Wernicke Encephalopathy

Wernicke encephalopathy is an acute neuropsychiatric emergency from thiamine (vitamin B1) deficiency.

• Causes: alcohol use disorder (most), hyperemesis gravidarum, bariatric surgery, malnutrition, malignancy, dialysis, anorexia, prolonged parenteral nutrition without thiamine, refeeding syndrome, HIV.

• Classic triad (ophthalmoplegia, ataxia, confusion) is present in under 20%.

• Mortality 10 to 20% untreated; 80% of survivors develop Korsakoff syndrome.

• Pathology: periventricular and mamillary body necrosis.

• Confusion or reduced consciousness, nystagmus, lateral rectus palsy, conjugate gaze palsy, gait and truncal ataxia.

• Hypothermia, hypotension, peripheral neuropathy, lactic acidosis.

• Any alcohol dependent or malnourished patient with unexplained confusion should be treated.

• Clinical diagnosis (Caine criteria: two of dietary deficiency, oculomotor abnormalities, cerebellar dysfunction, altered mental state or mild memory impairment).

• Whole blood thiamine pyrophosphate level (low), not required to start treatment.

• MRI brain (T2/FLAIR hyperintensity in medial thalami, mamillary bodies, periaqueductal grey, tectal plate; sensitivity 50%).

• Glucose, magnesium, electrolytes, liver tests, ammonia, toxicology to exclude other causes.

• Give thiamine before glucose. IV thiamine 500 mg three times daily for 2 to 3 days (slow infusion over 30 minutes), then 250 mg IV/IM daily for 3 to 5 days, then oral 100 mg daily.

• Correct magnesium (magnesium sulphate 2 g IV), a cofactor for thiamine.

• Prophylaxis in at risk patients: thiamine 100 to 250 mg IV/IM daily, 200 to 300 mg oral daily.

• Anaphylaxis is rare; have resuscitation facilities.

• Supportive: nutrition with multivitamins, hydration, alcohol withdrawal management (diazepam, chlordiazepoxide), refeeding syndrome precautions (phosphate, potassium).

• Hyperemesis gravidarum: thiamine 100 mg IV daily.

• Rehabilitation and addiction treatment.