Diversion colitis: a trigger for ulcerative colitis in the in-stream colon?

Abstract

The aetiology of ulcerative colitis is unknown. Two patients without pre-existing inflammatory bowel disease in whom end colostomy for faecal incontinence was complicated by diversion colitis in the defunctioned rectosigmoid colon, are described. In both instances, colitis with the clinical, colonoscopic, and microscopic features of ulcerative colitis developed about a year later in the previously normal in-stream colon proximal to the colostomy. These cases suggest that diversion colitis may be a risk factor for ulcerative colitis in predisposed individuals and that ulcerative colitis can be triggered by anatomically discontinuous inflammation elsewhere in the large intestine.

Figure 1

Patient 1: (A) biopsy specimen from rectal stump showing active chronic inflammation with crypt abscesses and distortion of crypt architecture; (B) biopsy specimen of in-stream colon showing no abnormality; (C) biopsy specimen from in-stream colon five months later showing active chronic inflammation.

Figure 2

Patient 2: (A) excised rectal stump showing active chronic inflammation with lymphoid follicles, crypt abscesses, and mild crypt architectural distortion; (B) resected in-stream colon showing similar but less severe changes.