🫁 Chapter 35: Bronchiolitis

RSV predominant · Infants 3-6 months · Clinical features (wheeze, crackles, tachypnoea, apnoea) · Risk factors (prematurity, CHD, immunodeficiency) · Severity classification · Supportive care · HFNC/NIV · Role of bronchodilators (limited) · Hypertonic saline · Palivizumab prophylaxis

🔍 Core Concepts: Bronchiolitis

📌 Pathophysiology
Acute inflammation, oedema, necrosis of small airways, increased mucus production, bronchospasm. Most common in infants 3-6 months, winter months.
🦠 Aetiology
RSV (75%) most common. Others: rhinovirus, parainfluenza, influenza, adenovirus, human metapneumovirus.
📊 Severity classification
Mild: normal feeding, no O2 requirement. Moderate: decreased feeding, may need O2, intercostal retractions. Severe: poor feeding (<50%), grunting, nasal flaring, severe retractions, irritability/lethargy.
💨 Respiratory support
Oxygen to maintain SpO2 >92%. HFNC for moderate distress. CPAP for moderate-severe. Intubation for severe failure (apnoea, rising PaCO2, exhaustion).
💊 Controversial therapies
Bronchodilators not routinely recommended. 3% hypertonic saline may reduce length of stay. Steroids NOT indicated. Ribavirin reserved for immunocompromised.
🛡️ Prevention
Palivizumab (monoclonal antibody) prophylaxis for high-risk infants (prematurity <35w, CHD, CLD). Hand hygiene to prevent nosocomial spread.

🩺 Stepwise Approach: Bronchiolitis Management

1
Assess severity & risk factors
Mild: tachypnoea, mild retractions, feeding well, SpO2 >92%. Moderate: retractions, decreased feeding, SpO2 88-92%. Severe: grunting, nasal flaring, severe retractions, poor feeding, lethargy/apnoea, SpO2 <88%.
2
Supportive care (all patients)
Nasal suctioning, head-up position, maintain hydration (NG/IV if poor feeding). Oxygen to maintain SpO2 >92% (target 92-95%). Avoid over-hydration (risk of SIADH).
3
Respiratory support escalation
Mild hypoxaemia: nasal cannula (0.5-2 L/min). Moderate distress: HFNC (2 L/kg/min up to 10 L). Moderate-severe: CPAP (5-8 cmH2O) or BiPAP. Severe failure: intubation.
4
Adjunctive therapies (limited role)
Trial of bronchodilators (salbutamol) ONLY if strong history of atopy/asthma; discontinue if no improvement. 3% hypertonic saline may reduce length of stay. Avoid routine steroids.
5
Indications for PICU admission
Severe respiratory distress, apnoeic episodes, FiO2 >0.5 to maintain SpO2 >92%, rising PaCO2 with acidosis, altered mental status, haemodynamic instability.
6
Discharge criteria
Clinically stable and improving, no respiratory distress, SpO2 ≥92% on room air, feeding adequately (≥2/3 normal), family confident and able to return.