Lambert-Eaton 肌无力综合征 (LEMS) 是罕见疾病,患病率受以下几种决定有关疾病过程发生率的因素影响:潜在癌症(CA-LEMS;小细胞肺癌最常见)或自身免疫性疾病 (NCA-LEMS)。估计全球患病率为 3-4 人/百万。[4]Orphanet. Lambert-Eaton myasthenic syndrome. November 2013. http://www.orpha.net/ (last accessed 26 September 2017).http://www.orpha.net//consor/cgi-bin/OC_Exp.php?Lng=GB&Expert=43393LEMS 通常始于晚年,但也有儿童患病的罕见情况。CA-LEMS 男性患者居多,中位发病年龄在六十几岁。[1]Titulaer MJ, Wirtz PW, Kuks JB, et al. The Lambert-Eaton myasthenic syndrome 1988-2008: a clinical picture in 97 patients. J Neuroimmunol. 2008;201-202:153-158.http://www.ncbi.nlm.nih.gov/pubmed/18644631?tool=bestpractice.com[3]Sanders DB, Juel VC. Chapter 9 The Lambert-Eaton myasthenic syndrome. Handb Clin Neurol. 2008;91:273-283.http://www.ncbi.nlm.nih.gov/pubmed/18631847?tool=bestpractice.com NCA-LEMS 男女发病率相等,且中位发病年龄在五十几岁。[5]Titulaer MJ, Verschuuren JJ. Lambert-Eaton myasthenic syndrome: tumor versus nontumor forms. Ann N Y Acad Sci. 2008;1132:129-134.http://www.ncbi.nlm.nih.gov/pubmed/18567862?tool=bestpractice.com[6]Wirtz PW, Willcox N, van der Slik AR, et al. HLA and smoking in prediction and prognosis of small cell lung cancer in autoimmune Lambert-Eaton myasthenic syndrome. J Neuroimmunol. 2005;159:230-237.http://www.ncbi.nlm.nih.gov/pubmed/15652424?tool=bestpractice.com 已说明 NCA-LEMS 的双峰分布:45 岁以下患者以女性居多;60 岁以上患者以男性居多。[5]Titulaer MJ, Verschuuren JJ. Lambert-Eaton myasthenic syndrome: tumor versus nontumor forms. Ann N Y Acad Sci. 2008;1132:129-134.http://www.ncbi.nlm.nih.gov/pubmed/18567862?tool=bestpractice.com