血痰を主訴とし, 胸部単純X線写真で異常を認めなかった肺Mycobacterium intracellulare症の1例

抄録

A 45-year-old man visited our clinic because of intermittent bloody sputum. The chest roentogenogram was normal, but the high-resolution computed tomography (HRCT) showed very small nodules and bronchiolitis adjacent to pleura in the upper right lung field. The bronchoscopic examination revealed blood-streaked bronchial secretion in the right upper lobe bronchus, and the cultures of the sputa and the bronchial washing specimen showed acid-fast bacilli identified as Mycobacterium intracellulare by DNADNA hybridization (DDH) method. This case was diagnosed as Mycobacterium intracellulare lung disease. The patient received isoniazid, levofloxacin, and clarithromycin for three years without clinical and bacteriological improvement. His hemoptysis and the number of colonies recovered from sputum cultures decreased without any medication later. The serial chest roentogenograms and HRCTs have showed no changes for 6 years after the diagnosis. This case may show some clues to elucidate the mechanism of the onset of Mycobacterium intracellulare lung disease without predisposing conditions.