How can I assess the severity of bronchiolitis in an infant during a consultation?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 16 August 2025Updated: 16 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

To assess the severity of bronchiolitis in an infant during a consultation, follow these steps:

  • Observe the infant's general condition: Note the degree of agitation and consciousness, as agitation or behavioural changes may indicate hypoxia.
  • Look for signs of respiratory distress: Check for exhaustion, cyanosis (bluish lips or extremities), and use of accessory muscles of respiration while the infant is at rest.
  • Measure vital signs: Record respiratory rate, pulse rate, and if possible, blood pressure.
  • Measure oxygen saturation: Use pulse oximetry on room air if available, noting that persistent oxygen saturation below 92% is concerning.
  • Assess hydration status: Evaluate capillary refill time, skin turgor, dryness of mucous membranes, and urine output.
  • Identify critical signs requiring immediate referral: Apnoea (observed or reported), severe respiratory distress (e.g., grunting, marked chest recession, respiratory rate over 70 breaths/min), central cyanosis, or if the infant looks seriously unwell.
  • Consider referral if: Respiratory rate is over 60 breaths/min, difficulty with breastfeeding or inadequate oral fluid intake (50–75% of usual volume), clinical dehydration, or persistent oxygen saturation less than 92% on air.
  • Take into account risk factors that lower the threshold for hospital admission: Age under 3 months, prematurity (especially before 32 weeks gestation), chronic lung disease, significant congenital heart disease, neuromuscular disorders, immunodeficiency, and social factors affecting care.

Use this comprehensive clinical assessment to determine severity and the need for urgent referral or hospital admission.

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Educational content only. Always verify information and use clinical judgement.