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Wernicke encephalopathy and Korsakoff syndrome
Wernicke encephalopathy is an emergency caused by thiamine deficiency, presenting with confusion, eye movement disturbance and ataxia — and high-dose intravenous thiamine is given on suspicion, before glucose, because untreated it progresses to irreversible Korsakoff syndrome.
Why it matters in the exam
Questions present a patient with chronic alcohol use, a woman with severe vomiting in pregnancy, or a patient after bariatric surgery, arriving confused, with nystagmus or double vision and an unsteady gait. The key point: only a minority show the full triad, so 2 of 4 signs (dietary deficiency, eye signs, cerebellar dysfunction, altered mental state or memory) are enough to treat. A classic distractor is giving glucose before thiamine, or a low oral dose. Korsakoff syndrome is also tested: anterograde amnesia with confabulation and clear consciousness, along with MRI findings (symmetric high signal in the mammillary bodies, medial thalamus and periaqueductal grey). Magnesium must also be checked and corrected, because its deficiency blunts the response to treatment. Eye signs usually improve within hours to days of treatment, ataxia improves more slowly, and memory impairment is the part that tends to remain.
Key points
- Wernicke is caused by thiamine deficiency: confusion, eye movement disturbance and ataxia.
- The full triad is seen in a minority; 2 of 4 criteria are enough to treat.
- Thiamine 200 mg intravenously 3 times daily, before glucose.
- At risk: alcohol, severe vomiting in pregnancy, bariatric surgery and malnutrition.
- Korsakoff: amnesia and confabulation, usually irreversible.
Summary table
| Aspect | Finding or rule | Note |
|---|---|---|
| At-risk groups | Alcohol, severe vomiting in pregnancy, bariatric surgery, malnutrition, cancer, dialysis, refeeding | In every at-risk patient receiving glucose — thiamine first |
| Clinical picture | Confusion, nystagmus, 6th nerve or gaze palsy, ataxia | The full triad in a minority; 2 of 4 criteria are enough for suspicion |
| Treatment | Thiamine 200 mg intravenously 3 times daily until no further improvement | Before glucose; correct magnesium |
| Imaging | MRI: high signal in the mammillary bodies, medial thalamus and around the aqueduct | A clinical diagnosis — do not wait for MRI |
| Korsakoff | Anterograde amnesia, confabulation, preserved alertness | Usually irreversible; prevented by early treatment of Wernicke |
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Sources
- EFNS Guidelines for Diagnosis, Therapy and Prevention of Wernicke Encephalopathy, 2010 — Diagnosis and thiamine dosing
- Operational Criteria for the Classification of Chronic Alcoholics (Caine et al., J Neurol Neurosurg Psychiatry), 1997 — Clinical criteria for Wernicke encephalopathy
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.