Clinical Relevance and Characteristics of Nontuberculous Mycobacterial Pleuritis

Nontuberculous mycobacteria (NTM) disease is of increasing public health concern; however, data regarding pleural effusion in NTM disease patients are limited. The purpose of this study was to investigate the clinical relevance and characteristics of NTM pleuritis. Patients with pleural effusion and NTM disease diagnosed between April 2012 and November 2017 were enrolled and their medical records were retrospectively reviewed. Clinical characteristics and treatment outcomes were analyzed. A total of seven among 100 patients with NTM disease had NTM pleuritis (7%). Flow cytometry of T and B lymphocytes revealed varying degrees of cellular immunodeficiency in five cases (71.4%). NTM pleuritis with pneumothorax occurred in five patients (71.4%) and bronchopleural fistula (BPF) was also found in four of them. All seven patients had delayed diagnosis and the mean time of diagnosis was 7 months (1-24 months). Four patients successfully completed treatment, while three patients (42.8%) succumbed to progressing NTM disease. Low CD4-positive T-cell counts were common in NTM pleuritis patients. Delayed diagnosis and treatment resulted in increased incidence of NTM pleurisy and poor prognosis. Moreover, BPF is perhaps a characteristic feature of Mycobacterium avium complex-associated pleuritis.