Wernicke's Encephalopathy Following 40 Days of Water-Only Fasting: A Case Report.

Wernicke's encephalopathy (WE) is an acute neurological disorder that develops due to thiamine (vitamin B1) deficiency. While it is common in chronic alcoholism, WE can also manifest due to other conditions, including extreme fasting. This report presents a unique case of WE occurring after a 40-day water-only fast, emphasizing the importance of recognizing nonalcoholic causes of WE. A 36-year-old male presented with diplopia, gait instability, and confusion following a 40-day water-only fast. Neurological examination revealed bilateral sixth cranial nerve palsy, ataxic gait, and confusion. Magnetic resonance imaging demonstrated bilateral medial thalami and periaqueductal hyperintensities, consistent with WE. He received high-dose intravenous thiamine and electrolyte correction, resulting in substantial improvement. This case underscores the potential occurrence of WE in healthy individuals following extreme fasting. Early identification and treatment with thiamine are essential to prevent irreversible neurological damage. Clinicians should be cautious of WE in at-risk patients without a history of alcohol use.