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Myasthenic crisis — RACP Adult Medicine MCQ

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HardNeurologyMyasthenic crisisRACP Adult Medicine

A 61-year-old woman has fluctuating diplopia and ptosis for 2 months. She now presents with dysphagia and breathlessness after a chest infection. Examination shows fatigable proximal weakness and single-breath count is reduced. What is the most likely diagnosis?

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Correct answer: A — Myasthenic crisis

Fluctuating ocular and bulbar weakness with respiratory compromise indicates myasthenic crisis, often precipitated by infection. Lambert-Eaton typically improves with exercise and is less ocular-predominant. Stroke, motor neurone disease and periodic paralysis do not explain months of fatigable ocular-bulbar symptoms.

Reference: Therapeutic Guidelines (eTG); AMH