A 55-year-old man with chronic alcohol dependence presents with profound anterograde amnesia and fabricated detailed stories about recent events he never experienced. He had an episode of confusion, ophthalmoplegia, and ataxia three weeks ago that was treated inadequately. Which lesion site and nutrient deficiency explain this syndrome?

• A Cerebellar vermis; niacin deficiency
• B Hippocampi bilaterally; vitamin B12 deficiency
• C Frontal cortex; folate deficiency
• D Mammillary bodies and dorsomedial thalamus; thiamine deficiency ✓

Explanation

Wernicke encephalopathy (confusion, ophthalmoplegia, ataxia) can evolve into Korsakoff syndrome, an amnestic disorder with prominent confabulation. The pathology involves mammillary bodies, periaqueductal grey matter, and dorsomedial nuclei of the thalamus due to thiamine (vitamin B1) deficiency. The cerebellar vermis lesion causes alcoholic cerebellar degeneration with ataxia but not dense amnesia, which defeats option A.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.