Clinical, laboratory, and microbiological factors associated with bronchiolitis severity: a prospective study

Aims: Bronchiolitis is a leading cause of pediatric emergency visits and hospitalization in infants, with a broad spectrum of clinical severity. This prospective study aimed to evaluate demographic, clinical, laboratory, radiological, and microbiological characteristics of children with bronchiolitis and to analyze their association with disease severity according to Wang’s criteria. Methods: A total of 305 children aged 0–24 months who presented to the pediatric emergency department of our institution and were diagnosed with bronchiolitis were prospectively enrolled. Patients were classified as having mild, moderate, or severe bronchiolitis. Demographic features, clinical findings, laboratory parameters, imaging results, respiratory support requirements, length of hospital stay, and viral and bacterial etiologies were recorded and analyzed.Results: The median age was 7 months, and 61.6% of patients were male. Mild, moderate, and severe bronchiolitis were observed in 49.8%, 31.5%, and 18.7% of patients, respectively. Recurrent respiratory tract infections were more frequent in moderate and severe disease (29.2% and 22.8%) compared with mild cases (11.2%; p=0.001). Chronic comorbidities were also associated with higher severity (p=0.007). Hospitalization rates increased significantly with severity (14.5% in mild vs 80.2% in moderate and 57.9% in severe cases; p