General GI Pathology

Question 1

What is Hirschsprung’s disease?

Answer 1

Absence of ganglion cells in the myenteric plexus

Question 2

What is the male to female ratio of Hirschsprung’s disease?

Answer 2

4:1

Question 3

Name a disorder associated with Hirschsprung’s disease

Answer 3

Down syndrome

Question 4

Name a gene associated with Hirschsprung’s disease

Answer 4

RET proto-oncogene Cr10

Question 5

Describe the histological findings on biopsy in Hirschsprung’s disease

Answer 5

Hypertrophied nerve fibres, no ganglia

Question 6

What is volvulus?

Answer 6

Complete twisting of a bowel loop at the mesenteric base around the vascular pedicle

Question 7

Where is the most common site of volvulus?

Answer 7

Infants: small bowel
Elderly: sigmoid colon

Question 8

State the two most common sites of ischaemic colitis

Answer 8

Splenic flexure (transition of superior mesenteric artery to inferior mesenteric artery), rectosigmoid (transition of inferior mesenteric artery to internal iliac artery)

Question 9

State the peak age of onset of Crohn’s disease and ulcerative colitis

Answer 9

Crohn’s disease: 20-29

Ulcerative colitis: 20-25

Question 10

State the monozygotic twin concordance of Crohn’s disease and ulcerative colitis

Answer 10

Crohn’s disease: 50%

Ulcerative colitis: 15%

Question 11

Describe the histological appearance of Crohn’s disease on biopsy

Answer 11

Patchy distribution (skip lesions), areas of healthy mucosa above diseased mucosa (cobblestone appearance), rosethorn ulcers, non-caseating granulomas, transmural inflammation

Question 12

What is the first lesion in Crohn’s disease called?

Answer 12

Aphthous ulcer

Question 13

Describe the histological appearance of ulcerative colitis on biopsy

Answer 13

Continuous mucosal involvement extending proximally from rectum, extensive superficial broad ulcers, mucosal inflammation, pseudopolyps from islands of regenerating mucosa (can fuse to form mucosal bridges)

Question 14

Describe the typical presentation of Crohn’s disease

Answer 14

Intermittent diarrhoea, pain, fever

Question 15

Describe the typical presentation of ulcerative colitis

Answer 15

Bloody, mucus-y diarrhoea, crampy abdominal pain relieved by defecation

Question 16

State two ocular manifestations of inflammatory bowel disease

Answer 16

Uveitis, conjunctivitis

Question 17

State at least three dermatological manifestations of inflammatory bowel disease

Answer 17

Erythema nodosum, pyoderma gangrenosum, erythema multiforme, digital clubbing

Question 18

What is erythema nodosum?

Answer 18

Tender bruise-like swellings on shins

Question 19

State at least three joint manifestations of inflammatory bowel disease

Answer 19

Migratory asymmetrical large-joint polyarthropathy, sacroiliitis, myositis, ankylosing spondylitis

Question 20

State at least two hepatic manifestations of inflammatory bowel disease

Answer 20

Pericholangitis, steatosis, primary sclerosing cholangitis (especially UC)

Question 21

State at least three complications of Crohn’s disease

Answer 21

Strictures, fistulae, abscess formation, perforation

Question 22

State the three main complications of ulcerative colitis

Answer 22

Severe haemorrhage, toxic megacolon, adenocarcinoma (20-30x risk)

Question 23

What is toxic megacolon?

Answer 23

Colonic dilatation from damage to the muscularis propria and neuromuscular function

Question 24

State the management of an acute episode of Crohn’s disease

Answer 24

If mild: oral prednisolone

If severe: IV hydrocortisone, metronidazole

Question 25

State the management of an acute episode of ulcerative colitis

Answer 25

If mild: oral prednisolone and mesalazine
If moderate: oral prednisolone, mesalazine, steroid enema twice a day
If severe: admit, nil by mouth, IV fluids and hydrocortisone, rectal steroids

Question 26

State the maintenance drugs used in Crohn’s disease

Answer 26

Azathioprine, methotrexate, infliximab

Question 27

State the maintenance drugs used in ulcerative colitis

Answer 27

1st line: Aminosalicylates (5-ASA) e.g. Mesalazine

2nd line: Azathioprine