["Pouchitis"; histology].

"Pouchitis" is a well recognised complication of restorative proctocolectomy characterised by acute diarrhoea, sometimes with blood, often complicated by incontinence, malaise, arthritis, erythema nodosum and fever. The ileal mucosa is hyperaemic, there may be shallow ulcers and contact bleeding. Biopsies characteristically show villous atrophy, a poly-morphonuclear infiltrate and chronic inflammatory cells, but the histopathological features are often patchy and may be difficult to differentiate from ischaemic ileitis, colonic metaplasia or Crohn's disease. "Pouchitis" is probably due to an overgrowth of intestinal bacteria secondary to stasis but there is some evidence that there may be an ischaemic factor. Most patients respond rapidly to oral metronidazole.