It is common belief that axonal neuropathies are characterized by simple axonal degeneration and loss and that the electrophysiological correlates are just reduced compound muscle action potential and sensory nerve action potential amplitudes with normal or slightly slow conduction velocity. However, axonal autoimmune neuropathies with involvement of the nodal region and axonal neuropathies due to energy restriction such as occurring in nerve ischemia, thiamine deficiency, critical illness, and mitochondrial disorders present conduction failure that can be either reversible with prompt recovery or progress to axonal degeneration with poor outcome. Moreover autoimmune axonal neuropathies due to nodal voltage gated sodium channels dysfunction/disruption may show slowing of conduction velocity, even in the demyelinating range, possibly due to prolongation of the depolarization time required to reach the threshold for action potential regeneration at subsequent nodes. These observations widen the spectrum of the electrophysiological features in some axonal neuropathies, should be taken into account to avoid misdiagnoses and for correct prognostication, and should stimulate the quest of timely targeted treatments that can eventually halt the progression from conduction failure to axonal degeneration.

中文翻译：

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轴突神经病的电生理学：不仅仅是轴突丢失的证据

人们普遍认为，轴突神经病的特征是简单的轴突变性和丢失，电生理学相关性只是复合肌肉动作电位和感觉神经动作电位幅度降低，传导速度正常或稍慢。然而，累及淋巴结区域的轴突自身免疫性神经病和由能量限制引起的轴突神经病，例如发生在神经缺血、硫胺素缺乏、危重疾病和线粒体疾病中，会出现传导衰竭，这种情况可以迅速恢复可逆或进展为轴突变性结果不佳。此外，由于淋巴结电压门控钠通道功能障碍/中断引起的自身免疫性轴突神经病可能显示传导速度减慢，即使在脱髓鞘范围内，可能是由于在后续节点达到动作电位再生阈值所需的去极化时间延长。这些观察结果拓宽了一些轴突神经病的电生理特征范围，应予以考虑以避免误诊和正确的预后，并应刺激寻求及时的靶向治疗，最终阻止从传导衰竭到轴索变性的进展。