Surg

Question 1

Causes of mechanical bowel obstruction

Answer 1

extraluminal: adhesions, herniae, abscess, neoplasm, volvulus
intraluminal: faecolith, intussusception, gallstone ileus, meconium
mural: atresia, inflammatory bowel disease, diverticulosis, neoplasm

Question 2

Psuedo obstruction of bowel

Answer 2

Pseudo-obstruction refers to the presentation of
symptoms and signs mimicking mechanical obstruction but with no obstructing
lesion. It is more common in elderly patients suffering from chronic medical conditions.
Treatment is conservative.

Question 3

Spiking temperatures

Answer 3

abscess/collection formation

Question 4

Repairing AAA

Answer 4

Elective surgical repair of aneurysm
is indicated with an aneurysm diameter greater than 5.5 cm. Operative options include replacement with a prosthetic graft or endovascular stent graft repair.

Mortality from aneurysm rupture without surgery
is 100 per cent; and even if the patient reaches the hospital surgical unit alive, overall mortality is very high (80–95%).

Question 5

Signs and symptoms of carcinoma of the large bowel vary depending on site

Answer 5

Right-sided lesions in the caecum/ascending colon are associated with
weight loss and anaemia, whereas symptoms of change in bowel habit and bleeding
per rectum are more common in the sigmoid colon/rectum.

Question 6

Pancreatic psudocyst

Answer 6

Usually located in the lesser sac adjacent to the pancreas.
Occur due to ductal leakage following inflammation of the pancreas (acute or chronic).
Present non-specifically with abdominal discomfort,
nausea, early satiety etc.

Complications of pancreatic pseudocyst include
infection (most common), obstruction (of common bile duct leading to jaundice)
and perforation.

Rarely erosion of nearby vessels cause pseudoaneurysm formation which can be fatal.

Most pseudocysts resolve spontaneously. CT shows a round/ovoid fluid-filled cavity encapsulated by a fibrous wall. A pseudocyst does not have a true epithelial lining.

Pancreatic pseudocysts can be treated
by drainage if it is felt that there is a high risk of complication

Question 7

Managing rectal fissure

Answer 7

Initially medical with liberal use of stool softeners to break the cycle of pain. GTN/diltiazem ointment may be
applied topically to relax the sphincter. Surgical procedures include lateral internal sphincterotomy and controlled sphincter dilatation.

Question 8

Abdominoperineal resection

Answer 8

Operation of choice for lower rectal tumours
where sphincter preservation is not possible. It involves the removal of the anus, rectum and part of the sigmoid colon, and the formation of a permanent
colostomy.

Question 9

Indications for a Hartmann’s

Answer 9

Hartmann’s procedure involves excision of part of the left colon with end colostomy and closure or exteriorization of the distal remnant.

Relief of obstruction – for example in a patient presenting with obstruction secondary to sigmoid colon carcinoma. The malignancy with appropriate margins can be excised and a colostomy formed. The Hartmann’s procedure can be reversed at a later date.

Perforation of sigmoid colon. The patient presents as an emergency with a perforated sigmoid diverticulum/secondary to undiagnosed malignancy. A primary anastomosis is not possible with the degree of inflammation and peritonitis.

Refractory sigmoid volvulus. Occasionally sigmoid volvulus fails to resolve by conservative measures/passing of flatus tube etc., and emergency surgery is required. If primary anastomosis is deemed likely to fail, then a Hartmann’s procedure is performed in the first instance (can be reversed later depending on
the case).

Question 10

Shoulder tip pain

Answer 10

Referred from peritiontic (eg diaphragm and

gallbladder). Acromion - diaphragm. Angle of scapula - gallbladder

Question 11

Embryological origins of epigastic pain

Answer 11

Mainly foregut structures - stomach, duodenum, liver, gallbladder, spleen and pancreas. T8 T9

Question 12

Embyrological origins of periumbilical pain

Answer 12

Midgut structures - small bowel, ascending colon, appendix. T10 T11

Question 13

Embryological origins of suprapubic pain

Answer 13

Hindgut pain - colon, rectum, bladder, uterus, fallopian tubes, testicular. T12 L1

Question 14

Body fluid breakdown

Answer 14

60% body weight H20, 40% intracellular, 20% extravellular (5% IV, 15% interstitial).
Intracellular ions - High K Low Na
Extracellular ions - Low K High Na (K is 98% IC)
Interstitial - V low protein
IV - High protein

Question 15

Blood vs Colloids vs Crytalloids vs 5% dextrose

Answer 15

Blood - fills up IV space almost exclusively

Colloid - majority stays IV due to high high osmotic potential

Crystalloid - will distribute over entire extravascular compartment (4 times bigger than IV) so 1L hartmans only 250ml stays IV

5% dextrose - will distribute over both IC and EC compartments

Question 16

Normal daily fluid losses

Answer 16

Urine 2000ml + 80-130mmol Na + 60mmol K
Faeces 300ml
Insensible (lungs and skin) 400ml

Total 2700

Question 17

GIT causes of water and electrolyte imbalances

Answer 17

D&V, ileostomy, NG aspiration, fistulous losses, pyloric stenosis, pancreatic fistula

In paralytic ileus and bowel obstruction, several litres of fluid may become acutely sequestered in the gut contributing to hypovolaemia. Resolution of an ileus is marked by diuresis

Question 18

Is potassium supplementation requires post surgery or trauma?

Answer 18

NO, potassium is released from damaged tissue, and can be further increased by transfusion. Supplementary potassium should not be needed in first 48h post

Question 19

Effect of surgery on fluid balance

Answer 19

Activation of vasopressin, catecholamines, RAS and steroids result in oliguria and water retention.

Clinical examination - if euvolaemic, overhydration may dilute blood causing pulmonary oedema and provide a salt load the patient cannot excrete

Potassium is released from damaged tissue, and can be further increased by transfusion. Supplementary potassium should not be needed in first 48h post. Esp watch in RF where excess K cannot be excreted.

Question 20

Preoperative fluid management in elective case

Answer 20

NBM and clear fluids up to 2-3h pre surgery unless gastric emptying is affected (DM, carcinoma of head of pancreas). Pre-op carbohydrate drinks (2-3h pre surg) reduce preoperative anxiety and postop N&V

Question 21

Electrolyte contents of 0.9% saline (vs human plasma)

Answer 21

Osmolality: 308 (291)
Na: 154 (135-145)
K: 
Ca: 
Mg: 
Cl: 154 (94-111)
Lactate: 
HCO3:

Question 22

Electrolyte contents of Hartmann’s (vs human plasma)

Answer 22

Osmolality: 278 (291)
Na: 131 (135-145)
K: 5 (3.5-5)
Ca: 2 (2.2-2.6)
Mg: 
Cl: 111 (94-111)
Lactate: 29 (1-2) 
HCO3:

Question 23

Electrolyte contents of 5% albumin (vs human plasma)

Answer 23

Osmolality: 300 (291)
Na: 150 (135-145)
K: 
Ca: 
Mg: 
Cl: 150 (94-111)
Lactate: 
HCO3:

Question 24

Electrolyte contents of 4% dextrose + 0.18% saline (vs human plasma)

Answer 24

Osmolality: 283 (291)
Na: 30 (135-145)
K: 
Ca: 
Mg: 
Cl: 30 (94-111)
Lactate: 
HCO3:

Question 25

Sample fluid replacement of lost fluid in typical adult without co-morbidities and no fluid deficit

Answer 25

1.5-3L fluid + Na 50-100mmol + K 40-80mmol / 24h 3 x 1L fluids per 24h 0.4% dextrose + 0.18% saline + 20mmol K in each bag or Using hartmann's Na/K/Cl/Lactate/Ca

Question 26

Calculating fluid deficit

Answer 26

Clinically <5% No clinical signs 5-10% Dry mucous membranes, loss of skin turgor, tachycardia and postural hypotension, low JV pressure >15% circulatory collapse So 70kg man with 10% - 10% x 60% x 70 = 4.2L If state of fluid depletion is unclear, fluid challenge with 200ml bolus of colloid or balances crystalloid solution

Question 27

Physiology of malnutrition

Answer 27

Depletion of glycogen stores leads to fat catabolism resulting in the primary energy source for the brain to be ketones. IC minerals Mg and PO4 become depleted. Insulin production is halted, and though initially protein is preserved muscle catabolism occurs (occurs earlier with sepsis and trauma). Impaired immune responces lead to infection and worse wound healing.

Question 28

Anthropometric measurements of malnutrition

Answer 28

Triceps skin fold thickness (reflect fat stores) Midarm muscle circumference (MAMC) Hand grip strength (non dominant)

Question 29

Principles of preoperative assessment (3 things to do)

Answer 29

1. History and confirmation of initial indication for surgery still exists 2. If the patient fit enough for the procedure? 3. Are co-morbidities managed? (eg if HBA1c 100 probs best to postpone elective surgery)

Question 30

Taking a pre-op history - PMHx

Answer 30

DM - medications. Can result in gastroparesis (gastric stasis) increasing aspiration risk despite fasting. Resp - nature of disease, how far away from best is patient? Cardio - what is exercise telerance? Stable/unstable RA - associated with unstable C spine. XR needed Rheumatic fever, cardiac heart disease, prosthesis - needs prophylactic Abx SSD - prone to sickle cell crisis under GA and post op

Question 31

Taking a pre-op history - PSHx

Answer 31

Nature - what has been done, indication, complications (DVT/PE, infection, MRSA, dehiscence)

Question 32

Taking a pre-op hisotry - Anaesthetics

Answer 32

``` Difficult intubation Aspiration Rare (scoline apnoea - AD pseudocholinesterase deficiency results in prolonged paralysis with short acting muscle relaxants like suxamethonium; malignant hyperpyrexia - AD uncontrolled increase in muscle oxidative metabolism leads to difficult to control pyrexia) ```

Question 33

Taking a pre-op history - Social

Answer 33

Alcohol and fags Substance abuse - think hepatitis and HIV Allergies - latex, anaesthetics, antimicrobials, iodine

Question 34

Pre op management of DM

Answer 34

1. Diet controlled - nil 2. Oral hypoglycaemics/SC insulin - stop night before, commenced on glucose+insulin infusion. Esp avoid long acting insulin which can cause intraoperative hypoglycaemia. Diabetic - first on list

Question 35

Pre op management of asthma

Answer 35

Peak flow, if possible avoid pollinating months when planning elective surgery

Question 36

Pre op management of COPD

Answer 36

Consider regional anaesthesia, whether pt requires post op ventilation on ICU. Think epidural

Question 37

Pre op management of CABG/Angioplasty

Answer 37

Assess cardiac function - ECG ± Echo | Consider local anaesthesia

Question 38

Pre op management - oral anticoagulants

Answer 38

``` Eg Warfarin, Dibigatran, Apixaban Indication important Should be discontinued prior to surgery Eg. AV prosthesis generally safe to discontinue to a while but MV prothesis not If needed, switch to SC heparin ```

Question 39

Pre op management - oral antiplatelets

Answer 39

Discuss with cardio regarding dual antiplatelet therapy | Should ideally be stopped 10 days prior to surgery

Question 40

Pre op management - COCP

Answer 40

Increased risk of DVT/PE - stop 6 weeks before major surgery. POP safe. Counsel need to change to condoms.

Question 41

Pre op management - Roids

Answer 41

Patients who are steroid dependant will require IV hydrocortisone to tide them over perioperative stress

Question 42

Pre op management - Immunosupression

Answer 42

More prone to post op infection and absorbtion of immunosupressants may be affected

Question 43

Pre op management - diuretics

Answer 43

Important to have normal K levels pre op

Question 44

Pre op management - MOIs

Answer 44

Rarely used now, but interact with anaesthetic agents to cause hypotension

Question 45

Pre op management - obstructive jaundice

Answer 45

These pts often have prolonged PTT and require vitK and either human prothrombin complex or FFP. Intraoperatively maintain diuresis with fluid replacement and mannitol as susceptible to AKI (HR syndrome)

Question 46

ASA grades (mortality)

Answer 46

I - no cormobidities (<0.1%) II - mind systemic disease does not limit activity (0.3%) III - severe systemic disease, not incapacitating (2-4%) IV - Incapacitating constantly life threatening disease (20-40%) V - not expected to survive >24h with or without surgery (>50%)

Question 47

Timetable for post op complications

Answer 47

<24 hours - LOCAL:haemorrhage, anatomical injury (eg ligation of ureter during pervic surgery) GENERAL asphyxia - aspiration of vomit, obstructed airway 24h-3weeks - LOCAL: paralytic ileus, infection (wound, peritonitis, pelvic, subphrenic), secondary haemorrhage, dehiscence (wound, anastamosis), obstruction due to fibrous adhesions. GENERAL pulmonary collapse, bronchopneumonia, embolus, retention, ATN, enterocolitis, bed sore Late - LOCAL: obstruction due to fibrosis, incisional hernia, recurrance of lesion (malignancy). GENERAL: anaemia, vitamin deficiency, diarrhoea, OP,

Question 48

Dumping Syndrome

Answer 48

A group of symptoms, including weakness, abdominal discomfort, and sometimes abnormally rapid bowel evacuation, occurring after meals in some patients who have undergone gastric surgery.

Question 49

Type of surgery vs infection risk

Answer 49

Clean - eg hernia repair. No viscera opened, without inflammation, infection <1% Clean contaminated - viscous opened with little or no spillage, infection <10% Contaminated - obvious spillage, obvious inflammatory disease (eg gangrenous appendix), infection 15-20% Dirty - eg gunshot, frank pus or gross soiling (eg bowel perforation). Infection 40%

Question 50

Gas gangrene

Answer 50

Gas gangrene (also known as clostridial myonecrosis and myonecrosis) is a bacterial infection that produces gas in tissues in gangrene. This deadly form of gangrene usually is caused by Clostridium perfringens bacteria. It is a medical emergency. Especially likes poorly vascularized tissue eg amputation stump.

Question 51

Prophylactic Abx in bowel and biliary surgery

Answer 51

Depends on what you want to cover. Good choice is 3rd gen cephalosporin with metronidazole to cover anaerobes. Fluconazole for candida may also be required.

Question 52

Antibiotic associated enterocolitis

Answer 52

C. Diff is a grap positive spore forming bacteria. Extensive enterocolitis causes diarrhoea and bowel will show mucosal inflammation with psudomembrane formation. Sigmoidoscopy shows red friable mucosa with whitish/yellow patches which may form psudomembranes. Feaco-oral transmission associate with PPI use Id of toxins A & B in stool diagnostic. Complications of toxic megacolon and rapid dehydration Good infection control with oral metronidazole 14 days

Question 53

Notable MDR organisms

Answer 53

``` MRSA VISA VRSA ESBL (extended spectrum B lactamases) CRE (carbopenem resistant enterobacteriaceae) VRE (vancomycin resistant enterococci) ```

Question 54

Basal atelectasis post op

Answer 54

Some degree of pulmonary collapse occurs after almost every abdominal or transthoracic procedure. Mucous is retained in bronchial tree, blocking smaller bronchi. The alveolar air is absorbed leading to collapse of the supplied lung segments. While normal, increased risk of infection

Question 55

Post op pulmonary collapse

Answer 55

Some occurs normally (basal atelectasis) Smokers, Chronic pulmonary diseas, chest wall disease increase risk Anaesthetic drugs increase mucous secretion and depress ciliary action, while post op pain inhibits taking deep breaths and causes mucous retension Occurs in first 48hours. Dyspnoea, tachypnoea, T, fruity cough, diminished breath sounds that side, basal dullness and air entry depresses with course crackles. Prevention - postpone surgery until all infections cleared. Pre op breathing exercises and stop smoking Post op encourage coughing (small dose opiates to limit pain but not high enough to affect coughing reflex) with breathing exercises. Abx if becomes infected.

Question 56

Post op DVT

Answer 56

Virchows triad - flow (immobilization on operative table and post op in bed with depression of respiration), vessel wall (damage prompts thrombus formation, can be caused by pressure by matress on calf or direct at op), thrombotic tendency (intraoperative blood loss and platelet consumption leads to new platelets being formed, peaking at 10 days post op. Fibrinogen also rises) Ascertain other risk factors, incl genetic (eg G20210A prothrombin mutation or fVL ``` Good prophylaxis (eg COCP), early mobilisation, intermittant calf comression during surgery, TED stockings and elevation, SC LMWH Wells Score ``` In established case - LMWH with conversion to warfarin in future

Question 57

Post op PE

Answer 57

PE classically occur day 10 post op Signs - tachyponeoa, pleuritic chest pain, raised JVP (reflecting right heart strain), cyanosis, pleural rub CTPA, CXR, ECG (may show rhythm changes, right heart strain, S1Q3T3) ABG Oxygen + LMWH ± Analgesia Critical options include streptokinase (CI following surgery) or pulmonary embolectomy

Question 58

Factors which impair wound healing

Answer 58

Uraemia, cachexia with protein deficiency, vitamin C deficiency, jaundice, obesity, steroids, DM

Question 59

Managing wound dehiscence

Answer 59

Reassure with morphine and antiemetic Cover contents with sterile guaze soaked with saline and prepare for operation. Resuture under GA using nylon strong sutures passed through all layes of abdominal wall Prognosis good unless underlying disease takes over High risk for future incisional hernia

Question 60

Signs of wound dehiscence

Answer 60

Abdomen usually day 10 Warning sign if pink fluid discharges through incision - represents serous effusion (always present in abdominal cavity after operation), tinged with blood and which seeps through the hole in wound. If this progresses, patient finds bowel or omentum through wall, usually after cough or strain.

Question 61

Post op hypotension - management

Answer 61

In a surgical patient hypotension is hypovolaemia until proven otherwise. Resuscitate with a fluid challenge and monitor clinical response while sending bloods for FBC and clotting

Question 62

Duct of Lushka

Answer 62

Duct of Luschka is used to refer to an accessory bile duct. They are small ducts that distinctly enter the gallbladder bed, or small tributaries of minor intrahepatic radicals of the right hepatic ductal system.

Question 63

Common complication post laparoscopy

Answer 63

Umbilical port site bleed / haematoma

Question 64

Steroid cover during surgery

Answer 64

Minor surgery - if less than 10mg/d no cover needed, if more than 10mg/d give 25mg preop IV hydrocortisone the return to normal steroid use post op Intermediate surgery - 25mg IV hydrocortisone pre op, then every 8h for 24h until normal resumed Major surgery - 50mg IV hydrocortisone preop then 50mg IV every 8h for 72h then resume normal

Question 65

Manage: urgent surgery pt on warfarin with INR 3

Answer 65

Discontinue warfarin, vit K 2-3mg, monitor INR every 6-8h post op and have FFP, cryoprecipitate and XM blood ready to cover the surgery

Question 66

Insulin sliding scale during surgery

Answer 66

Add 50 units of Actarapid to 0.9% saline to total volume 50ml (1ml = 1 unit). Calculated as 1 ml (unit) / h. Blood glucose should be measured hourly and scale adjusted. ``` BM > 16 - 6 ml/h BM 13-16 - 4ml/h BM 10-13 - 3 ml/h BM 7-10 - 2ml/h BM 5-7 - 1ml/h BM 4-5 - 0.5ml/h ``` Medical staff monitor every 2-4h to ensure glucose within 5-10mmol/L This needs to be run with 5% dextrose with 20mmol/L KCl supplementation through the same cannula to avoid hypos if cannula blocks

Question 67

Half live of IV insulin

Answer 67

2.5 minutes

Question 68

Causes of post op cellulitis

Answer 68

Staph Aureus and Strep Pyogenes, if immunocompromised staph epidermidis

Question 69

Initial first line fluid replacement for trauma ATLS

Answer 69

2L Hartmann's

Question 70

Typical daily requirements for adults (H2O, Na, K)

Answer 70

1-2.5L H2O 1mmol/kg Na 0.5-1mmol/kg K

Question 71

Electrolytes in ileal fluid (important in high output ileostomies)

Answer 71

130 mmol/L Na 110 mmol/L Cl 10 mmol/L K

Question 72

Post op fistula

Answer 72

Serious if involves alimentary canal or biliary/pancreatic adnexea following abdominal surgery. Escape of bowel / bile contents through drainage site. If in doubt methylene blue given orally. Sample of fluid tested for creatinine (urinary), bile (biliary), amylase (pancreatic). Injection of radio opaque dye at time of ct will visualise size and if distal obstruction.

Question 73

Treating post op fistula

Answer 73

1. Protect skin around fistula - edges covered by Stomadhesive (adheres to moist surfaces) or silicone barier cream. Consider colostomy appliance 2. Replace loss of fluids, electrolytes, nutrients and vitamins 3. Reduce sepsis - abx and pus drainage On this conservative management fistula may heal but if in site of inflammatory disease (CD) or malignant in origin needs surgery. Patient will likely be toxic and rapid catabolism occurs

Question 74

Post op pyrexia

Answer 74

Mild pyrexia normal response to surgery. | Examine and exclude infection

Question 75

Risks of Laparoscopic surgery

Answer 75

Cannula insertion - perforation of viscus, bladder, aorta Insufflation - vagal stimulation causing profound bradycardia, CO2 retention, CO2 embolism Surgery itself - bleeding, trauma Port closure - inadequate closure leading to hernia

Question 76

Risks of OGD

Answer 76

Oesophageal perforation, variceal bleeding

Question 77

Risks of ERCP

Answer 77

perforative cholangitis, pancreatitis

Question 78

Risks of Colonoscopy

Answer 78

perforation, esp if polypectomy or stenting of stricture

Question 79

Commonest causative agent in cellulitis

Answer 79

Group A B haemolytic strep (eg pyogenes)

Question 80

Why do abscesses cause swinging fever?

Answer 80

Initially abscess is hard, red and painful. Becomes soften and fluctuant and if not drained discharges into body cavity. Abscess if established needs drainage

Question 81

True vs False diverticulum

Answer 81

True - outpouching covered by all layers of the bowel wall (e.g. Meckel's) False - lacking normal muscle coat of the bowel

Question 82

Causes of colonic diverticuli

Answer 82

Low fibre diet - disease of western civilisation Structural abrnomalities - CTD incl Marfans and Ehler Danlos Abnormal motility and increased intraluminal pressure.

Question 83

Complications of diverticuli

Answer 83

Diverticulitis resulting in perforation into either peritioneum (peritonitis) or pericolic tissues (pericolic abscess) Large bowel obstruction - muscular hypertrophy and inflammatory fibrosis Haemorrhage - erosion of vessel within diverticular fundus.

Question 84

Managing acute diverticulitis

Answer 84

Conservative - fluids, metronidazole + ciprofloxacin / penicillin + gentamycin Pericolic abscess - percutaneous drainage If stable, surgery may be avoided. If sepsis controlled, laparotomy and resection of diseased segment. If emergency usually Hartmann's

Question 85

Managing chronic diverticular disease

Answer 85

Conservative - Milpar (lubricant laxative) plus high roughage diet including F&V, wholemeal bred, bran.

Question 86

Angiodysplasia - investigating and treatment

Answer 86

Colonoscopy - GS, bright red submucosal lesions 0.5-1cm with small dilated vessels visible on close inspection. Visible on barium enema Mesenteric angiogram - actively bleeding angiodysplasias will feature contrast bleeding into bowel. Treatment - transfuse if severe, colonoscopic electrocoagulation or argon plasma coagulation may be curative. Resection (usually R hemi) may be required.

Question 87

UC and colon cancer

Answer 87

5-12% op patients with colitis for 20years duration will develop malignant change. Annual / biannual colonoscopy with biopsies

Question 88

Surgery for refractive severe UC

Answer 88

Usually total colectomy and rectum removal with either permanent ileostomy or ileoanal anastamosis with interposed pouch of ileum. All patients will likely be on high dose steroids - IV hydrocortisone cover

Question 89

Familial history in CRC

Answer 89

Baseline lifetime risk CRC - 1/50 1 FDR - 1/17 1FDR <45 - 1/10 Think FAP and HNPCC

Question 90

FAP

Answer 90

FAP gene, AD, 0.5% all CRC, 25% de novo | Prophylactic total colectomy with ileoanal pouch befor 25 years olf

Question 91

HNPCC

Answer 91

AR, 5% all CRC, MSH2 (60%) MLH1 (30% MMR genes | Tumours favour R colon,

Question 92

Dukes classification CRC (+ 5 yr survival %)

Answer 92

A - confined to muscularis mucosae (90%) B - extends through muscularis mucosae (65%) C - local lymph nodes (30%) D - mets (<30%) * More likely today to use TNM classification

Question 93

Red flag for CRC

Answer 93

Change in bowel habit | Mucous / Blood

Question 94

Screening CRC

Answer 94

Faecal occult blood test (screening offered every 2 years to all 60-74 year olds) Bowel scope screening - this additional one-off test is gradually being introduced in England. It is offered to men and women at the age of 55

Question 95

Investigating suspected CRC

Answer 95

``` Faecal occult blood tests Sigmoidoscopy / Colonoscopy (biopsy is able to be taken as well) CT colonography (virtual colonoscopy) replaced barium enema (which used to show apple core appearance) CEA levels useful, but baseline important ```

Question 96

CRC - principles of surgical treatment

Answer 96

Wide resection of mass together with regional lymph nodes. If bowel unobstructed, can be prepared beforehand and primary anastamosis possible. If obstructed (anastamosis CI) defunction distal bowel with colostomy or ileostomy for possible anastamosis at a later date. Even palliatively best scenario is tumour removal to avoid obstruction. If not, try at least stenting

Question 97

Chemotherapy in CRC

Answer 97

Adjuvant therapy in CRC includes 5-fluorouracil (5FU) and may reduce recurrance. Survival prolonging treatments include 5FU + irinotecan, cetuximab (mAb against epidermal growth factor) and bevacizumab (mAb against VEGF)

Question 98

Colostomy - what do think about when you see one?

Answer 98

Need to divert faeces to allow healing of more distal bowel anastamosis or fistula Decompression of a dilated colon, prelude to resection of obstructing lesion Removal of distal colon and rectum

Question 99

Loop vs End vs Double barreled colostomy

Answer 99

Loop - colon bought to surface and antimesenteric border opened. Rod or similar device stops bowel from moving back inside. Temporary measure to divert faeces and rest distal bowel. Easy to reverse and better blood supply to bowel End - permanent. May be used in a patient undergoing total rectal excision or following perforated diverticular disease where primary anastamosis not viable. Double barrelled (Paul Mikulicz) - proximal and distal ends both out, kind of like loop but divided fully. Rarely used as distal segment often too short.

Question 100

Complications of colostomy formation

Answer 100

Retraction - real (due to tension) or apparent (necrosis of terminal bowel) Stenosis - due to ischaemia or poor apposition of colonic mucosae Paracolostomy hernia - peritoneal contents herniate through adbsominal wall defect made to hold stoma Prolapse Lateral space bowel obstruction Then there are complications arising from poor fitting appliances or poorly made stomas

Question 101

Managing a new colostomy

Answer 101

In the first few weeks faecal discharge is semi liquid but this gradually reverts to normal solid stools Appliances are both wind and waterproof Most patients find they pass one stool a day despite no sphincter (morning shits are the norm) Large amounts of v&g can cause diarrhoea and flatus

Question 102

AXR - small bowel obstruction

Answer 102

Ladder pattern of dilated loops Central position Striations - vena conniventes, which pass completely across width of distended loop

Question 103

AXR - large bowel obstruction

Answer 103

Bowel tends to lie peripherally, haustrations of taenia coli, not extending the whole width of bowel Coffee bean sign if sigmoid volvulus CT with oral gastrograffin contrast to image further

Question 104

Preop management of acute bowel obstruction

Answer 104

NG tube + aspiration to decompress bowel and reduce aspiration risk IV fluids - these pts will sequested huge amounts of fluid in the gut. Hartman's or Saline with K Ab

Question 105

Operating principles of bowel obstruction

Answer 105

Determine viabilility of bowel: Loss of peristalsis Loss of normal sheen Colour (green/black is non viable, purple may recover) Loss of arterial pulsation in supplying mesentery If extensive areas are doubtful reopen 48h (remember Mr Tsohazis case) to reassess Small bowel can be excised at will, as due to excellent blood supply and cleanliness easy to anastamose. Large bowel obstruction treated by primary ileocolic anastamosis if lesion proximal to spleinc flexure. Left sided lesions managed with excision, and temporary colostomy with mucus fistula (if distal end will not reach surface fo Hartman's)

Question 106

Closed loop obstruction

Answer 106

Specific form of mechanical bowel obstruction. Combination of distal complete obstruction + competent ileocaecal valve preventing reflux. Highly distended caecum at risk of perforation.

Question 107

Adhesion obstruction

Answer 107

Adhesions account for 3/4 of all SB obstructions. Initially conservative with IV fluids and NG suction. If strangulation, perforation or failure to respond urgent laparotomy

Question 108

Sigmoid volvulus

Answer 108

Think elderly, constipated patients. M>W 4:1. 2% of intestinal obstructions in UK. More common in other parts of world. Loop of sigmoid colon usually anticlockwise from 1/2 to 3 turns

Question 109

Treating sigmoid volvulus

Answer 109

Long soft rectal tube passed through sigmoid colon - usually untwists and early volvulus - accompanied by huuge amounts of flatus and liquid shit. If this fails, laparotomy to untwist followed by tube decompression. If gangrene, excise and both open ends brought to surface (Paul-Mikulewicz procedure) as a double barelled colostomy, subsequently closed

Question 110

Mesenteric oclusion

Answer 110

++++ AF Mural thrombus 2* to MI Vegetation on valve Paradoxical embolus from DVT (which crossed to other side via patent foramen ovale) Atherosclerosis - usually preceding Hx of "angina", pain after meals as gut struggles to process with limited blood supply

Question 111

Rigler's sign

Answer 111

Radiograph - gas on both sides of the bowel wall