多发性神经病是外周神经的一种广泛性疾病。据估计，一般人群的发病率为2%~7%。[1]Italian General Practitioner Study Group (IGPSG). Chronic symmetric symptomatic polyneuropathy in the elderly: a field screening investigation in two Italian regions. I. Prevalence and general characteristics of the sample. Neurology. 1995;45:1832-1836.
http://www.ncbi.nlm.nih.gov/pubmed/7477977?tool=bestpractice.com
[2]Bharucha NE, Bharucha AE, Bharucha EP. Prevalence of peripheral neuropathy in the Parsi community of Bombay. Neurology. 1991;41:1315-1317.
http://www.ncbi.nlm.nih.gov/pubmed/1650932?tool=bestpractice.com
[3]Savettieri G, Rocca WA, Salemi G, Meneghini F, et al. Prevalence of diabetic neuropathy with somatic symptoms: a door-to-door survey in two Sicilian municipalities. Sicilian Neuro-Epidemiologic Study (SNES) Group. Neurology. 1993;43:1115-1120.
http://www.ncbi.nlm.nih.gov/pubmed/8170554?tool=bestpractice.com
多神经病是全身性疾病的常见神经系统表现。例如：约50％的糖尿病患者和晚期艾滋病患者会出现多神经病。[4]Dyck PJ, Kratz KM, Karnes JL, et al. The prevalence by staged severity of various types of diabetic neuropathy, retinopathy, and nephropathy in a population-based cohort: the Rochester Diabetic Neuropathy Study. Neurology. 1993 Apr;43(4):817-24.
http://www.ncbi.nlm.nih.gov/pubmed/8469345?tool=bestpractice.com
[5]Simpson DM, Kitch D, Evans SR et al. HIV neuropathy natural history cohort study: assessment measures and risk factors. Neurology. 2006;66:1679-1687.
http://www.ncbi.nlm.nih.gov/pubmed/16769940?tool=bestpractice.com
毒素和代谢因素造成的大多数神经病变是轴索病变。脱髓鞘性多神经病（例如格林-巴利综合征、单克隆免疫球蛋白病）的病因目前知之甚少。
临床表现
最常见的表现是双脚和下肢远端的对称性麻木、感觉异常和感觉迟钝（远端对称性多发性神经病）。在严重的病例中，感觉症状和体征呈袜子-手套形状分布。平衡和步态可能受损。早期的运动体征包括足内在肌萎缩和踝关节无力。自主神经系统可能受累，导致的症状包括早饱、腹泻或便秘、性功能问题、泌汗障碍和直立性头晕。
对于非对称性神经病，或以上肢症状、体征为首发表现的神经病，临床医生应注意修正诊断，包括神经卡压症（局灶性神经病）、血管炎性神经病（多灶性神经病）。局灶性神经病和多灶性神经病的鉴别诊断常有重叠，但与多神经病则大不同。
