Korsakoff's syndrome

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Korsakoff's syndrome
Classification and external resources
ICD-10F106
ICD-9291.1, 294.0
DiseasesDB14107
eMedicinemed/2405
MeSHD020915
 
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Korsakoff's syndrome
Classification and external resources
ICD-10F106
ICD-9291.1, 294.0
DiseasesDB14107
eMedicinemed/2405
MeSHD020915

Korsakoff's syndrome (also called Korsakoff's dementia, Korsakoff's psychosis, or amnesic-confabulatory syndrome) is a neurological disorder caused by a lack of thiamine (vitamin B1) in the brain. Its onset is linked to chronic alcohol abuse and/or severe malnutrition. The syndrome is named after Sergei Korsakoff, a Russian neuropsychiatrist who described it during the late 19th century.

Contents

Symptoms

There are six major symptoms of Korsakoff's syndrome:

  1. anterograde amnesia
  2. retrograde amnesia, severe memory loss
  3. confabulation, that is, invented memories which are then taken as true due to gaps in memory sometimes associated with blackouts
  4. meager content in conversation
  5. lack of insight
  6. apathy - the patients lose interest in things quickly and generally appear indifferent to change.

These symptoms are caused by a deficiency of thiamine (vitamin B1), which is thought to cause damage to the medial thalamus and mammillary bodies of the hypothalamus as well as generalized cerebral atrophy.[1]

When Wernicke's encephalopathy accompanies Korsakoff's syndrome, the combination is called the Wernicke-Korsakoff syndrome. Korsakoff's is a continuum of Wernicke's encephalopathy, though a recognised episode of Wernicke's is not always obvious.

Korsakoff's involves neuronal loss, that is, damage to neurons; gliosis which is a result of damage to supporting cells of the central nervous system; and hemorrhage or bleeding in mammillary bodies. Damage to the dorsomedial nucleus or anterior group of the thalamus (limbic-specific nuclei) is also associated with this disorder. Cortical dysfunction may have arisen from thiamine deficiency, alcohol neurotoxicity, and/ or structural damage in the diencephalon.[2]

Originally it was thought that a lack of initiative and a flat affect were important characteristics of emotion. Studies have questioned this, proposing that it is not necessarily a symptom of Korsakoff’s. Research suggesting that Korsakoff patients are emotionally unimpaired has made this a controversial topic. It can be argued that apathy, which usually characterizes Korsakoff patients, reflects a deficit of emotional expressions, without affecting the experience or perception of emotion.[3]

Research has demonstrated that implicit spatial, verbal, and procedural memory functioning among patients with Korsakoff's remains intact.[4]

Deficits in source memory are characteristic of such patients.[5]

Research has also suggested that Korsakoff patients have impaired executive functions, which can lead to behavioral problems and interfere with daily activities. It is unclear however, which executive functions are affected most.[6]

At first it was thought that Korsakoff patients used confabulation to fill in memory gaps. However, it has been found that confabulation and amnesia do not necessarily co-occur. Studies have shown that there is dissociation between provoked confabulation, spontaneous confabulation (which is unprovoked) and false memories.[7] That is, patients could be led to believe certain things that haven’t happened, just like people without Korsakoff’s syndrome.

Signs

Causes

Conditions resulting in the vitamin deficiency and its effects include chronic alcoholism and severe malnutrition. Alcoholism may be an indicator of poor nutrition, which in addition to inflammation of the stomach lining, causes thiamine deficiency.[8] Other causes include dietary deficiencies, prolonged vomiting, eating disorders, or the effects of chemotherapy. It can also occur in pregnant women who have a form of extreme morning sickness known as hyperemesis gravidarum.[9] Mercury poisoning can also lead to Korsakoff's syndrome.[10] It has also been caused by centipede (mukade) bites in Japan.[11]

PET scans show that there is a decrease of glucose metabolism in the frontal, parietal and cingulated regions of the brain in Korsakoff patients. This may contribute to memory loss/ amnesia. Structural neuroimaging has also shown the presence of midline diencephalic lesions and cortical atrophy.[12]

Risk factors

A number of factors may increase a person's risk to develop Korsakoff's syndrome. These factors are often related to patients' general health and their food intake habits.[13]

The prevalence varies from country to country, but is estimated to be between 0-3% of the population.[14]

Treatment

It was once assumed that anyone suffering from Korsakoff's syndrome would eventually need full time care. This is still often the case, but rehabilitation can help regain some, often limited, level of independence.[15] Treatment involves the replacement or supplementation of thiamine by intravenous (IV) or intramuscular (IM) injection, together with proper nutrition and hydration. However, the amnesia and brain damage caused by the disease does not always respond to thiamine replacement therapy. In some cases, drug therapy is recommended. Treatment of the patient requires taking thiamine orally for 3 to 12 months, though only about 20 percent of the cases are reversible. If treatment is successful, improvement will become apparent within two years although recovery is slow and often incomplete.

Treatment for the memory aspect of Korsakoff’s syndrome can also include domain-specific learning, which when used for rehabilitation is called the method of vanishing cues. Such treatments aim to use patients’ intact memory processes as the basis for rehabilitation. Patients who used the method of vanishing cues in therapy were found to learn and retain information more easily.[16]

Prevention

The most effective method of preventing Korsakoff's syndrome is to avoid B vitamin/thiamine deficiency. In Western nations, the most common causes of such a deficiency are alcoholism and weight disorders.

Case studies

A famous case study is recounted by Oliver Sacks in "The Lost Mariner" and "A Matter of Identity", which can be found in The Man Who Mistook His Wife for a Hat. Other cases include German entertainer Harald Juhnke, artist Charles Blackman,[17] and entertainer Graham Kennedy.[18]

In popular culture

See also

References

  1. ^ Kolb, Bryan; Whishaw, Ian Q. (2003). Fundamentals of human neuropsychology. New York: Worth Publishers. p. 473. ISBN 978-0-7167-5300-1. OCLC 55617319. 
  2. ^ Paller, K. A.; Acharya, A. (1997). "Functional neuroimaging of cortical dysfunction in alcoholic Korsakoff’s syndrome". Journal of Cognitive Neuroscience 9 (2): 277–293. doi:10.1162/jocn.1997.9.2.277. 
  3. ^ Doulas, J.; Wilkinson, D. A. (1993). "Evidence of normal emotional responsiveness in alcoholic Korsakoff’s syndrome in the presence of profound memory impairment". Addiction 88 (12): 1637–1645. doi:10.1111/j.1360-0443.1993.tb02038.x. PMID 8130702. 
  4. ^ Oudman, Erik (2011). "Intact memory for implicit contextual information in Korsakoff's amnesia". Neuropsychologia 49 (10): 2848–2855. doi:10.1016/j.neuropsychologia.2011.06.010. 
  5. ^ Kessels, R. P. C.; Kortrijk, H. E.; Wester, A. J.; Nys, G. M. S. (2008). "Confabulation behavior and false memories in Korsakoff’s syndrome: Role of source memory and executive functioning". Psychiatry and Clinical Neurosciences 62: 220–225. doi:10.1111/j.1440-1819.2008.01758.x. 
  6. ^ Kessels, R. P. C.; Van Oort, R. (2009). "Executive dysfunction in Korsakoff’s syndrome: time to revise the DSM criteria for alcohol-induced persisting amnestic disorder?". International Journal of Psychiatry in Clinical Practice 13 (1): 78–81. doi:10.1080/13651500802308290. 
  7. ^ Kessels, R. P. C.; Kortrijk, H. E.; Wester, A. J.; Nys, G. M. S. (2008). "Confabulation behavior and false memories in Korsakoff’s syndrome: Role of source memory and executive functioning". Psychiatry and Clinical Neurosciences 62: 220–225. doi:10.1111/j.1440-1819.2008.01758.x. 
  8. ^ "What is Korsakoff’s syndrome?". Alzheimer's Society. October 2008. http://www.alzheimers.org.uk/site/scripts/documents_info.php?categoryID=200171&documentID=98. 
  9. ^ Jasmin, Luc (13 February 2008). "Wernicke-Korsakoff syndrome". MedlinePlus Medical Encyclopedia. United States National Library of Medicine. http://www.nlm.nih.gov/medlineplus/ency/article/000771.htm. Retrieved 16 July 2009. 
  10. ^ ATSDR. 1999. Toxicological Profile for Mercury. Atlanta, GA:Agency for Toxic Substances and Disease Registry. http://www.atsdr.cdc.gov/toxprofiles/tp46.pdf
  11. ^ Mohri S, Sugiyama A, Saito K, Nakajima H (March 1991). "Centipede bites in Japan". Cutis; Cutaneous Medicine for the Practitioner 47 (3): 189–90. PMID 2022129. 
  12. ^ Paller, K. A. & Acharya, A. (1997). Functional neuroimaging of cortical dysfunction in alcoholic Korsakoff’s syndrome.” Journal of Cognitive Neuroscience, 9(2), 277.
  13. ^ Rosenblum, Laurie B. (Last reviewed March 2011). "Korsakoff's Syndrome". NYU Langone Medical Center. http://psych.med.nyu.edu/conditions-we-treat/conditions/korsakoffs-syndrome. Retrieved February 12, 2012. 
  14. ^ Harper, C., Gold, J., Rodriguez, M., Perides, M. (1989). The prevalence of the Wernicke-Korsakoff syndrome in Sydney, Australia: a prospective necropsy study. J Neurol Neurosurg Psychiatry. 52 (2), 282-285.
  15. ^ Kopelman MD, Thomson AD, Guerrini I, Marshall EJ (2009). "The Korsakoff syndrome: clinical aspects, psychology and treatment". Alcohol and Alcoholism 44 (2): 148–54. doi:10.1093/alcalc/agn118. PMID 19151162. 
  16. ^ Komatsu, S., Mimura, M., Kato, M., Wakamatsu, N. & Kashima, H. “Errorless and effortful processes involved in the learning of face-name associations by patients with alcoholic Korsakoff’s Syndrome.” (2000). Neuropsychological Rehabilitation, 10(2), 113-132. doi: 10.1080/096020100389200
  17. ^ "Artist's wonderland is back in town". Melbourne: TheAge.com.au. 29 July 2006. http://www.theage.com.au/news/arts/artists-wonderland-is-back-in-town/2006/07/28/1153816384482.html. 
  18. ^ "Bulletin - Graham Kennedy". Bulletin.NineMSN.com.au. Archived from the original on 2005-06-19. http://web.archive.org/web/20050619210114/http://www.bulletin.ninemsn.com.au/bulletin/site/articleIDs/6D71054423628356CA25700D0005E365. 
  19. ^ "Korsakoff's Syndrome" by Davey Volner.

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