Emphysematous changes in chronic hypersensitivity pneumonitis: A retrospective analysis of 12 patients

Abstract

Introduction: Emphysema is most commonly associated with smoking but has been reported to occur in chronic hypersensitivity pneumonitis (CHP).The aim of this study was to further explore this association. Methods: A retrospective, computer-assisted search was performed to identify patients with CHP seen at Mayo Clinic, Rochester from 1997-2014. Demographic, clinical, and imaging features were analyzed. Patients with ≥10 pack year smoking history were excluded. Results: 12 patients (9 males, 3 females) with CHP and CT evidence of emphysematous changes were identified.Ten were never smokers and two were ex-smoker (5 pack-years and pipe smoker, respectively). The median age at the time of diagnosis was 47(range, 29-77) yrs. The median duration between the onset of the onset of symptoms and diagnosis was 27 (range, 2-161) months.The most common presenting symptom in these patients was dyspnea (83%); followed by cough (± phlegm) and weight loss (33%). In eight patients (67%) there was identifiable exposure to inciting antigens.Six (50%) had positive HP serologies. The diagnosis was confirmed by surgical lung biopsy in nine subjects (75%), one (8%) had transbronchial biopsy. Five subjects (42%) had restrictive defect whereas three (25%) had obstruction and three (25%) had normal spirometry. The severity of emphysema varied from mild to severe and extensive including bullae. Centrilobular type of emphysema was most commonly seen whereas in two subjects paraseptal distribution was also present. Emphysema could be seen in any lobe with slight predilection for upper lobes (42%). Conclusion: Emphysematous parenchymal lung destruction can be seen in patients with CHP.