Clinical features

It occurs in children under 2 years of age and most commonly in the first year of life, peaking between 3 and 6 months.

• symptoms usually peak between 3 and 5 days, and that cough resolves in 90% of infants within 3 weeks
  
• bronchiolitis can be diagnosed if the child has a coryzal prodrome lasting 1 to 3 days, followed by:
  • persistent cough and either tachypnoea or chest recession (or both)
  • and either wheeze or crackles on chest auscultation (or both)
• following symptoms are common in children with this disease:
  • fever (in around 30% of cases, usually of less than 39°C)
  • poor feeding (typically after 3 to 5 days of illness)
• young infants with this disease (in particular those under 6 weeks of age) may present with apnoea without other clinical signs
  
  
• in a mild illness the child may improve. However in some cases the condition progresses with increasing breathlessness, wheeze, cyanosis and pyrexia
• in severe illness on examination the child has rapid, laboured breathing, tachycardia, gross lung hyperinflation producing a barrel-shaped chest, prominent neck veins and downward displacement of the liver. Auscultation reveals widespread wheeze and crepitations over both lung fields. There is increased expiratory time
  
  
• consider a diagnosis of pneumonia if the child has:
  • high fever (over 39°C)
  • and/or persistently focal crackles

Reference:

• NICE (August 2021). Bronchiolitis in children