Ischaemic colitis (necrotizing colitis, pseudomembranous colitis) in acute schistosomiasis mansoni: report of two cases

Two cases of ischaemic necrosis of the sigmoid colon (necrotizing colitis) are reported in 2 brothers aged 7 and 4 years, diagnosed within a 10 d interval. The children had bathed in streams suspected to be contaminated by Schistosoma mansoni about 50–60 d before the onset of acute disease. Both patients had been previously exposed to schistosome-infested streams without showing signs or symptoms of infection. Before admission, S. mansoni eggs had not been found in the stool. Both patients presented with an apparently identical, relatively symptomatic clinical course with rapid evolution to an acute abdomen. Laparotomy disclosed, in both patients, extensive necrosis (ischaemic necrotizing colitis of schistosomal aetiology) of about 20 cm in the first child and 8 cm in the second, extending from part of the descending colon to the sigmoid. The patients were successfully operated upon (hemicolectomy plus colostomy). The histopathological findinngs were similar in both patients. Ischaemic necrosis with complete destruction of the mucosa and part of the submucosa was detected in the first case; in the necrotic areas a few eggs of S. mansoni were seen, with no granulomatous reaction, but surrounded by cell shadows, pycnotic nuclei and amorphous material. Necrosis extended to the muscular layer and serosa, in which schistosome granulomas in the necrotic-exudative phase were seen, as well as diffuse granulocytic exudate and fibrin. Sections of tissue from both patients contained numerous eggs and granulomas all in the same exudative phase in regional lymph nodes and near the thrombotic vessels. After surgery, the 2 patients progressed similarly. About 10 d after hospital discharge, the patients received anti-schistosomal treatment with oxamniquine. No further sign of infection was detected at subsequent recall visits.