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Myasthenic crisis — SCE Neurology MCQ

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HardNeuromuscularMyasthenic crisisSCE Neurology

A 54-year-old woman with AChR-positive myasthenia gravis has bulbar weakness after pneumonia. She is unable to count beyond 8 in one breath and forced vital capacity is 12 mL/kg. Oxygen saturation is 94% on air and CO2 is rising on blood gas. What is the most appropriate management?

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Correct answer: A — Intubation planning with IVIg or plasma exchange

Intubation planning with IVIg or plasma exchange is the best answer. Bulbar weakness with low FVC and rising CO2 indicates impending myasthenic respiratory failure requiring critical-care support plus IVIg or plasma exchange. Pyridostigmine alone is inadequate and can worsen secretions; magnesium and beta-blockers can worsen myasthenia; outpatient antibiotics are unsafe. Clinical pearl: Oxygen saturation can remain deceptively normal until ventilatory failure is advanced.

Reference: ABN myasthenia gravis guidance; BNF; NICE TA1069