老年男性,波动性肌无力并口干、眼干3个月——重症肌无力Lambert-Eaton叠加综合征

Old male with fluctuating weakness and dry mouth and eye for 3 months-myasthenia gravis Lambert-Eaton overlap syndrome(MLOS)

本文报告1例重症肌无力Lambert-Eaton叠加综合征。患者男,64岁,波动性四肢近端无力、吞咽费力和活动后呼吸困难3个月,呈晨轻暮重和病态疲劳,伴口干和眼干的自主神经受损表现,神经系统查体示四肢近端肌力约4级,四肢腱反射减退,新斯的明试验阳性,电生理显示多条神经静止时运动传导波幅减低(左正中、面和尺神经均≤5.0 mV),大力收缩15 s后波幅上升超过2倍,左面神经、双尺神经重复电刺激(repetitive nerve stimulation,RNS)低频(3 Hz、5 Hz)递减(17.4%~35.6%)、高频(15 Hz、20 Hz)递增(153%~328%),血清AChR-Ab和Titin-Ab阳性,VGCC-Ab阴性,合并胸腺瘤,最终诊断为重症肌无力Lambert-Eaton叠加综合征(myasthenia gravis Lambert-Eaton overlap syndrome,MLOS)。经小剂量糖皮质激素(甲泼尼龙8~24 mg/d)抑制免疫联合胆碱酯酶抑制剂(溴比斯的明60 mg,2~4次/d)控制症状,病情好转后行胸腺瘤切除,肌无力症状明显改善、眼干消失。MLOS临床罕见,以波动性肌无力为主要表现时,容易忽略自主神经受累表现和遗漏检查,影响准确而全面的诊断。通过报告1例MLOS病例,以提高对MLOS诊断和治疗要点的认识。

We report a case of myasthenia gravis Lambert-Eaton overlap syndrome(MLOS).A 64-year-old male,manifested as fluctuating proximal muscle and oculo-bulbar weakness,and dyspnea after activity for 3 months,accompanied by autonomic symptoms with dry mouth and eye.Weakness was light in the morning and heavy in the evening.Neurological examination showed reduction in bilateral proximal muscle strength(grade 4)and tendon reflexes.Electrophysiology showed low compound muscle action potential at rest(left median,facial,and ulnar nerves were≤5.0 mV);amplitude increment more than twice after 15 seconds of maximum voluntary contraction;amplitude decrement of 17.4%~35.6%at low frequency(3 Hz,5 Hz)and increment of 153%~328%at high frequency(15 Hz,20 Hz)with repetitive nerve stimulation(RNS).Serum AChR-Ab and Titin-Ab were positive,while VGCC-Ab was negative.Thymoma was detected by histopathological examination.The final diagnosis was myasthenia gravis Lambert-Eaton overlap syndrome(MLOS).Thymectomy was performed after the condition was stabilized by treatment with cholinesterase inhibitor(Pyridostigmine,60 mg,2-4 times/day)and low dose glucocorticoid(Methylprednisolone,8-24 mg/day).Myasthenia symptoms were significantly improved and dry eyes was resolved following thymectomy.MLOS is rare in clinical practice.The typical nature of manifestation of fluctuating myasthenia make it easy to ignore autonomic symptoms,thereby leading to insufficient examinations.As a result,it affects the accurate and comprehensive diagnosis.This case report may improve our understanding of the diagnosis and treatment of MLOS.