Croup

Croup (laryngotracheobronchitis) is a common viral illness, usually caused by parainfluenza virus, affecting children between about 6 months and 3 years. Subglottic oedema narrows the airway.

Clinical presentation

A barking, seal-like cough, hoarse voice and inspiratory stridor, typically worse at night and following a coryzal prodrome. Severity is judged clinically (for example with the Westley score).

Radiographic features

Croup is a clinical diagnosis and imaging is not routinely needed. It may be used when the diagnosis is uncertain.

Frontal neck radiograph

• The steeple sign: loss of the normal shouldering of the subglottic airway, giving a tapered, church-steeple shape

Lateral neck radiograph

• Overdistension of the hypopharynx; the epiglottis is normal

Treatment and prognosis

A single dose of oral dexamethasone is effective for all severities. Nebulised adrenaline is used for moderate to severe stridor. Most children recover within a few days.

Differential diagnosis

• Epiglottitis (thumb sign on the lateral view; a toxic, drooling child)
• Bacterial tracheitis
• Inhaled foreign body
• Retropharyngeal abscess

Practical points

Never send a child with suspected epiglottitis or severe stridor for radiographs unaccompanied — keep the child calm and secure the airway first.