Clinical Presentation and Diagnosis

The classic triad of Wernicke’s encephalopathy is: 

• confusion or mental impairment (estimated to occur in 80% of cases) 
• ataxia (approximately 20% to 25% of cases) 
• eye signs such as nystagmus or ophthalmoplegia (approximately 30% of cases). 

Only a minority of patients with Wernicke’s encephalopathy (estimated at 10%) exhibits all three signs. In rare cases, untreated Wernicke’s encephalopathy may result in hypothermia, hypotension, coma and death. Wernicke’s encephalopathy is grossly under-diagnosed: 

• Post-mortem studies reveal Wernicke’s encephalopathy in 12.5 per cent of people who drink heavily (compared to 1.5% of the general population), and only 20 per cent are diagnosed before post-mortem. 
• Clinical features of Wernicke’s encephalopathy may be misinterpreted as intoxication, withdrawal, head injury, or other causes of confusion in people who drink heavily. 
• While there are no specific routine diagnostic tests for Wernicke’s encephalopathy, MRI can usually detect symmetric alterations in the mamillary bodies, medial thalami, tectal plate, and the periaqueductal gray area in the brain. In patients with a history of alcohol abuse, contrast media can identify mamillary body lesions typical for Wernicke’s encephalopathy, even in the presence of normal unenhanced MRI. 

Diagnosis of Wernicke’s encephalopathy requires a high index of suspicion among people with heavy or chronic alcohol use, especially if there are any clinical features (such as memory impairment) consistent with Wernicke’s encephalopathy or Korsakoff’s syndrome. Patients with suspected Wernicke’s encephalopathy or Korsakoff’s syndrome should be assessed for other forms of alcohol-related brain injury, such as dementia.