Medlock M D, Hanigan W C, Cruse R P
Department of Neuroscience, University of Illinois College of Medicine, Peoria.
J Neurosurg. 1993 Nov;79(5):752-5. doi: 10.3171/jns.1993.79.5.0752.
A 2-month-old infant demonstrated clinical brain death 48 hours after suffering a closed head injury accompanied by cardiac arrest. Two nuclear cerebral blood flow (CBF) studies demonstrated normal perfusion. On the 11th day following injury, cerebral electrical activity ceased and a normal glucose metabolic gradient between gray and white matter was documented on positron emission tomography. Autopsy revealed widespread necrosis with mononuclear cell infiltrates throughout all cerebral cortical layers. Nine children have previously been described with clinical brain death, electrocerebral silence, and evidence of CBF by radionuclide scan. The dissociation between cerebral electrical activity and blood flow may be explained by an increase in cranial volume allowed by the expansile neonatal skull, preventing both intracranial hypertension and a reduction in perfusion pressure. The persistence of glucose metabolism may be associated with the presence of inflammatory microglial cells in the ischemic cortex. The authors conclude that persistence of CBF and glucose metabolism in brain-dead children may not indicate neuronal survival. If repeated neurological examinations with or without electroencephalography support the diagnosis of brain death, the presence of CBF and glucose metabolism should not alter this conclusion.
一名2个月大的婴儿在遭受闭合性头部损伤并伴有心脏骤停48小时后出现临床脑死亡。两项核素脑血流（CBF）研究显示灌注正常。受伤后第11天，脑电活动停止，正电子发射断层扫描记录到灰质和白质之间存在正常的葡萄糖代谢梯度。尸检显示全脑皮质各层均有广泛坏死并伴有单核细胞浸润。此前已有9例儿童被描述为临床脑死亡、脑电静息且通过放射性核素扫描有脑血流证据。脑电活动与血流之间的分离现象可能是由于新生儿颅骨可扩张，使颅腔容积增加，从而防止了颅内高压和灌注压降低。葡萄糖代谢的持续存在可能与缺血皮质中炎性小胶质细胞的存在有关。作者得出结论，脑死亡儿童中脑血流和葡萄糖代谢的持续存在可能并不表明神经元存活。如果反复进行的神经系统检查（无论有无脑电图）支持脑死亡的诊断，脑血流和葡萄糖代谢的存在不应改变这一结论。
