This disease, notably frequent among chronic alcoholics, is due to a deficiency of vitamin B1 or thiamine.The poor diet of alcoholics who are suffering from this syndrome leads to lesions and increased microhemorrhages in the mammillary bodies, thalamus and brainstem. This syndrome can also be associated with diseases of the GI tract when there is inadequate thiamine absorption.
Neurologic symptoms include confusion, memory loss, impaired movements and peripheral neuropathy. Immediate administration of thiamine is usually successful in treating the symptoms, but sometimes permanent memory loss occurs.
Korsakoff's syndrome is a brain disorder usually associated with heavy alcohol consumption over a long period. Historically it has also been called 'Korsakoff's psychosis', although this can be confusing, as there are no true psychotic symptoms in the medical sense. Sometimes it is referred to as 'alcohol amnestic syndrome' − 'amnestic' meaning loss of memory − although in rare cases alcohol is not the cause. Although Korsakoff's syndrome is not strictly speaking a dementia, people with the condition experience loss of short-term memory. This factsheet outlines the causes, symptoms and treatment of the syndrome.
What causes Korsakoff's syndrome?
Korsakoff's syndrome is caused by lack of thiamine (vitamin B1), which affects the brain and nervous system. Thiamine deficiency is often seen in people who consume excessive amounts of alcohol. This is because:
- Many heavy drinkers have poor eating habits. Their nutrition is inadequate, and does not contain essential vitamins.
- Alcohol can inflame the stomach lining and impede the body's ability to absorb the key vitamins it receives.
- Korsakoff's syndrome may also occur in other conditions where there is severe malnutrition, but this is extremely rare in the UK.
Korsakoff's syndrome is part of Wernicke-Korsakoff syndrome, which consists of two separate but related stages: Wernicke's encephalopathy and Korsakoff's syndrome. However, not all cases of Korsakoff's syndrome are preceded by an episode of Wernicke's.
How does Wernicke's encephalopathy develop?
An encephalopathy is a disorder affecting the brain. Wernicke's encephalopathy usually develops suddenly. There are three main symptoms, though these are not always present, so diagnosis may be difficult. They are:
involuntary, jerky eye movements or paralysis of muscles moving the eyes poor balance, staggering gait or inability to walk drowsiness and confusion.
If Wernicke's is suspected, immediate treatment is essential. Treatment consists of high doses of thiamine injected into a vein or muscle. If treatment is carried out in time, most symptoms should be reversed in a few hours. However, if Wernicke's is left untreated, or is not treated in time, brain damage may result. In some cases the person may die.
How does Korsakoff's syndrome develop?
If Wernicke's encephalopathy is untreated, or is not treated soon enough, Korsakoff's syndrome may follow. It is likely to develop gradually. Brain damage occurs in important small areas in the mid part of the brain, resulting in severe short-term memory loss. Many other abilities may remain intact.
What are the symptoms of Korsakoff's syndrome?
The main symptom is memory loss - particularly of events arising after the onset of the condition. Sometimes, memories of the more distant past can also be affected. Other symptoms may include: difficulty in acquiring new information or learning new skills change in personality − at one extreme the person may show apathy (unconcern, lack of emotional reaction), or at the other, talkative and repetitive behaviour lack of insight into the condition. Even a person with great gaps in their memory may believe that their memory is functioning normally confabulation − inventing events to fill the gaps in memory. For example, a patient who has been in hospital for several weeks may talk convincingly about having just visited his auntie on the south coast earlier that day. This is more common in the early stages of the illness.
This symptom is probably behind the historical use of the term 'psychosis' in Korsakoff's. Medically, psychosis means the presence of delusions representing fixed false beliefs, or hallucinations. In Korsakoff's, the confabulations can seem so fanciful that they could be seen as delusional. However, rather than being fixed, the content of confabulations comes and goes, and is in fact memory-related. Although psychotic thoughts and confabulations alike involve a lack of insight by the person involved, confabulation does not respond to antipsychotic medication.
People usually retain skills that they acquired before developing the disorder, so they are often able to manage with appropriate support.
How is Korsakoff's syndrome diagnosed?
Korsakoff's syndrome cannot be diagnosed until the person has abstained from alcohol for at least four-to-five weeks, to enable the acute symptoms of alcohol withdrawal to subside.
Psychological tests of the person's memory and other abilities will then be carried out to see whether they may have Korsakoff's syndrome or some other condition. They will also be observed to see whether their condition progresses without alcohol. If their condition does not change, they may be diagnosed with a form of dementia, such as Alzheimer's disease. It is possible to have both Korsakoff's syndrome and a dementia.
Who is affected by the syndrome?
Those affected tend to be men between the ages of 45 and 65 with a long history of alcohol misuse, though it is possible to have Korsakoff's syndrome at an older or a younger age.
Women can also be affected. They tend to develop Korsakoff's syndrome at a slightly younger age than men, as they appear to be more vulnerable to the impact of alcohol. It has been suggested that whereas it may take around 20 years for a man to develop Korsakoff's syndrome, it may take about half that time for a woman.
It is not yet clear why some heavy drinkers develop Korsakoff's syndrome and others do not, although this may relate to diet.
How is it treated?
- The progress of Korsakoff's syndrome can be completely halted if the person:
- completely abstains from alcohol
- adopts a healthy diet and takes vitamin supplements.
- While it remains unclear whether additional thiamine helps people improve once the brain damage has already occurred, it may help prevent further damage from occurring.
What is the prognosis?
Any improvement usually occurs within a period of up to two years. It has been estimated that about a quarter of those affected make a very good recovery. About half make a partial recovery and need support to manage their lives. An further quarter make no recovery, and may need long-term care. If the person continues to drink heavily and has poor nutrition, Korsakoff's syndrome is likely to continue to progress.
Other problems associated with heavy drinking
- Alcohol can have a harmful effect on nerve cells in the brain cortex. A wide range of skills and abilities can be affected by this. This is sometimes known as alcoholic dementia. However, if the person abstains from alcohol completely then deterioration ceases, and there is often some recovery over time. At present, much research is being carried out into alcoholic dementia and how it may overlap with Korsakoff's syndrome.
- There may be physical disorders associated with drinking, such as damage to the liver or damage to nerves in the legs and arms.
- People with drinking problems are more likely to have experienced head injuries due to accidents, fights or epileptic seizures.
- Korsakoff's syndrome patients have often lived an unhealthy lifestyle, which increases their risk of developing vascular problems and hence vascular dementia (see Factsheet 402, What is vascular dementia?).