A case of ulcerative colitis after administration of therapeutic agents for nontuberculous mycobacterial infection

A 53-year-old man who suffered from continuous cough was referred to our hospital for the treatment of pulmonary nontuberculous mycobacterial infection (NTM) . After beginning administration therapeutic agents for including which were rifampicin, ethambutol and clarithromycin, the patient was hospitalized because of severe diarrhea and abdominal pain. The patient did not improve by stopped the drugs. Then the patient underwent fasting and treatment with IV fluids for over 1 month. Abdominal CT scan and colonoscopy suspected Pan-ulcerative colitis. General symptom and diarrhea improved after the administration of 5-aminosalicylic acid (5-ASA) . The final pathological diagnosis was ulcerative colitis (UC) . The characteristic of drug-induced enterocolitis is that discontinuation of the drug leads to rapid improvement of symptoms. The criteria for diagnosing UC may require exclusion of drug-induced enterocolitis. The reasons why this case was diagnosed with UC were that diarrhea did not improve for over 1 month after discontinuation of the drugs, and UC was strongly suspected by colonoscopy, CT scan and pathological diagnosis. Herein, we reported the rare case of UC that was difficult to differentiate from drug-induced enterocolitis.