Anaphylaxis — MCCQE Part 1 MCQ

Correct answer: C — Give intramuscular epinephrine immediately

Give intramuscular epinephrine immediately is best because airway/respiratory and circulatory involvement after allergen exposure is anaphylaxis. Wait for confirmatory testing before any stabilisation is suboptimal because resuscitation and time-critical treatment should not wait when instability is present; Discharge once symptoms temporarily improve is suboptimal because temporary improvement can precede deterioration; Give an adjunctive medication as the sole first-line treatment is suboptimal because adjuncts do not replace definitive stabilisation; Delay escalation until cardiac arrest or respiratory failure occurs is suboptimal because early escalation is central to emergency care. Epinephrine is first-line; antihistamines are adjuncts.

Reference: Canadian Immunization Guide anaphylaxis management; CSACI guidance