Franssen H
Rudolf Magnus Institute of Neurosience, Department of Neurology, F02.230, Neuromuscular Research Group, University Medical Center Utrecht, PO Box 85500, 3508 GA Utrecht, The Netherlands.
Expert Rev Neurother. 2008 Mar;8(3):417-31. doi: 10.1586/14737175.8.3.417.
Demyelinating neuropathies are disorders of the peripheral nervous system in which the myelin sheath of axons is affected by immune-mediated or genetically determined processes. In single axons, demyelination yields conduction block due to extinction of action potentials or conduction slowing. Motor nerve conduction studies assess these phenomena in nerves, which consist of many axons. It is important to distinguish demyelinating from axonal polyneuropathies as this allows accurate diagnosis and institution of appropriate treatment. Immunological treatment in acquired demyelinating polyneuropathies is often successful. Criteria were developed for motor conduction velocity slowing and for conduction block, which assume demyelination if the findings cannot be explained by axon loss. Criteria-sets for the diagnosis of specific polyneuropathies require that several variables are consistent with demyelination in several nerves. However, these sets are based on expert opinion and have a low sensitivity such that treatable neuropathies may be underdiagnosed. Evidence-based sets are currently being developed. Axon loss is the main determinant of the clinical deficit in demyelinating neuropathies and, if its mechanisms are further elucidated, it may be prevented by pharmacological treatment. Excitability testing, which assesses axonal membrane potential and ion-channel activities, may reveal some of these mechanisms.
脱髓鞘性神经病是外周神经系统的疾病，其中轴突的髓鞘受到免疫介导或基因决定的过程影响。在单个轴突中，脱髓鞘由于动作电位的消失或传导减慢而导致传导阻滞。运动神经传导研究评估由许多轴突组成的神经中的这些现象。区分脱髓鞘性与轴索性多发性神经病很重要，因为这有助于准确诊断并采取适当的治疗措施。获得性脱髓鞘性多发性神经病的免疫治疗通常是成功的。已经制定了运动传导速度减慢和传导阻滞的标准，如果这些发现不能用轴突丢失来解释，则假定为脱髓鞘。特定多发性神经病的诊断标准集要求几个变量在几条神经中与脱髓鞘一致。然而，这些标准集基于专家意见，敏感性较低，以至于可治疗的神经病可能诊断不足。目前正在制定基于证据的标准集。轴突丢失是脱髓鞘性神经病临床缺陷的主要决定因素，如果其机制能进一步阐明，可能通过药物治疗来预防。评估轴突膜电位和离子通道活性的兴奋性测试可能揭示其中一些机制。
