Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives

Abstract

Nontuberculous mycobacteria (NTM) are emerging pathogens that affect both immunocompromised and immunocompetent patients. The incidence and prevalence of NTM lung disease are increasing worldwide and rapidly becoming a major public health problem. For the diagnosis of NTM lung disease, patients suspected to have NTM lung disease are required to meet all clinical and microbiologic criteria. The development of molecular methods allows the characterization of new species and NTM identification at a subspecies level. Even after the identification of NTM species from respiratory specimens, clinicians should consider the clinical significance of such findings. Besides the limited options, treatment is lengthy and varies by species, and therefore a challenge. Treatment may be complicated by potential toxicity with discouraging outcomes. The decision to start treatment for NTM lung disease is not easy and requires careful individualized analysis of risks and benefits. Clinicians should be alert to those unique aspects of NTM lung disease concerning diagnosis with advanced molecular methods and treatment with limited options. Current recommendations and recent advances for diagnosis and treatment of NTM lung disease are summarized in this article.

Keywords: Mycobacterium; Mycobacterium avium complex; Mycobacterium kansasii; Nontuberculous Mycobacteria.

Figure 1. The fibrocavitary form of Mycobacterium intracellulare pulmonary disease in a 73-year-old male patient. Chest computed tomography shows a large cavity in the right upper lobe. Note the emphysema in both lungs.

Figure 2. The nodular bronchiectatic form of Mycobacterium intracellulare pulmonary disease in a 70-year-old female patient. Chest computed tomography shows severe bronchiectasis in the right middle lobe and the lingular segment of the left upper lobe. Note the multiple small nodules and tree-in-bud appearances suggesting bronchiolitis in both lungs.