Lower gastrointestinal surgery

Question 1

A 50-year-old man with a family history of bowel carcinoma was investigated for change in his bowel habit and copious mucoid stools. Blood tests showed
haemoglobin 13.7 g/dL, white cell count 4.3 x 109/L, sodium 137 mmol/L,
potassium 3.0 mmol/L, urea 3.9 mmol/L, creatinine 98mmol/L. Tumour markers
were normal and faecal occult blood was negative. Colonoscopy was performed and a 1.1 cm sessile polyp was identified in the distal sigmoid colon. Histological examination showed profound dysplastic change in the epithelial component. The most likely diagnosis is:

A. Benign disease
B. Villous adenoma
C. Hamaratoma
D. Tubular adenoma
E. Carcinoid

Answer 1

B. Villous adenoma

Colonic polyps are common and can often precede malignant disease.

Villious adenomas (B) charecteristically secrete large quantities of potassium rich mucus, leading to hypokalaeimia, as seen here. Compared to Tubular adenomas (D), villous adenomas have a far greater malignant potential due to the level of epithelial dysplastic change.

a Hamaratoma (C) is a term for any vergrowth of normal cells, as seen in Iris Hamaratomas, ‘Lisch nodules’ charecteristic of neurofibromatosis type 1.

Carcinoid tumours (E) most commonly arise at the appendix, but can occur anywhere on the ailimentery tract. Although diarrhoea could be suggestive of carcinoid syndrome the histopathology doesn’t suport this.

Question 2

A postoperative patient has been moved to a side room after developing diarrhoea following the start of a course of antibiotics. Faecal samples test positive for Clostridium difficile toxin and intravenous metronidazole is started. After 10 days the antibiotic course is finished and nursing staff repeat the toxin assay on a formed stool sample, which is again positive. What is the most appropriate next management step?

A. No further action required
B. Continue metronidazole for a further 10 days
C. Start intravenous vancomycin
D. Start oral vancomycin
E. Urgent colonoscopy as this patient is at significant risk of
pseudomembranous colitis

Answer 2

A. No further action required

Overgrowth with C.difficile is a common side efffect followin broad spectrum antibiotic treatment. In this case the salient point is that the patient is now passing formed stool, and is therefore asymptomatic. It is important to realise that the toxin assay will remain positive for at least 2 weeks following the clearance of the infection, taking this into account no further action is indicated (A).

IV Vanomycin (C) is not the appropriate treatment option in this case, if the patient was still passing loose stool then oral Vancomycin (D) would be the next escalation. If the metronidazole had failed to resolve the diarrhoea after a 10 day course then it would indicate resistance and further metronidazole would be inappropriate (B).

Colonoscopy (E) is inappropriate for an otherwise well patient.

Question 3

A 60-year-old patient is being treated for colonic carcinoma. The primary lesion has been excised and chemotherapy started. However, computed tomography (CT) scanning identifies a 1 cm metastasis in the right lobe of the liver. The patient has no history of alcohol misuse or viral hepatitis. CT chest and CT brain show no abnormalities. The most appropriate next stage of management would be:

A. Liver resection
B. Gadolinium-enhanced liver magnetic resonance imaging
C. CT/ultrasound-guided biopsy
D. Referral to a palliative care setting with appropriate counselling and support
E. Monitor lesion – if size exceeds 1.5 cm, add irinotecan to 5-fluorouracil
and folinic acid chemotherapy

Answer 3

B. Gadolinium-enhanced liver magnetic resonance imaging

Identification of metastatic disease in colon cancer often takes place after colonic resection, as removal of the primary lesion is always best practice in those fit for surgery.

In this case the prescence of distant mets makes this a Dukes stage D disease, giving a 5-year survival of <5%. If the distant metastasis is isolated to a single lobe of the liver, and this is agesively treated it can increase survival to over 30%.

Taking all of this into account, this patient needs imaging to absolutely confirm that the disease is isolated to a single lobe prior to surgical resection of the liver (A)

The gold standard imaging is Gadolinium-enhanced liver MRI (B).

Biopsy (C) is not indicated as this patient has no risk factors for HCC so this is unlikely to be a second primary, the risk of ‘seeding’ the biopsy tract makes this an unwarrented risk. (D) is not the next step here, and (E) is inappropriate.

Question 4

On colonoscopy a malignant lesion is identified 5 cm proximal to the splenic
flexure. There are no contraindications to resection and the decision is made to
operate with curative intent. The most appropriate procedure would be:
A. Right hemicolectomy
B. Transverse colectomy
C. Left hemicolectomy
D. Anterior resection
E. Extended right hemicolectomy

Answer 4

E. Extended right hemicolectomy

Given the location of the lesion (distal transverse colon) an anterior resection (D), which removes a portion of the rectum, and a right hemicolectomy (A) are completely inappropriate.

The choice of the correct procedure then comes down to the basic principle of tumour surgery, that the aim is to get clear margins, and the technical considerations of the procedure. In this case it is technically not desirable to anastomose colon to colon, making a left hemicolectomy (C) and a tranverse colectomy (B) undesirable.

This means that the preferred technique for tumours of the transverse colon is an extended right hemicolectomy.

Question 5

A 32-year-old female patient presents with a 6-week history of bloody bowel
motions. She has noticed significant weight loss over the preceding 6 weeks with increasing lethargy and fatigue. She has previously had constipation and admits to regular laxative use. What is the most likely diagnosis?
A. Bowel cancer
B. Irritable bowel syndrome
C. Diverticular disease
D. Inflammatory bowel disease
E. Anal fissure

Answer 5

D. Inflammatory bowel disease

The key to answering this question is noting that the phrasing asks for the ‘most likely diagnosis’.

The prescence of bloody stool, lethergy and fatigue over 6 weeks points to a systemic disease process. As such we can rule out Anal fissure (E) easily, and rule out IBS (B) as this should never a first diagnosis in the prescence of bloody stool. Diverticular disease (C) is less likely to present systemically in this way.

For the purposes of the question we can select IBD over Bowel Ca (A), simply on the basis of likelihood given this patient’s age.

Question 6

Which one of the following statements regarding stomas is the most correct?

A. Hartmann’s procedure results in a defunctioned rectum and loop
colostomy
B. An abdominoperineal resection may be reversed by formation of an ileal
J-pouch
C. A mucus fistula functions to decompress residual distal bowel
D. Small bowel obstruction is a common complication and indicates need
for revision
E. Hypokalaemic metabolic acidosis is a common and always long-term
postoperative complication of small bowel stomas

Answer 6

C. A mucus fistula functions to decompress residual distal bowel

Taking each of these statements;

• Hartmann’s procedure does result in a defunctioned rectum but not
a loop colostomy. The stoma formed is an end or terminal
colostomy which may be reversed in 60–70 per cent of cases.
• Abdominoperineal resection is not reversible as it leaves the patient
without an anus.
• Option C is true. The aim of a mucus fistula is to protect the
resection margins of the distal segment by avoiding the potential
build-up of mucoid secretions from the defunctioned bowel. More
often the distal bowel is sown to the underside of the abdominal
wall and left as a ‘potential mucus fistula’ which may be easily
opened if the need arises.
• Small bowel obstruction complicates 10–15 per cent of stomas,
particularly loop stomas. The majority resolve with conservative
measures, however, and they rarely necessitate revision.
• Immediately following small bowel stoma formation, large
quantities of sodium-rich secretions may be lost. This results in
hypokalaemia and metabolic alkalosis as sodium is conserved in
exchange for potassium and protons in the renal tubules. Option E
incorrectly states that the complication is always long term.

Question 7

You are called to see an 85-year-old female patient as the nursing staff are
concerned that the patient has not passed stool for 4 days. The patient has been admitted after family members became increasingly concerned regarding her general deterioration in health and level of function. She is orientated but frail and complains of increasing abdominal discomfort. On examination bowel sounds are increased. The abdomen is distended with generalized tenderness but no rebound or guarding. There is a firm palpable mass in the left iliac fossa. Digital rectal examination shows an empty rectum. The diagnosis is:
A. Simple constipation
B. Ileus
C. Sigmoid volvulus
D. Peritonitis secondary to diverticular disease
E. Neoplasia

Answer 7

E. Neoplasia

This is a difficult one to distiguish between simple constipation (A) and neoplasia (E).

THe other options here are easier to exclude, ileus (B) would present with absent bowel sounds. Sigmoid volulus (C) would be a more acute presentation than 4 days and there would be a greater element of systmic upset and severe pain. Peritonitits (D) would also be expected to present with a far greater degree of systemic upset, although guarding and rebound tenderness are not always present in elderly patients.

Choosing between simple constipation and neoplasia requires more thought, the empty rectum and history of a general and rapid deterioration make a diagnosis of simple constipation less likely. The pharsing of the question is also implicit in looking for a unifying diagnosis, as oppossed to a ‘most likely diagnosis’ which therefore makes neoplasia (E) the better choice.

Question 8

An 85-year-old male patient with a history of chronic constipation presents with acute severe colicky abdominal pain and absolute constipation. Plain abdominal film shows a grossly dilated oval of large bowel arising from the left lower quadrant. A diagnosis of sigmoid volvulus is made. The next step in management is:
A. Laparotomy
B. Sigmoidoscopy with flatus tube insertion
C. Sigmoid colectomy with colostomy
D. Barium swallow
E. Computed tomography

Answer 8

B. Sigmoidoscopy with flatus tube insertion

This is classic sigmoid volvulus, volvulus this is where a loop of bowel gets twisted on it’s mesentary, occluding the lumen as well as the blood supply. Rapid decompression is needed to prevent ischaemia and gangrene.

Sigmoid volvulus is more common in men than women (4:1), it is more common in the elderly and those with a history of constipation. On radiographs you see a classic ‘coffee-bean’ or ‘bent inner-tube’ sign.

Treatment for these patients involves resucitationand management of shock, but definitively the affected loop of bowel needs to be decompressed as soon as possible, as in option (B). Following this the patient needs to be monitored for any signs of bowel ischaemia, which would then indicate the need for laparotomy and colectomy (A)(C).

There is no role for a barium swallow (D) in sigmoid volvulus, and a CT (E) adds nothing in this scenario.

Question 9

Which one of the following does not occur as a systemic manifestation of
inflammatory bowel disease.
A. Amyloidosis
B. Pyoderma gangrenosum
C. Scleritis
D. Osteoporosis
E. Sclerosing cholangitis

Answer 9

D. Osteoporosis

The systemic manifestations of IBD are numerous, osteoporosis is not one of them though. Osteoporosis can be a consequence of steroid treatment, but the IBD process is not a direct cause (it can, however, cause osteomalacia).

The commonest MSK associations with IBD are; arthritis, sacroiliitis, and ankylosing spondylitis.

Sclerosing cholangitis (E) is primarily associated with ulcerative colitis, leading to a raised risk of cholangiocarcinoma.

Scleritis (C) and Iritis are common manifestations of IBD and require prompt treatment as they are sight-threatening. Episcleritis is less severe but more common.

Pyoderma gangrenosum (B) is a manifestation of both UC and Crohn’s, but may also be seen in PBC, Rheumatoid arthritis and neoplasia.

Amyloid deposition may be an indicator of any chronic systemic inflammatory process, so Amyloidosis (A) is a rare complication of IBD.

Question 10

Which one of the following statements regarding diverticular disease is the most
correct?
A. Colonic diverticula are true diverticula
B. Diverticular disease describes the outpouching of colonic mucosa between the muscle layers of the colonic wall
C. The most common site of diverticula is the rectum, where the highest pressures occur
D. Saint’s triad consists of diverticular disease, cholelithiasis and inguinal herniation
E. 95 per cent of complications from diverticula occur at the sigmoid colon

Answer 10

E. 95 per cent of complications from diverticula occur at the sigmoid colon

Diverticula are outpouchings of the wall of a hollow viscus, that are either congenital or aquired.

A true divertuiculum has all components of the viscus within it’s walls. This menas that colonic diverticulum are not true diverticulum (A) as they are outpouchings of mucosa between the taenia coli. From this description it can be seen that option (B) is also incorrect as the diverticulum do not pass between muscle layers.

Diverticula occur in approximately 30% of adults over 60, but not all of these patients have diverticular disease (a term to describe diverticula with complications).

The most common site for diverticula to form is the sigmoid colon, they do not form in the rectum (C) as the taenia coli are fused together in the rectal wall. As such the correct option here is (E).

Saints triad (D) describes the association between diverticula, cholelithiasis and hiatus herniation, all of which occur more frequently in Western societies.

Question 11

A 78-year-old patient is admitted with colicky abdominal pain and bleeding per rectum. On assessment his blood pressure is 110/55 mmHg, respiratory rate is 30 breaths/min and he is in atrial fibrillation with a ventricular response of 130
beats/min. He is known to you as he has previously presented in the outpatients department and been investigated for intermittent abdominal pain associated with food. He had a colonoscopy 3 months ago which was normal. The diagnosis is:
A. Obstruction secondary to neoplasia
B. Inflammatory colitis
C. Ischaemic colitis secondary to embolus
D. Angiodysplasia
E. Mesenteric atherosclerosis

Answer 11

E. Mesenteric atherosclerosis

This is a classic presentation of mesenteric vascular occlusion, which is a triad of; Shock, rectal bleeding and coliky abdominal pain. It then becomes a question of determing the cause of this obstruction.

Of the other options here, the recent normal colonoscopy makes a malignant obstruction (A) incredibly unlikely, angiodysplasia (D) would present with painless rectal bleeding. inflammatory colitis (B) would not cause intermittent pain associated with food.

Determining between the remaining two option is down to the history here, the chronic nature of the condition and it’s relation to food suggests an chronic narrowing of the mesenteric vessels that becomes symptomatic on ‘exertion’, hence why mesenteric atherosclerosis (E) is known as ‘intestinal angina’.

Although the AF might suggest an embolic event (C), it is unlikely given the chronic nature of the presentation, additionally the AF may well be a result of the hypovoelemic shock and not a cause.

Question 12

A 27-year-old patient is seen in outpatients, as part of the follow-up for his ulcerative colitis. His current maintenance drugs include mesalazine and azathioprine, but he has not been tolerating azathioprine, and complains of malaise, nausea and vomiting. The next treatment option is:
A. Long-term oral steroids
B. 6-mercaptopurine
C. Ciclosporin
D. Infliximab
E. Methotrexate

Answer 12

E. Methotrexate

Pharmacological management of IBD is very complex, but broadly speaking it can be thought about in terms of treating flare ups, or maintaining remission, and there are differences in the management of ulcerative colitis and Crohn’s. In this question we are concerned with the maintainence of remission in ulcerative colitis.

Steroids are useful in the acute settingto control a flare-up, and topical steroid treatment (enemas) can be used to maintain remission, but systemic treatment is obviously avoided in long term treatment (A).

Mesalazine is first line treatment for all IBD, although it is less effective in treating Crohn’s. Second line treatment is with azathioprine, however 33% of patients will not tolerate it and so should be switched to 6-mercaptopurine (B). Despite being a breakdown product of azathioprine, 6-mercaptopurine is tolerated by 50% of patients switched on to it.

Patient’s intolerant or unresponsive to first and second-line treatments are given ciclosporin (C) in ulcerative colitis and methotrexate (E) in Crohn’s. Infliximab (D) is very effecctive in Crohn’s but it’s use is restricted by NICE.

Question 13

An 18-year-old patient presents with a 5-day history of abdominal pain and
pyrexia. On examination bowel sounds are present and the abdomen is soft with no rebound. A mass in the right iliac fossa is palpable. Abdominal computed tomography confirms the diagnosis of an appendix mass with an associated abscess. The patient is started on metronidazole and admitted for observation and conservative management. After 2 days the mass has not reduced in size and the temperature remains raised. The next stage in management is:
A. Continue metronidazole for further 14 days ± cefuroxime
B. Proceed to appendicectomy
C. Percutaneous drainage
D. Colonoscopy
E. Laparoscopy

Answer 13

C. Percutaneous drainage

An appendix mass occurs when an inflammed appendix becomes walled off due to adhesions to the surrounding omentum. As the majority of these cases (80%) resolve spontaneously the usual management is to treat with a short course of Abx and then followed up with an elective appendectomy in 3 months when the inflammation has settled.

Performing an appendectomy in the acutte setting is dangerous (B). Laproscopy (E) would be indicated if the diagnosis of appendicitis was uncertain, but that is not the case here. As the diagnosis is not disputed a colonoscopy (D) has no place in the management here.

Continued use of antibiotics (A) in a case where the mass has not resolved will lead to the development of a chronic inflammatory mass full of abscesses (bad). As with the old surgical axiom, ‘if there’s pus about, let it out’, the next step here is to drain the mass (C). Failure to drain the mass will result in the abscess following it’s natural course, it will continue to enlarge until it erodes into an epithelial surface and discharges, becoming a sinus or fistula. Commonly the appendix mass will erode into the abdominal cavity, bladder, rectum or to the skin.

Question 14

A 60-year-old homosexual man presents with a 6-month history of passing fresh blood per rectum and anal pain. His presentation has been precipitated by recent loss of continence to faeces. The blood coats the stool and he has noticed it on the paper after wiping. On rectal examination the patient has an empty rectum. You identify a third-degree haemorrhoid in the 11 o’clock position, as well as two further second-degree haemorrhoids. No other masses are palpable. The diagnosis is:
A. Anal squamous carcinoma
B. Haemorrhoids
C. Sigmoid adenocarcinoma
D. Diverticular disease
E. Anal fissure

Answer 14

A. Anal squamous carcinoma

The history here of blood covered stool suggests distal pathology, making (C) unlikely here.

Any bleeding due to diverticular disease (D) is likely to be a more acute presentation due to the large volume of bleeding.

The loss of anal continence points away from haemorrhoids (B) and anal fissure (E) as neither of these cause this, although loss of continence may arise as a result of treatment.

Carcinoma of the anal canal (A), however, does commonly cause bleeding and loss of continence as 70% have involvement of the sphincter. 50% have perianal pain, and it’s important to note that there will only be a palpable lesion in 25% of cases.

Carcinoma of the anus is closely associated with HPV and as such is more common in homosexual men, hence the relevance.

Question 15

Which of the following statements regarding the anatomy of the anal canal is
false?
A. There is no touch or pain sensation above the dentate line
B. The anal canal below the dentate line drains lymph to the inguinal nodes
C. The anorectal ring is made up of the blended fibres of the puborectal muscle and internal anal sphincter
D. The superior rectal vein drains into the portal system
E. The pelvic diaphragm delineates the point at which the rectum becomes
the anal canal

Answer 15

C. The anorectal ring is made up of the blended fibres of the puborectal muscle and internal anal sphincter

(A) is true, the nervous supply above the dentate line is from the autonomic hypogastric plexus and so only responds to stretch.

(B) is true, the anal canal above the dentate line drains vial the internal inguinal nodes.

(C) is false, the anorectal ring is made up from the combined fibres of the puborectal muscle and the external sphincter. The internal sphincter is hypertrophied smooth muscle

(D) is true, hence why this is a site of portal-systemic shunting.

(E) is true, the pelvic diaphragm is made up from levator ani and coccygeus muscles and divides the pelvis from the perineum and therefor the division of rectum and anus.

Question 16

A 60-year-old diabetic patient presents with an 8-hour history of being unable to pass urine. On taking his history he reports a 3-day history of pyrexia and
throbbing pain around the back passage. He is also concerned as he has also noticed he has been passing urine increasingly frequently and worries that his
diabetes is getting worse since increased urinary frequency was how his condition was initially diagnosed. On examination of his abdomen there is no evidence of peritonism. On digital rectal examination there are no abnormalities visible in the perianal area; the procedure is extremely painful. However, the prostate feels normal and is in the normal position. The diagnosis is:
A. Ischiorectal abscess
B. Acute prostatitis
C. Urinary tract infection
D. Invasive pelvic malignancy
E. Supralevator abscess

Answer 16

E. Supralevator abscess

The short history of throbbing pain and sepsis indicates this patient has an abcess, and is not what would be expected from a malignant process (D) or an uncomplicated UTI (C). Acute prostatitis (B) is a possible diagnosis in a patient with a fever and painful urinary retention, the pain is non-specific and may be felt deep in the pelvis, between the legs, the lower back or the rectum. The description of the pain as throbbing is classic for an abcess, and the prostate would feel boggy and enlarged in prostatitis, which is not the case here.

It then comes down to differentiating the site of infection, the majority of peranal abcesses originate from infections in one of the glands that lie between the internal and external sphincters. In 65% of cases the infection tracks downwards to form a perianal abcess, presenting as a discrete erythemoutous swelling close to the anal verge.

In 15% of cases the infection tracks through the external sphincters and into the ischiorectal fossa forming an ischiorectal abcess (A). This fossa is full of fat and lacks any barriers to the spread of infection, meaning that they present systemically unwell with extreme pain on DRE.

In 15% of cases the infection remains in the muscle layers, forming an intersphincteric abcess, presenting with chronic anal pain and tenderness on DRE.

In the final 5% of cases the infection spreads upwards through levator ani, forming a supralevator abcess (E). These casue significant inflammation adjacent to the bladder, presenting with systemic illness, perianal discomfort and bladder irritation.

Question 17

A patient with a previous anal abscess presents with persistent discharge from the anus and perianal discomfort. On examination a sinus is identifiable at the 6 o’clock position with the patient in the lithotomy position. A fistula is diagnosed and the patient is booked for theatre. What procedure is the surgeon most likely to perform?
A. Seton insertion
B. Plug insertion
C. Open exploration of tract
D. Endoanal ultrasound
E. Magnetic resonance imaging

Answer 17

B. Plug insertion

The majority (70%) of fistula in ano are intersphincteric (they do not involve the sphincter muscles), a further 23% do involve the sphincter muscles but not the anorectal ring. Both can easily be identified by passing a probe under anaestesia. Once the path of the tract has been confirmed and is considered safe then it can be opened to the surface.

Seton insertion (A) is only necessary if the anal ring is involved, or closely associated. Open exploration (C) is not an acceptable technique. Endoanal ultrasound (D) may be used intraoperatively where doubt remains. MRI (E) is reserved for complex cases, typically in reccurence or Crohn’s disease.

Question 18

Which of the following is not an option when treating an anal fissure?
A. Propranolol
B. Botulinum toxin A injections
C. Glyceryl trinitrate cream
D. Diltiazem cream
E. Laxatives

Answer 18

A. Propranolol

Laxatives () are commonly used as they treat the major underlying problem. In conjuction with laxatives the patient will recieve advice on toilet habits and dietery modification, although this management may still fail.

The most effective medical treatmetn is a combination of topical GTN (C) and diltiazem cream (D), this may lead to resoloution in up to 75% of cases. Lidnocaine gel is also prescribed to aid pain management.

Failing the above measure botulinum toxin A (B) injections can be used and have been shown to be effective at avoiding surgical management.

Question 19

Which of the following is not encountered when making a Lanz incision during an open appendicectomy?
A. External oblique aponeurosis
B. Rectus abdominis
C. Peritoneum
D. Internal oblique muscle
E. Transversus abdominis

Answer 19

B. Rectus abdominis

The traditional open appendectomy incision involved a gridiron dissection made over McBurney’s point. The current practice is to use a Lanz incision, this is a lower incision and follows the skin crease transversely, it is more comestically appealing.

In both approaches subcutaneous tissues are diveded to expose the external oblique aponeurosis, wich is divided to expose the internal oblique. Following the splitting of these fibres exposes the transversus abdominus, which reveals the peritonium when split. This incision is made lateral to the rectus which should never be involved. This approach which splits muscles rather than cutting fibres preserves thier strength and means that wound dehiscence and incisional hernias are rare in this procedure.

Question 20

Which of the following is not a sign associated with acute appendicitis?
A. Murphy’s sign
B. Cope sign
C. Psoas sign
D. Rovsing’s sign
E. Pain on rectal examination

Answer 20

A. Murphy’s sign

This is a classic description of appendicitis, with peritonitis over McBurney’s point. However with abnormal abdominal anatomy the presentation of appendicitis can be extremely varied.

Rovsing’s sign (D) is positive when pain is experienced in the right iliac fossa when pressure is placed on the lef iliac fossa.

Cope sign (B) is positive when there is pain on flexion and internal rotation of the right hip, and it indicates a low lying appendix in close association with obturator internus.

Psoas sign (C) is pain on extension of the hip and indicates a retrocaecal appendix.

Pain on rectal examination (E) indicates a low lying appendix or pus in the pouch of douglas.

Murphy’s sign (A) is the odd one out here as it is associated with acute cholecystitis. It involves palpating the costal margin at the tip of the 9th rib whilst the patient is in expiration and then asking them to take a deep breath. It is postive if there is pain causing the patient to catch thier breath on the right side, but NOT on the left.

Question 21

All of the following may cause a right iliac fossa mass that is palpable on
abdominal examination, except:
A. Mucocele
B. Ulcerative colitis
C. Tuberculosis
D. Appendicitis
E. Ovarian cancer

Answer 21

B. Ulcerative colitis

UC starts as proctitis and moves proximally, as such it is found on palpation of the left iliac fossa. The casues of a right iliac fossa mass can be summarised as below;

• General: appendix mass/abscess, colorectal carcinoma, Crohn’s,
distended gallbladder, lymphadenopathy
• Urological: pelvic kidney, renal transplant, tumour in an
undescended testis
• Gynaecological: ovarian cyst, ovarian tumour, fibroid
• Vascular: iliac artery aneurysm
• Orthopaedics: chondrosarcoma or osteosarcoma of the ileum (rare!)
• Infective: psoas abscess, ileocaecal TB

Question 22

Which of the following is not a syndrome associated with an increased risk of
colonic adenocarcinoma?
A. Congenital hypertrophy of retinal pigment epithelium
B. Familial adenomatous polyposis coli
C. Hereditary non-polyposis colon cancer
D. Multiple endocrine neoplasia syndrome II
E. Gardner’s syndrome

Answer 22

D. Multiple endocrine neoplasia syndrome II

FAP (B) is an autosomal dominant condition caused by a mutation in the APC gene. It results in the development of hundreds of poyps in the colon and carries a 100 percent lifetime risk of colorectal cancer, so these patients are offered prophylactic proctocolecomy with ileorectal pouch at a young age. 50% of those patients also develop gastric and duodenal polyps, and so need regular endoscopic screening.

Gradner’s (E) is closely related to FAP, but has extra-intestinal manifestations. It is charecterised by colonic polyps, epidermoid cysts and osteomas.

CHRPE (A) is another FAP variant, it may be detected on indirect opthalmoscopy in up to 75% of those with adenomatous polyposis coli.

Heriditary non-polyposis colon cancer (C) is the most common cause of hereditary colon cancer, accounting for 3% of of all colonic carcinoma. The genes involved are varied, but are involved in DNA repair.

The MEN syndromes (D) may have GI manifestations, including neuroendocrine tumours of the duodenum and pancreas, as well as megacolon secondary ro motility dysfunction. Adenocarcinoma is not a feature.

Question 23

Which of the following is the most common site for colonic carcinoma?
A. Rectum
B. Sigmoid colon
C. Caecum and ascending colon
D. Descending colon
E. Transverse colon

Answer 23

A. Rectum

33% of all colonic malignancy is in the rectum

25% in the sigmoid

18% in the caecum and ascending colon

9% in the transverse

and 5% in the descending colon

This is directly correlated to the transit time faecal matter, those sections of the colon with the longest transit time have the highest rates of malignancy.

Question 24

Which of the following is not an indication for radiotherapy or chemotherapy in
colonic cancer?
A. Dukes’ stage B
B. Intraoperative peritoneal contamination during resection
C. Dukes’ stage C
D. All rectal tumours <10 cm from anal verge
E. Dukes’ stage D

Answer 24

A. Dukes’ stage B

Althought this question may seem complex but a limited knowledge of the Dukes staging system makes the answer obvious. Dukes D means distant metastatic disease, Dukes C means lymph node involvement, whereas Dukes B means that it is locally contained. As such option (A) is the obvious answer here.

(B) is definitely an indication for chemotherapy.

(B) is controversial but reasearch has shown a benefit for radiotheray in such cases.

Question 25

An 85-year-old patient is admitted to the emergency department in shock with a short history of large-volume fresh bleeding per rectum. You resuscitate the patient with blood and fluids. There is no identifiable source on rectal examination. However, the patient continues to be unstable and you suspect continued bleeding. Her bowels open and pass an additional large volume of blood. Your next stage of management is:
A. Laparotomy
B. Radionucleotide red cell scanning
C. Oesophagogastroduodenoscopy
D. Mesenteric angiography
E. Colonoscopy

Answer 25

C. Oesophagogastroduodenoscopy

Upper GI bleeds account for 80% of all gastrointestinal haemorrhage.

of the lower GI bleed 95% is from the colon, the key to management is accurate localisation. Any blind surgical management is to be avoided as the re-bleeding rate is high.

Initial management of any rectal bleed is to exclude any anorectal causes with a careful rectal examination and rgid proctoscopy/sigmoidoscopy. If no source is found the next stage is to exclude an upper gastrointestinal cause as 15% of rectal bleeds origionate above the ligament of Treitz (suspensory muscle of the duodenum), the traditional demarcation of upper and Lower GI.

Following a negative OGD further management will depend on the haemodynamic status of the patient. A colonoscopy is gold standard for mild to moderate bleeding, but is compromised in large bleeds. Major bleeders who are haemodynamically compromised can be investigated with red-cell scanning, angiography or an emergency laparotomy.

Question 26

The most common cause of large bowel obstruction in the developing world is:
A. Adhesions
B. Intestinal parasites
C. Volvulus
D. Hernia
E. Neoplasia

Answer 26

D. Hernia

In the western world adhesions (A) are the most common cause of obstruction, due to the greater number of surgical procedures performed.

The most common cause in the developing world is hernia (D), although volvulus (C) (due to increased diatery fibre leading to intestinal loading) and parasitic causes (B) are more common.

Neoplastic disease (E) causes more obstructions in the developing world due to delayed diagnosis.

Question 27

A 45-year-old woman is admitted through the emergency department with central colicky abdominal pain, vomiting and absolute constipation. She is fluid
resuscitated and a nasogastric tube is placed. Abdominal radiograph demonstrates dilated loops of bowel with valvulae conniventes clearly identifiable. The next stage of management is:
A. Contrast computed tomography
B. Barium meal
C. Diagnostic laparoscopy
D. Gastrografin via a nasogastric tube
E. Radio-opaque contrast enema

Answer 27

D. Gastrografin via a nasogastric tube

Obstruction may be due to mechanical or non-mechanical causes. Of the mechanical causes they may be partial or complete. A complex obstruction is one where there are signs of vascular compromise, whereas a closed loop obstruction is where there is where there is no route of pressure release , making these particularly prone to complications.

Initial management in all cases is blood tests, fluid resuscitation and NG tube insertion, with aspiration, ‘drip and suck’. Complete mechanical obstructions typically require surgery, but the inital investigations are intended to rule out a non-obstructive cause.

Gastrograffin via an NG tube (D) is a diagnostic investigation as well as a part of the management as a minority of obstructions will resolve following oral gastrograffin. This should therefore always be an early investigation. All patients should also have a gastrograffin enema (E) and abdominal CT (A) prior to theatre,

Laparoscopy (C) is not a first line investigation and an barium meal (B) is contraindicated due to risk of perforation

Question 28

Which of the following is not a recognized complication of a Meckel’s
diverticulum?
A. Volvulus
B. Adenocarcinoma
C. Peptic ulceration
D. Intussusception
E. Pancreatitis

Answer 28

E. Pancreatitis

Meckel’s is the most common congenital abnormality of the GI tract, occuring in 2% of the population. It is an embryological remmnant of the vitello-intestinal duct and so is located around 30cm from the ileocaecal valve. The cells lining the vitello-intestinal duct are pluripotent and may differentiate into any tissue, commoly the the diverticulum is lined with heterotrophic gastric epithelium (50%) or pancreatic tissue (5%). Meckel’s diverticulum commonly presents as gastrointestinal haemorrhage secondary to peptic ulceration of the abnormal epithelium. This is commonly seen in children around 10 years old as an episode of melaena. There can also be malignant changes, leading to adenocarcinoma (B).

There is also a risk of mechanical complications of Meckel’s diverticulum, there can be diverticulitis which has symptoms clinically indistinguishable from acute appendicitis. The abnormal segment is also liable to cause intussceptions (D) or to twist on it’s fibrous band leading to volvulus (A). Other presentations include perforation or umbilical fistulation, where the entire vitello-intestinal duct remains patent.

Question 29

Carcinoid tumours occur most commonly in which site?
A. Large bowel
B. Duodenum
C. Appendix
D. Stomach
E. Lung

Answer 29

C. Appendix

Carcinoid tumours are closely related to neural crest cells and are otherwise known as APUD tumours. They are can be derived from foregut structures (Thymus, respiratory system), midgut (stomach, duodenum, jejunum, right colon) or hindgut (left colon and rectum).

Foregut and midgut carcinoids secrete serotonin (5-HT) whereas hindgut tumours rarely do. They can also secrete other peptide hormones such as bradykinin, vasoactive intestinal peptide, gastrin, insulin, ACTH, thyroxin and others.

The most common site is the appendix, but they can be found anywhere on the ailimentary tract, and 10% occur in the lung.

Carcinoid syndrome is caused by systemically released serotonin causing flushing (90%), diarrhoea (70%), abdo pain (40%), and bronchospasm (10%). Normally these peptide hormones undergoe first pass metabolism, so if a patient has systemic carcinoid syndrome it indicates metastasis to the liver where the hormones can escape to the circulation. The more common presentation is a mechanical obstruction or a mass effect.

Question 30

Which of the following histopathological features is not characteristic of Crohn’s disease?
A. Rose thorn abscesses
B. Cobblestoning
C. Skip lesions
D. Lead piping
E. Serosal involvement

Answer 30

D. Lead piping

The difference between the histology/radiology of Crohn’s and ulcerative colitis is important as a finals topic.

Radiologically the loss of the haustra seen in ulcerative colitis leads to the colon appearing straight on radiographs, so called ‘lead-piping’ (D). This is unique to ulcerative colitits and so is the odd one out here.

Radiologically the deep serosal lesions (E) of Crohn’s disease can be seen on radiographs as charecteristic ‘rose-thorn’ abcesses (A). These lesions in Crohn’s are skip lesions (C), in that there is unbroken mucosal tissue between lesions, as oppossed to the confluent involvement in UC. On Barium radiographs these skip lesions can give the ‘cobblestoned’ (B) appearence of the bowel.