skip to main content

Myasthenia gravis — SCE Neurology MCQ

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

ModerateNeuromuscularMyasthenia gravisSCE Neurology

A 71-year-old woman presented with fluctuating ptosis, diplopia and fatigable chewing worse by evening. On examination, there was bilateral ptosis increasing on upgaze with normal pupils. Initial investigations showed: AChR antibodies were positive and repetitive nerve stimulation showed decrement. What is the most appropriate investigation?

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

Reveal the answer and explanation

Correct answer: C — AChR antibodies and neurophysiology with respiratory assessment

AChR antibodies and neurophysiology with respiratory assessment is the best answer because the vignette describes Myasthenia gravis: fatigable ocular-bulbar weakness with AChR antibodies indicates myasthenia gravis. Carotid duplex ultrasound is plausible in a neighbouring presentation, but the chronology, examination or investigation pattern does not match the key discriminator here. Serum and CSF autoimmune antibody panel and MRI whole spine with contrast are less appropriate because they would require different localisation, timing or test findings; MRI internal auditory meatus with gadolinium would fit a different syndrome. Clinical pearl: Lambert-Eaton improves with exercise and has autonomic features.

Reference: NICE NG42; ABN myasthenia gravis guidance; EAN/PNS GBS-CIDP guidance