Background and study aims: This study assesses the diagnostic value of colonoscopy performed at an early stage of a first attack of acute, severe hemorrhagic colitis.
Patients and methods: One hundred fourteen consecutive patients were prospectively studied. The colonoscopic diagnosis was compared with the final diagnosis of the colitis, which was based on clinical, microbiological, endoscopic, and histological criteria during the acute illness, but also on the results of a thirty-month follow-up of the patients aiming to confirm whether the colitis was relapsing or nonrelapsing in nature.
Results: The colonoscopic diagnosis was ulcerative colitis (UC) in 40, Crohn's disease in four, and infective colitis (IC) in 70 patients. The endoscopic diagnosis was finally confirmed in all 40 UC patients and in 68 of 70 (97.1%) IC patients. Two patients with an initial endoscopic and histological diagnosis of IC presented with typical attacks of UC 28 and 30 months later, respectively. Prominent endoscopic appearances in IC were mucosal edema, erythematous areas, hemorrhagic spots, bleeding, microaphthoid ulcers, and luminal exudate. Although rectal sparing was occasionally seen, endoscopic lesions were continuous and severe in the distal colon, but were patchily and unevenly distributed in other parts of the colon in IC. In UC, prominent colonoscopic findings were bleeding, mucosal friability, granularity, and ulceration; lesions were continuously distributed in the involved area.
Conclusions: Colonoscopy is a useful procedure in the differential diagnosis of severe bloody diarrhea of unknown cause.