Gastric Bypass Presenting as Mixed Beriberi and Wernicke Encephalopathy.

Thiamine deficiency can lead to a spectrum of neurologic and cardiovascular manifestations, most notably beriberi and Wernicke encephalopathy. This condition is further separated into wet (cardiovascular manifestations) and dry (neurological manifestations) beriberi. Beriberi is often caused by a prolonged mild to moderate thiamine deficiency. In contrast, Wernicke encephalopathy occurs due to a severe, short-term thiamine deficiency that can present as the classic triad of mental status changes, ocular abnormalities, and gait ataxia. Since both conditions are due to the same cause of thiamine deficiency, they can coexist, but this often makes diagnosis more difficult, especially when findings are more subtle. We describe a 46-year-old female with a history of Roux-en-Y gastric bypass surgery who was admitted for non-infectious colitis and subsequently new-onset right lower extremity weakness and numbness, altered mental status, hypotension, and tachycardia. Empiric IV thiamine was initiated based on clinical suspicion despite an otherwise reassuring workup. She was later confirmed to have severe thiamine deficiency. This case highlights the importance of having high suspicion for vitamin deficiencies despite nonclassical symptoms.