CASE HISTORY – November 2006

Wernicke-Korsakoff’s syndrome and memantine: a case report

Authors: Aleksei Rakitin, Kristiina Kompus, Maarika Nurm, Markku Braschinsky

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Abstract

Korsakoff’s syndrome, a chronic amnestic disorder, is defined as severe anterograde amnesia in which memory is not transferred from short- to long-term storage. It is believed to be a consequence of Wernicke’s encephalopathy, a thiamine-deficient state resulting in encephalopathy, nystagmus, abducens and conjugate gaze palsies and mental confusion. Thiamine deficiency is most often associated with alcohol misuse. The glutamatergic system of the brain, with its N-metyl-D-aspatate (NMDA) receptors, is suggested to be involved in toxic neuronal loss due to an altered glutamate neurotransmission in Wernicke-Korsakoff’s syndrome (WKS) patients.
Chronic alcohol exposure blocks the NMDA receptors, causing an increase in glutamate receptors (up-regulation). Cessation of alcohol use releases the receptors to receive more glutamate. Glutamatergic overstimulation may result in neuronal damage, a phenomenon that has been termed excitotoxicity. Memantine, an uncompetitive
NMDA-receptor antagonist, is a relatively new drug specially developed for use in moderate-to-severe dementia. This drug may also be effective in the treatment of Korsakoff’s amnestic syndrome. We report a case of a 45-year-old woman with WKS, who was treated with 20 mg memantine (Axura) daily for the period of 28 weeks. The patient’s cognitive status was evaluated using the following tests: mini-mental state examination (MMSE), Buschke selective reminding test, trail making test and Rey-Osterrieth complex figure test. No significant improvement was observed in the patient’s anterograde amnesia. Larger trials are needed to substantiate the efficacy of memantine for treatment of memory impairment in Korsakoff’s syndrome.