What is Wernicke's (Wernicke) encephalopathy?

From the Guidelines

Wernicke encephalopathy is a serious neurological condition caused by thiamine (vitamin B1) deficiency, most commonly seen in alcoholics but also in patients with malnutrition, prolonged vomiting, or after bariatric surgery. It presents with the classic triad of confusion, ataxia (unsteady gait), and eye movement abnormalities (nystagmus or ophthalmoplegia), though all three symptoms may not be present in every case.

Key Characteristics

• The condition occurs because thiamine is essential for carbohydrate metabolism in the brain, and its deficiency leads to focal damage in vulnerable areas like the mammillary bodies, thalamus, and brainstem 1.
• Importantly, glucose administration before thiamine replacement in thiamine-deficient patients can precipitate or worsen Wernicke encephalopathy, so thiamine should always be given before glucose in at-risk patients.

Treatment and Prevention

• Treatment requires immediate administration of thiamine, and high-dose parenteral thiamine supplementation is mandatory if Wernicke’s encephalopathy is suspected 1.
• The level of evidence for the prophylactic prescription of thiamine is low but the benefit-risk balance is considered favourable, especially in alcohol-dependent individuals where thiamine deficiency is common 1.
• Thiamine should be prescribed as part of the withdrawal process to prevent the onset of Wernicke's encephalopathy, with a recommended dose of 100–300 mg/day for 4–12 weeks for prevention and 100–500 mg/day for 12–24 weeks for management 1.

Clinical Considerations

• Wernicke encephalopathy is a medical emergency that can progress to Korsakoff syndrome (permanent memory impairment) or even death if untreated.
• Regular monitoring is necessary, especially in patients with decompensated liver disease, to guide dosage adjustment and ensure no seizure occurs 1.

From the Research

Definition and Causes of Wernicke's Encephalopathy

• Wernicke's encephalopathy (WE) is a medical emergency and an acute neuropsychiatric state that requires immediate attention to prevent permanent neurological morbidity and mortality 2, 3.
• It is caused by thiamine (vitamin B1) deficiency, with alcohol abuse being the primary culprit, although non-alcoholic WE can also occur 3, 4.
• The condition can present with a classic triad of symptoms, including confusion, ophthalmpray, and gait ataxia, but these symptoms are not always present 3, 5.

Clinical Presentation and Diagnosis

• WE is a clinical diagnosis, and the initial clinical diagnosis is critical 5.
• The common findings include mental status changes, ocular dysfunction, and a gait apraxia, but these symptoms are not always present 5.
• Recognition of nutritional deficiency and any portion of the classic triad should prompt treatment 5.
• Neuroimaging, such as MRI, can play an important role in the diagnosis of non-alcoholic WE 3.

Treatment and Prevention

• The primary treatment for WE includes timely administration of thiamine, although the route and dosage remain controversial 2, 5.
• High-dose IV thiamine is often recommended, with treatment regimens consisting of 500 mg IV 3 times daily for 3 to 5 days, followed by 250 mg IV daily for a minimum of 3 to 5 additional days 2.
• However, a randomized controlled trial found no significant differences between different dosage conditions, and the results support a recommendation for patient-specific treatment 6.
• Clinical judgment should be exercised in diagnosis and treatment, and overdiagnosis and overtreatment may be preferred to prevent prolonged or persistent neurocognitive impairments given the excellent safety profile of thiamine 5.