Viral bronchiolitis is the most common reason for infants to be admitted to hospital

Bronchiolitis is a condition characterised by acute bronchiolar inflammation.  Respiratory syncytial virus (RSV) is the pathogen in 75-80% of cases.

Epidemiology

• most common cause of a serious lower respiratory tract infection in < 1yr olds (90% are 1-9 months, with a peak incidence of 3-6 months). Maternal IgG provides protection to newborns against RSV
• higher incidence in winter

Cause

• respiratory syncytial virus (RSV) is the pathogen in 75-80% of cases
• other causes: mycoplasma, adenoviruses
• may be secondary bacterial infection
• more serious if bronchopulmonary dysplasia (e.g. Premature), congenital heart disease or cystic fibrosis

PC

The initial signs of an upper respiratory tract infection followed by the lower respiratory tract signs suggest bronchiolitis.

• coryzal symptoms (including mild fever) precede:
• dry cough
• increasing breathlessness
• wheezing, fine inspiratory crackles (not always present)
• feeding difficulties associated with increasing dyspnoea are often the reason for hospital admission