Consolidations in Nodular Bronchiectatic Mycobacterium Avium Complex Lung Disease: Mycobacterium Avium Complex or Other Infection?

PURPOSE The objective of this study is to define the clinical implications of consolidations in nodular bronchiectatic type Mycobacterium avium complex (NBMAC) infection. MATERIALS AND METHODS A total of 69 patients (M : F = 17 : 52; mean age, 64 years; age range, 41-85 years) with MAC isolated in the sputum culture and nodular bronchiectasis on the initial and follow-up CT scans were included. We retrospectively reviewed the incidence of consolidation and analyzed its clinical course by using radiographic changes with or without anti-MAC drug therapy. RESULTS In 44 of the 69 cases (64%), focal consolidations were seen on the initial and follow-up CT images. In 35 of the 44 (80%) cases, consolidations completely regressed, and in 3 cases (7%), consolidations partially regressed within 2 months with only antibiotics. In 2 cases (5%), the consolidations remained stable for over 2 months without anti-MAC drug therapy. Only in 4 cases (9%) did the consolidations improve after anti-MAC drug therapy. In 11 of the 38 cases (29%) with responsiveness to antibiotics, non-mycobacterial micro-organisms were identified in sputum, including pseudomonas, hemophilus, staphylococcus, and others. CONCLUSION In NB-MAC, consolidations are commonly present on CT. In these conditions, most of consolidations result from pneumonia other than MAC.