In December 2002, a 90-year-old man was diagnosed with pulmonary tuberculosis via an abnormal chest X-ray and an AFB smear that was done on his bronchial washing fluids. He was treated with antitubercular agents, including isoniazid (INH; 400 mg/day), rifampin (RFP; 600 mg/day), pyrazinamide (PZ; 1500 mg/day), and ethambutol (EMB; 800 mg/day). Thereafter, the findings on his chest X-ray gradually improved, but he complained of intermittent loose stool.
1 month later, his diarrhea took a turn for a worse: it was bloody and mucoid with a jelly-like appearance and he suffered from lower abdominal cramping pain. In February 2003, the patient was admitted to our hospital because of frequent bloody, mucoid, jelly-like diarrhea and lower abdominal pain. He had a poor oral intake of food and drink due to his continuing diarrhea, which occurred 4 to 5 times per day. The patient was afebrile and his vital signs were normal. His breathing sounds were still coarse on both lung fields and his bowel movements were very frequent. The abdomen was soft and flat, but tenderness was noted on LLQ area without rebound tenderness. His white blood cell count was 13,600/mm3 with 54.2% segmented neutrophils. The stool culture was negative for C.difficile toxin and salmonella-shigella. Sigmoidoscopy revealed multiple yellowish plaque lesions from the rectum to the sigmoid colon (Figure 2A), and mucosal biopsy from the sigmoid colon showed chronic inflammation with mucous exudates (Figure 3). There was the strong likelihood that the antitubercular agents were causing PMC, so we discontinued these agents. After oral metronidazole 250 mg three times a day and conservative therapy with intravenous fluid and electrolytes, the symptoms of the patient were ameliorated and then the patient was discharged.
After 2 weeks, we restarted antitubercular agents with the 4 drugs regimen (HERZ) at the same initial doses. The patient again developed abdominal pain and diarrhea within only 3days after the retreatment with antitubercular agents. So the patient occasionally withheld the antitubercular agents by himself according to symptom, and when symptoms were relieved, he restarted taking the drugs.
Only 3 weeks after discharge, he admitted with complains of mucoid, bloody diarrhea, severe abdominal pain and fever up to 38.4 C. His chest X-ray showed little change during this interval compared with the previous films (Figure 1). The white blood cell count was 20,200/mm3 with 78.7% segmented neutrophils. We stopped all medication including the anti-tubercular agents except the metronidazole. For 3 days, conservative management was done including fluid therapy and fasting, but he did not show improvement. So sigmoidoscopy was again done and it revealed diffuse white plaque and debris on the colon mucosa from the rectum to the sigmoid colon, with scattered whitish erosion (Figure 2B). Mucosal biopsy of the colon was compatible with a diagnosis of PMC on account of the ulceration with exudates of a pseudomembrane made up of inflammatory cells, fibrin, and necrotic debris. C. difficile toxin and stool culture were negative. 11 days after admission, the patient's symptoms were much resolved and follow-up sigomidoscopy demonstrated a much improved state of the colitis. 2 days later, the antitubercular agents were retried with regimen of 3drugs without the RFP (INH 400 mg, PZ 1500 mg, EMB 800 mg) and we observed the patient for another 10 days. The patient had no further recurrence of diarrhea, and he recovered his general condition; the follow-up sigmoidoscopy did not show any evidence of recurrent PMC (Figure 2C), and he was then discharged.