Cerebral dysfunction in chronic alcoholism: role of alcoholic liver disease.

Evidence suggests that liver disease per se may contribute to the cognitive and motor impairments encountered in chronic alcoholics. Neuropathologic studies reveal astrocytic changes (Alzheimer type II astrocytosis) in the brains of alcoholic cirrhotic patients who died in hepatic coma. Pathophysiologic mechanisms responsible for hepatic (portal-systemic) encephalopathy in alcoholics include the loss of neuron-astrocytic metabolic trafficking as well as selective alterations of serotoninergic and dopaminergic function. In addition, there is evidence to suggest that endogenous ligands for both central-type (GABA-related) and "peripheral-type" (astrocytic) benzodiazepine receptors are implicated in the pathogenesis of hepatic encephalopathy in these patients. Chronic liver disease may also interfere with brain thiamine homeostasis and thus contribute to the pathogenesis of the Wernicke-Korsakoff syndrome in chronic alcoholism.