Aims To assess whether auscultation findings at presentation with bronchiolitis vary with age or viral aetiology.
Methods We conducted an opportunistic prospective cohort study of infants who presented to the Emergency Department (ED) with bronchiolitis (diagnosed by ED doctors). Chest auscultation findings in all children were assessed and recorded prospectively at presentation. Viral PCR was carried out on nasopharyngeal aspirates when requested by clinician. Chest auscultation findings were correlated with age and viral aetiology. Our outcome measures were variation of auscultatory signs with age and viral aetiology
Results 86 children were recruited to the study. The mean age (±SE) was 22±1.5 weeks and 40% were female. Infants who presented with wheeze were significantly older ((mean ±SE) 26.6±1.9 weeks) than babies who presented without wheeze (17.3±2.1 weeks) (ANOVA, p=0.002). Those who presented without normal auscultation findings were younger than those with wheeze or crackles or both (15.1±2.6 weeks vs 24.4±1.7 weeks) (ANOVA, p=0.006). There was no difference in auscultation findings depending on the virus responsible for bronchiolitis. In 68% of cases (n=34) bronchiolitis was caused by RSV, 32% (n=16) by rhinovirus, 10% (n=5) by adenovirus.
Conclusion Chest auscultation findings associated with bronchiolitis vary according to age, with infants older than 24 weeks likely to present with wheeze and those younger than 16 weeks more likely to present without auscultatory chest signs. This is a crucial finding as it has been previously reported that crackles are a consistent feature of bronchiolitis1. Differences in chest signs may reflect differences in pathomechanisms of bronchiolitis and may explain why there are variations in response to medical treatment reported in the literature. Clinicians should be especially vigilant with young infants (<16 weeks) who are relatively more likely to present without any auscultatory chest signs.