1. Definition
Korsakoff syndrome (KS) is a chronic neuropsychiatric condition predominantly caused by thiamine (vitamin B1) deficiency, often associated with chronic alcoholism. It is characterized by severe anterograde and retrograde amnesia, confabulation, and cognitive impairments.
The combination of Korsakoff syndrome with Wernicke’s encephalopathy is known as Wernicke-Korsakow syndrome.
2. Etiology
2.1. Thiamine deficiency
The primary etiologic factor in Korsakoff syndrome is a chronic deficiency of thiamine, a vitamin required for the metabolism of glucose within the brain. Chronic alcohol use disrupts the absorption, storage, and utilization of thiamine, eventually causing neuronal injury, especially of the mammillary bodies, thalamus, and hippocampus.
Factors, contributing to a thiamine deficiency, also include malnutrition, chronic gastrointestinal disease, long-term parenteral nutrition without proper supplementation, and hyperemesis gravidarum.
2.2. Other causes
Cerebral haemorrhages (e.g. due to haemorrhagic stroke or aneurysm) in the anterior communicating artery also possible triggers of KS. Poisoning (e.g. carbon monoxide intoxication), oxygen deficiency and certain infections (encephalitis, meningitis etc.) can also cause brain damage.
3. Symptoms
Patients with Korsakoff syndrome present with the following symptoms:
- Severe anterograde amnesia: Extensive deficit in the creation of new memories
- Retrograde amnesia: Forgetting of already learned memories, often temporally graded
- Confabulation: Creation of information to compensate for memory loss, often unintentional
- Executive dysfunction: Deficient problem-solving, planning, and decision-making
- Apathy and disorientation: Decreased initiative, social withdrawal, and temporal-spatial disorientation
4. Diagnosis
Diagnosis of Korsakoff syndrome is basically clinical, dependent on history, symptomatology, and exclusion of other neurodegenerative illness. Imaging scans like MRI may show atrophy of the mammillary bodies and thalamic lesions. Neuropsychological tests can determine the degree of impairment of cognition. Laboratory investigations may show thiamine deficiency and chronic alcohol-related liver disease.
5. Treatment and Management
- Thiamine Replacement Therapy: Parenteral thiamine in high doses (intravenous, followed by oral supplementation) is the mainstay of treatment
- Nutritional Support: Convalescence is facilitated by a well-balanced diet and multivitamin supplements
- Alcohol Abstinence: Abstinence from alcohol is mandatory to avoid worsening of the neurological status
6. Prognosis
The prognosis of Korsakoff syndrome depends on the timeliness of treatment. Although early, aggressive thiamine repletion will stop deterioration, established KS usually results in permanent cognitive disability.
Complete recovery is uncommon, but partial recovery of memory function and adaptive adjustment will improve quality of life.