From the Guidelines
To diagnose Wernicke encephalopathy, order thiamine (vitamin B1) levels, complete blood count, comprehensive metabolic panel, liver function tests, ammonia levels, magnesium, and phosphate levels, as these tests can help identify the underlying cause of the condition and rule out other potential diagnoses. According to the European Association for the Study of the Liver (EASL) clinical practice guidelines on the management of hepatic encephalopathy 1, patients with suspected vitamin/micronutrient deficiencies, such as thiamine deficiency, should be treated promptly. The guidelines highlight the importance of treating demonstrated or suspected vitamin/micronutrient deficiencies, as they can compound hepatic encephalopathy. Key laboratory tests to order include:
- Thiamine levels: to diagnose thiamine deficiency, the direct cause of Wernicke encephalopathy
- Complete blood count: to assess for malnutrition and identify underlying conditions like alcoholism that predispose to thiamine deficiency
- Comprehensive metabolic panel: to evaluate liver function and identify potential electrolyte imbalances
- Liver function tests: to assess liver disease, which often accompanies alcoholism and affects thiamine metabolism
- Ammonia levels: to rule out hepatic encephalopathy, which can present similarly to Wernicke encephalopathy
- Magnesium and phosphate levels: to identify potential deficiencies that can exacerbate thiamine deficiency or mimic symptoms. As noted in the EASL guidelines 1, deficiencies in water-soluble vitamins, particularly thiamine, are common in patients with both alcohol- and non-alcohol-related cirrhosis.
From the Research
Laboratory Tests for Wernicke Encephalopathy
To diagnose Wernicke encephalopathy, the following laboratory tests can be ordered:
- Total thiamine in blood sample should be measured immediately before its administration 2
- MRI can be used to support the diagnosis of acute Wernicke encephalopathy both in alcoholics and non-alcoholics 3, 2
Other Diagnostic Considerations
- The clinical diagnosis of Wernicke encephalopathy should take into account the different presentations of clinical signs between alcoholics and non-alcoholics 2
- The diagnosis of Wernicke encephalopathy in alcoholics requires two of the following four signs: dietary deficiencies, eye signs, cerebellar dysfunction, and either an altered mental state or mild memory impairment 2
- Recognition of nutritional deficiency and any portion of the classic triad should prompt treatment 4
Treatment and Prevention
- Thiamine is indicated for the treatment of suspected or manifest Wernicke encephalopathy, and it should be given before any carbohydrate, 200 mg thrice daily, preferably intravenously 2
- Parenteral thiamine should be given to all at-risk subjects admitted to the Emergency Room 2
- After bariatric surgery, follow-up of thiamine status for at least 6 months and parenteral thiamine supplementation are recommended 2