ulcerative colitis

Other Definitions
ulcerative colitis (dict)

Ulcerative colitis is an inflammatory disease of the bowel, that usually affects the distal end of the large intestine and rectum. It has no known cause, although there is a genetic component to susceptibility. Ulcerative colitis is similar to Crohn's disease, but there are characteristic differences: ulcerative colitis is usually confined to the mucosa and submucosa, and affects whole areas of intestine. Crohn's disease, on the other hand tends to be patchy, and affect more layers of intestine, being transmural in nature.

Features

Chronic (> 6 months) of diarrhea (sometimes bloody).
No infective cause of diarrhea found.
Inflammatory changes are mainly left sided or in the distal large bowel.
Disease variable in severity from patient to patient and time to time.
Significant risk of carcinoma after 10 years, which may in some cases require frequent surveillance biopsies or even prophylactic bowel removal.
Patients may have other auto-immune features and extra-bowel complications including but not limited to iritis, uveitis, episcleritis, migratory polyarthritis, sacroiliitis, erythema nodosum, fingertip clubbing, and ankylosing spondylitis.
Fistula formation is rare but does occur. However, unlike Crohn's disease, the probability of recurrence is low.
Prevalent in former smokers. Stopping smoking can cause a reduction in the protective mucus lining the colon. When this protective mucus is reduced, the bacteria in the colon can attack the colon lining causing the immune system to become active and fight the bacteria. For unknown reasons, this causes damage to the lining (ulcers) of the colon walls in one or more places. Resumption of nicotine either through patches or smoking can extend remission time although the benefits versus the other health risks of smoking are questionable.

Cause

The cause of ulcerative colitis is unknown, although infective agents have been suspected, and there is a genetic component to susceptibility. Immune system over-activity has also been suspected as a cause.

Diagnosis

A long-standing history of bloody diarrhea, with no sign of infection, is consistent with ulcerative colitis. A biopsy can help confirm the diagnosis. Ulcerative colitis mainly affects the left side of the colon.

Course

People with ulcerative colitis may initially have bloody diarrhea (the severity of which is variable from time to time). Because of destruction of the nerves in the bowel, movement may be impaired, and the intestine may dilate. This results in an extreme diarrheal disease, toxic megacolon. Eventually the inflamed mucosa develops a risk of malignancy, requiring biopsy every few months. Sometimes the risk of malignancy is such that bowel resection is offered.