Wernicke Encephalopathy

Background

• Wernicke encephalopathy is an acute neuropsychiatric syndrome caused by thiamine (vitamin B1) deficiency, usually presenting with ≥ 1 of confusion or other mental status changes, gait ataxia, and oculomotor and ocular abnormalities such as horizontal nystagmus.
• It most commonly occurs in patients with alcohol use disorder, but it can also be seen in patients with other conditions that may lead to poor nutrition and thiamine deficiency, such as cancer, gastrointestinal surgery, hyperemesis gravidarum, starvation or fasting, gastrointestinal disease, bariatric surgery, and AIDS.
• Mortality reported in up to 20% of patients. A large number of survivors experience Korsakoff syndrome, a chronic condition characterized by anterograde amnesia, short-term memory loss with compensatory confabulation, and relative preservation of long-term memory and other cognitive skills.

Evaluation

• Take a thorough history, consulting a knowledgeable informant if possible and assessing risk factors for thiamine deficiency, particularly alcohol use disorder.
• Suspect Wernicke encephalopathy (WE) in patients with
  • ≥ 1 of confusion or other mental status changes, oculomotor abnormalities such as horizontal nystagmus, and/or gait abnormalities
  • history of alcohol use disorder, nutritional deficiencies, high metabolic requirements, or other condition that may lead to thiamine deficiency.
• If WE is suspected or patient is at high risk for thiamine deficiency, start immediate treatment with parenteral thiamine while further evaluations are conducted (ideal administration is within 48-72 hours of symptom onset).
• Commonly used clinical diagnostic criteria: diagnose WE if ≥ 2 of
  • dietary deficiencies or malnourishment (may be due to high alcohol use or another conditions leading to poor nutrition)
  • confusion (most common presentation) or other mental status changes such as apathy, cognitive impairment, dizziness, drowsiness, impaired concentration, impaired memory, and spatial disorientation
  • gait ataxia (can range from mild to unable to stand)
  • oculomotor and ocular abnormalities such as horizontal nystagmus and other signs including bilateral abducens palsy, diplopia, reduced visual acuity, and other palsies.
• Consider the following diagnostic testing:
  • Blood tests to help assess for malnutrition, alcohol use, and other conditions. Testing thiamine levels might be helpful to evaluate for thiamine deficiency, but are technically difficult and lack specificity for Wernicke encephalopathy.
  • Brain imaging to help evaluate for other conditions. Magnetic resonance imaging (MRI) is more sensitive than computed tomography (CT) and can assess for brain lesions associated with Wernicke encephalopathy, although absence of findings cannot rule out Wernicke encephalopathy.

Management

• If WE is suspected or patient is at high risk for thiamine deficiency, start prophylactic treatment with parental thiamine while further evaluations are conducted (ideal administration is within 48-72 hours of symptom onset).
• Start high-dose IV thiamine to treat WE, but evidence is insufficient to determine ideal regimen.
  • Reported regimens include:
    • 200-500 mg IV 3 times daily for 5-7 days, then 100 mg orally 3 times daily for 1-2 weeks, then 100 mg orally once daily
    • if unclear diagnosis of WE, consider lower dose such as ≥ 100-200 mg IV 3 times daily for 3-5 days, then 100 mg orally 3 times daily for 1-2 weeks, then 100 mg orally once daily.
  • Use slow infusion for IV thiamine, such as diluted in 100 mL normal saline and given over 15-30 minutes.
  • Start before glucose drip or carbohydrate load; glucose may precipitate acute WE in patients with thiamine deficiency.
  • Monitor for anaphylaxis (rare but severe potential complication).