Evidence of improved small airways function after azithromycin treatment in diffuse panbronchiolitis

Abstract

A 67-year-old never-smoker was diagnosed with diffuse panbronchiolitis (DPB) and was started on 250 mg azithromycin twice weekly. Over a 16-month observation period, lung function was assessed monthly, including a dedicated small airways test, the multiple breath nitrogen washout (MBW) with indices Scond and Sacin of ventilation heterogeneity at the level of the conductive and acinar air spaces, respectively. Baseline measurements indicated moderate airway obstruction, air trapping and considerable dysfunction of the small airways around the acinar entrance. Treatment resulted in excellent symptomatic improvement paralleled by marked improvements in FEV 1, FVC, RV/TLC, Scond and Sacin; by contrast, there were no consistent changes in FEF75 or TLCO. While improvements were such that Scond fell within normal limits after 5 months, Sacin remained abnormal even after 16 months of treatment. This suggests a distinct acinar structural abnormality in DPB that cannot be reversed by azithromycin. © 2012 S. Karger AG, Basel.