Persistence of enterocolitis following diversion of faecal stream in Hirschsprung's disease

Mucosal defence mechanisms of the excluded bowel were studied in 12 patients with Hirschsprung's disease. The entire resected segment of colon obtained following Swenson's operation was cut at 0.5-cm intervals and serially examined by routine haematoxylin and eosin staining, immunocytochemistry, and mucin histochemistry. Seven patients who had clinical evidence of enterocolitis prior to defunctioning colostomy showed histological and immunological evidence of enterocolitis (crypt abscesses, ulceration, leucocyte aggregation, Paneth cell metaplasia, and marked immunocyte responses) in the excluded bowel even several months after diversion of the faecal stream. Mucin histochemistry showed marked depletion of neutral mucins and sulphomucins in the excluded bowel with inflammatory changes and reversal of the sialo- to sulphomucin ratio. These results indicate that patients with enterocolitis complicating Hirschsprung's disease have persistent inflammatory changes in the excluded large bowel after diversion of the faecal stream by colostomy. Environmental factors such as bacterial stimulation and proliferation probably cause inhibition of cell renewal, resulting in abnormalities of mucin fractions. Changes in mucin composition, which is an important mechanical and chemical factor of the mucosal defence mechanism, may lead to altered susceptibility to bacterial degradation and hence may be important in the pathogenesis of enterocolitis.Offprint requests to: P. Puri