Antigen avoidance and environmental inhalation challenge for successful diagnosis of fibrotic hypersensitivity pneumonitis mimicking idiopathic pulmonary fibrosis.

A 77-year-old man was initially diagnosed with idiopathic pulmonary fibrosis (IPF) and treated with anti-fibrotic nintedanib. Despite undergoing anti-fibrotic treatment for one year, his condition remained unstable. The patient was admitted to our hospital for exertional dyspnea. We performed an exposure assessment, including 2-week antigen avoidance and an environmental inhalation challenge, and successfully re-diagnosed him with fibrotic hypersensitivity pneumonitis (HP), known as chronic farmer's lung. Adding oral glucocorticoids to the nintedanib treatment improved his condition. Although antigen avoidance and environmental inhalation challenge tests are not standardized, they may be useful for diagnosing fibrotic HP when properly applied.

Macrolide resistant Mycobacterium avium complex pulmonary disease following clarithromycin and ethambutol combination therapy.

RATIONALE: Whether two-drug therapy (clarithromycin and ethambutol) for Mycobacterium avium complex (MAC) pulmonary disease contributes to the development of macrolide-resistant MAC is unclear. OBJECTIVE: To compare the incidence of macrolide-resistant MAC between patients treated with two-drug therapy (clarithromycin and ethambutol) and the standard three-drug therapy (clarithromycin, ethambutol, and rifampicin) for MAC pulmonary disease. METHODS: We retrospectively reviewed 147 patients with treatment-naive MAC pulmonary disease who had received two-drug therapy (n = 47) or three-drug therapy (n = 100) between 1997 and 2016 at National Hospital Organization, Tenryu Hospital, Hamamatsu, Japan. The risk of development of macrolide-resistant MAC was evaluated by calculating the cumulative incidence rate using Gray's test. RESULTS: The median follow-up period was 74.5 months. During the follow-up period, one of the 47 patients (2.1%) in the two-drug group developed macrolide-resistant MAC, compared to 12 of the 100 patients (12.0%) in the three-drug group. The cumulative incidence rate of macrolide-resistant MAC was lower in the two-drug group than in the three-drug group (0.0023; 95% confidence interval, 0.002 to 0.107 versus 0.200; 95% confidence interval, 0.100 to 0.324, p = 0.0593). CONCLUSIONS: These results suggest that two-drug treatment with clarithromycin and ethambutol for MAC pulmonary disease does not lead to a higher incidence of resistance acquisition to clarithromycin than the standard three-drug treatment.