skip to main content

Myasthenic crisis with impending respiratory failure — SCE Acute Medicine MCQ

Instant feedback + full explanation. One question, done properly.

ModerateNeurology and ophthalmologyMyasthenic crisis with impending respiratory failureSCE Acute Medicine

A 36-year-old woman with myasthenia gravis presents with diplopia, dysphagia and increasing breathlessness after a chest infection. Respiratory rate is 28/min, single-breath count is 8 and forced vital capacity is 12 mL/kg. ABG shows pH 7.38, PaCO2 5.7 kPa and PaO2 10.2 kPa on air. What is the most appropriate next step in management?

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

Reveal the answer and explanation

Correct answer: A — Urgent critical care review for impending ventilatory failure

Myasthenic crisis is suggested by bulbar symptoms and low vital capacity; normal pH does not reassure because respiratory failure can develop rapidly. Critical care involvement is needed before frank hypercapnic acidosis or hypoxia occurs. Magnesium may worsen neuromuscular transmission and should be avoided.

Reference: Association of British Neurologists myasthenia guidance; NICE CKS myasthenia gravis