Background:
Viral bronchiolitis is the most common lower respiratory tract infection in children under the age of 12 months, and the most common cause of hospitalisation in children less than 6 months. Respiratory syncytial virus (RSV) accounts for most causes of bronchiolitis worldwide. There is little data on the viral aetiology of bronchiolitis and outcomes.
Methods:
Consecutive subjects with bronchiolitis admitted to a public hospital over two 1-year periods (2010 and 2012) were studied retrospectively. Viral aetiology of bronchiolitis, obtained by nasal polymerase chain reaction results was recorded. Primary outcomes were length of hospital stay. Secondary outcomes studied were triage category on admission, need for transfer to a tertiary center and need for respiratory support.
Results:
Over the 2 years studied there were 692 bronchiolitis admissions. NPA results were recorded in 570 subjects (82.3%). Transfer to a specialist tertiary center was required in 14 subjects (2%). RSV was the most common cause of bronchiolitis but accounted for only 38.7% of cases. Rhinovirus accounted for 19.9% of causes and 11.6% of NPA results were negative for respiratory viruses. Subjects who were positive for RSV had a longer mean length of stay. Subjects who had a negative NPA results had a significantly shorted mean length of stay. Neither positive NPA results (all cause) nor RSV positive NPA results were associated with a significant increase in transfer rate. A triage category of 1 or 2 on admission was significantly associated with RSV positive NPA results. Six subjects (0.9%) required respiratory support with continuous positive airway pressure (CPAP). No subjects requiring CPAP were positive for RSV.
Conclusion:
NPA results were positive for RSV in only 38.7% of bronchiolitis subjects. RSV positive subjects had a longer length of hospital stay compared to those who were positive for viruses other than RSV. RSV positivity was significantly associated with a higher triage category on admission but not need for transfer or respiratory support.