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Postoperative myasthenic crisis — FRCA Final MCQ

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HardICUPostoperative myasthenic crisisFRCA Final

A 50-year-old woman with myasthenia gravis is ventilated after thymectomy. On day two she fails a spontaneous breathing trial with weak cough, negative inspiratory force is poor, and she has increasing ptosis. There is no fever and chest radiograph is clear. What is the most likely cause of the complication?

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Correct answer: A — Myasthenic weakness causing ventilatory failure

Bulbar and respiratory muscle weakness with ptosis after thymectomy suggests myasthenic ventilatory failure. Pneumonia is less likely without fever, infiltrates or secretions. Opioid withdrawal does not cause ptosis and weak respiratory mechanics. Management includes neurologist input, optimisation of anticholinesterase therapy, and consideration of IV immunoglobulin or plasma exchange depending on severity.

Reference: Association of Anaesthetists neuromuscular disease guidance; RCoA Final FRCA Syllabus 2026