A 52-year-old man with a 20-year history of alcohol use disorder presents to the emergency department with acute confusion, bilateral eye movement abnormalities, and gait ataxia. MRI brain (sagittal T2-weighted image) shows bilateral hyperintense signal in the structures marked **B** and medial thalami. Which of the following is the most appropriate immediate management?

Explanation

## Why Intravenous thiamine 500 mg three times daily for 3 days, administered BEFORE any glucose-containing fluids is right The bilateral hyperintense signal in the structures marked **B** (mammillary bodies) is pathognomonic for Wernicke encephalopathy, a medical emergency caused by acute thiamine (vitamin B1) deficiency. The clinical triad of confusion, ophthalmoplegia (CN VI palsy and nystagmus), and ataxia in an alcoholic patient confirms the diagnosis. The mammillary bodies are a critical component of the Papez circuit for memory and are highly vulnerable to thiamine deficiency. Urgent IV thiamine 500 mg three times daily for 3 days is the standard of care. Critically, thiamine MUST be given BEFORE glucose-containing fluids in malnourished patients, as glucose administration without thiamine can precipitate or worsen Wernicke encephalopathy. IV magnesium should also be administered as a cofactor. This is a time-sensitive diagnosis where delayed treatment leads to irreversible Korsakoff syndrome (mammillary body atrophy, anterograde and retrograde amnesia, confabulation). [Harrison 21e; Sutton Radiology] ## Why each distractor is wrong - **Intravenous dextrose 50% followed by thiamine supplementation after glucose correction**: This is dangerous and contradicts standard practice. Administering glucose before thiamine in a malnourished alcoholic can precipitate acute Wernicke encephalopathy or worsen existing disease. Thiamine must be given first. - **Oral thiamine 100 mg daily with supportive care and alcohol cessation counseling**: While prophylactic oral thiamine 100 mg daily is appropriate for chronic alcoholics, acute Wernicke encephalopathy requires urgent high-dose IV thiamine (500 mg TID × 3 days). Oral replacement is insufficient and delays critical treatment. - **Corticosteroids and antibiotics pending CSF analysis for suspected meningitis**: The clinical presentation and characteristic MRI findings (bilateral mammillary body and medial thalamic hyperintensity) are diagnostic of Wernicke encephalopathy, not meningitis. CSF analysis would be normal in Wernicke disease. Unnecessary antibiotics delay definitive thiamine therapy. **High-Yield:** In any malnourished or alcoholic patient presenting with confusion, ophthalmoplegia, or ataxia — give IV thiamine BEFORE glucose. Mammillary body hyperintensity on MRI is pathognomonic for Wernicke encephalopathy. [cite: Harrison 21e; Sutton Radiology]