The incidence and characteristics of reservoir inflammation after rest
orative proctocolectomy for ulcerative colitis were studied in a serie
s of 179 patients. The median follow up time was 27 months (range 6-80
). Pouchitis occurred in 36 patients (20%) and nine of these (5%) deve
loped a chronic, persisting pouchitis. There were no pouch failures as
a result of pouchitis and no significant adverse effect on longterm f
unctional outcome. The overall cumulative risk to develop pouchitis fo
ur years after surgery was 23%. The risk of pouchitis is unpredictable
on clinical grounds except that there were significantly less patient
s with left sided colitis in the group who subsequently developed pouc
hitis. Morphological and histochemical studies showed a greater degree
of colonic metaplasia in the pouch mucosa in patients with pouchitis
and patients with a chronic pouchitis had the highest degree of change
s. The results support the view that pouchitis is a novel manifestatio
n of inflammatory bowel disease in heal mucosa that has changed slowly
to a colon like mucosa.