Two common respiratory emergencies of infancy: bronchiolitis (supportive care, oxygen thresholds, HFNC/CPAP, what not to give) and croup (steroids for all, nebulised adrenaline for stridor at rest, and the dangerous mimics including diphtheria).
At the bedside
Timed steps- 1
Which one is it?
AssessBronchiolitis: <2 years (peak 3–6 months), coryza then cough, tachypnoea, recession, fine crackles ± wheeze, poor feeding. Croup: usually 6 months–3 years, barking cough, hoarse voice, inspiratory stridor, worse at night, often low fever. Toxic look, drooling or no barking cough → think epiglottitis, bacterial tracheitis, diphtheria, foreign body.
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Oxygen and feeding
BronchiolitisGive oxygen if SpO₂ persistently <90% (≥6 weeks old, no underlying condition) or <92% (<6 weeks or with underlying conditions). Suction nose only if secretions cause distress or feeding difficulty. If oral intake <50–75% of usual: NG/OG feeds; IV isotonic fluids only if NG not tolerated or impending respiratory failure.
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Escalate respiratory support
BronchiolitisRising work of breathing or hypoxaemia despite low-flow O₂: HFNC (commonly 2 L/kg/min) as rescue; CPAP for impending respiratory failure; intubate for apnoea, exhaustion or failure of CPAP. Monitor with continuous SpO₂ and a blood gas (capillary acceptable).
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What NOT to give
BronchiolitisNo routine salbutamol, adrenaline, ipratropium, hypertonic saline, montelukast, corticosteroids or antibiotics (unless secondary bacterial infection suspected). No routine chest X-ray or blood tests.
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Steroid for every croup
CroupDexamethasone 0.15–0.6 mg/kg orally once (IM/IV if vomiting); 0.15 mg/kg is effective for mild–moderate croup. Alternative: nebulised budesonide 2 mg (e.g. if vomiting), or oral prednisolone 1 mg/kg. Keep the child calm on the parent's lap; avoid distressing interventions.
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Stridor at rest
CroupModerate–severe croup (stridor at rest, recession): nebulised adrenaline 0.5 mL/kg of 1 mg/mL (1:1000), max 5 mL, with oxygen; may repeat. Observe at least 2–4 h after adrenaline for rebound.
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Impending respiratory failure
CroupAgitation or lethargy, cyanosis, decreasing air entry, reduced stridor with tiring: call senior anaesthetist/ENT, give oxygen and adrenaline nebs, intubate in theatre/controlled setting with a tube 0.5–1 mm smaller than predicted.
Croup — all severities
Dexamethasone (croup)
- Dose
- 0.15–0.6 mg/kg single dose (0.15 mg/kg effective for mild–moderate; 0.6 mg/kg often used in severe)
- Worked example
- 12 kg: 1.8 mg (0.15 mg/kg) up to 7.2 mg (0.6 mg/kg). Injection 4 mg/mL can be given orally mixed with juice.
Croup with stridor at rest
Adrenaline (epinephrine) — paediatric
- Dose
- 0.5 mL/kg of 1 mg/mL (1:1000), max 5 mL, undiluted or made up with saline
- Worked example
- 8 kg: 4 mL of 1 mg/mL; ≥10 kg: 5 mL.
Croup — if oral steroid not possible
Budesonide (nebulised)
- Dose
- 2 mg single dose
Westley croup score
| Feature | 0 | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|---|
| Level of consciousness | Normal | — | — | — | — | Disoriented |
| Cyanosis | None | — | — | — | With agitation | At rest |
| Stridor | None | With agitation | At rest | — | — | — |
| Air entry | Normal | Decreased | Markedly decreased | — | — | — |
| Retractions | None | Mild | Moderate | Severe | — | — |
Total ≤2 mild; 3–5 moderate; 6–11 severe; ≥12 impending respiratory failure.
Stridor: croup and its dangerous mimics
| Condition | Clues | Action |
|---|---|---|
| Croup | Barking cough, hoarse, well-looking, 6 m–3 y | Dexamethasone ± nebulised adrenaline |
| Epiglottitis | Toxic, drooling, tripod, soft stridor, no bark; unimmunised for Hib | Do not examine throat; senior airway + ENT; ceftriaxone |
| Bacterial tracheitis | Croup-like but toxic, high fever, poor response to adrenaline, purulent secretions | Intubation often needed; IV antibiotics (anti-staphylococcal) |
| Diphtheria | Grey adherent pseudomembrane, bull neck, unimmunised; India and outbreaks | Isolation, diphtheria antitoxin, penicillin/erythromycin, ECG; notify |
| Foreign body | Sudden onset choking, no fever | Rigid bronchoscopy; do not attempt blind finger sweep |
| Retropharyngeal abscess | Fever, neck stiffness/torticollis, drooling | Imaging, ENT, antibiotics |
| Anaphylaxis | Rapid onset, urticaria, wheeze, exposure | IM adrenaline 0.01 mg/kg (max 0.5 mg) |
Calculators for this topic
References
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Croup severity pathway
Step 1 of ~3
From recognition to steroids, adrenaline, and escalation.
Decision: Toxic, drooling, membrane or sudden choking?
Based on Gates A, Gates M, Vandermeer B, et al; World Health Organization. Educational use; follow local protocol.
Pathophysiology
Bronchiolitis: epithelial necrosis, mucus plugging and oedema of small airways → air trapping, atelectasis, V/Q mismatch and increased work of breathing; infants tire and develop apnoea (especially young/premature). Croup: subglottic oedema at the narrowest part of the child's airway; resistance rises with the fourth power of the radius reduction, and agitation increases turbulent flow.
Evidence
- NICE NG9 (2015, updated 2021) and AAP 2014: supportive care only; oxygen thresholds 90%/92%; no bronchodilators, steroids, hypertonic saline (in the ED), antibiotics or routine investigations; consider CPAP for impending respiratory failure.
- PARIS (Franklin, NEJM 2018): 1,472 infants <12 months on wards in Australia/NZ; treatment failure requiring escalation 12% with HFNC vs 23% with standard oxygen; ICU admission (about 12% vs 14%), length of stay and duration of oxygen did not differ significantly.
- Croup steroids (Cochrane 2018, 43 trials): glucocorticoids reduce symptoms at 2 h, return visits and length of stay. Bjornson 2004 (NEJM): single oral dexamethasone 0.6 mg/kg reduced return visits in mild croup (7.3% vs 15.3%). Lower dose 0.15 mg/kg appears comparable in several trials.
- Nebulised adrenaline relieves symptoms within 30 min; effect wanes by 2 h, without true 'rebound' worsening below baseline.
Controversies
- HFNC as first-line vs rescue in bronchiolitis (cost, crowding, 'treatment creep').
- Optimal croup dexamethasone dose (0.15 vs 0.6 mg/kg).
- Nirsevimab and maternal RSV vaccination for prevention — not widely available in India yet.
🇮🇳 India notes
- Diphtheria still occurs in India, particularly in under-immunised communities and outbreaks; always ask about immunisation and look at the throat in a calm setting if diphtheria is suspected (but not if epiglottitis is). Diphtheria antitoxin (DAT) is dosed by severity (roughly 20,000–100,000 units — verify with current national/CDC guidance) and is often scarce; inform public health.
- Bubble CPAP is a low-cost, effective option for bronchiolitis and pneumonia in Indian district hospitals.
- Dexamethasone injection (4 mg/mL) is cheap and universally available and can be given orally.
References
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