PE25.3 | Acute Laryngotracheobronchitis — Summary & Reflection

KEY TAKEAWAYS

Acute laryngotracheobronchitis (croup) is the most common cause of acute stridor in children aged 6 months to 3 years, caused primarily by parainfluenza virus types 1 and 2. The pathophysiology involves viral subglottic inflammation and oedema; the small paediatric subglottic radius means that even 1 mm of oedema causes a 16-fold increase in resistance (Poiseuille's law). The clinical triad is barking cough, hoarse voice, and inspiratory stridor with a low-grade fever and URTI prodrome. Severity is graded using the Westley Croup Score: mild (<3), moderate (3-7), severe (≥8). The radiological steeple sign on AP neck X-ray confirms the diagnosis in 50-60% of cases. Treatment is stratified: mild croup receives single-dose oral dexamethasone 0.15 mg/kg; moderate-severe receives nebulised adrenaline (L-epinephrine 5 mL of 1:1000) plus dexamethasone 0.6 mg/kg; every child receiving nebulised adrenaline must be observed for 2-4 hours for rebound. Antibiotics and steam/mist therapy are not indicated.

REFLECT

Think about what it means to a parent when their child wakes at 2 AM with the barking, seal-like cough of croup for the first time. They have never heard this sound before and are terrified. Part of your job as a paediatrician is not just to treat the child but to explain — clearly and calmly — what croup is, why the child is safe at home with the treatment given, exactly what to watch for (worsening stridor at rest, blue colouration, progressive drooling, extreme distress), and when to return immediately. How will you deliver that safety-net information in a way that empowers rather than frightens? And how does your ability to accurately score the severity and calculate the dexamethasone dose by weight underpin your confidence in that conversation?