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.