Etiological spectrum and clinical phenotype profiling of bronchiectasis in a pediatric cohort

Abstract Background This study aims to delineate the etiological spectrum of pediatric bronchiectasis in western China and compare the clinical characteristics among different etiologies. Methods We conducted a retrospective cohort study of children newly diagnosed with bronchiectasis by high-resolution chest computed tomography at a tertiary pediatric hospital in western China (2018–2022). We collected clinical data on demographics, symptoms, airway comorbidities, imaging, pulmonary function, microbiological data, and bronchoalveolar lavage cellular data. The data underwent both descriptive and etiology-based inter-group analyses. Results This study included 484 children newly diagnosed with bronchiectasis between 2018 and 2022. An etiology was identified in 99% of cases, with post-infection (65.5%) being the most common, followed by either immunodeficiency (16.5%), mucociliary clearance apparatus or epithelial disease (3.7% total; PCD 2.7%, CF 1.0%). The immunodeficiency and genetic disorder groups (including PID, PCD, and CF) had a significantly higher male predominance (73.8%; 70.1%) and a later median diagnosis age (11 years). These two groups also had significantly higher modified Reiff scores on computerized tomography, but no difference in lung function. The most common pathogens isolated from lower respiratory tract specimens (sputum or BALF) were Haemophilus influenzae and Mycobacterium tuberculosis . Fungal infections occurred exclusively in children with immunodeficiency. Conclusions This study presents the etiological spectrum of pediatric bronchiectasis in western China and describes how clinical phenotypes differ across etiologies. It highlights the necessity of actively seeking underlying causes in affected children, with special attention to genetic etiologies.