Ulcerative colitis complicating pseudomembranous colitis of the right colon

A 65-year-old man in the remission stage of ulcerative colitis developed severe bloody diarrhea and high fever. He was treated with imipenem/cilastatin and clindamycin for infectious enterocolitis at a local hospital, but there was no improvement in his condition. Steroid pulse therapy was also ineffective. Colonoscopy revealed pseudomembranous colitis extending from the ascending colon to the cecum, and Clostridium difficile toxin was positive in the feces. The administration of vancomycin in addition to oral steroids resulted in rapid improvement of the condition. Total colonoscopy is recommended for precise diagnosis when patients with ulcerative colitis develop intractable diarrhea during or after antibiotic therapy.