Contribution of post-infectious bronchiolitis obliterans to non-cystic fibrosis bronchiectasis in children.

Post-infectious bronchiolitis obliterans (PIBO) is a complication of severe childhood respiratory infection resulting in small airway injury, bronchiectasis, and prolonged respiratory consequences. Risk factors for PIBO and PIBO-associated bronchiectasis are unclear.This retrospective study identified all children with PIBO at a South African tertiary hospital between 1 January 2016 and 31 December 2022. The clinical characteristics, chest CT findings, and details of prior hospitalisation for respiratory infection were collected, and the characteristics of those with and without bronchiectasis were compared.A total of 59 children were included (median age at primary lung insult: 10 months, IQR 6-17; median age at PIBO diagnosis: 16 months, IQR 11-28). Twenty-three had comorbidities, most frequently premature birth (30.5%) and HIV infection (6.8%). The most common pathogen was adenovirus (n = 41; 69.5%). At initial lung insult, 19 (32.2%) required mechanical ventilation. Mosaic attenuation on the chest CT was present in all. Thirty-three (55.9%) had bronchiectasis. The clinical characteristics, ventilation, causative pathogen, and comorbidity were similar in those with and without bronchiectasis.Bronchiectasis occurs frequently in paediatric PIBO and is present within months of initial respiratory insult with no identified risk factors. Premature birth is common and may contribute to PIBO development..