EVALUATION OF COLONOSCOPIC FINDINGS IN PATIENTS WITH DIARRHEAGENIC ESCHERICHIA COLI-INDUCED HEMORRHAGIC COLITIS

Background: We evaluated the clinical significance of colonoscopic findings in the acute infectious phase of diarrheagenic Escherichia coli (E. coli)‐induced hemorrhagic colitis. Methods: According to the strain of cultured pathogen, 38 patients with diarrheagenic E. coli‐induced hemorrhagic colitis were divided into an enterohemorrhagic E. coli (EHEC) group consisting of 20 patients and a non‐EHEC group consisting of 18 patients. The inflammatory findings were classified into five grades primarily according to the severity of the edema, and attendant on the degree of erythema. The inflammatory grade was determined for each part of the colon, rectum, and terminal ileum. Results: In the EHEC group, colonoscopy manifested characteristic findings of an inflammatory gradient in most patients. Additionally, in approximately half of the patients, longitudinal ulcers were observed in part of the transverse colon and/or the descending colon. In the non‐EHEC group, inflammatory findings were milder than those of EHEC‐induced colitis, and were restricted to the left‐side colon in most patients. In five of 18 patients, colonoscopic findings closely resembled those of transient ischemic colitis. In two of 18 patients, geographic ulcerations were seen in the left‐side colon. In 11 of 18 patients, only mild inflammations were observed in restricted segments of the colon. Conclusions: In the EHEC group, colonoscopy manifested characteristic findings not seen in other colonic diseases, and which are useful in predicting the probability of EHEC as the causative pathogen in patients with hemorrhagic colitis. In the non‐EHEC group, colonoscopic findings did not demonstrate the common inflammatory findings seen in the EHEC group.