Idiopathic chronic obliterative bronchiolitis: a multicentric retrospective cohort

Abstract

Rationale: Idiopathic chronic obliterative bronchiolitis (OB) in adults is a very rare entity that has been little described. We aimed at evaluating the clinical, functional, radiological, and pathologic characteristics of patients with OB.

Methods: After IRB approval, a retrospective cohort study was conducted in the OrphaLung Network in France. Patients with a histological confirmation or direct features of bronchiolitis at chest CT (peripheral micronodules, and/or branching infiltrates in V or Y shape) were considered eligible. Imaging eligibility criteria were confirmed by two experienced pulmonologists. Cases related to connective tissue disease, drugs, transplantation or other etiologies were excluded.

Results: A total of 68 patients were included, with a median age of 55 years (18-72 years), and 70% of females. Only 26 patients had a history of smoking (mean 17 pack-years). The mean FVC was 76% ±21 of predicted. The mean FEV1 was 58% ±22%. The mean FEV1/FVC was 0.61(±0.17). DLco was 68% ±19% and Kco was 90% ±21%. Airflow obstruction was present despite bronchodilators in 47 patients (69%). Direct signs of bronchiolitis were present on CT in 55 patients (81%). Lung pathology available in 24 patients demonstrated follicular (7 cases), granulomatous (3), lymphocytic (8), and constrictive (6) bronchiolitis, respectively. The median duration of follow-up was 5 years (5-20 years). Outcome data will be presented.

Conclusion: OB is a rare chronic condition associated with frequent persistent airflow obstruction, and various pathologic patterns. Typical CT features may be missing. Prospective studies are needed to evaluate the benefit of potential treatments.