Ischaemia: a pathogenetic clue in diversion colitis?

Abstract

It is not common that, after diversion of the faecal stream by a colostomy, the defunctioned colon develops colitis. The pathogenesis of this colitis is still unclear and it has been proposed that ischaemia may play a major role. Our aim is to look for signs of ischaemia in a group of patients developing colitis after diversion colostomy for various causes. Surgical specimens from 32 patients resected for colitis developed after diverting colostomy were examined with routine (haematoxylin-eosin) and Elastic-Van Gieson and Perls' stains. The histological features related to mucosal crypt architecture, crypt epithelium and inflammation were mild, non specific or related to the underlying disease. Fibrosis was present in 21 (65.6%) patients, superficial coagulative necrosis was found in 18 (56%) patients, splitting and/or thickening of muscularis mucosae was present in 20 (62%) patients. The vessels were substantially normal or ectasic without thrombi or alterations in the wall. Evident ischaemia with coagulative necrosis, submucosal oedema and focal fibrosis was detected in only two (6%) patients and an intermediate picture between acute and chronic ischaemia was present in 16 (50%) patients. It is possible that ischaemia plays some role in the pathogenesis of diversion colitis; however, further studies are needed to firmly establish its role.