A 3-year-old presents with acute onset inspiratory stridor, a barking cough, and mild fever following an upper respiratory tract infection. Lateral neck X-ray shows a 'steeple sign' (subglottic narrowing). What is the pathogenesis and FIRST-LINE treatment?

• A Supraglottic epiglottis inflammation; IV ceftriaxone
• B Subglottic hemangioma causing fixed obstruction; propranolol
• C Subglottic mucosal edema from viral laryngotracheobronchitis; nebulized epinephrine and dexamethasone ✓
• D Foreign body impacted at the subglottis; emergency bronchoscopy

Explanation

The clinical scenario describes viral croup (acute laryngotracheobronchitis), most commonly caused by parainfluenza virus type 1. The steeple sign on AP neck X-ray (or pencil sign on lateral) reflects subglottic mucosal edema that narrows the subglottis. First-line management includes a single dose of oral/IM dexamethasone (0.6 mg/kg) to reduce airway edema, and nebulized racemic epinephrine (or L-epinephrine) for acute stridor relief via alpha-adrenergic-mediated mucosal vasoconstriction. Ceftriaxone treats bacterial epiglottitis (which presents with a 'thumb sign' on lateral X-ray, not steeple sign).

Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.