A 45-year-old alcoholic presents with bilateral foot drop, ophthalmoplegia, nystagmus, and ataxia, followed by confusion and memory impairment. The vitamin deficiency most responsible for this clinical picture is:

• A Niacin (vitamin B3)
• B Pyridoxine (vitamin B6)
• C Cobalamin (vitamin B12)
• D Thiamine (vitamin B1) ✓

Explanation

Thiamine deficiency in alcoholics causes Wernicke-Korsakoff syndrome, the triad of ophthalmoplegia, ataxia, and confusion (Wernicke encephalopathy) progressing to Korsakoff psychosis with anterograde amnesia. Thiamine pyrophosphate (TPP) is an essential cofactor for pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, transketolase, and branched-chain keto acid dehydrogenase. High metabolic activity areas like the mammillary bodies and periaqueductal gray are selectively vulnerable to TPP depletion.

Reference: Harper's Illustrated Biochemistry, 32nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.