L14-15: Gut Diseases

Question 1

Define: Inflammatory Bowel Disease

Answer 1

Chronic inflammatory and ulcerating disorders of the GI tract due to disregulated response to intestinal flora (microbiome)

Question 2

Two major forms of IBD

Answer 2

Ulcerative Colitis and Crohn’s disease

Question 3

Ulcerative Colitis

Answer 3

Chronic inflammatory disease of the colon

Question 4

Defining feature of ulcerative colitis

Answer 4

Involvement of rectal mucosa and varying portions of the large intestine. Usually occurs as a chronic disease but mild to severe exacerbations occasionally occurs in acute fulminating form

Question 5

Clinical features of UC

Answer 5

Diarrhoea, blood loss p.r., abdominal pain

Systemic signs: fever, joint pains and inflammation of the eye

Question 6

Macroscopic changes in UC

Answer 6

1. Mucosa - hyperaemic, granular or shallow ulceration with bridges of mucosa which later re-epithelialise to resemble polyps
2. Colon shortened and without haustra

Question 7

Microscopic salient features of active ulcerative colitis

Answer 7

1. Distorted tubular structure and irregular mucosal surface with luminal pus
2. Goblet cell depletion and reactive hyperplasia of epithelium
3. Focal polymorph infiltration of crypt epithelial lining and crypt abscesses
4. increased chronic inflammatory cell content of lamina propria with oedema
5. Vascular congestion
6. Loss of epithelium with ulceration

Question 8

Epithelium surface contains which immune cells

Answer 8

CD8+ T cells

Question 9

Microscopic changes in ulcerative colitis in remission

Answer 9

1. Loss of tubular parallelism with branching
2. Short tubules, separated from one another
   and from the muscularis mucosae
3. Thickening of the muscularis mucosae
4. Paneth cell metaplasia
5. Epithelial dysplasia

Question 10

Define: dysplasia in IBD

Answer 10

Unequivocal neoplastic transformation of the intestinal epithelium by the basement membrane that can be recognised by abnormal cellular and architectural alterations.

Question 11

Histological features of dysplasia in UC

Answer 11

1. Glands lined by cells showing loss of mucin, nuclear enlargement, nuclear pleomorphism, loss of polarity, pseudostratification and abnormal mitoses
2. May see villous transformation or glands lying back-to-back
3. Classified as low or high grade dysplasia

Question 12

Factors determining development of carcinoma in UC

Answer 12

1. Disease of longer than 10 years duration
2. Onset of disease in childhood
3. Severe first attack and evidence of continuing activity
4. Extent of colitis (pan colitis)

Question 13

Crohn’s Disease

Answer 13

Chronic inflammatory condition, potentially involving any part of the alimentary tract from mouth to anus; most commonly the distal ileum (small intestine) and proximal colon, with the rectum frequently spared.
Characterised by segmental areas of involvement, with normal intervening bowel and trans-mural extension of the disease process

Question 14

Clinical features of CD

Answer 14

• Diarrhoea, abdominal pain and fever
• Extraintestinal manifestations may be present
• Complications include fistula formation and strictures
• Fat and vitamin malabsorption with small bowel involvement

Question 15

Anatomic distribution of CD

Answer 15

Most common involvement of ileum and right colon (ileocolonic involvement), followed by small bowel alone, and subsequently colon alone.