Charness M E
Department of Neurology (Neuroscience), Harvard Medical School, West Roxbury, Massachusetts 02132.
Alcohol Clin Exp Res. 1993 Feb;17(1):2-11. doi: 10.1111/j.1530-0277.1993.tb00718.x.
Brain lesions in alcoholics are multifactorial in origin. Ethanol neurotoxicity, Wernicke's encephalopathy, hepatocerebral degeneration, head trauma, central pontine myelinolysis, Marchiafava-Bignami syndrome, pellagra, and premorbid pathological conditions, such as fetal alcohol syndrome, may all contribute to cognitive dysfunction in alcoholics. With the exception of ethanol neurotoxicity, all of these conditions are associated with specific neuropathological lesions. Wernicke's encephalopathy, the neurological syndrome of thiamine deficiency, is frequently overlooked during life and may cause global dementia as well as the more familiar Korsakoff's amnestic syndrome. Distinguishing ethanol neurotoxicity from nutritional deficiency can be facilitated by magnetic resonance imaging, which can visualize some of the specific macroscopic lesions of Wernicke's encephalopathy, central pontine myelinolysis, cerebellar degeneration, and Marchiafava-Bignami syndrome. Computerized morphometric studies of alcoholic brains have revealed ventricular enlargement, selective loss of subcortical white matter, and alterations in neuronal size, number, architecture, and synaptic complexity. These lesions tend to be more severe when there is coexisting nutritional deficiency or liver disease, suggesting that ethanol neurotoxicity may not be the sole cause. A search for similar lesions in nonalcoholic Wernicke's encephalopathy and nonalcoholic liver disease will help determine the specificity of these lesions.
酗酒者脑部病变的成因是多因素的。乙醇神经毒性、韦尼克脑病、肝脑变性、头部外伤、中枢性桥脑髓鞘溶解症、马奇亚法瓦-比尼亚米综合征、糙皮病以及病前病理状况,如胎儿酒精综合征,都可能导致酗酒者出现认知功能障碍。除乙醇神经毒性外,所有这些情况都与特定的神经病理病变相关。韦尼克脑病是硫胺素缺乏的神经综合征,在生前常被忽视,可导致全面性痴呆以及更为常见的科萨科夫遗忘综合征。磁共振成像有助于区分乙醇神经毒性和营养缺乏,它能显示韦尼克脑病、中枢性桥脑髓鞘溶解症、小脑变性和马奇亚法瓦-比尼亚米综合征的一些特定宏观病变。对酗酒者脑部进行计算机形态计量学研究发现有脑室扩大、皮质下白质选择性丢失以及神经元大小、数量、结构和突触复杂性的改变。当同时存在营养缺乏或肝脏疾病时,这些病变往往更严重,这表明乙醇神经毒性可能不是唯一原因。在非酒精性韦尼克脑病和非酒精性肝病中寻找类似病变将有助于确定这些病变的特异性。