Relapsing-remitting inflammatory disorder of the colonic mucosa

may just affect the rectum (proctitis), extend into part of the colon (left-sided colitis) or into the entire colon (pancolitis)

Does not affect the GI tract proximal to the ileocaecal valve

Epidemiology:

• More common in western and northern hemispheres
• Most patients diagnosed between 20-40yrs, 2nd peak occurs at approximately 60yrs

Pathology

• red, raw mucosa, bleeds easily
• no inflammation beyond submucosa (unless fulminant disease)
• widespread ulceration with preservation of adjacent mucosa which has the appearance of polyps ('pseudopolyps')
• inflammatory cell infiltrate in lamina propria
• neutrophils migrate through the walls of glands to form crypt abscesses
• depletion of goblet cells and mucin from gland epithelium
• granulomas are infrequent

Distinctive features

C – Continuous inflammation

L – Limited to colon and rectum

O – Only superficial mucosa affected

S – Smoking is protective

E – Excrete blood and mucus