9th September 2020

A 32-year-old man presents to the GP complaining of blurred vision and leg weakness

A 32-year-old man presents to the GP complaining of blurred vision and leg weakness that is only noticeable in the evenings. On examination, he has demonstrable fatigability in the proximal leg muscles. He is currently being investigated for an abnormal anterior mediastinal mass seen on a chest X-ray.

For the patient above, please select the SINGLE most likely underlying cause of their muscle weakness. Select ONE option from the list above.