About Alzheimer's & Dementia
What is Korsakoff Syndrome?
Korsakoff syndrome is a chronic memory disorder caused by severe deficiency of thiamine (Vitamin B1). Thiamine aids brain cells in producing energy from sugar. When the level of thiamine becomes very low, brain cells do not have enough energy resources to function properly. Korsakoff syndrome causes difficulty in learning new information, remembering recent events and affects long-term memory. The most common cause is chronic alcohol abuse. It can also be caused by other factors such as prolonged vomiting, eating disorders, cancer chemotherapy, chronic infections and even AIDS.
Korsakoff syndrome is often associated with (or preceded by) an episode of Wernicke encephalopathy. This is an acute brain reaction to a severe lack of thiamine. Wernicke encephalopathy is a medical emergency that causes life-threatening brain dysfunction, confusion, staggering and stumbling, lack of coordination, and abnormal involuntary eye movements.
Since the chronic memory loss of Korsakoff syndrome has been found to follow an episode of Wernicke encephalopathy, the condition is sometimes known as Wernicke-Korsakoff syndrome. Korsakoff syndrome can also develop in individuals who have not had a prior episode of Wernicke encephalopathy.
What are the symptoms?
Korsakoff syndrome affects the ability to learn new information, remember recent events and causes long-term memory gaps. Memory challenges can be the most prominent symptom, while other thinking and social skills might remain relatively unaffected. For example, individuals may be able to carry on a conversation, but moments later have difficulty recalling the conversation.
People living with Korsakoff syndrome may "confabulate," or invent events to fill the gaps in their memory. This differs significantly from telling falsehoods or lying. The person may genuinely believe their invented explanations. For instance, a person who has been in hospital for several weeks may speak convincingly about having just visited a family member’s house earlier that day. This is more common in the early stages of the illness. Scientists don't yet fully understand why Korsakoff syndrome may cause confabulation.
Causes and risks
We do not have complete information regarding how Korsakoff syndrome affects the brain. Research has shown that a severe thiamine deficiency disrupts several chemicals in the brain that play key roles in carrying signals among brain cells and storing and retrieving memories. These disruptions destroy brain cells and cause frequent microscopic bleeding and scar tissue.
Most cases of Korsakoff syndrome are linked to alcohol abuse, but not all people diagnosed with alcoholism will have symptoms of Korsakoff syndrome. It’s still unknown why heavy drinking causes severe thiamine deficiency in some people, while others may be affected by liver, stomach, heart, intestines or other conditions related to alcoholism.
Researchers have identified several genetic variations that may increase susceptibility to Korsakoff syndrome. Poor nutrition also may raise a person’s risks.
Korsakoff syndrome also can be linked to eating disorders like anorexia; fasting, starvation or weight-loss surgery; uncontrolled vomiting; AIDS; kidney dialysis; chronic infection; or cancer that has spread throughout the body.
How is it diagnosed?
Korsakoff syndrome is a clinical diagnosis based on symptoms and medical history. There are currently no lab tests or imaging procedures to confirm this disorder. It may be difficult to diagnose as it may be masked by symptoms of other conditions, including intoxication or withdrawal, infection or head injury.
It is recommended that a workup for memory loss or other cognitive changes always include questions about an individual's alcohol consumption habits. Anyone admitted to the hospital for an alcohol-related condition should be professionally screened for memory loss and cognitive changes, particularly changes in short-term memory.
What kind of treatment is available?
It is recommended that people with alcoholism and others at risk of thiamine deficiency take oral supplements of thiamine and other vitamins under the supervision of their doctor.
Once symptoms improve, individuals should be carefully evaluated to determine if their medical history, alcohol consumption 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. Permanent abstinence from alcohol consumption is recommended.
There are few studies on long-term outcomes for people who develop Korsakoff disease with or without a preceding Wernicke encephalopathy. Available data suggest that about 25% of people who develop Korsakoff syndrome eventually recover, about half notice improvements only, and another 25 % remain unchanged. Some research suggests that people recovering from an episode may have a normal life expectancy if they abstain from consuming alcohol.