Mareska Michael, Gutmann Laurie
Department of Neurology, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506-9108,USA.
Semin Neurol. 2004 Jun;24(2):149-53. doi: 10.1055/s-2004-830900.
Lambert-Eaton myasthenic syndrome (LEMS) is an idiopathic or paraneoplastic syndrome producing antibodies against presynaptic voltage-gated P/Q calcium channels. This decreases calcium entry into the presynaptic terminal, which prevents binding of vesicles to the presynaptic membrane and acetylcholine release. LEMS is most often associated with small cell lung cancer, although idiopathic presentations comprise approximately 40% of the cases. The most common initial complaint is proximal muscle weakness involving the lower extremities more than the upper extremities. Depressed deep tendon reflexes and autonomic dysfunction are frequently present. Involvement of the bulbar or respiratory muscles is rare. Diagnosis is confirmed by electrophysiological testing, which demonstrates small compound muscle action potentials and facilitation with exercise or 20-Hz repetitive stimulation. A serum test for voltage-gated calcium channel antibodies is commercially available. Treatment involves removing the cancer associated with the disease. If cancer is not found, immunosuppressive medications and acetylcholinesterase inhibitors are used with moderate success. Patients with idiopathic LEMS should be screened every 6 months with chest imaging for cancer.
兰伯特-伊顿肌无力综合征（LEMS）是一种特发性或副肿瘤性综合征，可产生针对突触前电压门控P/Q钙通道的抗体。这会减少钙进入突触前终末，从而阻止囊泡与突触前膜结合以及乙酰胆碱释放。LEMS最常与小细胞肺癌相关，不过特发性表现约占病例的40%。最常见的初始症状是近端肌无力，下肢受累多于上肢。常伴有深部腱反射减弱和自主神经功能障碍。延髓或呼吸肌受累罕见。通过电生理检查确诊，其显示复合肌肉动作电位小，且运动或20赫兹重复刺激后有易化现象。有针对电压门控钙通道抗体的血清检测试剂盒可供使用。治疗包括切除与该疾病相关的癌症。如果未发现癌症，则使用免疫抑制药物和乙酰胆碱酯酶抑制剂，有一定疗效。特发性LEMS患者应每6个月进行胸部影像学检查以筛查癌症。
