Pseudomembranous colitis and co-trimoxazole.

An 80-year-old woman was admitted to hospital with a fractured neck of the femur, which was managed by internal fixation. Antibiotic cover was not provided for the operation. On the sixth day after operation she developed a fever, which was clinically attributed to a urinary infection, although no organism was subsequently cultured. Treatment was started with cotrimoxazole (Septrin), two tablets twice daily. On the 15th day after operation the patient developed offensive diarrhoea, but the co-trimoxazole was not discontinued until the 20th day. Culture of the stool showed no pathogen, and the diarrhoea did not respond to symptomatic treatment (Kaomycin (neomycin sulphate and kaolin) on days 20-26; Lomotil (diphenyloxylate hydrochloride and atropine sulphate) on days 25-27). A surgical opinion was sought on the 27th day. On examination the patient was ill and dehydrated. Abdominal examination showed nothing abnormal, but rectally large humps of mucosa could be felt. A barium enema examination showed a pancolitis with a cobblestone appearance suggestive of mucosal oedema. Rectal biopsy confirmed the typical histological appearances of fibrinous exudate on the mucosal surface mixed with mucus from distended crypts. The patient was treated with oral cholestyramine and parenteral nutrition. The diarrhoea did not remit and the patient died 32 days after operation. At necropsy the whole colon showed the changes of pseudomembranous colitis, the rectum and descending colon being the worst affected.