Pseudomembranous colitis (PMC) may develop with long-term antibiotic administration, but is rarely reported to be caused by antitubercular agents. We present a case of PMC that occurred 120 days after starting rifampicin. A 74-year-old man was diagnosed with pulmonary tuberculosis and started on a standard HERZ regimen (isoniazid, ethambutol, rifampicin, pyrazinamide). After 4 months of HERZ, he presented with frequent bloody, mucoid, jelly-like diarrhea and lower abdominal pain. Sigmoidoscopy revealed multiple whitish plaques with edematous mucosa that were compatible with PMC. Biopsies from these lesions showed ulcer-related necrotic and granulation tissue. We stopped antitubercular treatment and started the patient on oral metronidazole. His symptoms completely resolved within 2 weeks. Antitubercular treatment was restarted by replacing rifampicin with levofloxacin. The patient did not present with diarrhea or bloody stool throughout the rest of treatment.

Advancing age is a well-known risk factor for Clostridium difficile infection (CDI). However, age-specific clinical differences in CDI are uncertain. A retrospective comparative analysis was performed based on age in 1367 patients with CDI in Korea. Most clinical features were similar in the two age groups studied, however malignancy was more common in the older group (age ≥ 65 y) (p < 0.001), while chemotherapy and transplantation were more common in the younger group (age < 65 y) (p < 0.001). Endoscopic examinations were more commonly performed in the older group (p = 0.010), which had a high positive predictive value (88.3%). More patients recovered from CDI without specific antibiotic treatment in the younger group than in the older group (p < 0.001). Although advancing age is an important risk factor for CDI, the clinical features of younger patients are similar to those of the older patient population.