A 3-Year-Old with Stridor and a Barking Cough

Most likely diagnosis: Croup (acute laryngotracheobronchitis) - viral (parainfluenza), characterised by barking cough, hoarse voice, and inspiratory stridor, typically in children aged 6 months to 3 years.

Key differentials:

• Epiglottitis - drooling, toxic, tripod position, no barking cough; now rare with Hib vaccination. This child has none of these features.
• Bacterial tracheitis - toxic, high fever, purulent secretions; usually more unwell.
• Inhaled foreign body - sudden onset, no prodrome.
• Retropharyngeal abscess - neck stiffness, drooling, fever.
• Spasmodic croup - afebrile, recurrent, often at night.

Immediate management priority: Do not leave the child in the waiting room. The critical judgement point is that stridor at rest with recession indicates moderate-to-severe croup and requires immediate assessment in a resuscitation area with staff trained in paediatric airway management.

Immediate actions:

1. Keep the child calm - agitation worsens obstruction. Allow the child to remain on the parent's lap; avoid unnecessary distress.
2. Assess severity - stridor at rest, recession, oxygen saturation, level of consciousness, ability to drink.
3. Administer a single dose of oral dexamethasone (0.15-0.6 mg/kg) - effective for all severities.
4. Nebulised adrenaline (1:1000, 0.5 mL/kg, max 5 mL) for moderate-to-severe croup with stridor at rest - provides rapid but temporary relief; observe for at least 2-4 hours afterwards for rebound.
5. Oxygen if saturations fall below 92%.
6. Prepare for airway emergency - anaesthetic and ENT support, difficult airway trolley.

Do not examine the throat with a tongue depressor in a child with stridor - this can precipitate airway obstruction, particularly if epiglottitis is a possibility.

Discharge criteria for croup:

1. Resolution of stridor at rest after observation for at least 2-4 hours post-adrenaline (rebound can occur).
2. No or minimal recession - comfortable breathing.
3. Able to drink and tolerate oral intake.
4. Normal oxygen saturation on room air.
5. Alert and interactive - no lethargy or irritability suggesting hypoxia.
6. Reliable caregivers with transport and access to healthcare, and able to return if symptoms worsen.
7. Parental education - written safety-netting advice: return if stridor at rest recurs, increased work of breathing, drooling, difficulty swallowing, lethargy, or fever.

Factors that would make you admit:

• Persistent stridor at rest after adrenaline.
• Recurrent stridor requiring repeated adrenaline - suggests more severe or alternative pathology.
• Hypoxia (saturations <92%).
• Increased work of breathing - severe recession, nasal flaring, grunting.
• Lethargy or altered consciousness.
• Poor oral intake or dehydration.
• Suspicion of alternative diagnosis - epiglottitis, bacterial tracheitis, foreign body, retropharyngeal abscess.
• Young age (<6 months) or significant comorbidity.
• Social concerns - unreliable follow-up.

Additional points:

• A single dose of dexamethasone is usually sufficient; some protocols use a second dose at 12-24 hours if symptoms persist.
• Antibiotics are not indicated for viral croup.
• Humidified air has limited evidence but is often used.
• Recurrent croup (≥3 episodes) warrants investigation for underlying airway pathology (e.g., subglottic stenosis, laryngomalacia).

Differential for recurrent croup (≥3 episodes):

1. Subglottic stenosis - congenital or acquired (post-intubation); a narrowed subglottis causes recurrent croup-like symptoms with minor viral illnesses.
2. Subglottic haemangioma - typically presents in infancy with progressive stridor, worse with crying; may have cutaneous haemangiomas.
3. Laryngomalacia - usually presents earlier, but may be unmasked by viral illness.
4. Gastro-oesophageal reflux - associated with recurrent croup and airway irritation.
5. Vocal cord paralysis - bilateral causes stridor; unilateral causes hoarseness.
6. Subglottic web or cyst.
7. Tracheomalacia or vascular ring - if there is wheeze or feeding difficulty.
8. Allergic or spasmodic croup - recurrent, afebrile, often at night.
9. Immunodeficiency - recurrent infections.
10. Foreign body - if there is a history of choking or unilateral symptoms.

What to do differently:

• Take a detailed history - birth history (intubation, prematurity), previous airway surgery, feeding difficulties, failure to thrive, cutaneous haemangiomas, reflux symptoms, choking episodes.
• Examination - assess for stridor at rest, voice quality, and cutaneous haemangiomas.
• Flexible nasendoscopy in clinic (if tolerated) to assess the larynx and subglottis.
• Refer to paediatric ENT for microlaryngoscopy and bronchoscopy under general anaesthesia - the definitive investigation for recurrent croup, allowing direct visualisation and diagnosis of subglottic stenosis, haemangioma, or other pathology.
• Consider reflux assessment and trial of anti-reflux therapy if suspected.
• Imaging (CT/MRI) if a vascular ring or extrinsic compression is suspected.

Key judgement point: Recurrent croup is not simply recurrent viral illness - it warrants investigation for an underlying structural airway abnormality, particularly subglottic stenosis or haemangioma.