or devascularization of the parathyroid glands, leading to hypoparathyroidism and resultant hypocalcaemia. ⸻ Option breakdown: • A) Recurrent laryngeal nerve injury: ❌ Causes hoarseness, not tingling/spasm. • B) Seroma: ❌ Causes neck swelling, not neuromuscular signs. • C) ✅ Hypocalcaemia: Correct • D) Hyperthyroidism: ❌ Wouldn’t present like this acutely post-op. • E) Tracheomalacia: ❌ Leads to airway collapse, stridor — not tetany. ⸻ Mnemonic: “Tingling + twitch = Calcium glitch.”

Answer 142

Correct answer: ✅ B) Percutaneous transhepatic cholangiography and stenting Explanation: This patient has a hilar cholangiocarcinoma (Klatskin tumor) — a cancer at the confluence of the right and left hepatic ducts, which often presents late with: • Progressive painless jaundice, • Pruritus, • Cholestatic LFTs. By the time of diagnosis, many cases are unresectable, especially if vascular invasion or bilobar involvement is present. In such cases, palliative biliary drainage is key for symptom relief. ⸻ Best palliative option: ✅ Percutaneous transhepatic cholangiography (PTC) with stent placement is preferred for proximal obstructions (hilar tumors), as ERCP access is difficult. ⸻ Option breakdown: • A) Surgical resection: ❌ May not be possible if advanced disease — only for selected early-stage. • B) ✅ PTC + stent: Correct • C) Chemotherapy: ❌ Has limited efficacy; supportive role only. • D) Radiotherapy: ❌ Not first-line for palliation of obstruction. • E) Endoscopic biopsy: ❌ Diagnostic step — not therapeutic palliation. ⸻ Mnemonic: “Klatskin block? Go percutaneous to unlock.”

Answer 143

Correct answer: ✅ D) Referral for urgent ENT assessment Explanation: A non-healing oral ulcer lasting more than 3 weeks — particularly in a patient who smokes and drinks alcohol — must be considered oral squamous cell carcinoma until proven otherwise. 🔴 Red flags: • 3 weeks duration • Located on the lateral tongue (high-risk site) • Risk factors: tobacco, alcohol, poor oral hygiene 👉 The correct action is a two-week urgent referral to ENT/head and neck cancer team for biopsy and staging. ⸻ Option breakdown: • A) Swab for culture: ❌ May delay diagnosis — not helpful for malignancy. • B) Trial of antibiotics: ❌ Inappropriate without signs of infection — delays urgent referral. • C) Excision biopsy under local anaesthetic: ❌ Should be done in a specialist setting, after assessment. • D) ✅ Urgent ENT referral: Correct • E) Dental review: ❌ Useful for oral hygiene but not for suspected malignancy. ⸻ Mnemonic: “Tongue ulcer + smoker = fast-track cancer check.”

Answer 144

Correct answer: ✅ C) CT chest, abdomen and pelvis Explanation: For colorectal cancer staging, the first-line imaging is: • CT chest, abdomen and pelvis (CT-CAP), which assesses: • Local extent, • Lymph node involvement, • Distant metastases (especially to liver and lungs). This imaging guides decisions about surgical planning and adjuvant therapy. ⸻ Option breakdown: • A) Flexible sigmoidoscopy: ❌ Already had colonoscopy; no added value. • B) PET-CT scan: ⚠️ Used if metastasis is suspected or recurrence — not first-line. • C) ✅ CT chest, abdomen and pelvis: Correct • D) MRI pelvis: ❌ Used for rectal cancers, not sigmoid. • E) Endorectal ultrasound: ❌ For early rectal cancers, not for sigmoid lesions. ⸻ Mnemonic: “See the full spread — CT chest to pelvis.”

Answer 145

Correct answer: ✅ C) Pilonidal sinus Explanation: This patient has the classic presentation of a pilonidal sinus: • Young adult male, • Tender, fluctuant mass near the sacrococcygeal region, • Chronic discharging sinus, • History of recurrence. A pilonidal sinus is a chronic skin infection caused by ingrown hair and debris collecting in a midline skin pit. It can lead to abscess formation and chronic sinus tracts. ⸻ Option breakdown: • A) Perianal abscess: ❌ Typically closer to the anal verge, with acute symptoms. • B) Hidradenitis suppurativa: ❌ Affects axilla/groin, often bilateral. • C) ✅ Pilonidal sinus: Correct • D) Anal fistula: ❌ Usually arises from a previous anal abscess; located more perianally. • E) Epidermoid cyst: ❌ Not typically recurrent with pus drainage in this region. ⸻ Mnemonic: “Pit of pain in the gluteal plane = Pilonidal.”

Answer 146

Correct answer: ✅ A) Intravenous antibiotics Explanation: In the case of an open tibial fracture, the first and most critical step is to administer IV antibiotics as soon as possible — ideally within 1 hour of injury. This drastically reduces the risk of deep infection and osteomyelitis, which are common complications of open fractures. ⸻ The sequence of management follows this general order: 1. IV antibiotics immediately 2. Tetanus prophylaxis if needed 3. Sterile dressing and splint 4. Urgent surgical debridement (ideally within 6 hours) 5. Fracture stabilization — may include external fixation ⸻ Option breakdown: • A) ✅ IV antibiotics: Correct • B) Wound closure: ❌ Delayed closure is preferred after proper debridement. • C) Plaster cast: ❌ Not used initially for open fractures. • D) MRI: ❌ Not indicated in acute trauma for fractures. • E) External fixation: ❌ Important but comes after initial antibiotics and assessment. ⸻ Mnemonic: “Open fracture? Antibiotics first — fix later.”

Answer 147

Correct answer: ✅ C) Pilonidal sinus Explanation: This patient has the classic presentation of a pilonidal sinus: • Young adult male, • Tender, fluctuant mass near the sacrococcygeal region, • Chronic discharging sinus, • History of recurrence. A pilonidal sinus is a chronic skin infection caused by ingrown hair and debris collecting in a midline skin pit. It can lead to abscess formation and chronic sinus tracts. ⸻ Option breakdown: • A) Perianal abscess: ❌ Typically closer to the anal verge, with acute symptoms. • B) Hidradenitis suppurativa: ❌ Affects axilla/groin, often bilateral. • C) ✅ Pilonidal sinus: Correct • D) Anal fistula: ❌ Usually arises from a previous anal abscess; located more perianally. • E) Epidermoid cyst: ❌ Not typically recurrent with pus drainage in this region. ⸻ Mnemonic: “Pit of pain in the gluteal plane = Pilonidal.”

Answer 148

✅ Correct Answer: C. Urine metanephrines Explanation: A patient with headache and high blood pressure presenting episodically is highly suggestive of pheochromocytoma. The most sensitive screening test for pheochromocytoma is urinary metanephrines, as these metabolites are elevated due to increased catecholamine secretion by the adrenal medulla.

Answer 149

✅ Correct Answer: A. Spine Osteoarthritis Explanation: Reduced joint space combined with the presence of osteochondral cysts is characteristic of osteoarthritis of the spine (also known as degenerative disc disease). Typical radiological findings include narrowed disc spaces, subchondral sclerosis, osteophytes, and cyst formation.

Answer 150

✅ Correct Answer: A. Abdominoperineal resection (APR) Explanation: For anal cancer, particularly squamous cell carcinoma, the standard surgical treatment in advanced cases or where chemoradiation fails is an abdominoperineal resection (APR). This involves the complete removal of the rectum and anus, resulting in a permanent colostomy. However, initial treatment typically involves chemoradiotherapy (Nigro protocol), reserving APR for persistent or recurrent disease.

Answer 151

✅ Correct Answer: C. 7 Explanation: Let’s break it down using the Glasgow Coma Scale (GCS): • Eye opening to pain = 2 • Incomprehensible sounds (verbal response) = 2 • Flexion withdrawal (motor response) = 3 Total GCS = 2 + 2 + 3 = 7 A GCS of 7 indicates a severe head injury and often warrants intensive monitoring and neuroimaging.

Answer 152

✅ Correct Answer: A. Simmonds test Explanation: The Simmonds test (also known as the Thompson test) is the most reliable clinical test for diagnosing Achilles tendon rupture. The test is performed by squeezing the calf muscle while the patient lies prone. In a normal tendon, this action causes plantarflexion. If the tendon is ruptured, there is no movement of the foot.

Answer 153

✅ Correct Answer: A. Pelvic splanchnic nerve Explanation: The pelvic splanchnic nerves (arising from S2–S4) provide parasympathetic innervation to the pelvic organs, including the cavernous nerves that are crucial for erection. Injury to these nerves during pelvic surgeries (e.g. rectal or prostate surgery) can lead to erectile dysfunction due to disruption of the parasympathetic pathway responsible for penile vasodilation.

Answer 154

✅ Correct Answer: A. Circumflex artery Explanation: During mitral valve surgery, the left circumflex artery is most at risk because of its close anatomical relationship to the mitral valve annulus, particularly the posterolateral commissure. Injury to this artery can result in myocardial ischemia or infarction, making careful dissection critical in that region.

Answer 155

✅ Correct Answer: A. Aortic stenosis Explanation: Aortic stenosis significantly increases perioperative risk due to the fixed cardiac output state. These patients are preload-dependent and poorly tolerate anesthesia-induced vasodilation or hypovolemia. Severe AS is associated with high mortality if not carefully managed in the perioperative setting, especially during non-cardiac surgery.

Answer 156

✅ Correct Answer: B. Radical wound debridement in the operating theatre Explanation: The presence of discharge, blisters, and crepitus strongly suggests necrotizing fasciitis or another severe soft tissue infection with gas-forming organisms. This is a surgical emergency, and the mainstay of treatment is prompt, radical surgical debridement in the OR. Delay in intervention can be fatal.

Answer 157

✅ Correct Answer: B. 2 days Explanation: Apixaban, a direct Factor Xa inhibitor, should generally be stopped 48 hours (2 days) before high-bleeding-risk surgeries to reduce the risk of intraoperative bleeding. For procedures with lower bleeding risk, 24 hours may be sufficient. Always individualize based on renal function and procedural risk.

Answer 158

✅ Correct Answer: C. Factor Xa inhibitor Explanation: Rivaroxaban and apixaban are direct Factor Xa inhibitors. They inhibit both free and clot-bound Factor Xa, which prevents the conversion of prothrombin to thrombin—crucial for clot formation. • Option B refers more to warfarin, which inhibits vitamin K-dependent clotting factors (II, VII, IX, X).

Answer 159

✅ Correct Answer: A. IPC & low molecular weight heparin Explanation: Postoperative patients, especially after major abdominal surgery like anterior resection, are at high risk of venous thromboembolism (VTE). The best practice involves dual prophylaxis with: • Intermittent pneumatic compression (IPC) to enhance venous return, • Plus low molecular weight heparin (LMWH) for pharmacological prophylaxis. Using both together provides better VTE prevention than either alone.

Answer 160

✅ Correct Answer: C. Tibial nerve Explanation: The tibial nerve runs through the deep posterior compartment of the leg along with the posterior tibial artery and veins, and is responsible for innervating the posterior leg muscles and plantar foot. • The sciatic nerve is more proximal and bifurcates into the tibial and common peroneal nerves at the popliteal fossa.

Answer 161

✅ Correct Answer: A. Sural nerve Explanation: A deep laceration posterior to the lateral malleolus is most likely to injure the sural nerve, which runs superficially in that region and provides cutaneous innervation to the lateral foot and ankle. • The deep peroneal nerve lies more anteriorly and deep, making it less likely to be affected in this location.

Answer 162

✅ Correct Answer: A. Pigmented Explanation: Hereditary spherocytosis causes chronic hemolysis, leading to increased bilirubin turnover. This results in the formation of pigment stones, which are typically black and made of calcium bilirubinate. These are distinct from cholesterol or mixed stones, which are more common in non-hemolytic conditions.

Answer 163

✅ Correct Answer: B. Tertiary hyperparathyroidism Explanation: Tertiary hyperparathyroidism occurs when long-standing secondary hyperparathyroidism (typically due to chronic kidney disease) leads to autonomous parathyroid hyperplasia, resulting in increased PTH secretion even after renal transplant. This presents as: • High calcium, • Low phosphate, • Elevated PTH, despite normal or improved kidney function.

Answer 164

✅ Correct Answer: A. Inferior vesical artery Explanation: During a radical cystectomy, especially in men, the inferior vesical artery, which supplies the bladder base and prostate, is typically ligated and removed along with the bladder. • The superior vesical artery arises from the umbilical artery and supplies the upper part of the bladder—it may or may not be preserved depending on the extent of resection.

Answer 165

✅ Correct Answer: C. Hyperchloremia Explanation: When a segment of bowel is used for urinary diversion (e.g., ileal conduit or neobladder), chloride ions from the urine can be reabsorbed through the intestinal mucosa, leading to hyperchloremic metabolic acidosis. This type of acidosis has a normal anion gap and is a common long-term complication of urinary diversion using intestinal segments.

Answer 166

✅ Correct Answer: B. β2 Explanation: Dobutamine is primarily a β1 agonist, increasing cardiac output by enhancing heart rate and contractility. However, it also has β2 agonist activity, which causes vasodilation and can result in a drop in blood pressure, especially in hypovolemic or vasodilated states. • α1 stimulation causes vasoconstriction, not hypotension. • The hypotensive effect seen with dobutamine is primarily due to β2 receptor–mediated vasodilation.

Answer 167

✅ Correct Answer: B. Adrenaline Explanation: Adrenaline (epinephrine) acts on both α and β receptors: • β1: increases heart rate and contractility → ↑ cardiac output • α1: causes vasoconstriction → ↑ blood pressure This makes it highly effective in shock states, especially anaphylaxis or cardiac arrest, where both perfusion and cardiac activity need rapid support. • Noradrenaline mainly increases BP (via α1) but has less impact on cardiac output. • Dobutamine mainly increases cardiac output but may drop BP due to β2 vasodilation.

Answer 168

✅ Correct Answer: A. Acetylcholine Explanation: The presynaptic neurotransmitter that stimulates chromaffin cells in the adrenal medulla is acetylcholine, released from preganglionic sympathetic fibers. This acetylcholine then binds to nicotinic receptors, prompting the adrenal medulla to secrete adrenaline and noradrenaline into the bloodstream. • Norepinephrine and adrenaline are the secretory products, not the presynaptic neurotransmitter.

Answer 169

✅ Correct Answer: B. Inhibition of nicotinic receptors in preganglionic adrenergic receptors Explanation: Nicotine primarily stimulates nicotinic acetylcholine receptors at preganglionic synapses in the autonomic nervous system. Chronic stimulation can cause receptor desensitization and dysfunction. In blood vessels, this disrupts the sympathetic nervous system, leading to endothelial dysfunction, increased vascular resistance, and promotion of atherosclerosis. So, the impact is primarily on nicotinic receptors at preganglionic sympathetic (adrenergic) synapses—not postganglionic or cholinergic ones.

Answer 170

✅ Correct Answer: D. Median nerve Explanation: The median nerve is the most commonly injured nerve in supracondylar humerus fractures, especially in children. The nerve runs anterior to the humerus and is at risk of being stretched, trapped, or injured during the fracture or surgical fixation. Injury can lead to sensory and motor deficits in the thumb, index, and middle fingers, and weakness in wrist and finger flexion.

Answer 171

✅ Correct Answer: A. Left common iliac vein posterior to right common iliac artery Explanation: The left common iliac vein lies posterior to the right common iliac artery at the level of L5, and this anatomical relationship is clinically important because: • It is the classic site of compression in May–Thurner syndrome, which predisposes to left-sided DVT. Other options involve incorrect pairings of arteries and veins or are anatomically inconsistent.

Answer 172

The level of spinal cord at which compression affects respiration is C3–C5, due to the origin of the phrenic nerve, which innervates the diaphragm — the primary muscle responsible for breathing. Anatomically, this region corresponds to the cricoid cartilage (approximately C6), just below the thyroid cartilage (C4–C5). Given the options: • A. Thyroid cartilage – C4–C5 • B. Cricoid cartilage – C6 • C. Manubrium – T3–T4 • D. Sternal angle – T4–T5 • E. Xiphoid process – T9 The best answer is: B. Cricoid cartilage This level is closest to the C3–C5 spinal segments where the phrenic nerve originates, making it the most relevant for respiratory compromise due to spinal cord compression.

Answer 173

C. Measure abdominal compartment pressure 🧠 Explanation: This clinical picture is suggestive of abdominal compartment syndrome (ACS), a known complication after open or endovascular AAA repair. It leads to: • 🚫 Reduced renal perfusion → oliguria • ⬆️ Hyperkalemia & creatinine due to acute kidney injury (AKI) The definitive diagnostic step is measuring intra-abdominal pressure. If ACS is confirmed, the treatment is urgent surgical decompression. Other options: • A. Hartmann’s – May worsen compartment pressure • B. Insulin with dextrose – Temporizes K⁺ but doesn’t treat the cause • D. Hemodialysis – Not first-line unless life-threatening hyperkalemia • E. Furosemide – Won’t help if kidneys are compressed

Answer 174

D. Duodenal perforation 🧠 Explanation: ERCP is an invasive endoscopic procedure, and perforation of the duodenum is a serious, though rare, complication. This patient has: • ⚡ Severe pain and tachycardia (suggests peritonitis) • 🔬 Normal enzymes (rules out pancreatitis) • 🧪 Normal LFTs and no signs of cholangitis or retained stone These findings strongly point to perforation, especially in the absence of laboratory evidence for other complications. Other options: • A. Pancreatitis – Should elevate amylase/lipase • B. Cholangitis – Requires systemic infection signs + LFT derangement • C. Missed stone – Pain but no peritonitis • E. Liver abscess – Rare so early post-ERCP

Answer 175

C. Breslow thickness is the most important prognostic factor in malignant melanoma. ⸻ 🧠 Explanation: Breslow thickness measures the depth (in mm) from the granular layer of the epidermis to the deepest point of tumor invasion. It directly correlates with survival: Thickness 5-year Survival ≤1 mm ~95% 1–2 mm ~80–90% 2–4 mm ~60–75% >4 mm ~50% or less Other options: • A. Lymphovascular invasion – Important but secondary • B. Clark level – Less predictive than Breslow, now obsolete • D. Tumor ulceration – Important but adds to staging only if thickness known • E. Mitotic index – Used in thin tumors but not the main determinant

Answer 176

B. Superior gluteal nerve ⸻ 🧠 Explanation: This patient has a positive Trendelenburg sign, which indicates weakness of the hip abductors on the weight-bearing side. The superior gluteal nerve (L4–S1) innervates: • Gluteus medius • Gluteus minimus • Tensor fascia lata Damage causes: • Pelvic drop on the opposite side (because abductors can’t stabilize the pelvis) • Classic “waddling gait” or Trendelenburg gait ⸻ Why not the others? • A. Inferior gluteal nerve – Innervates gluteus maximus (hip extension) • C. Sciatic nerve – Motor to posterior thigh, entire lower leg — would cause much broader deficits • D. Obturator nerve – Controls hip adductors, not abductors • E. Femoral nerve – Controls hip flexion and knee extension

Answer 177

C. Fasciotomy ⸻ 🧠 Explanation: This is acute compartment syndrome of the leg — another orthopedic emergency. Key signs: • 💥 Pain out of proportion to exam • 🔥 Pain on passive stretch • 🚫 Paresthesia or paralysis (late) • 🦵 Tense, swollen compartment Dorsiflexion weakness = deep peroneal nerve compression (runs in anterior compartment) ⸻ Immediate management: ➡️ Emergency fasciotomy to relieve pressure and prevent: • Muscle necrosis • Nerve damage • Limb loss ⸻ Why not the others? • A. Elevation – Reduces arterial perfusion in ACS • B. IV antibiotics – Not helpful unless infection • D. MRI – Delays intervention • E. DVT scan – Wrong pathology ⸻ 🚑 Remember: time = muscle in compartment syndrome.

Answer 178

D. Right kidney ⸻ 🧠 Explanation: This wound enters just below the right costal margin anteriorly and exits posteriorly — that’s around L1–L2 in anatomical terms, hitting retroperitoneal structures. At this level, posteriorly on the right, the key organs include: • Right kidney (retroperitoneal) • Duodenum (retroperitoneal, but medial) • Gallbladder (anterior/superior) • Liver (extends above costal margin) ⸻ The correct logic: • Gallbladder is anterior and higher (around 9th costal cartilage) • Pylorus and duodenum sit more medially • Pancreas is on the left or central • So the right kidney is directly in the bullet’s path ⸻ 📚 Clinical pearl: Penetrating trauma at L1 level may injure: • Right kidney • Duodenum (2nd part) • Inferior vena cava • Liver tail

Answer 179

C. Partially compensated respiratory acidosis ⸻ 🧠 Explanation: 1. Primary problem: • High pCO₂ (8.2 kPa) ➜ Respiratory acidosis • Low pH (7.28) ➜ Confirms it’s not compensated fully 2. HCO₃⁻ is elevated (29): • This shows renal compensation is starting — kidneys retain bicarbonate to buffer acid ⸻ Why “partially compensated”? • If this were fully compensated, the pH would be normal • If uncompensated, HCO₃⁻ would still be normal or low ⸻ Morphine + COPD: • 🚷 Depresses respiratory drive • 😮‍💨 In COPD, CO₂ retention is already high — small increases can cause CO₂ narcosis • 🧠 Leads to acidosis + altered mental state ⸻ Summary: • pH < 7.35 → acidemia • CO₂ ↑ → respiratory cause • HCO₃ ↑ → kidneys trying to help ➡️ = Partially compensated respiratory acidosis

Answer 180

Correct Answer: B. Superior mesenteric artery Explanation: The transpyloric plane is an anatomical landmark located at the level of L1 vertebra. It typically crosses: • The pylorus of the stomach • Neck of the pancreas • Origin of the superior mesenteric artery (SMA) • Fundus of the gallbladder • Hila of the kidneys • End of spinal cord (in neonates) While the gallbladder fundus may lie at this level, the SMA is the more critical structure here due to its vascular importance and frequent implication in trauma and ischemic bowel events. Hence, B is the best choice.

Answer 181

Correct Answer: B. Midgut Explanation: Meckel’s diverticulum is a true congenital diverticulum resulting from the incomplete obliteration of the vitelline (omphalomesenteric) duct, which connects the yolk sac to the midgut in the embryo. It’s typically found about 2 feet from the ileocecal valve and represents a remnant of the embryonic midgut. It can cause bleeding, obstruction, or inflammation and is often remembered by the “rule of 2s”: • 2% of the population • 2 inches long • 2 feet from the ileocecal valve • 2 types of ectopic tissue (gastric and pancreatic) • Presents by age 2

Answer 182

Correct Answer: A. C3 Explanation: Respiration, particularly diaphragmatic function, is primarily controlled by the phrenic nerve, which arises from C3–C5 (commonly remembered as “C3, 4, 5 keep the diaphragm alive”). Compression at C3 can compromise the phrenic nerve, leading to diaphragmatic paralysis and respiratory failure. C6 and lower levels do not directly affect the diaphragm’s innervation.

Answer 183

Correct Answer: C. Hypercalcemia Explanation: The most common electrolyte abnormality in metastatic breast cancer is hypercalcemia, often due to: • Bone metastases, which increase bone resorption, or • Paraneoplastic secretion of parathyroid hormone-related peptide (PTHrP). Symptoms may include lethargy, nausea, constipation, and confusion. It’s a medical emergency when severe.

Answer 184

Correct Answer: C. 40 mmol Explanation: The daily potassium requirement for an average adult (~70 kg) is typically 30–60 mmol/day, with 40 mmol being a commonly accepted average for maintenance. Potassium is primarily lost via the kidneys and GI tract, and requirements increase with: • GI losses (vomiting, diarrhea), • Diuretics, • Renal conditions.

Answer 185

Correct Answer: C. Tetralogy of Fallot Explanation: Tetralogy of Fallot is a cyanotic congenital heart defect comprising: 1. Ventricular septal defect (VSD) 2. Right ventricular outflow tract obstruction (due to conus arteriosus defect) 3. Overriding aorta 4. Right ventricular hypertrophy The conus arteriosus (infundibulum) is the embryologic outflow tract of the right ventricle. Maldevelopment leads to pulmonary stenosis, contributing to cyanosis.

Answer 186

Correct Answer: C. 40 mmol Explanation: The daily potassium requirement for an average adult (~70 kg) is typically 30–60 mmol/day, with 40 mmol being a commonly accepted average for maintenance. Potassium is primarily lost via the kidneys and GI tract, and requirements increase with: • GI losses (vomiting, diarrhea), • Diuretics, • Renal conditions.

Answer 187

Correct Answer: C. A band Explanation: During muscle contraction, the sarcomere shortens, but the A band remains unchanged. Here’s a quick breakdown: • A band: Contains the entire length of thick (myosin) filaments—does not change length. • I band: Contains only thin (actin) filaments—shortens during contraction. • H zone: Central part of the A band with only myosin—shortens. • Z lines: Move closer together. • M line: Structural anchoring site—does not change, but is not described as “unchanged” in the context of length.

Answer 188

Correct Answer: C. Salmonella spp. Explanation: In sickle cell disease, the most common organism causing osteomyelitis is Salmonella spp.—a unique feature due to altered splenic function and susceptibility to encapsulated organisms. While Staphylococcus aureus is the most common cause of osteomyelitis in the general population, Salmonella has a stronger association in sickle cell patients.

Answer 189

Correct Answer: C. Staphylococcus aureus Explanation: Staphylococcus aureus is the most common cause of lactational mastitis, especially in breastfeeding women. The infection usually originates from the infant’s oral flora and enters through cracked nipples. • It can cause localized inflammation, breast pain, fever, and sometimes abscess formation. • Management includes continued breastfeeding or pumping, antibiotics (e.g., flucloxacillin), and sometimes drainage.

Answer 190

Correct Answer: C. Streptococcus pneumoniae Explanation: Hemolytic uremic syndrome (HUS) has two main forms: • Typical HUS: Often follows diarrheal illness (E. coli O157:H7) • Atypical HUS or non-diarrheal HUS: Can follow upper respiratory tract infections, often caused by Streptococcus pneumoniae S. pneumoniae-associated HUS is less common but can occur due to neuraminidase activity, which exposes the Thomsen-Friedenreich antigen on red blood cells, leading to hemolysis.

Answer 191

Correct Answer: B. Yersinia enterocolitica Explanation: Yersinia enterocolitica is linked to: • Pig exposure (often transmitted via undercooked pork), • Appendicitis-like symptoms (terminal ileitis and mesenteric lymphadenitis), • Erythema nodosum, especially in children and young adults. It mimics acute appendicitis and can lead to unnecessary surgery if misdiagnosed.

Answer 192

Correct Answer: D. Staphylococcus aureus Explanation: Staphylococcus aureus food poisoning is characterized by: • Very rapid onset (typically within 1–6 hours), • Vomiting, abdominal cramps, sometimes diarrhea, • Caused by preformed enterotoxin, not the bacteria itself, • Often linked to improperly stored foods like meats, pastries, and dairy. Salmonella, by contrast, usually causes symptoms 12–72 hours post-ingestion.

Answer 193

Correct Answer: A. Campylobacter jejuni Explanation: Campylobacter jejuni is a leading cause of bacterial gastroenteritis, typically acquired through: • Undercooked poultry (e.g., BBQ chicken), • Causes colicky abdominal pain, bloody diarrhea, and fever, • May also be associated with Guillain-Barré syndrome as a post-infectious complication.

Answer 194

Correct Answer: D. AFP (Alpha-fetoprotein) Explanation: Yolk sac tumors (also known as endodermal sinus tumors) are germ cell tumors that characteristically secrete alpha-fetoprotein (AFP). • Elevated AFP is a diagnostic and monitoring marker. • hCG is elevated in choriocarcinomas and some seminomas. • CEA is associated with colorectal cancer. • CA-125 is for ovarian epithelial tumors. • LDH is sometimes elevated in seminomas.

Answer 195

Correct Answer: B. Seminoma Explanation: Men with cryptorchidism, even after orchidopexy, have an increased risk of developing testicular cancer—most commonly a seminoma. • Seminomas tend to occur in men aged 30–50 and are radiosensitive. • Other types like yolk sac tumors and teratomas are more common in children and younger adults.

Answer 196

Correct Answer: E. Ultrasound Explanation: Ultrasound is the best imaging modality for follow-up of an infected hydronephrosis post-nephrostomy. It allows assessment of: • Residual hydronephrosis • Drain position • Perinephric collections or abscesses • It is non-invasive, readily available, and safe without radiation or contrast.

Answer 197

Correct Answer: A. Nucleus pulposus Explanation: The nucleus pulposus of the intervertebral disc is the direct embryological remnant of the notochord. It serves as a shock absorber in the spine. • The annulus fibrosus is derived from mesoderm, not the notochord. • The conus medullaris, filum terminale, and ligamentum flavum have different embryological origins unrelated to the notochord.

Answer 198

Correct Answer: D. Duodenum (distal to major papilla) Explanation: The coeliac trunk supplies foregut structures, which include: • Stomach • Liver • Spleen • Proximal duodenum (up to the major duodenal papilla) • Pancreas (via splenic and pancreaticoduodenal branches) The distal duodenum (beyond the major papilla) is part of the midgut and is supplied by the superior mesenteric artery (SMA).

Answer 199

Correct Answer: A. Hirschsprung’s disease Explanation: Hirschsprung’s disease is the most common cause of delayed passage of meconium in a newborn. It results from absence of enteric ganglion cells in the distal colon, leading to a functional obstruction. Key signs include: • Failure to pass meconium within 48 hours • Abdominal distension • Vomiting • Enterocolitis in severe cases

Answer 200

Correct Answer: D. Elemental enteral feeding Explanation: In Crohn’s disease with malnutrition or hypoalbuminemia, elemental enteral feeding is preferred because: • It provides easily absorbable nutrients, • Reduces bowel workload, • Helps in mucosal healing, • Is less invasive than total parenteral nutrition (TPN) and has fewer complications. TPN is reserved for cases where the GI tract cannot be used (e.g., severe obstruction, high-output fistulas).

Answer 201

Correct Answer: B. 0.9% saline and 5% dextrose Explanation: For a stable post-gastrectomy patient with: • Good urine output, • No nasogastric tube (NGT) losses, • Normal electrolytes, A combination of 0.9% saline and 5% dextrose is appropriate to meet maintenance fluid and basic glucose needs. Electrolyte supplementation (like potassium) may be added based on lab results and ongoing losses.

Answer 202

Correct Answer: C. Intravenous fluids and oxygen Explanation: Fat embolism syndrome (FES) is a complication of long bone fractures, especially the femur. Management is supportive: • Oxygen therapy to correct hypoxia, • IV fluids to maintain perfusion, • Ventilatory support in severe cases (ARDS-like presentation). Anticoagulants and thrombolytics are not effective, as the emboli are fat, not clots.

Answer 203

Correct Answer: C. Median nerve Explanation: The median nerve innervates the thenar muscles, including the opponens pollicis, which is essential for thumb opposition. Damage to the median nerve (e.g., in carpal tunnel syndrome or trauma) leads to: • Difficulty with opposition • Thenar muscle wasting • Weak grip strength

Answer 204

Correct Answer: B. Sartorius muscle Explanation: The femoral triangle is bounded by: • Superiorly: Inguinal ligament • Medially: Adductor longus • Laterally: Sartorius muscle (which forms the inferolateral border) • Floor: Iliopsoas and pectineus muscles The triangle contains the femoral nerve, artery, vein, and lymphatics.

Answer 205

Correct Answer: D. Posterior ethmoidal sinus Explanation: The superior meatus receives drainage from the: • Posterior ethmoidal sinuses Here’s a breakdown of other structures and their drainage: • Maxillary and frontal sinuses → Middle meatus • Nasolacrimal duct → Inferior meatus • Sphenoidal sinus → Sphenoethmoidal recess (above superior meatus)

Answer 206

Correct Answer: B. Glossopharyngeal and vagus Explanation: The baroreceptor reflex helps regulate blood pressure by sensing stretch in vessel walls. • Glossopharyngeal nerve (CN IX) carries afferents from the carotid sinus. • Vagus nerve (CN X) carries afferents from the aortic arch. These signals are relayed to the nucleus tractus solitarius in the brainstem, which modulates sympathetic and parasympathetic outflow accordingly.

Answer 207

Correct Answer: D. Common carotid artery Explanation: In the neck, the phrenic nerve runs: • On the surface of the anterior scalene muscle • Lateral to the common carotid artery • Posterior to the subclavian vein • Anterior to the subclavian artery Thus, the common carotid artery is medial to the phrenic nerve.

Answer 208

Correct Answer: E. Lesser splanchnic nerve Explanation: Early periumbilical pain in appendicitis is visceral in nature and mediated by autonomic afferents via the lesser splanchnic nerve (T10 dermatome). • Somatic pain (sharp, localized to the right iliac fossa) occurs later when inflammation irritates the parietal peritoneum, involving spinal nerves like iliohypogastric and ilioinguinal.

Answer 209

Correct Answer: E. Quadratus lumborum Explanation: It seems there’s a mix-up here—let’s clarify two “triangles” of the back: 1. Lumbar (Petit’s) triangle: • Borders: • Medial: Latissimus dorsi • Lateral: External oblique • Inferior: Iliac crest • Floor: Internal oblique 2. Superior lumbar triangle (Grynfeltt’s): • Floor: Quadratus lumborum Since the question asked about the floor of the lumbar triangle, and if referring to Petit’s triangle, the correct answer should have been internal oblique—not external oblique or quadratus lumborum.

Answer 210

Correct Answer: C. C4 Explanation: The common carotid artery typically bifurcates into the internal and external carotid arteries at the level of the C4 vertebra, which corresponds anatomically to the upper border of the thyroid cartilage.

Answer 211

Correct Answer: B. Extensor muscles of the forearm Explanation: The deep branch of the radial nerve, also known as the posterior interosseous nerve after it pierces the supinator, supplies the extensor muscles of the forearm. These include: • Extensor digitorum • Extensor carpi ulnaris • Extensor pollicis longus/brevis • Abductor pollicis longus Palmaris longus is innervated by the median nerve, not the radial.

Answer 212

Correct Answer: A. Facial artery Explanation: The facial artery is the most likely to be injured in submandibular trauma, as it: • Courses through the submandibular gland, • Lies just anterior to the masseter at the mandible’s lower border, • Is superficial and vulnerable in trauma to this area. The lingual artery is deeper and primarily involved in tongue and floor of mouth supply.

Answer 213

Correct Answer: C. Ascending aorta Explanation: At the sternal angle (Angle of Louis), located at the T4/T5 intervertebral disc level, several important structures are seen: • Ascending aorta: just lateral to the sternal angle on the right • Pulmonary trunk: more to the left • Aortic arch begins at the sternal angle and arches over to the left • Tracheal bifurcation, azygos vein arch, and thoracic duct crossing also occur at this level

Answer 214

Correct Answer: C. Superficial inguinal nodes Explanation: The scrotal skin drains to the superficial inguinal lymph nodes, just like the skin of the penis and perineum. In contrast: • The testes drain to the para-aortic nodes due to their embryologic origin from the posterior abdominal wall. • Deep inguinal nodes are involved in drainage of the glans penis and deeper structures.

Answer 215

Correct Answer: D. Para-aortic (lumbar) Explanation: The testes develop high in the posterior abdominal wall and descend into the scrotum during development. As a result, their lymphatic drainage follows the testicular vessels back to the para-aortic (lumbar) lymph nodes, not to the inguinal nodes. • This is crucial in staging and management of testicular cancer.

Answer 216

Correct Answer: A. Observation Explanation: In infants and young children, most hydroceles are communicating and result from a patent processus vaginalis. They often resolve spontaneously by 1–2 years of age. • Observation is appropriate unless the hydrocele persists beyond 2 years or becomes symptomatic, in which case surgical repair may be indicated.

Answer 217

Correct Answer: B. Doppler ultrasound Explanation: Sudden scrotal pain in a male should always raise suspicion for testicular torsion. Doppler ultrasound is the initial investigation of choice to assess testicular blood flow. If the clinical suspicion is high (e.g., acute onset, elevated testis, absent cremasteric reflex), immediate surgery may be warranted without imaging. However, for less clear-cut cases, Doppler is an essential diagnostic tool.

Answer 218

Correct Answer: C. Peripheral neuropathy Explanation: Metronidazole, especially with prolonged use, is known to cause peripheral neuropathy. This is particularly relevant in patients with an ileoanal pouch, where long-term or repeated use of metronidazole is common for treating pouchitis. • Symptoms include tingling, numbness, or burning in the extremities. • Monitoring for neurotoxicity is essential with extended treatment.

Answer 219

Correct Answer: C. Local excision with 1 cm margin Explanation: For a melanoma < 0.8 mm Breslow thickness, the recommended initial management is: • Wide local excision with a 1 cm margin • Sentinel lymph node biopsy is not routinely done unless there are additional high-risk features (e.g. ulceration, mitotic rate) Margins are determined by Breslow depth: • <1 mm: 1 cm margin • 1–2 mm: 1–2 cm • 2 mm: 2 cm

Answer 220

Correct Answer: C. Axillary nerve Explanation: An upper trunk injury of the brachial plexus (Erb’s palsy) affects C5 and C6 nerve roots, which contribute to: • Axillary nerve (deltoid and teres minor) • Musculocutaneous nerve (biceps, brachialis) • Suprascapular nerve This results in: • Arm adduction and internal rotation • Loss of shoulder abduction (deltoid) and external rotation

Answer 221

Correct Answer: A. Intraperitoneal Explanation: Intraperitoneal bladder injury occurs when the bladder dome ruptures—often from blunt trauma (e.g. full bladder with seatbelt injury). This leads to urine in the peritoneal cavity, requiring surgical repair. In contrast, extraperitoneal injuries often occur from pelvic fractures and may be managed conservatively.

Answer 222

Correct Answer: B. Failure of mesoderm migration Explanation: Bladder exstrophy results from failure of mesoderm to migrate between the ectoderm and endoderm, leading to a defect in the lower abdominal wall and exposure of the bladder mucosa.

Answer 223

Correct Answer: E. Gastroduodenal artery Explanation: The gastroduodenal artery is a common culprit for postoperative gastric bleeding, especially after gastrectomy or peptic ulcer surgery, due to its proximity to the duodenum and stomach.

Answer 224

Correct Answer: C. Splenic artery Explanation: A posterior gastric ulcer near the tail of the pancreas can erode into the splenic artery, leading to massive upper GI bleeding.

Answer 225

Correct Answer: A. Hyperglycemia Explanation: In pancreatic necrosis, destruction of islets of Langerhans leads to hyperglycemia. Other signs include: • Systemic inflammation • Hypocalcemia • High amylase/lipase

Answer 226

Correct Answer: C. Accessory Explanation: The spinal accessory nerve (CN XI) traverses the posterior triangle superficially and is vulnerable during lymph node biopsy or trauma, leading to trapezius weakness.

Answer 227

Correct Answer: B. Iliopsoas Explanation: The iliopsoas inserts onto the lesser trochanter, acting as a primary hip flexor. The gluteals insert on the greater trochanter.

Answer 228

Correct Answer: B. Lateral Explanation: The femoral ring is the entrance to the femoral canal, which lies medial to the femoral vein—important in femoral hernia anatomy.

Answer 229

Correct Answer: B. Parasympathetic innervation to pelvic organs Explanation: Pelvic splanchnic nerves (S2–S4) provide parasympathetic innervation to the bladder, rectum, and reproductive organs—important for micturition and sexual function.

Answer 230

Correct Answer: A. Median Explanation: Ulnar deviation occurs due to unopposed action of flexor carpi ulnaris, implying median nerve injury, which paralyzes flexor carpi radialis.

Answer 231

Correct Answer: D. Obstructive shock Explanation: Cardiac tamponade leads to obstructive shock due to compression of the heart by pericardial fluid, which impairs diastolic filling and reduces cardiac output. • Signs include hypotension, jugular venous distension, and muffled heart sounds (Beck’s triad). • Cardiogenic shock is due to intrinsic pump failure, not external compression.

Answer 232

Correct Answer: B. SVR ↓, HR ↓, CO ↓ Explanation: In neurogenic shock, typically due to spinal cord injury, there is: • Loss of sympathetic tone, leading to vasodilation → ↓ SVR • Bradycardia due to unopposed parasympathetic (vagal) activity → ↓ HR • Resultant ↓ cardiac output This combination distinguishes it from other types of shock which often present with tachycardia and increased SVR.

Answer 233

Correct Answer: B. S1Q3T3 pattern Explanation: A classic (though not highly sensitive) ECG finding in pulmonary embolism (PE) is the S1Q3T3 pattern: • Deep S wave in lead I • Q wave in lead III • Inverted T wave in lead III It suggests acute right heart strain, which can occur with a significant PE.

Answer 234

Correct Answer: C. Supraclavicular (Virchow’s) node Explanation: The left supraclavicular node, known as Virchow’s node, is a classic site for gastric cancer metastasis. This occurs via the thoracic duct, which drains lymph from the abdomen into the left subclavian vein. • Its enlargement is a sign of advanced disease and often called Troisier’s sign.

Answer 235

Correct Answer: D. POSSUM Explanation: The POSSUM (Physiological and Operative Severity Score for the enumeration of Mortality and Morbidity) is a scoring system used to estimate surgical risk, including: • Postoperative mortality • Morbidity rates It considers physiological parameters and surgical severity—especially helpful in preoperative risk assessment. Glasgow-Blatchford is for upper GI bleeding—not surgical mortality.

Answer 236

Correct Answer: C. Inhibits fibrinolysis Explanation: Tranexamic acid is an antifibrinolytic agent. It works by: • Inhibiting plasminogen activation to plasmin, • Preventing fibrin clot degradation, • Often used in trauma, surgery, and menorrhagia to reduce bleeding.

Answer 237

Correct Answer: C. Between sternocleidomastoid and trapezius Explanation: The spinal accessory nerve (CN XI) traverses the posterior triangle of the neck by: • Exiting the sternocleidomastoid (SCM), • Crossing the triangle superficially, making it vulnerable, • Entering the trapezius. This course puts it at risk during lymph node biopsy or neck dissection.

Answer 238

Correct Answer: C. Hypoglossal nerve Explanation: The hypoglossal nerve (CN XII) innervates all intrinsic and most extrinsic muscles of the tongue. Injury to this nerve causes: • Ipsilateral tongue deviation (towards the side of the lesion), • Atrophy and fasciculations on the affected side.

Answer 239

Correct Answer: C. Increases water reabsorption in collecting ducts Explanation: ADH (antidiuretic hormone) is secreted by the posterior pituitary and: • Acts on the collecting ducts in the nephron, • Promotes insertion of aquaporins, • Leads to increased water reabsorption, concentrating the urine. This is crucial in water homeostasis, especially during dehydration or hypotension.

Answer 240

Correct Answer: B. Visual field defects Explanation: The posterior cerebral artery (PCA) supplies the occipital lobe, which is responsible for vision. Therefore, a PCA stroke typically causes: • Contralateral homonymous hemianopia or visual field loss, • Sometimes with macular sparing. This contrasts with: • ACA stroke → lower limb weakness • MCA stroke → upper limb/face weakness and aphasia

Answer 241

Correct Answer: C. Lower limb weakness and sensory loss Explanation: The anterior cerebral artery (ACA) supplies the medial aspect of the cerebral hemispheres, especially the motor and sensory cortices related to the lower limbs. An ACA stroke typically causes: • Contralateral lower limb weakness and sensory loss • May also cause urinary incontinence and abulia (lack of motivation)

Answer 242

Correct Answer: C. Radial nerve Explanation: Wrist drop is the hallmark of radial nerve injury, which supplies: • The extensor muscles of the forearm, • Sensory innervation to the dorsum of the hand. Common causes include: • Midshaft humerus fractures • Compression (e.g., Saturday night palsy)

Answer 243

Correct Answer: B. Epidural hematoma Explanation: An epidural hematoma, often due to rupture of the middle meningeal artery, is classically associated with: • A lucid interval after initial trauma, • Followed by rapid deterioration due to expanding arterial bleed. In contrast: • Subdural hematomas usually have a gradual onset due to venous bleeding (bridging veins).

Answer 244

Correct Answer: B. Comprehension deficit with fluent but nonsensical speech Explanation: A lesion in Wernicke’s area (posterior part of the superior temporal gyrus in the dominant hemisphere) causes: • Fluent aphasia: speech is fluid but lacks meaning, • Poor comprehension, • Often unawareness of the deficit. This contrasts with Broca’s aphasia, where speech is non-fluent but comprehension is preserved.

Answer 245

Correct Answer: C. 2nd intercostal space, midclavicular line Explanation: For emergency needle decompression of a tension pneumothorax, the standard site is: • 2nd intercostal space, midclavicular line, typically on the affected side. This location allows rapid entry into the pleural space to relieve pressure. (Though some recent guidelines also accept 4th/5th intercostal space midaxillary in certain settings.)

Answer 246

Correct Answer: D. Metanephrines Explanation: The best screening test for pheochromocytoma is the measurement of plasma free metanephrines or 24-hour urinary metanephrines. • These are metabolites of catecholamines (like epinephrine and norepinephrine) and are more stable and reliably elevated than the catecholamines themselves.

Answer 247

Correct Answer: A. Fasting serum gastrin level Explanation: Zollinger-Ellison syndrome is caused by a gastrinoma that secretes excessive gastrin, leading to: • Peptic ulcers • Refractory GERD • Diarrhea The first-line diagnostic test is a fasting serum gastrin level: • Elevated levels (>1000 pg/mL) are highly suggestive. • If equivocal, a secretin stimulation test may follow.

Answer 248

Correct Answer: C. Correct dehydration and electrolyte imbalance Explanation: The initial step in treating hypertrophic pyloric stenosis (HPS) is: • Resuscitation with IV fluids, correcting dehydration, hypokalemia, and hypochloremic metabolic alkalosis. • Only after stabilization is pyloromyotomy (Ramstedt procedure) performed. Immediate surgery without correction increases anesthesia and postoperative risk.

Answer 249

Correct Answer: D. Infrarenal abdominal aorta Explanation: The infrarenal abdominal aorta is the most common site for the development of abdominal aortic aneurysms (AAA) due to: • High turbulence • Lower elastin content in the wall • Susceptibility to atherosclerosis Aortic arch is more prone to thoracic aneurysms, not AAAs.

Answer 250

Correct Answer: A. Malunion Explanation: A malunion occurs when a fractured bone heals in an abnormal position, which may lead to functional impairment or deformity. • Nonunion: failure of healing. • Delayed union: healing takes longer than expected but still progresses. • Pseudarthrosis: formation of a false joint, often in long-standing nonunion.

Answer 251

Correct Answer: B. Ulcerative colitis Explanation: Crypt abscesses—collections of neutrophils within the colonic crypts—are pathognomonic for ulcerative colitis. • Crohn’s disease may show granulomas, skip lesions, and transmural inflammation, but crypt abscesses are hallmark for UC.

Answer 252

Correct Answer: C. 60 mL/hr Explanation: The maintenance fluid rate for children is calculated using the Holliday-Segar formula: • First 10 kg: 100 mL/kg/day → 1000 mL • Next 8 kg: 50 mL/kg/day → 400 mL • Total = 1400 mL/day → ~60 mL/hr

Answer 253

Correct Answer: B. Popliteal artery Explanation: In a femoral-popliteal (fem-pop) bypass, the graft is typically placed: • From the common or superficial femoral artery • To the popliteal artery, either above or below the knee. Anterior tibial artery is more distal and less commonly used unless bypassing very distal disease.

Answer 254

Correct Answer: A. Anterior compartment of the leg Explanation: Great toe extension tests the function of the extensor hallucis longus, which is located in the anterior compartment of the leg and innervated by the deep peroneal (fibular) nerve. • It’s a crucial test in assessing for compartment syndrome of the anterior leg.

Answer 255

Correct Answer: C. Para-aortic nodes Explanation: The fundus of the uterus drains lymph to the: • Para-aortic (lumbar) nodes via lymphatics following the ovarian vessels, • It may also have connections to superficial inguinal nodes via the round ligament, but the main drainage is to para-aortic nodes.

Answer 256

Correct Answer: A. Radial artery Explanation: A scaphoid fracture puts the radial artery at risk, particularly its dorsal branch, which supplies the proximal pole of the scaphoid. This area has poor blood supply, making it prone to: • Avascular necrosis • Nonunion The flexor carpi radialis runs nearby but is less commonly injured directly.

Answer 257

Correct Answer: C. Median nerve Explanation: The median nerve passes anterior to the elbow, between the two heads of the pronator teres and deep to the bicipital aponeurosis. It’s vulnerable to injury in: • Supracondylar fractures of the humerus, • Anterior dislocations. The ulnar nerve is posterior to the medial epicondyle, and the musculocutaneous nerve typically terminates in the forearm.

Answer 258

Correct Answer: C. Measure compartment pressure Explanation: While fasciotomy is the definitive treatment for compartment syndrome, the initial step—especially when the diagnosis is uncertain—is to measure the compartment pressure. • Pressures >30 mmHg or within 30 mmHg of diastolic pressure typically indicate the need for fasciotomy. • If diagnosis is clinically obvious, urgent fasciotomy should not be delayed.

Answer 259

Correct Answer: C. Reduces opioid use and promotes early mobilization Explanation: The ERAS (Enhanced Recovery After Surgery) protocol includes: • Minimal fasting and early oral nutrition • Avoiding routine NGT and drains • Reducing opioid use (favoring multimodal analgesia) • Early ambulation • Shorter hospital stays and faster recovery

Answer 260

Correct Answer: B. Gluteus maximus Explanation: An intramuscular injection in the upper outer quadrant of the gluteal region is done to: • Avoid the sciatic nerve (which lies more medial and inferior), • The needle pierces the gluteus maximus to reach the gluteus medius beneath. This location is safest for injections and minimizes nerve injury risk.

Answer 261

Correct Answer: B. Extensor pollicis longus Explanation: The anatomical snuffbox is a triangular depression on the lateral aspect of the wrist. Its boundaries are: • Lateral (anterolateral): Abductor pollicis longus & Extensor pollicis brevis • Medial (posteromedial): Extensor pollicis longus • Floor: Scaphoid and trapezium bones

Answer 262

Correct Answer: D. Levator palpebrae superioris Explanation: The levator palpebrae superioris, which elevates the upper eyelid, is innervated by the oculomotor nerve (CN III). The facial nerve (CN VII) innervates: • Muscles of facial expression (e.g., orbicularis oculi, buccinator, platysma) • Stapedius (in the middle ear)

Answer 263

• A 5.5 cm external iliac artery aneurysm would typically warrant intervention due to the risk of rupture. • However, in the context of extensive ovarian cancer with limited life expectancy, the benefit of repair (even endovascular) may not outweigh the risks, especially if the aneurysm is asymptomatic. • Surveillance (Option d) may be considered a pragmatic approach, focusing on quality of life rather than aggressive intervention. Updated Correct Answer: d. Surveillance within 3 months This reflects a patient-centered, palliative approach, aligning treatment decisions with the overall clinical picture and expected survival.

Answer 264

Correct Answer: B. Internal iliac artery Explanation: The superior gluteal artery is the largest branch of the posterior division of the internal iliac artery. It exits the pelvis through the greater sciatic foramen above the piriformis muscle and supplies: • Gluteus medius and minimus • Tensor fasciae latae

Answer 265

Correct Answer: D. Greater wing of sphenoid Explanation: The foramen ovale is located in the greater wing of the sphenoid bone and transmits: • The mandibular division (V3) of the trigeminal nerve • Accessory meningeal artery • Lesser petrosal nerve (occasionally)

Answer 266

Correct Answer: C. Salmonella species Explanation: In patients with sickle cell disease, Salmonella species are a unique and common cause of osteomyelitis, particularly affecting: • Long bones • Vertebrae Staphylococcus aureus is the most common cause in the general population, but Salmonella has a strong association with sickle cell due to splenic dysfunction and impaired clearance.

Answer 267

Correct Answer: C. Staphylococcus aureus Explanation: Staphylococcus aureus is the most common pathogen responsible for lactational mastitis, especially in: • Nursing mothers • Through cracked nipples, allowing bacterial entry Management usually includes flucloxacillin (or clindamycin if penicillin-allergic) and continued breastfeeding.

Answer 268

Correct Answer: E. Common carotid artery Explanation: In the neck, the phrenic nerve: • Runs anterior to the anterior scalene muscle, and • Is lateral to the common carotid artery, which lies medial to it. This anatomical relationship is important in surgeries like central line placement or neck dissections.

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