Croup

Croup

Croup, or acute laryngotracheobronchitis, is a common viral infection that affects the upper airway in young children. It’s characterised by inflammation and swelling of the larynx and trachea, leading to the classic symptoms. UK guidance from the National Institute for Health and Care Excellence (NICE) focuses on careful clinical assessment and a structured, evidence-based management plan.

 

Aetiology and Clinical Presentation

  • Cause: The most common cause is Parainfluenza virus type 1, but others include RSV, Influenza, and Adenovirus. It typically affects children between 6 months and 3 years old, with a peak incidence in autumn and winter.

  • Presentation: The illness often starts with a viral upper respiratory tract infection (URTI) with a runny nose and low-grade fever. Within a day or two, the child develops the hallmark signs: a “barking” cough (like a seal), hoarse voice, and inspiratory stridor. Stridor is often worse at night.

  • Differentials: It’s crucial to differentiate croup from other causes of stridor, particularly life-threatening conditions.

    • Epiglottitis: This is a serious bacterial infection that presents with sudden-onset high fever, drooling, and a very unwell-looking child.

    • Bacterial Tracheitis: A bacterial infection of the trachea that can follow a viral URTI and presents with a toxic-looking child and high fever.

    • Foreign Body Aspiration: This should be suspected if there is a sudden onset of stridor or respiratory distress without a preceding viral illness.

 

Assessment and Red Flags

Assessment is primarily clinical. Avoid distressing the child as this can worsen airway obstruction.

  • Observation: Note the child’s overall appearance and state of comfort. Monitor their respiratory rate, heart rate, and oxygen saturation (SpO2).

  • Red Flags: The presence of any of these indicates severe disease and the need for urgent medical attention:

    • Stridor at rest: Any stridor when the child is calm and not crying.

    • Biphasic stridor: Stridor on both inspiration and expiration.

    • Hypoxia: SpO2 < 92% in room air.

    • Signs of respiratory distress: Including nasal flaring, chest wall recession, and tracheal tug.

    • Reduced level of consciousness or a “toxic” appearance.

 

Management

Management is based on a severity score and the presence of risk factors. The key treatment is a single dose of a corticosteroid to reduce airway inflammation.

 

Mild Croup

  • Criteria: Barking cough and hoarseness with no stridor at rest. The child is not in respiratory distress.

  • Treatment: Administer a single oral dose of Dexamethasone (0.15 mg/kg, max 6 mg). In some settings, nebulised budesonide may be used as an alternative.

  • Disposition: The child can be safely discharged home with clear safety-netting advice for parents on when to return to the hospital.

 

Moderate to Severe Croup

  • Criteria: Stridor at rest, signs of respiratory distress (e.g., chest recession), or an SpO2 < 92%.

  • Treatment:

    • Admit to hospital.

    • Give a single oral dose of Dexamethasone (0.15 mg/kg).

    • If the child is in significant respiratory distress, administer nebulised adrenaline (epinephrine) to provide rapid, temporary relief of airway swelling. The dose is 0.4 ml/kg of 1:1000 adrenaline (max 5 ml). This can be repeated after 30 minutes if needed.

    • Monitor the child closely.

  • Escalation: If the child’s condition worsens, call for senior support and consider a referral to a paediatric anaesthetist for potential intubation.

 

Discharge Criteria

A child can be discharged from the hospital after a period of observation if they meet the following criteria:

  • They have had no stridor at rest for at least 3 hours.

  • They are clinically improving and appear well.

  • Their SpO2 is consistently > 92% in room air.

  • Parents are confident and have received clear instructions and safety-netting advice.