A chronic alcoholic presents with Wernicke-Korsakoff syndrome, characterized by confusion, ataxia, and nystagmus. This condition is primarily due to a deficiency in which vitamin?

The correct answer to the question "A chronic alcoholic presents with Wernicke-Korsakoff syndrome, characterized by confusion, ataxia, and nystagmus. This condition is primarily due to a deficiency in which vitamin?" is Option A: Vitamin B1 (Thiamine).

The other options — B) Vitamin B2 (Riboflavin), C) Vitamin B6 (Pyridoxine), D) Vitamin B12 (Cobalamin) — are incorrect for this USMLE Exam Prep question. As explained above: Thiamine (Vitamin B1) is a crucial cofactor for several enzymes in glucose metabolism, especially in the brain. Chronic alcohol abuse impairs thiamine absorption and utilization, leading to Wernicke-…