Korsakoff's syndrome
Korsakoff’s syndrome[1] is a neurological condition characterized by severe memory loss and a loss of contact with reality which can result from chronic alcoholism and malnutrition. Brain damage occurs from cell loss in the thalamus and the hypothalamus. The condition is named after Sergei Korsakoff, a Russian physician who described the syndrome as a result of chronic alcoholism.
Pathophysiology
The first stage is accompanied by confusion, disorientation, tremors, a deficit in coordination and ataxia. The disorder progresses to a pattern of significant memory loss which impairs all but the distant past. Patients may not remember their career, where they are, or what they are doing. They often engage in confabulation by creating stories in response to questioning rather than admit an inability to remember. They create stories, usually nonsensical but sometimes rooted in fact, using fragment of memory and sensory information. They also display apathy towards their own state.
The memory impairment found in Korsakoff’s syndrome is most often a deficit in explicit memory.[2] Neuronal death in the medial thalamus and mammillary bodies of the hypothalamus have provided evidence for a theoretical neural circuit for explicit memory.[3] The other form is anterograde amnesia which is memory loss for information learned after the onset of the disorder. It appears anterograde memory is related to hippocampal white matter volume. A deficit in retrograde memory for previously learned information may also be present, although generally not as severe. This deficit is related to posterior cortical white matter volume.[4]
Causes
The syndrome is thought to be caused by a deficiency in thiamine (Vitamin B1) caused by poor diet[5] and poor absorption during digestion. Alcoholics tend to have a poor diet, and alcohol diminishes nutrition absorption.[6] Although thiamine is not the sole cause of the disorder, evidence from animal studies supports its importance. Animals fed on a thiamine deficient diet or treated with a thiamine antagonist show brain lesions in the same area of the brain, and have impaired learning and memory.[7]
Prevention
Prevention of Korsakoff's syndrome is accomplished by an adequate intake of thiamine and reduction in alcohol consumption. Harm reduction models propose the fortification of alcohol or with thiamine so drinkers will maintain adequate vitamin levels.[8] The Australian government passed a law in 1991 that made it a legal requirement for bread-making flour to contain no less than 6.4 mg/kg of thiamine. This was for the express purpose of reducing the incidence of Korsakoff's syndrome. Studies have reported an increased intake of thiamine, and a reduced number of cases.[9] However, enriching beer with thiamine may be the best prevention for several reasons. Beer is reported to be the beverage of choice for patients.[10] Thiamine hydrochloride can merge with the flavor of beer,[11] and has been estimated to be most cost effective than bread enrichment.[12]
Treatment and prognosis
Treatment consists of vitamin B1, which can take the form of supplements or an enriched diet, and abstaining from alcohol. Prognosis is poor, as most patients do not recover from this devastating loss of memory.[13] Detoxification may prevent further cognitive decline.[14]
The popular belief that alcohol permanently kills brain cells may not be completely true. While heavy and persistent alcohol consumption will cause brain damage, such as Korsakoff's syndrome, neuronal death may not be permanent. Some research suggests axons may regrow in the cortex following extended abstinence.[15] Regardless, research is conflicting and has not reached a consensus, and it is no reason to engage in unhealthy drinking.
References
- ↑ This condition is also known as Wenicke-Korsakoff syndrome, Korsakoff’s psychosis and alcoholic amnesic disease.
- ↑ Fama R, Pfefferbaum A, Sullivan EV (2006). "Visuoperceptual learning in alcoholic Korsakoff syndrome". Alcohol. Clin. Exp. Res. 30 (4): 680–7. DOI:10.1111/j.1530-0277.2006.00085.x. PMID 16573587. Research Blogging.
- ↑ Izquierdo I, Bevilaqua LR, Rossato JI, et al (2006). "The connection between the hippocampal and the striatal memory systems of the brain: a review of recent findings". Neurotox Res 10 (2): 113–21. PMID 17062373.
- ↑ Fama R, Marsh L, Sullivan EV (2004). "Dissociation of remote and anterograde memory impairment and neural correlates in alcoholic Korsakoff syndrome". J Int Neuropsychol Soc 10 (3): 427–41. DOI:10.1017/S135561770410310X. PMID 15147600. Research Blogging.
- ↑ Stacey PS, Sullivan KA (2004). "Preliminary investigation of thiamine and alcohol intake in clinical and healthy samples". Psychol Rep 94 (3 Pt 1): 845–8. PMID 15217037.
- ↑ Thomson AD, Cook CC (2000). "Putting thiamine in beer: comments on Truswell's editorial". Addiction 95 (12): 1866–8. PMID 11218367.
- ↑ Langlais PJ, Savage LM (1995). "Thiamine deficiency in rats produces cognitive and memory deficits on spatial tasks that correlate with tissue loss in diencephalon, cortex and white matter". Behav. Brain Res. 68 (1): 75–89. PMID 7619308.
- ↑ Yellowlees PM (1986). "Thiamin deficiency and prevention of the Wernicke-Korsakoff syndrome. A major public health problem". Med. J. Aust. 145 (5): 216–9. PMID 3747898.
- ↑ Harper CG, Sheedy DL, Lara AI, Garrick TM, Hilton JM, Raisanen J (1998). "Prevalence of Wernicke-Korsakoff syndrome in Australia: has thiamine fortification made a difference?". Med. J. Aust. 168 (11): 542–5. PMID 9640303.
- ↑ Price J (1985). "The Wernicke-Korsakoff syndrome in Queensland, Australia: antecedents and prevention". Alcohol Alcohol. 20 (2): 233–42. PMID 4052158.
- ↑ Price J, Theodoros MT (1979). "The supplementation of alcoholic beverages with thiamine--a necessary preventive measure in Queensland?". Aust N Z J Psychiatry 13 (4): 315–20. PMID 295212.
- ↑ Connelly L, Price J (1996). "Preventing the Wernicke-Korsakoff syndrome in Australia: cost-effectiveness of thiamin-supplementation alternatives". Aust N Z J Public Health 20 (2): 181–7. PMID 8799094.
- ↑ Al-Sanouri I, Dikin M, Soubani AO (2005). "Critical care aspects of alcohol abuse". South. Med. J. 98 (3): 372–81. PMID 15813165.
- ↑ Fujiwara E, Brand M, Borsutzky S, Steingass HP, Markowitsch HJ (2007). "Cognitive performance of detoxified alcoholic Korsakoff syndrome patients remains stable over two years". J Clin Exp Neuropsychol: 1–12. DOI:10.1080/13803390701557271. PMID 17852615. Research Blogging.
- ↑ Bates ME, Bowden SC, Barry D (2002). "Neurocognitive impairment associated with alcohol use disorders: implications for treatment". Exp Clin Psychopharmacol 10 (3): 193–212. PMID 12233981.