Misawa Tamako, Mizusawa Hidehiro
Department of Neurology and Neurological Science, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
Brain Nerve. 2010 Apr;62(4):339-45.
Anti-voltage-gated potassium channel antibodies (anti-VGKC-Ab) cause hyperexcitability of the peripheral nerve and central nervous system. Peripheral nerve hyperexcitability is the chief manifestation of Issacs syndrome and cramp-fasciculation syndrome. Morvan syndrome is characterized by neuromyotonia with autonomic and CNS involvement. Manifestations involving the CNS without peripheral involvement are characteristic of limbic encephalitis and epilepsy. The clinical features of anti-VGKC-Ab-associated limbic encephalitis are subacute onset of episodic memory impairment, disorientation and agitation. Hyponatremia is also noted in most patients. Cortico-steroid therapy, plasma exchange and intravenous immunoglobulin are effective in treating to not only the clinical symptoms but also hyponatremia. Unlike other anti-VGKC-Ab-associated neurological disorders, paraneoplastic cases are rare. Thus, anti-VGKC-Ab-associated limbic encephalopathy is considered to be an autoimmune, non-paraneoplastic, potentially treatable encephalitis. Morvan syndrome is characterized by widespread neurological symptoms involving the peripheral nervous system (neuromyotonia), autonomic system (hyperhidrosis, severe constipation, urinary incontinence, and cardiac arrhythmia) and the CNS (severe insomnia, hallucinations, impairment of short-term memory and epilepsy). Many patients have an underlying tumor, for example thymoma, lung cancer, testicular cancer and lymphoma; this indicates the paraneoplastic nature of the disease. Needle electro-myography reveals myokimic discharge. In nerve conduction study, stimulus-induced repetitive descharges are frequently demonstrated in involved muscles. Plasma exchange is an effective treatment approach, and tumor resection also improves symptoms. Both VGKC-Ab-associated limbic encephalitis and Morvan syndrome can be successfully treated. Therefore, when these diseases are suspected, it's important to measure the anti-VGKC-Ab level.
抗电压门控钾通道抗体（抗VGKC-Ab）可导致外周神经和中枢神经系统的兴奋性增高。外周神经兴奋性增高是艾萨克斯综合征和肌束震颤综合征的主要表现。莫旺综合征的特征是神经肌强直伴自主神经和中枢神经系统受累。无外周受累而仅累及中枢神经系统的表现是边缘性脑炎和癫痫的特征。抗VGKC-Ab相关边缘性脑炎的临床特征为发作性记忆障碍、定向障碍和激越的亚急性起病。大多数患者还存在低钠血症。皮质类固醇治疗、血浆置换和静脉注射免疫球蛋白不仅对临床症状有效，对低钠血症也有效。与其他抗VGKC-Ab相关的神经系统疾病不同，副肿瘤性病例罕见。因此，抗VGKC-Ab相关边缘性脑病被认为是一种自身免疫性、非副肿瘤性、潜在可治疗的脑炎。莫旺综合征的特征是广泛的神经系统症状，累及外周神经系统（神经肌强直）、自主神经系统（多汗、严重便秘、尿失禁和心律失常）和中枢神经系统（严重失眠、幻觉、短期记忆障碍和癫痫）。许多患者有潜在肿瘤，例如胸腺瘤、肺癌、睾丸癌和淋巴瘤；这表明该疾病具有副肿瘤性质。针电极肌电图显示肌颤搐放电。在神经传导研究中，受累肌肉常出现刺激诱导的重复放电。血浆置换是一种有效的治疗方法，肿瘤切除也可改善症状。抗VGKC-Ab相关边缘性脑炎和莫旺综合征均可成功治疗。因此，当怀疑这些疾病时，检测抗VGKC-Ab水平很重要。
