Epidemiology
Etiology
- Wernicke encephalopathy and Korsakoff syndrome are caused by a severe deficiency of thiamine (vitamin B1).
- Thiamine deficiency can be due to:
- Chronic heavy alcohol use (most common): due to inadequate intake, absorption, and hepatic storage of thiamine
- Inadequate intake
- Thiamine-deficient diets
- Anorexia nervosa, starvation
- In patients with low glucose intake, thiamine deficiency may be asymptomatic. However, this patient ingested a large quantity of glucose, which likely rapidly depleted her limited thiamine stores.
- Malabsorption
Pathophysiology
- Thiamine deficiency → decreased cerebral glucose metabolism and mitochondrial dysfunction → depleted ATP and increased free radicals → injury of neuronal elements (e.g., myelin sheaths, blood-brain-barrier, decreased neurotransmitters, etc.) → impaired axonal conduction → symptoms of Wernicke encephalopathy and Korsakoff syndrome
- In patients with Korsakoff syndrome: long term thiamine deficiency → permanent damage to components of the limbic system (e.g., mammillary bodies, anterior thalamic nuclei) → atrophy of these components → memory loss, apathy, and disrupted emotional processing
Clinical features
Wernicke encephalopathy (acute, reversible)
- Should be suspected in any patient with a history of chronic heavy alcohol use who presents with one/more symptoms of the classic triad of Wernicke encephalopathy
- Confusion (most common)
- Disorientation, impaired vigilance, and cognitive deficits
- Oculomotor dysfunction
- Gait ataxia: wide-based, small steps
- Due to a combination of peripheral neuropathy, vestibular dysfunction, and cerebellar dysfunction
- Romberg test positive
- Confusion (most common)
When to suspect
Wernicke encephalopathy should be suspected in any patient with chronic alcohol abuse or any form of malnutrition and any of the following: acute altered mental status, ophthalmoplegia, ataxic gait, delirium, and hypotension.