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PE25.3 | Acute Laryngotracheobronchitis — SDL Guide (Part 2)

Management of Croup

The management of croup is stratified by Westley severity score and is built around two pharmacological interventions — corticosteroids for their anti-inflammatory effect on the subglottic mucosa and nebulised adrenaline for its rapid vasoconstrictor-mediated reduction in mucosal oedema. Both are weight-based in paediatric practice, and both have evidence bases strong enough to make them standard of care in all moderate-to-severe cases. The overarching goal is to reduce subglottic oedema sufficiently to restore comfortable breathing and prevent progression to respiratory failure. A calm, low-stimulation environment reduces the child's work of breathing by minimising agitation-driven increased airflow demand — for this reason, unnecessary procedures and forced examinations should be avoided. Applied calmly, these two principles — pharmacological reduction of oedema and behavioural reduction of oxygen demand — are enough to manage the majority of moderate croup cases safely.

Corticosteroids (cornerstone of management at all but the very mildest severity):
- Dexamethasone is the corticosteroid of choice due to its long half-life (~36-72 h) and excellent oral bioavailability
- Mild croup (Westley <3): 0.15 mg/kg orally, single dose — reduces duration of symptoms and risk of re-presentation; can be given and child discharged
- Moderate-severe croup (Westley ≥3): 0.6 mg/kg orally/IM/IV, single dose — maximum 10 mg
- Oral dexamethasone is preferred; it is as effective as IM/IV and avoids the distress of injection
- Prednisolone 1-2 mg/kg/day is an alternative if dexamethasone is unavailable
- Budesonide nebulised (2 mg) may be used when the oral or IM route is not feasible (vomiting, severe distress)

Nebulised adrenaline (epinephrine) — for moderate-severe croup:
- Mechanism: alpha-adrenergic vasoconstriction of the subglottic mucosal vasculature reduces oedema within 10-30 minutes
- Dose: L-epinephrine (1:1000) 5 mL nebulised, OR racemic epinephrine 0.5 mL/kg (max 5 mL) of 2.25% solution diluted to 3-5 mL with normal saline
- Onset: 10-30 minutes; Duration: 1-2 hours
- Rebound phenomenon: symptoms can return to pre-treatment severity 2-3 hours after nebulisation as the vasoconstrictor effect wanes. Therefore, every child receiving nebulised adrenaline must be observed for a minimum of 2-4 hours post-nebulisation before discharge. Discharge is safe only when stridor at rest has resolved and the child remains stable off nebulisation.
- Nebulised adrenaline can be repeated every 20-30 minutes in severe cases while preparing for definitive airway management

Oxygen:
- Supplemental oxygen for oxygen saturation <92% or in moderate-severe distress
- High-flow humidified oxygen via face mask (avoid forcing the mask; blow-by acceptable in a distressed infant)

Indications for hospitalisation:
- Westley score ≥3 (moderate)
- Failure to improve with nebulised adrenaline
- Rebound after nebulised adrenaline requiring repeat dosing
- Age <6 months
- Unable to maintain adequate oral hydration

Indications for intubation:
- Westley score ≥8 with progressive respiratory failure, rising PCO₂, or depressed consciousness
- Intubation in croup uses a tube 0.5-1 mm smaller than age-appropriate (due to subglottic narrowing); extubation is typically possible within 2-3 days as oedema resolves

What NOT to use:
- Antibiotics are not indicated for viral croup (LTB)
- Mist therapy (steam/humidified air) was a traditional recommendation but is NOT supported by evidence and is no longer recommended
- Sedation is contraindicated (risks respiratory depression)

Management of Croup by Westley Score

Self-Assessment — Croup

Croup is a condition where pattern recognition, scoring, and decisive treatment combine to transform a frightening middle-of-the-night emergency into a safe, manageable encounter. Before attempting the self-assessment quiz, mentally rehearse the full clinical picture: a child between 6 months and 3 years, barking cough waking them from sleep, low-grade fever, a 1-3 day URTI prodrome, and inspiratory stridor at rest indicating at least moderate severity. The Westley score tells you the exact treatment tier. A single oral dose of dexamethasone at the correct weight-based dose and observation for rebound after nebulised adrenaline are the two actions that most directly improve outcomes. The ability to calculate these doses accurately by weight — never using a fixed adult dose — is what separates safe paediatric prescribing from dangerous practice.

Test yourself with the case-based quiz below.