A 24-year-old woman develops rapid onset urticaria, stridor, wheeze, and BP 70/40 mmHg five minutes after an intravenous antibiotic given for perforated appendicitis. The correct initial management is:

• A Intravenous chlorpheniramine 10 mg and observe
• B Hydrocortisone 200 mg intravenously as the sole first-line agent
• C Intravenous adrenaline bolus 1 mg as for cardiac arrest
• D Intramuscular adrenaline 0.5 mg (0.5 mL of 1:1000) into the anterolateral thigh ✓

Explanation

Anaphylaxis with airway compromise and shock requires immediate intramuscular adrenaline, 0.5 mg (0.5 mL of 1:1000) in adults, repeated at 5-minute intervals if needed, along with stopping the trigger, high-flow oxygen, and rapid crystalloid. Intravenous 1 mg adrenaline is reserved for arrest or refractory shock under close monitoring because of arrhythmia risk. Steroids and antihistamines are adjuncts with slow onset and must never delay adrenaline, the only drug that reverses both bronchospasm and vasodilatation.

Reference: Bailey and Love's Short Practice of Surgery, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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