30th April 2024

A 46-year-old man with a history of chronic alcohol misuse presents with acute onset of confusion, ataxia, and ophthalmoplegia.

A 46-year-old man with a history of chronic alcohol misuse presents with acute onset of confusion, ataxia, and ophthalmoplegia. He has been experiencing nausea and vomiting for the past week and has had minimal food intake. He is disoriented to time and place, has horizontal nystagmus, and is unable to walk without support due to severe unsteadiness.

Investigations:

Mental Status Examination: Disorientation, confusion, impaired short-term memory

Neurological Examination: Horizontal nystagmus, ataxia, ophthalmoplegia

General Physical Examination: Mild dehydration, no signs of trauma

Which test is most likely to help confirm the diagnosis?