Croup (laryngotracheobronchitis) is a common childhood respiratory disease. Approximately 80% of children presenting with an acute onset of stridor and a cough have croup.
Differential diagnoses for acute stridor:
- Foreign body in upper airway
- Angioedema or anaphylaxis
- Abscess (peritonsillar, parapharyngeal or retropharyngeal)
- Epiglottitis
- Bacterial tracheitis
Epidemiology
Croup affects about 3% of children per year, mostly between the ages of 6 months and 3 years. Boys are slightly more commonly affected than girls, with a ratio of around 1.4 to 1. Hospital admissions due to croup peak in September to December, but cases occur all year round.
Clinical features
Croup is a clinical syndrome of a hoarse voice, harsh barking cough (often described as seal-like), acute inspiratory stridor and respiratory distress. The symptoms are a result of upper-airway obstruction due to generalised inflammation of the airways as a result of viral infection (typically parainfluenza virus types 1 or 3).
Typically, there is a preceding coryzal illness with croup developing over several days. The symptoms are classically worse at night and typically last between 3 and 5 days but can last up to a week.
85% of children have mild croup. Around 5% of children with croup require admission to hospital and of these 1 - 3% require intubation. Uncommon complications include pneumonia and bacterial tracheitis (occurring in less than one in a thousand cases).
Assessment
Children with croup can be divided into four levels of severity using the Westley croup score.
- Mild (croup score 0-2)
- Moderate (croup score 3-5)
- Severe (croup score 6-11)
- Impending respiratory failure (croup score 12-17)
| Score |
Stridor |
Intercostal recession |
Air entry |
SaO2 < 92% |
Consciousness |
| 0 |
None |
None |
Normal |
None |
Normal |
| 1 |
On agitation |
Mild |
Mild decrease |
x |
x |
| 2 |
At rest |
Moderate |
Marked decrease |
x |
x |
| 3 |
x |
Severe |
x |
x |
x |
| 4 |
x |
x |
x |
On agitation |
x |
| 5 |
x |
x |
x |
At rest |
Decreased |
Management
Children with croup should be made comfortable and care should be taken to avoid agitating the child. Oxygen should be administered to any child with oxygen saturation < 92% on air.
The mainstay of treatment for croup, regardless of severity, is corticosteroids, which have been shown to shorten the duration of the illness, reduce the severity of the illness, reduce the number of children requiring to be admitted into hospital and reduce the number who require to be intubated. Oral dexamethasone 0.15 mg/kg is the treatment of choice which takes between two to four hours to have an effect. Oral prednisolone (1 – 2 mg/kg) is an alternative if dexamethasone is not available. Nebulised budesonide is another alternative to oral steroids if the child is unable to take oral medication.
Despite early treatment with steroids, some children do not respond and can deteriorate. Nebulised adrenaline is used in children with severe and life-threatening croup. Treatment is with 0.4-0.5 mL/kg of 1:1,000 concentration to a maximum dose of 5 mL. An improvement usually occurs within 30 minutes and lasts up to 2 hours. Nebulised adrenaline allows time for an experienced team including a senior anaesthetist to be gathered as well as rapidly improving the patient's distress; however as the effect wears off, the child's symptoms return to baseline level, and a proportion of children may even deteriorate further. Referral to a senior paediatric trained doctor and early consideration of PICU involvement is essential.
Most children with mild croup can be discharged home following a single dose of dexamethasone.
Those with moderate croup need to be observed for a minimum of four hours following a dose of dexamethasone and then re-assessed.
Those with severe croup must be admitted.
In children discharged home, advice must be given to a parent and documented in the notes regarding symptomatic relief of mild croup (e.g. keeping the child calm, administering paracetamol or ibuprofen for fever) and regarding when to return to hospital (e.g. if child is struggling to breathe, signs of respiratory distress, child drinking < 50% or having dry nappies).
