Lung Ultrasound May Help Distinguish Bronchiolitis from Infection-Triggered Wheezing in Children Under 2: Study
Spain: A new observational study published in the American Journal of Emergency Medicine suggests that lung ultrasound may aid clinicians in distinguishing between bronchiolitis and wheezing caused by infection in children under two years of age, potentially supporting more targeted treatment decisions in this vulnerable population.
The research, led by Mercedes Bueno-Campaña from the Department of Paediatrics and Neonatology at Hospital Universitario Fundación Alcorcón, Spain, explored the diagnostic utility of lung ultrasound (LUS) in young children presenting with lower respiratory tract infections (LRTIs), respiratory distress, and wheezing. Differentiating between bronchiolitis and recurrent wheezing is clinically important, as both conditions require different management approaches despite often presenting with similar symptoms.
Lung ultrasound has gained increasing attention as a non-invasive bedside tool for evaluating respiratory illnesses. While its usefulness has been demonstrated in several lower respiratory conditions, its role in distinguishing specific causes of wheezing in infants and toddlers has remained less clear. This study aimed to bridge that gap by systematically assessing ultrasound findings in affected children.
The prospective, multicentre study included 99 children younger than two years diagnosed with LRTIs and respiratory distress. Lung ultrasound examinations were conducted within 24 hours of hospital admission. Researchers evaluated five predefined lung regions and assigned scores ranging from 0 to 4 based on the severity and type of abnormalities observed. These scores were then combined to estimate overall lung involvement. The final clinical diagnosis—either bronchiolitis or recurrent wheezing triggered by infection—served as the primary outcome measure.
The study led to the following findings:
- Abnormal lung ultrasound findings were observed in nearly 85% of the study participants.
- Certain ultrasound patterns showed a correlation with bronchiolitis.
- B-lines, which indicate interstitial involvement, were more commonly seen in the right posterior lung regions in children with bronchiolitis.
- The localization of these findings demonstrated a moderate association with bronchiolitis.
- Overall diagnostic performance of lung ultrasound for predicting bronchiolitis was modest based on ROC-AUC analysis.
- Predictive accuracy improved significantly in children older than six months.
- In this subgroup, the presence of more than three B-lines showed high specificity for bronchiolitis.
- Despite high specificity, the sensitivity of these findings remained limited.
The authors emphasize that lung ultrasound could serve as a supportive diagnostic tool, especially when clinical presentation alone does not clearly differentiate between conditions. Identifying characteristic patterns, such as clustered or confluent B-lines in specific lung areas, may help clinicians make more informed decisions.
However, the study also highlights certain limitations. Variability in image acquisition and interpretation may affect consistency, and the relatively small sample size calls for caution in generalizing the findings. The researchers advocate for larger, standardized studies to validate these observations and to develop more objective scoring systems.
Overall, the findings highlight the growing role of lung ultrasound in pediatric respiratory care, particularly as a rapid and radiation-free modality that may enhance diagnostic precision in early childhood respiratory illnesses.
Reference:
Bueno-Campaña, M., Suarez-Cabezas, S., De la Torre-Martin, L., Del Olmo-Segura, P., Barral-Mena, E., Canet-Tarres, A., Hernández-Villarroel, A. C., & González-Bertolín, I. (2026). Lung ultrasound in diagnosis of wheezing triggered by infection in children less than 2 years: An observational study. The American Journal of Emergency Medicine, 106, 1-6. https://doi.org/10.1016/j.ajem.2026.04.018
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