9th September 2020

A 30-year-old man presents with progressive onset weakness in his ankles

A 30-year-old man presents with progressive onset weakness in his ankles. He also complains of numbness in his feet. On examination he has pes cavus and hammer toes. His ankle reflex is hyporeflexic and all sensory modalities in the feet are reduced.

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