A 2-year-old child is brought with a 2-day history of high fever followed by a barking cough, hoarse voice, and inspiratory stridor that worsens at night. There is no drooling or toxic appearance. Neck X-ray shows a 'steeple sign'. What is the causative organism?

• A Haemophilus influenzae type b
• B Parainfluenza virus type 1 ✓
• C Respiratory syncytial virus
• D Staphylococcus aureus

Explanation

This is laryngotracheobronchitis (croup), most commonly caused by parainfluenza virus type 1 (followed by types 2 and 3). It typically affects children 6 months to 3 years with the characteristic barking (seal-like) cough, hoarseness, and inspiratory stridor. The steeple sign on AP neck X-ray reflects subglottic narrowing. There is no drooling (distinguishing it from epiglottitis caused by H. influenzae type b). Treatment is dexamethasone (oral or IM) and nebulized epinephrine for moderate-severe cases.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.