Embedded Files
Common viral upper airway infection in young children causing inspiratory stridor and barking cough
Common viral upper airway infection in young children causing inspiratory stridor and barking cough
Risk Factors
Age: 6 months to 6 years (peak 1–2 years)
Season: Autumn and early winter (April–June in Australia)
Viral illness exposure (siblings, childcare)
Previous history of croup
Underlying airway abnormalities (e.g. subglottic stenosis – more severe/recurrent)
Aetiology
Viral infection causing inflammation of larynx, trachea, and bronchi
Most common virus
Parainfluenza virus type 1 (esp. in epidemics)
Others: RSV, influenza A/B, adenovirus, rhinovirus
Viral replication → subglottic oedema → airway narrowing → inspiratory obstruction
Pathophysiology
Subglottic region = narrowest part of the upper airway in young children
Oedema causes inspiratory airflow limitation
Leads to:
Stridor (inspiratory, ± expiratory in severe cases)
Barking cough (seal-like)
± respiratory distress (sternal/intercostal recession, tracheal tug)
Crying/agitation worsens stridor due to increased airflow demands
Diagnosis
Clinical diagnosis – no labs or imaging usually required
Key features:
Barking cough
Inspiratory stridor (worse at night)
Hoarse voice
Low-grade fever
± Respiratory distress (recession, tachypnoea, agitation)
Symptoms often worse at night, peak over 1–2 days, resolve in ~3–4 days
Alert, not toxic appearing
Differential Diagnosis
Epiglottitis – drooling, muffled voice, toxic, abrupt onset
Bacterial tracheitis – high fever, toxic, purulent secretions
Foreign body aspiration – sudden onset, asymmetry on auscultation
Peritonsillar abscess – older child, trismus, muffled voice
Retropharyngeal abscess – neck stiffness, dysphagia, drooling
Anaphylaxis – rapid onset swelling, urticaria, hypotension
Investigations
Clinical diagnosis – no investigations needed in typical cases
If atypical or severe:
Neck X-ray: "Steeple sign" (subglottic narrowing)
Lateral neck X-ray: to rule out epiglottitis if uncertain
Viral swabs: not routinely necessary
Avoid agitating child for bloods/imaging if not necessary
Management
General principles
Keep child calm – crying worsens symptoms
Single dose of oral dexamethasone (0.15–0.6 mg/kg; RCH uses 0.15 mg/kg PO or IV)
Reduces severity, improves sleep, shortens illness
Use even in mild cases
Monitor for stridor at rest, work of breathing, air entry
Moderate–Severe croup
Add nebulised adrenaline (epinephrine): 5 mL of 1:1000 via nebuliser
Rapid temporary improvement (~2 hrs)
Use if: stridor at rest, distress, poor feeding, or hypoxia
Observe for 2–4 hours post-adrenaline for rebound symptoms
Oxygen if SpO₂ < 92%
Keep NBM if severe distress – risk of aspiration
Admission criteria (RCH / local guidelines)
Stridor at rest after steroid + adrenaline
Persistent respiratory distress or hypoxia
Poor oral intake or dehydration
Age <6 months
Concern for alternative diagnosis
Poor social supports or access to care
Complications & Prognosis
Rare in most mild-moderate cases
Severe airway obstruction
Hypoxia
Secondary bacterial tracheitis
Hospitalisation or ICU – for repeated adrenaline doses or respiratory failure
Generally excellent prognosis
Symptoms peak at 1–2 days, resolve by day 3–4
<5% require hospital admission
Recurrence common in some children (up to 10–15%)
No long-term complications in most cases
Page updated
Google Sites
Report abuse