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Acute Severe Asthma — RACP Adult Medicine MCQ

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HardEmergency MedicineAcute Severe AsthmaRACP Adult Medicine

A 45-year-old with life-threatening asthma has received oxygen, repeated nebulised salbutamol plus ipratropium and systemic corticosteroid. PEF remains 25% predicted with poor air entry, but she is not yet exhausted and has no pneumothorax. Which adjunct should be given while senior airway support is mobilised?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Give IV magnesium 2 g over 20 minutes; continue bronchodilators and reassess ventilation and fatigue

Explanation lettering: B = shown as A · E = shown as B · A = shown as E

C is correct. Australian acute-asthma guidance supports a single IV magnesium dose in severe or life-threatening asthma with inadequate response to intensive inhaled bronchodilation; it is given alongside, not instead of, repeated inhaled therapy and critical-care assessment. D has a narrow therapeutic index and is not the routine preferred adjunct. E is not the usual next step when inhaled delivery is being achieved. A is reserved for a relevant upper-airway or anaphylactic mechanism. B has no role as rapid rescue therapy. Worsening fatigue, rising carbon dioxide, altered consciousness or a silent chest require immediate escalation for ventilatory support rather than repeated pursuit of pharmacological adjuncts.

Reference: Australian Asthma Handbook: Managing acute asthma in adults and adolescents in the emergency department: https://www.asthmahandbook.org.au/acute-asthma/adults-and-adolescents/managing-acute-asthma-in-adults-and-adolescents-in-the-ed Australian RACP: Divisional Written Examination: https://www.racp.edu.au/trainees/examinations/divisional-written-examination