Nontuberculous mycobacterial pulmonary diseases in immunocompetent patients

Abstract

Nontuberculous mycobacterial (NTM) infections are an increasingly recognized cause of chronic lung disease in immunocompetent adults, and the M. avium complex, M. kansasii, and a rapidly growing mycobacteria such as M. abscessus, M. fortuitum, and M. chelonae account for most of the pathogens involved. Because the clinical features of NTM disease are not distinguishable from those of tuberculosis, and NTM are ubiquitous in the environment, diagnosis requires that the bacilli are isolated and identified. NTM diseases have been difficult to treat, though since the introduction of new macrolides, the outcome for patients with some NTM diseases has improved significantly. For correct diagnosis and the successful treatment of NTM pulmonary disease, a knowledge of the full spectrum of clinical and radiological findings is important.

Fig. 1

A 46-year-old woman with M. avium infection. A. Initial chest radiograph shows cavitary lesions (arrows) in both upper lobes. Also note that bilateral reticulonodular lesions are present in upper and middle lung zones. B. High-resolution (1.0-mm collimation) CT scan obtained at the level of the thoracic inlet, and at the same time as A, depicts a cavitary lesion with pleural thickening in the right apex. Nodules (arrows) project from the wall of the cavitation into its lumen. C. CT scan obtained at the level of the inferior pulmonary vein shows centrilobular nodules and branching linear structures (arrows) in both lungs, suggesting the bronchogenic spread of disease. Also note the presence of bronchiectasis in the right middle lobe. D. Follow-up radiograph obtained 31 months after A, and after treatment, shows some increase in the extent of reticulonodular lesions, especially in left upper and middle lung zones (arrows).

Fig. 2

A 67-year-old woman with M. avium infection. A. Initial chest radiograph reveals airspace consolidation in the right upper lobe and reticulonodular lesions (arrows) in the right middle, and left middle and lower, lung zones. B. High-resolution (1.0-mm collimation) CT scan obtained at the level of the bronchus intermedius, and at the same time as A, shows air-space consolidation (arrows) at the bottom of the right upper lobe, and bronchiectasis and small centrilobular nodules (small arrows) in the lingular segment of the left upper lobe. C. CT scan obtained at the level of the right basal trunk depicts centrilobular nodules and branching linear structures (arrows), an acinar nodule (curved arrows), lobular consolidation (open arrows), and bronchiectasis. D. Follow-up radiograph obtained 31 months after A, and after treatment, shows that in both lungs, disease is less extensive.

Fig. 3

A 78-year-old man with M. kansasii infection. A. Chest radiograph reveals the presence of reticulonodular lesions in both upper lobes, which have decreased in volume. Also note right apical pleural thickening and emphysematous overinflation in remaining lung areas. B. High-resolution (1.0-mm collimation) CT scan obtained at the level of the aortic arch shows consolidation containing the open bronchus sign in the right upper lobe and thin-walled cavity (small arrows), and some areas of consolidation (arrows) in the left upper lobe. Also note the reduced volume of both upper lobes.

Fig. 4

A 54-year-old woman with M. abscessus infection. A. Chest radiograph depicts patchy areas of reticulonodular lesions in the entire right and left upper lung. B. High-resolution (1.0-mm collimation) CT scan obtained at the level of the aortic arch demonstrates bronchiectasis, small nodules, and ground-glass opacity in the right upper lobe. C. Reformed coronal image depicts bronchiectasis, small nodules, and ground-glass opacity in the entire right lung.

Fig. 5

A 33-year-old man with M. fortuitum infection. A. Chest radiograph shows focal opacification of the right upper lung zone. B. High-resolution (1.0-mm collimation) CT scan obtained at the level of the aortic arch shows nodules of various sizes in the right upper lobe. The dominant nodule contains internal cavitation (arrow).

Fig. 6

A 37-year-old woman with M. chelonae infection. A. Initial chest radiograph depicts reticulonodular lesions in both lungs, especially in the upper and middle zones. B. High-resolution (1.5-mm collimation) CT scan obtained at the level of the main bronchi, and at the same time as A, shows centrilobular nodules and branching linear structures (arrows) in both lungs. C. CT scan obtained at the level of the right inferior pulmonary vein reveals bronchiectasis in both lungs, which contain centrilobular nodules (arrows). D. Follow-up radiograph obtained 58 months after A shows that as a result of treatment, disease is less extensive.