Post-Bariatric Wernicke — RACP Adult Medicine MCQ

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ModerateEmergency MedicinePost-Bariatric WernickeRACP Adult Medicine

A 50-year-old man with a history of bariatric surgery (Roux-en-Y gastric bypass) 2 years ago presents with confusion, ophthalmoplegia, and ataxia. His BMI has decreased from 48 to 28. His diet has been poor for the past 3 weeks due to a viral illness. What is the diagnosis?

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Correct answer: D — Wernicke encephalopathy from thiamine deficiency

Wernicke encephalopathy (confusion, ophthalmoplegia, ataxia) occurs in bariatric surgery patients due to rapid weight loss, restricted dietary intake, and malabsorption of thiamine (B1). It can present months to years after surgery, particularly during periods of reduced oral intake, vomiting, or illness. IV thiamine (500 mg TDS for at least 3 days) must be given URGENTLY. All bariatric patients should receive lifelong multivitamin supplementation including thiamine, B12, iron, folate, calcium, and vitamin D.

Reference: eTG – 2025 – Neurology; ANZOS – 2024 – Post-Bariatric Nutritional Guidelines