Bronchiolitis

Pathophysiology

• Viral infection causes inflammation, oedema, and increased mucus in bronchioles

• Obstruction leads to air trapping, atelectasis, and impaired gas exchange

• V/Q mismatch and increased work of breathing

• Risk of apnoea in young infants due to immature respiratory control

Diagnosis

• Clinical diagnosis based on age and presentation – no routine need for CXR or labs

• Presentation: rhinorrhoea, cough, wheeze, increased work of breathing, poor feeding

• Tachypnoea, nasal flaring, subcostal and intercostal recession

• Crackles and/or wheeze on auscultation

• Apnoea may be the first sign in very young or premature infants

Management

Supportive

• Mainstay is supportive care

• Feeding support – NG or IV fluids if not feeding adequately

• Suctioning of nasal secretions

• Oxygen if SpO₂ persistently <92%

• Monitor for apnoea in high-risk infants

• No role for salbutamol, steroids, or antibiotics in typical bronchiolitis

Hospitalisation

• Indications include:

  • SpO₂ <92%

  • Moderate to severe work of breathing

  • Apnoea episodes

  • Dehydration or inadequate feeding

  • Significant comorbidities (e.g. cardiac, respiratory, neuromuscular, immunodeficiency)

• Severe cases may require HFNC, CPAP or ICU-level care

Complications

• Respiratory failure

• Apnoea

• Dehydration due to poor feeding

• Secondary bacterial pneumonia (rare)

• Prolonged cough or wheeze

• Increased risk of wheezing or asthma later in childhood

Prognosis

• Excellent in most healthy term infants – self-limiting illness resolving in 7–10 days

• Peak severity usually at day 3–5

• Higher morbidity in premature infants and those with comorbidities

• No long-term antiviral treatment; RSV prophylaxis (palivizumab) in high-risk groups only