Bronchiolitis

🍼🫁 Bronchiolitis – A monoclonal antibody to RSV (Palivizumab) is available as a monthly IM injection for high-risk preterm infants, though it is very expensive 💰.

🦠 Aetiology

• Primarily caused by Respiratory Syncytial Virus (RSV), which leads to inflammation, oedema, and necrosis in the small airways ➡️ airway obstruction.

📊 Epidemiology

• Most common in infants aged 1–9 months, can affect up to 2 years.
• ❄️ Peaks in winter months (Nov–March in the UK).
• ~30% of infants will be infected in their first year; a small proportion later develop asthma/reactive airway disease.

⚠️ Higher Risk Groups

• ❤️ Congenital heart disease
• 💨 Chronic lung disease / Bronchopulmonary dysplasia
• 🧠 Neuromuscular disorders (poor airway clearance)
• 🛡️ Immunodeficiency
• 👶 Preterm infants (immature lungs + narrow airways)

🩺 Clinical Presentation

• Starts with coryzal symptoms 🤧 (1–3 days) ➡️ then persistent cough.
• Other findings: pale, sweaty, tired appearance, nasal congestion, crackles + wheeze on auscultation.
• 🚩 Respiratory distress: grunting, nasal flaring, use of accessory muscles, tachypnoea, subcostal/intercostal recession.
• Red flags: apnoeas, cyanosis, difficulty feeding, poor urine output.

🔎 Differential Diagnoses

• Pneumonia, air leak, ARDS from sepsis
• Foreign body aspiration
• Pulmonary oedema (cardiac failure, congenital heart disease)

🧪 Investigations

• CXR: May show hyperinflation/patchy infiltrates, but ❌ not routine (changes mimic pneumonia).
• Blood gas: Only if severe/worsening distress or suspected respiratory failure (esp. if FiO₂ >50%).
• Virology swabs: May be used in hospital for cohorting but do not guide acute management.

🛡️ Prevention

• Palivizumab 💉: Monthly IM monoclonal antibody for high-risk infants (e.g., prematurity, congenital heart disease). Cost limits widespread use.
• Breastfeeding, smoke-free homes, and good hand hygiene reduce RSV spread.

💊 Management

• Home Care (mild cases):
  • 🛏️ Raise crib head to ease breathing.
  • 🌡️ Paracetamol for fever (>37.4°C); ibuprofen if >3 months.
  • 💧 Saline nasal drops before feeds.
  • 🌫️ Humidified/steamy environment (avoid burns).
  • 👃 Nasal suction/aspirator to clear mucus.
• Hospital Referral:
  • 📞 999 if: apnoea, severe distress (grunting, marked recession, RR >70), central cyanosis, SpO₂ <92% on air.
  • ➡️ Consider referral if: RR >60, poor feeding (<50–75% of usual intake), dehydration.
• Hospital Care:
  • 💧 Hydration (oral/NG/IV fluids if poor intake).
  • 🌡️ Antipyretics for fever.
  • 💨 Oxygen if SpO₂ persistently <92%.
  • ⚠️ Avoid: antibiotics, salbutamol, ipratropium, montelukast, hypertonic saline, nebulised adrenaline, corticosteroids (per NICE).
  • 🧴 Gentle suctioning if upper airway secretions impair breathing.
  • 💨 CPAP for impending respiratory failure.

🫁 Indications for Ventilation

• Progressive tachypnoea with increased work of breathing.
• Lethargy or frequent/prolonged apnoea.
• 📉 Worsening acidosis on blood gas.
• ⬆️ Increasing oxygen requirement despite CPAP/high-flow support.

🧑‍🏫 Exam Tip

Bronchiolitis is usually supportive management only. A common pitfall in exams and practice is prescribing salbutamol or steroids - ❌ they don’t work in RSV bronchiolitis! Always mention risk factors (prematurity, CHD, chronic lung disease) as they change admission thresholds.

📚 References

• NICE Bronchiolitis Guidance (2016)

Cases - Bronchiolitis

• Case 1 - Classic presentation 👶: A 6-month-old boy presents in December with cough, coryza, and increasing work of breathing. Exam: tachypnoea, chest recession, widespread crackles and wheeze. O₂ sats 90% on air. Diagnosis: bronchiolitis due to RSV. Managed with supportive care (oxygen, NG fluids) - no role for routine antibiotics or bronchodilators.
• Case 2 - Severe bronchiolitis 🚨: A 2-month-old ex-preterm infant (born at 30 weeks) presents with apnoeas, poor feeding, and lethargy. Exam: marked subcostal recession, nasal flaring, sats 86% despite oxygen. Diagnosis: severe bronchiolitis in a high-risk infant. Managed with high-flow nasal cannula oxygen in HDU, IV fluids, and close monitoring for impending respiratory failure.
• Case 3 - Risk of dehydration 💧: A 7-month-old girl presents with 4 days of cough, feeding <50% normal, and fewer wet nappies. Exam: mild recession, sats 93% on air, dry mucous membranes. Diagnosis: bronchiolitis with feeding difficulty and dehydration risk. Managed with NG feeding support, oxygen as needed, and discharge planning once feeding and oxygenation improve.

Teaching Point 🩺: Bronchiolitis is an acute viral LRTI (usually RSV) in infants <1 year. Features: coryza → cough, tachypnoea, recession, crackles/wheeze, poor feeding. Admission if: O₂ sats <92%, apnoea, poor feeding/dehydration, high-risk infant (ex-preterm, heart/lung disease, immunodeficiency). Management is supportive - oxygen, NG/IV fluids, suctioning. No routine salbutamol, steroids, or antibiotics.