Diagnosis and treatment of nontuberculous mycobacterial lung disease

Koh, Won Jung; Kwon, O Jung

Abstract

As the prevalence of tuberculosis declines, the proportion of mycobacterial lung disease due to nontuberculous mycobacteria (NTM) is increasing worldwide. In Korea, Mycobacterium avium-intracellulare complex and Mycobacterium abscessus account for most of the pathogens encountered, whilst Mycobacterium kansasii is a relatively uncommon cause of NTM lung diseases. When NTM lung disease occurs, it is likely to present in one of two forms: apical fibrocavitary disease often affecting older male smokers with previous tuberculosis or chronic obstructive pulmonary disease; nodular bronchiectasis classically occurring in middle-aged or older woman who never smoked and present with cough. Because its clinical features are frequently indistinguishable from those of pulmonary tuberculosis and NTMs are ubiquitous in the environment, the isolation and identification of causative organisms are mandatory for diagnosis, and some specific diagnostic criteria have been proposed. Treatment of disease depends on the infecting species, extent and form of disease, and overall condition of the patient, but decisions concerning the institution of treatment are never easy. Treatment requires the use of multiple drugs for 18 to 24 months. Thus, treatment is expensive, often has significant side effects, and is frequently not curative. Surgery for localized disease may be useful for those species expected to be refractory to medical therapy. Observation without treatment may be appropriate for some patients with slowly progressive disease that is expected to be particularly difficult to treat.