Wernicke-Korsakoff syndrome pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Aditya Govindavarjhulla, M.B.B.S. [3]
Pathophysiology
Wernicke-Korsakoff syndrome results from thiamin deficiency. It is generally agreed that Wernicke's encephalpathy results from severe acute deficiency of thiamine (Vitamin B1), whilst Korsakoff's psychosis results from chronic deficiency of thiamin. The metabolically active form of thiamine is thiamine diphosphate which plays a major role as a cofactor in glucose metabolism. The enzymes which are dependent on thiamin diphosphate are associated with the TCA Cycle and catalyse the oxidation of pyruvate,alphaketoglutarate and branched chain amino acids. Thus, anything that encourages glucose metabolism will exacerbate an existing clinical or sub-clinical thiamine deficiency. 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.
There is an unreplicated study that has associated susceptiblity to this syndrome with a hereditary deficiency of transketolase, an enzyme involved in thiamine metabolism.[1]
Gross Pathology
Wernicke-Korsakoff syndrome in alcoholics especially is associated with atrophy[2] of specific regions of the brain, especially the mamillary bodies. Other regions include the anterior region of the thalamus (accounting for amnesic symptoms), the medial dorsal thalamus, the basal forebrain, and median and dorsal raphe nuclei.[3]
Microscopic Pathology
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 of the thalamus is also associated with this disorder. Frequently, for unknown reasons, patients with Korsakoff's psychosis will exhibit marked degeneration of the mamillary bodies. The mechanism of this degeneration is unknown, but it supports current neurological theory that the mamillary bodies play a role in various "memory circuits" within the brain. An example of a memory circuit is the Papez circuit.
References
- ↑ Nixon P, Kaczmarek M, Tate J, Kerr R, Price J (1984). "An erythrocyte transketolase isoenzyme pattern associated with the Wernicke-Korsakoff syndrome". Eur J Clin Invest. 14 (4): 278–81. PMID 6434322.
- ↑ Kolb & Whishaw: Fundamentals of Human Neuropsychology, 2003, pages 473-473
- ↑ Mann K, Agartz I, Harper C, Shoaf S; et al. (2001). "Neuroimaging in alcoholism: ethanol and brain damage". Alcohol Clin Exp Res. 25 (5 Suppl ISBRA): 104S–109S. PMID 11391058.