Natural course of the nodular bronchiectatic form of Mycobacterium Avium complex lung disease: Long-term radiologic change without treatment

Abstract

Background/PurposeAlthough the incidence of Mycobacterium avium complex (MAC) lung disease is increasing, the long-term natural course of the nodular bronchiectatic form of MAC lung disease is not well described. The objective of our study is to evaluate long-term radiologic changes in untreated MAC lung disease by analyzing serial chest computed tomography (CT) scan findings.MethodsOf 104 patients with MAC lung disease, we selected 40 untreated nodular bronchiectatic MAC patients who underwent serial chest CTs without treatment for at least four years (mean = 6.23 years). Majority of patients have minimal symptoms. Two chest radiologists retrospectively reviewed initial and final chest CT scans. Each chest CT scan was scored for presence and extent of bronchiectasis, cellular bronchiolitis, consolidation, cavity, and nodule (maximum score: 30).ResultsOf 40 patients, 39 (97.5%) experienced a significant increase in overall CT score (overall difference = 4.89, p<0.001). On repeated measure analysis of variance analysis, cavity yielded the largest increase compared with cellular bronchiolitis (p = 0.013), nodule (p<0.001), and consolidation (p = 0.004). However, there was no significant difference in mean score change between cavity and bronchiectasis (p = 0.073). In analysis between radiologic parameters and the absolute number of involved segments, bronchiectasis showed most significant change compared with nodule (p<0.001) and consolidation (p<0.001).ConclusionsMost untreated nodular bronchiectatic MAC lung disease cases showed radiologic deterioration over long-term observation periods when we compared serial chest CT scans. Careful monitoring of MAC lung disease with serial chest CT scan can be beneficial in these untreated patients.

Treatment of Mycobacterium avium Complex (MAC)

“…It is apparent that many NB MAC-LD patients have indolent disease; therefore, MAC isolation from a respiratory specimen, even when diagnostic criteria are met, is not inevitably associated with progressive MAC-LD that requires treatment. 11,21 The decision to start or withhold therapy for NB MAC-LD requires a careful risk/benefit assessment for each patient. For mild NB MAC-LD, the treatment may have uncertain benefit while exposing patients to medication toxicity and side effects.…”

“…Those NB MAC-LD patients not started on therapy must be followed up indefinitely as there is mounting evidence for significant risk of MAC-LD-associated morbidity and mortality in patients not started on antimycobacterial therapy. 18,[21][22][23][24] There are few objective markers of MAC-LD disease progression. A recent study compared the clinical characteristics of MAC-LD patients who had a progressive course resulting in treatment initiation within 3 years of diagnosis with patients who exhibited a stable course for at least 3 years.…”

“…Park et al studied 40 untreated NB MAC-LD patients, mostly with minimal symptoms, who underwent serial chest CT scans without treatment for at least 4 years. 21 Each chest CT scan was scored for the presence and extent of bronchiectasis, bronchiolitis, consolidation, cavitation, and nodules. Thirty-nine patients (97.5%) experienced a significant increase in overall CT score with cavitation yielding the largest increase.…”

Assessing Response to Therapy for Nontuberculous Mycobacterial Lung Disease: Quo Vadis?

“…Untreated patients with NTM lung disease demonstrate progression of CT findings on serial studies that inform decisions to initiate treatment, particularly with the nodular bronchiectatic form of MAC lung disease ( Park et al, 2017 ). Similar to microbiologic endpoints, radiographic improvement at the conclusion of therapy can characterize successful treatment of NTM lung disease.…”

High-Resolution CT Findings as Predictive Factors for Recurrent Nontuberculous Mycobacterial Pulmonary Disease after Successful Treatment

“…Chest CT has been used in a wide variety of clinical settings for disease monitoring, determination of the timing of treatment initiation, and evaluation of the treatment response in NTM-PD [ 7 , 8 , 9 ]. Indeed, various studies have reported the radiologic course of MAC-pulmonary disease (MAC-PD) and M. massiliense infection [ 7 , 8 , 9 , 10 , 11 ]. Previous studies also reported a nodular bronchiectatic form on baseline CT was an independent predictor of recurrence in MAC-PD [ 6 , 12 ].…”