• Clinical science

Wernicke encephalopathy and Korsakoff syndrome


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.





Clinical features

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
    1. Confusion (most common)
    2. Oculomotor dysfunction
      • Gaze-induced horizontal/vertical nystagmus (most common)
      • Diplopia
      • Conjugate gaze palsy
      • Other manifestations (less common): anisocoria, delayed pupillary response, ptosis, scotoma, vertical gaze palsy, isolated vertical gaze palsy, internuclear ophthalmoplegia, and complete ophthalmoplegia
    3. Gait ataxia:wide-based, small steps
  • Other manifestations
    • Autonomic dysfunction: hypotension, syncope, hypothermia
    • Peripheral neuropathy: paresthesia, foot drop, decreased deep tendon reflexes
    • Cardiovascular dysfunction: tachycardia, exertional dyspnea
    • Diencephalic involvement: vegetative disorders (coma and stupor)

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
  • Hallucinations

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.



Laboratory tests or imaging should not delay treatment!




Differential diagnoses


The differential diagnoses listed here are not exhaustive.


  • Wernicke encephalopathy
    • Immediate IV administration of high-dose vitamin B1/thiamine until symptoms recede, followed by a lower dose
    • Long-term oral replacement of vitamins B1, B6, B12, and folic acid (vitamin B complex)
    • Abstinence from alcohol
  • Korsakoff syndrome
    • 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.

Because glucose increases thiamine demand and will worsen encephalopathy, IV glucose infusions must be administered AFTER thiamine!