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Wernicke encephalopathy and Korsakoff syndrome

Last updated: March 17, 2021

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Wernicke encephalopathy is an acute, reversible condition caused by severe thiamine (vitamin B1) deficiency, often due to chronic heavy alcohol use. 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 progresses to Korsakoff syndrome, which is characterized by irreversible personality changes, anterograde and retrograde amnesia, and confabulation. The diagnosis of both Wernicke encephalopathy and Korsakoff syndrome 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. While the prognosis in Wernicke encephalopathy is good if treated accordingly, that in Korsakoff syndrome is generally poor.


Wernicke encephalopathy (acute, reversible)

Korsakoff syndrome (chronic, irreversible)

Korsakoff syndrome is a late development in patients with persistent vitamin B1 deficiency. It is most often seen in thiamine deficiency due to chronic heavy alcohol use.

Wernicke's COAT: Confusion, Oculomotor dysfunction, Ataxia, and Thiamine administration (see Treatment section)
Korsakoff's CART: Confabulation, Anterograde and Retrograde amnesia, and altered Temper

Although often grouped together as a single syndrome (Wernicke-Korsakoff syndrome), the two conditions are distinct entities with different presentations, and, while both are due to severe chronic thiamine deficiency, Wernicke encephalopathy is reversible whereas Korsakoff syndrome is not.


MRI signs of periventricular hemorrhage and/or atrophy of mammillary bodies is a frequent finding in both Wernicke encephalopathy and Korsakoff syndrome.

Laboratory tests or imaging should not delay treatment!




The differential diagnoses listed here are not exhaustive.

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


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