Sporadic Obliterative Bronchiolitis: Case Series and Systematic Review of the Literature

OBJECTIVE: To describe the clinical characteristics and outcomes of patients diagnosed with obliterative bronchiolitis (OB) not associated with transplantation or point-source exposures to inhaled toxins. PATIENTS AND METHODS: We compiled all confirmed diagnoses of OB at our institution and analyzed their demographic characteristics, treatments, and outcomes as defined by pulmonary function tests (PFTs) and transplant-free mortality. The study period ranged from July 2007 to August 2017. Histological diagnosis was confirmed by a pathologist, and high-resolution chest computed tomography (CT) scans were reviewed and scored by chest radiologists. We also performed a systematic literature review of sporadic OB series. RESULTS: We identified 19 confirmed cases at our institution and 9 publications in the literature containing 104 patients. In both our series and the literature, patients were disproportionately middle-aged Caucasian women. The disease was idiopathic in 42% and was associated with connective tissue diseases and inhalational exposures in 31% and 15%, respectively. Chest CT showed expiratory air trapping in all patients. Patients were treated with corticosteroids, steroid-sparing agents, and macrolides in 77%, 46%, and 22%, respectively. Over a median follow-up in our series of 1703 days (range, 11-3206 days), PFTs did not change significantly. In all series combined, mortality incidence from any cause was 82/1000 patient-years (95% CI, 65-102). Of 14 patients who died, 3 deaths were due to respiratory failure and 5 were potentially related to complications of immunosuppressive therapy. CONCLUSION: Sporadic OB is a rare disease that is uniformly associated with air trapping on high-resolution chest CT. The diagnosis should be established with surgical biopsy if possible. The illness is not typically progressive.