Overview
Also known as laryngotracheobronchitis, croup is a common infective cause of stridor in children aged 6 months to 3 years. Parainfluenza viruses make up the majority of cases and infection leads to oedema of the larynx, trachea, and large bronchi, resulting in noisy airflow known as stridor.
Epidemiology
- Most common in children aged 6 months to 3 years. Uncommon after 6 years
- Cases occur all year round but hospital admissions peak in late autumn
- Boys are slightly more commonly affected than girls
Risk Factors
- Male sex
- Aged 6 months to 3 years
- Previous intubation
Presentation
Croup should be suspected in a patient with a sudden-onset seal-like barking cough. Other features include:
- Stridor
- Hoarse voice
- Prodromal fever and coryza for 12-72 hours
- The cough and symptoms are worse at night or with agitation
Assessment and Admission
Grading severity
NICE recommends the following criteria to grade severity:
- Mild:
- Seal-like barking cough
- No stridor or sternal/intercostal recession at rest
- Moderate:
- Seal-like barking cough
- Stridor and sternal/intercostal recession at rest
- No (or little) agitation/lethargy
- Severe:
- Seal-like barking cough
- Stridor and sternal/intercostal recession at rest
- Agitation/lethargy present
- Impending respiratory failure:
- Minimal barking cough, stridor harder to hear
- Increasing upper airway obstruction, sternal/intercostal recession
- Asynchronous chest wall and/or abdominal movement
- Fatigue, pallor, decreased consciousness, or tachycardia
- Respiratory rate >70 /min
- Chest wall recession may diminish as the child tires
Admission
Admit all children with features of moderate or severe illness, or impending respiratory failure
Consider admission for children with:
- Respiratory rate >60 /min
- A high fever or ‘toxic’ appearance (decreased alertness/activity, breathing difficulties, pallor, hypoxia, lethargy, inconsolably irritable)
- Features of an underlying disorder (e.g. <3 months, chronic lung disease such as bronchopulmonary dysplasia, congenital heart disease, neuromuscular disorders, immunodeficiency, premature infant)
- Factors affecting a carer’s ability to look after the child (e.g. adverse social circumstances)
- Longer distance to healthcare in case of deterioration
Differential Diagnoses
Bacterial tracheitis
- May present with fever and sudden-onset stridor after a viral-like respiratory illness where the patient appears to be recovering but suddenly becomes worse
Epiglottitis
- Sudden-onset high fever, dysphagia, drooling, non-barking cough
- The child prefers to sit upright with the head extended
- Rarely seen due to immunisation against Haemophilus influenzae B
Inhaled foreign body
- Symptoms such as cough present more suddenly
- Auscultation shows focal wheezing
- No fever or prodrome of symptoms of a viral illness
Peritonsillar abscess
- Dysphagia, drooling, occasional stridor, neck stiffness
- Unilateral cervical lymphadenopathy
- The uvula may deviate away from the affected side
Allergic reaction/anaphylaxis
- There may be a personal or family history of atopy
- Rashes may be present
- Wheezing may be seen
- Hypotension and tachycardia may be seen
- There may be an identifiable trigger (e.g. peanuts)
Investigations
Most children are diagnosed clinically.
- If a chest x-ray is performed it may show:
- Posteroanterior view: subglottic narrowing (steeple sign)
- Lateral view: swelling of the epiglottis (thumb sign)
Management
Awaiting admission
If the child is being admitted to hospital:
- Give controlled supplementary oxygen
- Give single dose of oral dexamethasone (0.15 mg/kg)
- If the child is too unwell, give single dose inhaled budesonide or single dose of IM dexamethasone
- Nebulised adrenaline may be considered in emergency cases
Admission not indicated
If admission is not indicated:
- Prescribe a single dose of oral dexamethasone (0.15 mg/kg) regardless of severity
Patient Advice
- Symptoms usually resolve within 48 hour
- Paracetamol/ibuprofen should be given for fever or pain
- Encourage regular fluid intake and feeding
- Carers should check on the child regularly, including throughout the night
- Carers should take the children to hospital if any of the following apply:
- Stridor can be heard continually
- The skin between the ribs is pulled in on each breath
- The child is restless/agitated
- Parents should call an ambulance if the child:
- Is very pale/grey/blue (including blue lips)
- Is unusually sleepy or unresponsive
- Has features of respiratory distress (abdomen sinking when breathing, skin between the ribs is pulled in on each breath, nasal flaring)
- Is agitated/upset while struggling to breathe and cannot be calmed down quickly
- Is unable to talk/drooling/has problems with swallowing, or wants to sit instead of lie down
Complications
- Bacterial tracheitis:
- Thought to be due to immune dysfunction following recovery from croup
- Requires broad-spectrum IV antibiotics and may require intubation
- Pneumonia:
- Thought to be due to immune dysfunction following recovery from croup
Prognosis
- Symptoms usually resolve within 48 hours but some episodes can last for a week