A 6-week-old infant develops sudden pallor, stridor and collapse 8 minutes after receiving the first dose of pentavalent vaccine. Pulse is feeble, blood pressure is unrecordable. Alongside airway and circulation support, the MOST important immediate drug is:

• A Intravenous hydrocortisone 4 mg/kg
• B Chlorpheniramine maleate 0.1 mg/kg intravenously
• C Adrenaline 0.01 mg/kg intramuscularly in the anterolateral thigh ✓
• D Nebulized salbutamol repeated every 20 minutes

Explanation

Anaphylaxis within minutes of an injection demands immediate intramuscular adrenaline at 0.01 mg/kg (0.01 mL/kg of 1:1000 solution) into the anterolateral thigh, repeatable every 5 to 15 minutes. The thigh is preferred over deltoid because of faster absorption and larger muscle mass. Antihistamines and steroids have no role in reversing airway obstruction or shock in the acute phase, and bronchodilators are adjuncts only when bronchospasm dominates.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.