Path Notes: Ulcerative Colitis*** Flashcards
What is Ulcerative Colitis?
Chronic, recurring, ulcero-inflammatory disease restricted to the colon and rectum.
Affects only the mucosa and submucosa (excepting only the most extreme cases)
Describe the extent / spread of UC
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)
UC epidemiology
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!
Macroscopic features of UC
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
Micro features of UC
- Diffuse mononuclear inflammatory infiltrate in lamine propria
- Infiltration into the lamina propria may lead to crypt abscesses (also seen in CD)
- Ulceration may extend into the submucosa but RARELY into the muscularis propria
- 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
Clinical Features of UC
- Relapsing disorder
- Bloody mucoid diarrhoea
- Lower abdo pain
- Pain relieved by defecation
- May have only one attack
- Precipitated by emotional stress
- 60% of patients have mild disease
What are the extra-intestinal features of UC?
- Migratory polyarthritis (like CD)
- Sacroiliitis (like CD)
- Ankylosing Spondylitis (like CD)
- Uveitis**
- Skin lesions**
- Pericholangitis and primary sclerosing cholangitis
Complications of CD and UC
In most severe cases:
- 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 - Tendency for dysplasia to occur in multiple sites
- UC = highest risk of cancer, in those with pancolitis