Korsakoff Syndrome

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and individuals. Such distribution does not constitute an endorsement of these parties or their activities by the Alzheimer’s Association.

Korsakoff syndrome

A topic in the Alzheimer’s Association

series on understanding dementia.

About dementia

Dementia is a general term for a decline in mental ability severe enough to interfere

with daily life. Dementia is not a single disease; it’s the umbrella term for an

individual’s changes in memory, thinking or reasoning. There are many possible

causes of dementia, including Alzheimer’s disease. Disorders grouped under the

general term “dementia” are caused by abnormal brain changes. These changes

trigger a decline in thinking skills, also known as cognitive abilities, severe enough to

impair daily life and independent function. They also affect behavior, feelings and

relationships.

Brain changes that cause dementia may be temporary, but they are most often

permanent and worsen over time, leading to increasing disability and a shortened life

span. Survival can vary widely, depending on such factors as the cause of the

dementia, age at diagnosis and coexisting health conditions.

Korsakoff syndrome

Korsakoff syndrome is a chronic memory disorder caused by severe deficiency of

thiamine (vitamin B1). Thiamine helps brain cells produce energy from sugar. When

levels fall too low, brain cells cannot generate enough energy to function properly.

Korsakoff syndrome is most commonly caused by alcohol misuse but can also be

associated with AIDS, cancers that have spread throughout the body, chronic

infections, poor nutrition, eating disorders and certain other conditions. It is also

common in people whose bodies do not absorb food properly (malabsorption). This

can sometimes occur with a chronic illness or after weight-loss (bariatric) surgery.

Korsakoff syndrome is often — but not always — preceded by an episode of

Wernicke encephalopathy, which is an acute brain reaction to severe lack of thiamine.

Wernicke encephalopathy is a medical emergency that causes life-threatening brain

disruption, profound confusion, staggering and stumbling, lack of coordination and

abnormal involuntary eye movements.

Because the chronic memory loss of Korsakoff syndrome often follows an episode of

Wernicke encephalopathy, the chronic disorder is sometimes known as Wernicke-

Korsakoff syndrome. Many physicians think of them as different stages of the same

disease. But Korsakoff syndrome can also develop in individuals who have not had a

clear-cut prior episode of Wernicke encephalopathy.

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and individuals. Such distribution does not constitute an endorsement of these parties or their activities by the Alzheimer’s Association.

Korsakoff syndrome and its associated thiamine deficiency is not the only mechanism

through which heavy drinking may contribute to chronic thinking changes and

cognitive decline. Alcohol misuse may also lead to brain damage through the direct

toxic effects of alcohol on brain cells; the biological stress of repeated intoxication

and withdrawal; alcohol-related cerebrovascular disease; and head injuries sustained

when inebriated.

Prevalence

Scientists do not know exactly how many people have Korsakoff syndrome alone, but

it’s estimated that Wernicke-Korsakoff syndrome occurs in 1% to 2% of the general

population in the United States. It’s widely considered less common than Alzheimer’s

disease, vascular dementia, frontotemporal dementia or dementia with Lewy bodies.

Like more common types of dementia, it may be underdiagnosed. The disorder

affects slightly more males than females, and is evenly distributed between ages 30

and 70.

Symptoms

Korsakoff syndrome can cause long-term memory gaps and problems with learning

new information and remembering recent events. Memory difficulties may be

strikingly severe while other thinking and social skills are less significantly affected.

For example, individuals may seem able to carry on a coherent conversation but

moments later are unable to recall that the conversation took place or with whom they

spoke.

Those with Korsakoff syndrome may “confabulate,” or make up, information they

can’t remember. They are not “lying” but may actually believe their invented

explanations. Scientists don’t yet understand the mechanism by which Korsakoff

syndrome may cause confabulation. The person may also see or hear things that are

not there (hallucinations).

Diagnosis

A Korsakoff syndrome diagnosis is made based upon a detailed clinical evaluation,

patient history and various tests, including routine laboratory screens and liver

function tests that can rule out other disorders. Testing for B1 and thiamine levels can

also help the diagnostic process. Experts recommend that a medical workup for

memory loss or other cognitive changes always includes questions about an

individual’s alcohol use. Brain imaging may identify brain changes indicative of

Korsakoff. The syndrome may sometimes be hard to identify because it may be

masked by symptoms of other conditions common among those who misuse alcohol,

including intoxication or withdrawal, infection or head injury.

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and individuals. Such distribution does not constitute an endorsement of these parties or their activities by the Alzheimer’s Association.

Anyone admitted to the hospital for an alcohol-related condition should be

professionally screened for memory loss and cognitive change. The screening should

include supplementary questions to assess recent memory. If screening suggests

impairment, the person should receive a more detailed cognitive workup.

Causes and risk factors

Scientists don’t yet know exactly how Korsakoff syndrome damages the brain.

Researchers do know that chronic alcohol exposure is neurotoxic (poisonous) to the

nervous system, causing brain damage. Also, chronic alcohol use lowers vitamin B1.

Studies have shown that severe vitamin B1/thiamine deficiency disrupts several

biochemicals that play key roles in carrying signals among brain cells and in storing

and retrieving memories. These disruptions destroy brain cells and cause widespread

microscopic bleeding and scar tissue.

Researchers have identified several genetic variations that may increase susceptibility

to Korsakoff syndrome. Poor nutrition may also raise risk.

Most cases of Korsakoff syndrome result from alcohol misuse. Scientists don’t yet

know why heavy drinking causes severe thiamine deficiency in some alcoholics,

while others may be affected primarily by alcohol’s effects on the liver, stomach,

heart, intestines or other body systems.

Korsakoff syndrome may sometimes be associated with disorders other than alcohol

misuse, including anorexia, overly stringent dieting, fasting, starvation or weight-loss

surgery; uncontrolled vomiting; AIDS; kidney dialysis; chronic infection; or cancer

that has spread throughout the body.

Outcomes

Wernicke encephalopathy, a related disorder that sometimes precedes Korsakoff

syndrome, is a medical emergency. Untreated, it causes death in up to 20% of cases

and progresses to Korsakoff syndrome in 85% of survivors. Abnormal eye

movements that occur in Wernicke encephalopathy may respond to injectable

thiamine within a few days. Lack of coordination and clumsiness may begin to

improve after about a week but may take several months to clear up completely.

Confusion also takes several months to clear up. As confusion clears, the severe

memory problems associated with Korsakoff syndrome may become more noticeable.

In those who develop Korsakoff syndrome with or without a preceding episode of

Wernicke encephalopathy, there are few studies on long-term outcomes. Available

data suggest that about 25% of those who develop Korsakoff syndrome eventually

recover, about half improve but don’t recover completely, and about 25% remain

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and individuals. Such distribution does not constitute an endorsement of these parties or their activities by the Alzheimer’s Association.

unchanged. Some research suggests that those who recover from an episode may have

a normal life expectancy if they abstain from alcohol.

Treatment

Some experts recommend that heavy drinkers and others at risk of thiamine

deficiency take oral supplements of thiamine and other vitamins under their doctor’s

supervision.

Many experts also recommend that anyone with a history of heavy alcohol use who

experiences symptoms associated with Wernicke encephalopathy, including acute

confusion, prolonged nausea and vomiting, unusual fatigue or weakness, or low body

temperature or blood pressure, be given injectable thiamine until the clinical picture

grows clearer.

Once acute symptoms improve, individuals should be carefully evaluated to

determine if their medical history, alcohol use and pattern of memory problems may

be consistent with Korsakoff syndrome. For those who develop Korsakoff syndrome,

extended treatment with oral thiamine, other vitamins and magnesium may increase

chances of symptom improvement. If there is no improvement, consideration should

be given to treatment of comorbid deficiencies and medical conditions, and the need

for long-term residential care or supportive accommodation.

Abstaining from alcohol and maintaining a healthy diet is a cornerstone of effective

long-term treatment. Those with Korsakoff syndrome have a reduced tolerance for

alcohol and may be at high risk for further alcohol-related health problems.

TS-0092 | Updated December 2022