Overview
Definition
A common viral respiratory infection in children that causes inflammation of the larynx and subglottic airway.
Epidemiology
Peak incidence between 6 months and 3 years of age. Typically occurs in the fall and winter.
Etiology & Risk Factors
- Parainfluenza virus (Types 1, 2, and 3 account for 75% of cases)
- RSV, Adenovirus, Influenza
Clinical Symptoms
- Prodrome of URI symptoms (coryza, low-grade fever)
- 'Barking' seal-like cough (hallmark)
- Inspiratory stridor
- Hoarseness
- Symptoms characteristically worsen at night
Clinical Approach
Diagnosis
- Clinical diagnosis
- Neck X-ray (AP view, if diagnosis is uncertain): 'Steeple sign' (subglottic narrowing)
- Must rule out more severe causes of stridor (e.g., Epiglottitis, foreign body aspiration)
Management
- Mild (no stridor at rest): Cool mist, oral Dexamethasone (single dose)
- Moderate/Severe (stridor at rest, retractions): Nebulized Racemic Epinephrine + IV/IM Dexamethasone
- Observation: Observe for 2-4 hours after racemic epinephrine to ensure no rebound stridor before discharge
Complications
- Respiratory distress / failure
- Secondary bacterial tracheitis