Younger Age and Viral Triggers Were Associated With Post-Infectious Bronchiolitis Obliterans in French Children.

Aim: Post-infectious bronchiolitis obliterans (PIBO) is a rare but severe chronic paediatric obstructive lung disease, characterised by the obliteration of small airways following severe lower respiratory tract infections. Epidemiological data in Europe remain limited.

Methods: This multicentre retrospective study examined the characteristics of paediatric patients diagnosed with PIBO from 2017 to 2023. Carried out by the French Reference Centre of Rare Lung Diseases network, it was based on clinical and radiological criteria and included age at diagnosis, medical history, symptoms, initial triggers, treatment, and outcomes.

Results: The study comprised 147 patients (58.5% male) diagnosed by 18 tertiary centres at a median age of 22 months. Most (83.7%) were hospitalised for the suspected initial infection: 36.7% in intensive care units and 47.0% in acute care wards. A younger age at diagnosis was associated with higher hospitalisation rates (p = 0.01). Microbiological triggers were identified in 66.0%, mostly adenoviruses (28.5%) and the respiratory syncytial virus (26.4%), often as co-infections. Lung function tests were performed on 23.1% of patients and bronchoscopies on 66.9%. Treatment included inhaled corticosteroids (90.5%), azithromycin (59.2%) and intravenous corticosteroid pulses (40.8%).

Conclusion: Age and causative agents were key factors in the initial severity of the infection that led to paediatric PIBO in our study.