- Clinical science
Wernicke encephalopathy is an acute, reversible condition caused by severe thiamine (vitamin B1) deficiency, often due to alcohol use disorder. Inadequate intake, impaired absorption, or increased excretion of thiamine can also cause Wernicke encephalopathy. The classical triad of confusion, oculomotor dysfunction, and gait ataxia is seen in about a third of patients. Chronic thiamine deficiency, especially in patients with alcohol use disorder, frequently evolves into Korsakoff syndrome, which is characterized by irreversible personality changes, anterograde and retrograde amnesia, and confabulation. The diagnosis is clinical, but laboratory tests confirming thiamine deficiency and brain imaging may be considered in ambiguous cases. Wernicke encephalopathy is an emergency and requires immediate high-dose IV thiamine therapy followed by long-term thiamine supplementation. Abstaining from alcohol is vital in both conditions. Even with psychiatric and psychological interventions, the prognosis for patients with Korsakoff syndrome remains poor.
- Wernicke encephalopathy and Korsakoff syndrome are caused by a severe deficiency of thiamine (vitamin B1).
Thiamine deficiency can be due to:
- Alcohol use disorder (most common): inadequate intake, absorption, and hepatic storage of thiamine
- Inadequate intake
- Increased demand (hypermetabolic states)
- Increased loss
- Thiamine pyrophosphatase (TPP) is the active form of thiamine.
- TPP is a cofactor for important enzymes involved in cerebral glucose and energy metabolism.
- The brain requires a constant source of thiamine to function properly.
- 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
Wernicke encephalopathy (acute, reversible)
Should be suspected in any patient with a history of alcohol use disorder who presents with one/more symptoms of the classic triad of Wernicke encephalopathy
- Confusion (most common)
- Oculomotor dysfunction
- Gait ataxia:wide-based, small steps
- Other manifestations
Korsakoff syndrome (chronic, irreversible)
- Personality changes (in frontal lobe lesions): apathy, indifference
- Anterograde and retrograde amnesia
- Confabulation: Patients produce fabricated memories to fill in lapses of memory.
- Disorientation to time, place, and person
Although often grouped together as a single syndrome (Wernicke-Korsakoff syndrome), the two conditions present differently. Both are due to chronic severe thiamine deficiency, but Wernicke encephalopathy is a reversible condition, while Korsakoff syndrome is irreversible.
- Usually a clinical diagnosis
- In ambiguous cases
- Laboratory tests
Brain MRI: periventricular lesions, lesions in the cranial nerve nuclei and cerebellum
- Acute Wernicke encephalopathy: T2-weighted hyperintense areas observed in the mamillary bodies, periventricular thalamus, and around the aqueduct
- Korsakoff syndrome: low-density lesions in periventricular structures, diencephalon, and midbrain with an atrophied mamillary body, cerebellum, and cerebrum
Laboratory tests or imaging should not delay treatment!
Wernicke encephalopathy (conditions that present with an acute onset of delirium/ataxia)
- Hypoxia/hypercarbia (post cardiac arrest)
- Postictal state
- CNS infections (e.g., )
- Korsakoff syndrome (conditions that present with amnesia, disorientation)
The differential diagnoses listed here are not exhaustive.
- Wernicke encephalopathy
- Oral thiamine supplementation to prevent further insult
- Abstinence from alcohol
- Psychiatric and psychological therapy
- Memory strengthening exercises and aids
- The use of signs and arrows at home can help with orientation.