概述
Ulcerative colitis (UC) is a chronic disease characterized by diff use
mucosal infl ammation limited to the colon. It involves the rectum
in about 95 % of cases and may extend proximally in a symmetrical,
circumferential, and uninterrupted pattern to involve parts or
all of the large intestine. Th e hallmark clinical symptom is bloody
diarrhea oft en with prominent symptoms of rectal urgency and tenesmus.
Th e clinical course is marked by exacerbations and remissions,
which may occur spontaneously or in response to treatment
changes or intercurrent illnesses ( 1,2 ). UC aff ects approximately
500,000 individuals in the United States with an incidence of 8 – 12
per 100,000 population per year; the incidence has remained relatively
constant over the last fi ve decades ( 3 – 8 ).
