Wernicke's Encephalopathy is primarily due to deficiency of which vitamin?

• A. Thiamine (B1)
• B. Vitamin D
• C. Vitamin C
• D. Vitamin K

Answer: (A)

Wernicke's Encephalopathy stems from a deficiency of thiamine (vitamin B1). Thiamine is a vital cofactor for enzymes involved in brain glucose metabolism, such as pyruvate dehydrogenase and α-ketoglutarate dehydrogenase, so without it the brain can’t efficiently produce energy. This energy failure leads to neuronal injury in regions like the mammillary bodies and thalamus, producing the classic signs of confusion, ophthalmoplegia, and ataxia, especially in malnourished or chronically alcohol-using patients. Prompt thiamine administration is essential and should be given before glucose to prevent worsening the energy deficit. The other vitamins listed are associated with different disorders (vitamin D with bone health, vitamin C with scurvy, vitamin K with coagulation) and do not cause this neurologic syndrome.