27th June 2023

A 30-year-old intravenous drug user presents with progressive weakness of both upper and lower limbs over the last few days

A 30-year-old intravenous drug user presents with progressive weakness of both upper and lower limbs over the last few days. On examination, he has significant symmetrical weakness of his lower limbs and upper limbs with absent bilateral lower limb reflexes. Sensation is normal. Cranial nerves are intact. He also reports having food poisoning ten days earlier.

Select the SINGLE most likely cause from the list below. Select ONE option only.