[The value of rectosigmoidoscopy and the bacteriologic culture of colon biopsies in the etiologic diagnosis of acute diarrhea of adults. A prospective study of 65 patients].

The goal of this study was to evaluate the contribution of sigmoidoscopy with bioptic microbiology to the etiologic diagnosis of acute diarrhea in adults. Patients and methods. Sixty-five patients with acute diarrhea were included prospectively from February 1993 to November 1994. Ages ranged from 17 to 83 years. In each patient, two stool samples were cultured and three examined for parasites. Clostridium difficile toxin was looked for in the 18 patients who had taken antimicrobials before onset of the diarrhea. Sigmoidoscopy with collection of biopsy specimens for bacteriologic cultures was performed routinely. Results. A pathogenic organism was identified in 35 patients (54%). Eighteen patients (28%) had positive stool cultures. Clostridium difficile toxin was detected in six patients. Colonic biopsy cultures were positive in 26 patients (40%). Endoscopic findings established the diagnosis of pseudomembranous colitis with negative tests for C. difficile toxin in two patients, diverticulitis in one, ischemic colitis in two, and cryptogenic colitis in seven. Conclusions. Sigmoidoscopy ensured the diagnosis in over 72% of cases of acute diarrhea. This investigation complements stool cultures and should be done routinely in adults with severe acute diarrhea.