Clinical characteristics and treatment outcomes of pleural effusions in patients with nontuberculous mycobacterial disease

Background The incidence of nontuberculous mycobacterial (NTM) infection has increased over the last 10 years. However, the clinical characteristics and treatment outcomes of patients with NTM pleuritis have not been well defined. Methods Patients with pleural effusion and NTM lung disease diagnosed between 1997 and 2013 were enrolled and their medical records were reviewed retrospectively. The subjects were divided into definite (n = 9, NTM isolated from the pleura or pleural effusion) and possible (n = 5, NTM lung disease with pleural effusion and improvement of effusion after anti-NTM treatment) groups. Clinical characteristics and treatment outcomes were analyzed. Patients with Mycobacterium avium complex (MAC) lung disease but without pleuritis were selected (the MAC-LD group) and compared with the MAC pleuritis (MAC-PD) group. Results The median age of the 14 NTM pleuritis patients was 68 years, and the majority were men (9/14, 64.3%). Mycobacterium intracellulare was the most common species detected (50.0%), followed by M. avium (35.7%), M. abscessus (7.1%) and M. kansasii (7.1%). The median lymphocyte frequency and adenosine deaminase level in the effusion were 83% and 97 IU/L, respectively. Eight patients successfully completed treatment, although 2 patients died as a consequence of uncontrolled NTM disease. The MAC-PD group had less nodular bronchiectatic lung features and a lower treatment success rate than the MAC-LD group. Conclusion The laboratory characteristics of pleural effusions from patients with NTM disease were similar to those of patients with tuberculous pleuritis. The treatment outcome of MAC-PD appears to be worse than that of MAC-LD. Therefore, clinicians need to be alert to successfully manage patients with MAC-PD.