[The development of pneumothorax in an elderly woman during treatment for nontuberculous mycobacterium].

We report the case of an 82-year-old woman who developed pneumothorax during treatment for nontuberculous mycobacterium (NTM). In year X, she was diagnosed with NTM at another hospital after abnormalities were pointed out on a chest X-ray. She received no treatment for NTM at that time. Antibiotic treatment was introduced at the department of respiratory medicine in our hospital in year X+15. The regimen was composed of clarithromycin (800 mg/day), ethambutol (750 mg/day) and rifampicin (600 mg/day); however, treatment with the three-drug antibiotic regimen was canceled at her request and changed to erythromycin. She was then referred to our department. However, right-side cavity wall thickening was detected on chest CT in year X+17.We resumed clarithromycin (600 mg/day), ethambutol (750 mg/day) and rifampicin (450 mg/day). On the 43rd day after treatment with three types of antibiotics, she felt dyspnea and she was admitted to the hospital and was diagnosed with right-side pneumothorax. The pneumothorax was thought to have been caused by a break in the adhesion of the cavity wall. The visceral pleura was weakened by the exacerbation of NTM and the thickness of the cavity wall was improved after the resumption of antibiotic therapy. This report is considered to be an important case in which pneumothorax developed as a complication in an elderly patient during treatment for NTM.