Path Notes: Ulcerative Colitis***

Question 1

What is Ulcerative Colitis?

Answer 1

Chronic, recurring, ulcero-inflammatory disease restricted to the colon and rectum.

Affects only the mucosa and submucosa (excepting only the most extreme cases)

Question 2

Describe the extent / spread of UC

Answer 2

Restricted to the rectum and colon

Tends to spread proximally from the rectum

Limited to mucosa and submucosa (excepting only the most severe cases)

Well formed granulomas are absent (unlike in CD)

Question 3

UC epidemiology

Answer 3

Slightly greater incidence than CD

More common in whites than blacks, and in females than males

Peak age = 20-25

Smoking reduces risk of UC!

Question 4

Macroscopic features of UC

Answer 4

UC involves the rectum, and then extends proximally to involve the entire colon

10% of patients with pan-colitis-distal-ileum may develop mucosal inflammation “backwash ileitis”

Appendix occasionally involved

Mucosa:

• Erythematous
• Granular
• Friable
• Bleeds easily

In severe inflammation:

• Extensive broad-based inflammation of colon mucosa that extends ints entire length
• Isolated islands of regenerative mucosa create ‘pseudo-polyps’
• Cycles of inflammation, damage, healing and progressive muscle atrophy leads to flattened surface

Question 5

Micro features of UC

Answer 5

1. Diffuse mononuclear inflammatory infiltrate in lamine propria
2. Infiltration into the lamina propria may lead to crypt abscesses (also seen in CD)
3. Ulceration may extend into the submucosa but RARELY into the muscularis propria
4. GRANULOMAS NOT PRESENT

Whilst in remission (of active disease), granulation tissue fills the ulcer craters, with regeneration of mucosal epithelium

There is general submucosal fibrosis, and mucosal architectural disarray and atrophy

Epithelium may become dysplastic (low-high grade) and progress to frank carcinoma - note that regenerative changes and actual dysplasia may be hard to differentiate between

Question 6

Clinical Features of UC

Answer 6

1. Relapsing disorder
2. Bloody mucoid diarrhoea
3. Lower abdo pain
4. Pain relieved by defecation
5. May have only one attack
6. Precipitated by emotional stress
7. 60% of patients have mild disease

Question 7

What are the extra-intestinal features of UC?

Answer 7

1. Migratory polyarthritis (like CD)
2. Sacroiliitis (like CD)
3. Ankylosing Spondylitis (like CD)
4. Uveitis**
5. Skin lesions**
6. Pericholangitis and primary sclerosing cholangitis

Question 8

Complications of CD and UC

Answer 8

In most severe cases:

1. TOXIC MEGACOLON
   - CD / UC does toxic damage to the muscularis propria and the neural plexus. This leads to shut-down of neuromuscular function. Causes swelling and becomes gangrenous = toxic megacolon
2. Tendency for dysplasia to occur in multiple sites
   - UC = highest risk of cancer, in those with pancolitis