A 52-year-old male from Delhi with a 15-year history of alcohol use disorder presents with acute confusion, ataxia, and ophthalmoplegia (inability to abduct both eyes). His wife reports he has not eaten properly for 2 weeks. On examination, he is disoriented to time and place, has nystagmus, and shows impaired eye movements. Blood glucose is 110 mg/dL, and liver function tests show mild elevation of transaminases. What is the most appropriate immediate management?

Explanation

## Clinical Diagnosis This patient presents with **Wernicke encephalopathy**, the acute neuropsychiatric manifestation of **thiamine (vitamin B₁) deficiency**. The classic triad is: 1. **Ophthalmoplegia** (6th nerve palsy → inability to abduct eyes) 2. **Ataxia** (cerebellar dysfunction) 3. **Confusion** (acute encephalopathy) **Key Point:** Wernicke encephalopathy is a medical emergency. Mortality is 10–15% if untreated; permanent neurological sequelae (Korsakoff syndrome) develop in 80% of survivors if thiamine is delayed. ## Why Thiamine BEFORE Dextrose ### Critical Mechanism Thiamine (as thiamine pyrophosphate, TPP) is a cofactor for: - **Transketolase** (pentose phosphate pathway) - **Pyruvate dehydrogenase** (glucose oxidation) - **α-ketoglutarate dehydrogenase** (TCA cycle) In thiamine deficiency, glucose metabolism is severely impaired. **Administering dextrose without thiamine causes acute depletion of remaining thiamine stores**, worsening encephalopathy and precipitating irreversible Korsakoff syndrome. **High-Yield:** The phrase "**Always give thiamine before dextrose**" is a cardinal rule in emergency medicine. Dextrose without thiamine in a malnourished patient is dangerous. ### Correct Sequence 1. **Thiamine 100 mg IV or IM immediately** (IV preferred for faster CNS penetration) 2. **Wait 30 minutes** to allow thiamine repletion 3. **Then administer dextrose** (if hypoglycemic or for nutritional support) **Clinical Pearl:** Parenteral thiamine is mandatory because oral absorption is poor in alcoholic patients with gastritis and malnutrition. IV/IM achieves rapid CNS levels. ## Pathophysiology of Wernicke Encephalopathy ```mermaid flowchart TD A[Chronic Alcohol + Malnutrition]:::outcome --> B[Thiamine Depletion]:::outcome B --> C[Impaired Transketolase<br/>& Pyruvate Dehydrogenase]:::outcome C --> D[Reduced ATP & NADH production<br/>Lactate accumulation]:::outcome D --> E[Neuronal dysfunction<br/>Mamillary body & 3rd/4th ventricle damage]:::outcome E --> F{Acute Presentation:<br/>Ophthalmoplegia + Ataxia + Confusion?}:::decision F -->|Yes| G[EMERGENCY:<br/>Thiamine 100 mg IV/IM]:::urgent G --> H{Dextrose needed?}:::decision H -->|Yes| I[Administer dextrose<br/>AFTER thiamine]:::action H -->|No| J[Supportive care<br/>& nutritional rehabilitation]:::action I --> K{Early treatment<br/>< 24 hours?}:::decision K -->|Yes| L[Good prognosis:<br/>Ophthalmoplegia reverses]:::outcome K -->|No| M[Risk of Korsakoff syndrome<br/>Permanent memory loss]:::urgent ``` ## Comparison: Wernicke vs. Korsakoff | Feature | Wernicke Encephalopathy | Korsakoff Syndrome | |---------|------------------------|-------------------| | **Onset** | Acute (days to weeks) | Insidious or follows untreated Wernicke | | **Key Signs** | Ophthalmoplegia, ataxia, confusion | Anterograde amnesia, confabulation | | **Reversibility** | 70–80% if thiamine given early | Largely irreversible (10–20% recovery) | | **Pathology** | Mamillary body, dorsomedial thalamus edema | Neuronal loss in mamillary bodies & thalamus | | **Thiamine Response** | Excellent if <24–48 hrs | Poor; memory deficits persist | **Warning:** Korsakoff syndrome is the chronic sequela of untreated Wernicke. Once established, thiamine cannot reverse the neuronal loss. This is why immediate thiamine is non-negotiable. ## Why Other Options Fail | Option | Problem | |--------|----------| | **Dextrose first** | Glucose metabolism requires TPP (thiamine). Dextrose without thiamine depletes remaining thiamine stores and worsens encephalopathy. Classic iatrogenic error. | | **Oral thiamine** | Absorption is negligible in malnourished alcoholics with gastritis. Parenteral route is mandatory for acute Wernicke. Oral is too slow. | | **MRI before thiamine** | While MRI may show mamillary body atrophy or thalamic hyperintensity, imaging delays life-saving treatment. Wernicke is a clinical diagnosis; thiamine must not be withheld pending imaging. | **Mnemonic:** **WEND** = **W**ernicke **E**ncephalopathy = **N**eurological **D**isaster if thiamine delayed.