Lambert-Eaton肌无力综合征6例临床与电生理特点分析

目的探讨Lambert-Eaton肌无力综合征(LEMS)的临床及电生理特点。方法分析2002-2011年作者医院诊断的6例LEMS患者的临床资料及神经电生理检查结果。结果 6例患者起病年龄34～65岁(中位数53岁),病程0.5～35个月(中位数4个月)。4例患者最初诊断为重症肌无力。5例患者伴恶性肿瘤。6例患者均以肢体近端无力起病。5例患者腱反射减低或消失。3例患者伴口干、眼干等自主神经症状。5例患者行新斯的明试验,其中4例阳性。6例患者均行神经电生理检查,共9次。5例行针极肌电图检查共6次,其中结果显示肌源性改变3次,神经源性改变2次,正常1次。5例行7次神经传导速度检查,全部提示复合肌肉动作电位明显减低。6例共行9次重复神经电刺激(RNS)检查,全部提示高频刺激波幅递增。结论掌握LEMS的临床及电生理特征有助于及时正确诊断。     

重症肌无力合并肌电图肌源性损害53例临床和电生理特点

目的研究重症肌无力（myasthenia gravis，MG）合并肌电图肌源性损害患者的临床和电生理特点。方法收集1998-2006年中国医学科学院北京协和医院神经科肌电图室收治的MG合并肌源性损害患者共53例，对其临床和电生理特点进行回顾性分析。结果在本组患者中，早发型患者占69．81％（37／53），早发型中女性患者明显多于男性（分别为26例和11例,X^2=5．281，P〈0．05）。延髓部肌肉受累者多见，占50．94％（27／53）。仅1例患者具有肌肉萎缩的临床表现。合并其他免疫相关疾病患者占15．09％（8／53）。2例患者（3．77％）重复频率电刺激正常，但肌电图示肌源性损害。15例患者进行肌酶谱检查，其中1例轻度异常。结论对于MG合并肌源性损害的患者，要结合临床特征、电生理检查等进行综合分析来区别“真性”和“假性”的肌源性损害。行甲状腺功能、自身抗体等检查有助于发现潜在的自身免疫系统疾病。     

癌性Lambert-Eaton肌无力综合征四例临床及电生理研究

目的研究癌性Lambert－Eaton肌无力综合征（LEMS）临床及电生理特征。方法回顾性地评价了4例病理证实的癌性LEMS（例1、2为小细胞性肺癌，例3为肾上腺癌，例4为乳腺癌）的临床和电生理资料。结果面神经、腋神经及尺神经重复电刺激示，诱发电位起始波幅减小（0．4～0．7mV）；5Hz以下低频刺激后波幅递减16％～54％（对照：小于15％），但在10Hz以上高频刺激后波幅递增120％～657％（对照：小于65％）；例2和例3肌电图和神经传导速度测定示，多发周围神经源性损害，以感觉神经纤维轴索损害为主。结论观察结果表明，部分癌性LEMS患者的神经肌肉接头和周围神经可同时受累。     

多系统萎缩患者的临床、影像及电生理分析

目的 探讨多系统萎缩(multiple system atrophy,MSA)的临床、影像以及电生理改变特点,为临床诊断提供依据.方法 对62例MSA患者的临床资料、神经影像学以及肌电图检查结果进行回顾性分析.结果 我们共收集拟诊MSA患者62例,其中MSA-A型29例(46.8 % ),主要临床特点表现为直立性低血压为主的自主神经系统症状;MSA-C型24例(38.7 % ),主要表现为小脑性共济失调;MSA-P型9例(14.5 % ),则以锥体外系症状为主.头颅MRI显示MSA-A型患者部分出现小脑病灶;MSA-C型患者主要病变在小脑、脑桥和延髓;MSA-P型患者病变主要在壳核.51例患者行肛门括约肌肌电图(external anal sphincter electromyography,EAS-EMG)检查,其中46例示典型神经源性损害;19例(30.6 % )曾被误诊为其他疾病.结论 MSA早期易漏诊或误诊,结合临床表现、神经影像学以及EAS-EMG检查,可提高MSA的诊断率.     

多系统萎缩患者的临床、影像及电生理分析

目的 探讨多系统萎缩(multiple system atrophy,MSA)的临床、影像以及电生理改变特点,为临床诊断提供依据.方法 对62例MSA患者的临床资料、神经影像学以及肌电图检查结果进行回顾性分析.结果 我们共收集拟诊MSA患者62例,其中MSA-A型29例(46.8 % ),主要临床特点表现为直立性低血压为主的自主神经系统症状;MSA-C型24例(38.7 % ),主要表现为小脑性共济失调;MSA-P型9例(14.5 % ),则以锥体外系症状为主.头颅MRI显示MSA-A型患者部分出现小脑病灶;MSA-C型患者主要病变在小脑、脑桥和延髓;MSA-P型患者病变主要在壳核.51例患者行肛门括约肌肌电图(external anal sphincter electromyography,EAS-EMG)检查,其中46例示典型神经源性损害;19例(30.6 % )曾被误诊为其他疾病.结论 MSA早期易漏诊或误诊,结合临床表现、神经影像学以及EAS-EMG检查,可提高MSA的诊断率.     

多系统萎缩患者的临床、影像及电生理分析

目的 探讨多系统萎缩(multiple system atrophy,MSA)的临床、影像以及电生理改变特点,为临床诊断提供依据.方法 对62例MSA患者的临床资料、神经影像学以及肌电图检查结果进行回顾性分析.结果 我们共收集拟诊MSA患者62例,其中MSA-A型29例(46.8 % ),主要临床特点表现为直立性低血压为主的自主神经系统症状;MSA-C型24例(38.7 % ),主要表现为小脑性共济失调;MSA-P型9例(14.5 % ),则以锥体外系症状为主.头颅MRI显示MSA-A型患者部分出现小脑病灶;MSA-C型患者主要病变在小脑、脑桥和延髓;MSA-P型患者病变主要在壳核.51例患者行肛门括约肌肌电图(external anal sphincter electromyography,EAS-EMG)检查,其中46例示典型神经源性损害;19例(30.6 % )曾被误诊为其他疾病.结论 MSA早期易漏诊或误诊,结合临床表现、神经影像学以及EAS-EMG检查,可提高MSA的诊断率.     

多系统萎缩患者的临床、影像及电生理分析

目的 探讨多系统萎缩(multiple system atrophy,MSA)的临床、影像以及电生理改变特点,为临床诊断提供依据.方法 对62例MSA患者的临床资料、神经影像学以及肌电图检查结果进行回顾性分析.结果 我们共收集拟诊MSA患者62例,其中MSA-A型29例(46.8 % ),主要临床特点表现为直立性低血压为主的自主神经系统症状;MSA-C型24例(38.7 % ),主要表现为小脑性共济失调;MSA-P型9例(14.5 % ),则以锥体外系症状为主.头颅MRI显示MSA-A型患者部分出现小脑病灶;MSA-C型患者主要病变在小脑、脑桥和延髓;MSA-P型患者病变主要在壳核.51例患者行肛门括约肌肌电图(external anal sphincter electromyography,EAS-EMG)检查,其中46例示典型神经源性损害;19例(30.6 % )曾被误诊为其他疾病.结论 MSA早期易漏诊或误诊,结合临床表现、神经影像学以及EAS-EMG检查,可提高MSA的诊断率.     

多系统萎缩患者的临床、影像及电生理分析

目的 探讨多系统萎缩(multiple system atrophy,MSA)的临床、影像以及电生理改变特点,为临床诊断提供依据.方法 对62例MSA患者的临床资料、神经影像学以及肌电图检查结果进行回顾性分析.结果 我们共收集拟诊MSA患者62例,其中MSA-A型29例(46.8 % ),主要临床特点表现为直立性低血压为主的自主神经系统症状;MSA-C型24例(38.7 % ),主要表现为小脑性共济失调;MSA-P型9例(14.5 % ),则以锥体外系症状为主.头颅MRI显示MSA-A型患者部分出现小脑病灶;MSA-C型患者主要病变在小脑、脑桥和延髓;MSA-P型患者病变主要在壳核.51例患者行肛门括约肌肌电图(external anal sphincter electromyography,EAS-EMG)检查,其中46例示典型神经源性损害;19例(30.6 % )曾被误诊为其他疾病.结论 MSA早期易漏诊或误诊,结合临床表现、神经影像学以及EAS-EMG检查,可提高MSA的诊断率.     

多系统萎缩患者的临床、影像及电生理分析

目的 探讨多系统萎缩(multiple system atrophy,MSA)的临床、影像以及电生理改变特点,为临床诊断提供依据.方法 对62例MSA患者的临床资料、神经影像学以及肌电图检查结果进行回顾性分析.结果 我们共收集拟诊MSA患者62例,其中MSA-A型29例(46.8 % ),主要临床特点表现为直立性低血压为主的自主神经系统症状;MSA-C型24例(38.7 % ),主要表现为小脑性共济失调;MSA-P型9例(14.5 % ),则以锥体外系症状为主.头颅MRI显示MSA-A型患者部分出现小脑病灶;MSA-C型患者主要病变在小脑、脑桥和延髓;MSA-P型患者病变主要在壳核.51例患者行肛门括约肌肌电图(external anal sphincter electromyography,EAS-EMG)检查,其中46例示典型神经源性损害;19例(30.6 % )曾被误诊为其他疾病.结论 MSA早期易漏诊或误诊,结合临床表现、神经影像学以及EAS-EMG检查,可提高MSA的诊断率.     

多系统萎缩患者的临床、影像及电生理分析

目的 探讨多系统萎缩(multiple system atrophy,MSA)的临床、影像以及电生理改变特点,为临床诊断提供依据.方法 对62例MSA患者的临床资料、神经影像学以及肌电图检查结果进行回顾性分析.结果 我们共收集拟诊MSA患者62例,其中MSA-A型29例(46.8 % ),主要临床特点表现为直立性低血压为主的自主神经系统症状;MSA-C型24例(38.7 % ),主要表现为小脑性共济失调;MSA-P型9例(14.5 % ),则以锥体外系症状为主.头颅MRI显示MSA-A型患者部分出现小脑病灶;MSA-C型患者主要病变在小脑、脑桥和延髓;MSA-P型患者病变主要在壳核.51例患者行肛门括约肌肌电图(external anal sphincter electromyography,EAS-EMG)检查,其中46例示典型神经源性损害;19例(30.6 % )曾被误诊为其他疾病.结论 MSA早期易漏诊或误诊,结合临床表现、神经影像学以及EAS-EMG检查,可提高MSA的诊断率.     

Stimulated single-fiber electromyography in Lambert-Eaton myasthenic syndrome.

The Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disorder of neuromuscular transmission. Electrodiagnosis is confirmed by an increase in compound muscle action potential amplitude during high-frequency repetitive nerve stimulation or following brief exercise. We describe the results of stimulated single-fiber electromyography in 4 patients with disorders of neuromuscular transmission: LEMS (2), LEMS/myasthenia gravis (MG) overlap (1), and MG (1). Stimulated SFEMG was performed in the extensor digitorum communis muscle with axonal intramuscular suprathreshold stimulation at low and high rates. In all 4 patients, a rate dependence of jitter was found. In LEMS and LEMS/MG, jitter and blocking improved with high stimulation rates, as compared with the opposite effect in MG. We conclude that stimulated SFEMG is a valuable technique in the diagnosis of LEMS.     

Low-dose guanidine and pyridostigmine: relatively safe and effective long-term symptomatic therapy in Lambert-Eaton myasthenic syndrome

Guanidine hydrochloride is known to be highly effective in the symptomatic treatment of the Lambert-Eaton myasthenic syndrome (LEMS). However, because of its potentially dangerous side reactions of hematologic abnormalities and renal insufficiency, 3,4-diaminopyridine, which is not readily available in the United States, is recommended as the preferred drug for LEMS. We used low-dose guanidine and pyridostigmine combination therapy in 9 patients with LEMS and analyzed its long-term safety and effectiveness. In all patients, a liberal amount of pyridostigmine was used, while daily guanidine dose was kept below 1000 mg a day, and guanidine was given between pyridostigmine dosings. This combination therapy was used for 3–102 months (mean: 34.1 months) and improved clinical status in all patients. Although guanidine had to be discontinued due to severe gastrointestinal symptoms in 3 cases, no serious side reactions such as bone marrow suppressions or signs of renal insufficiency developed in any case. Thus, we conclude that low-dose guanidine therapy is relatively safe and effective for long-term symptomatic treatment of LEMS when it is combined with pyridostigmine. © 1997 John Wiley & Sons, Inc. Muscle Nerve 20:1146–1152, 1997     

Stimulated single-fiber electromyography in Lambert-Eaton myasthenic syndrome before and after 3,4-diaminopyridine

A patient with LEMS unrelated to cancer was studied by stimulated single-fiber electromyography (SFEMG) before and 3 months after the onset of therapy with 3,4-diaminopyridine. All end-plates showed a progressive reduction in blockings and jitter with the increase in stimulation rate. Treatment significantly corrected this feature, but the overall pattern of frequency-improved jitter remained. Such widespread finding is rare but diagnostic for Lambert-Eaton myasthenic syndrome. Stimulated SFEMG can be used to monitor therapy in such patients. © 1997 John Wiley & Sons, Inc. Muscle Nerve, 20, 735–739, 1997.     

Diverse electrophysiological spectrum of the Lambert-Eaton myasthenic syndrome

Among 13 patients with the Lambert-Eaton myathenic syndrome (LEMS), three different patterns on the repetitive nerve stimulation test were observed at the time of initial testing. Type 1 pattern, seen in one patient, had low normal CMAP amplitude, decremental response at the low rate of stimulation (LRS), and relatively normal response at the high rate of stimulation (HRS). Type 2, seen in nine patients, had the classical triad: low CMAP amplitude, decremental response at LRS, and incremental response at HRS. Type 3, seen in three patients, showed low CMAP amplitude, decremental response at LRS, and initial decremental response at HRS. We believe that these three patterns represent different degrees of blocking in LEMS, from the mildest in type 1 to the most severe in type 3. Since types 1 and 3 can be misinterpreted as myasthenia gravis patterns, they must be recognized in LEMS and an incremental response documented by prolonged stimulation at HRS.     

Lambert-Eaton myasthenic syndrome presenting with severe respiratory failure

Two cases of Lambert-Eaton myasthenic syndrome (LEMS) who presented with primary respiratory failure are reported. In each case, although not initially suspected clinically, the electrophysiological findings, which included reduced compound muscle action potential amplitudes, decrement to 3-Hz stimulation, and potentiation after 40-Hz stimulation, led to the diagnosis in the critical care unit. Electrophysiological studies of the respiratory system, including repetitive nerve stimulation of the phrenic nerve, were extremely valuable in management. As shown by these cases, the severe respiratory failure in LEMS is reversible with treatment. Thus, LEMS should be considered in cases of unexplained respiratory failure, other clinical features of the disorder sought, and the electrophysiological hallmarks looked for, including studies of the respiratory system. © 1996 John Wiley & Sons, Inc.     

Associated autoimmune diseases in patients with the Lambert-Eaton myasthenic syndrome and their families

Abstract. In view of the clustering of autoimmune diseases (AIDs), we studied the frequency and nature of additional AIDs in patients with the Lambert-Eaton myasthenic syndrome (LEMS) and their family members, in both small cell lung carcinoma (SCLC) related and non-tumour (NT) related cases. Additional AIDs in patients with LEMS were assessed by interviewing the patient and studying the medical record. Family histories up to second-degree family members were established by interviewing patients, controls and family members. Forty-four patients with LEMS were assessed, of whom eighteen (41%) had SCLC. In the NT group seven patients (27%) had an additional AID, in the SCLC group two (11 %) (p=0.20). Thyroid disorder (five patients) and insulin dependent diabetes mellitus (two patients) were the most common AIDs. AIDs were significantly more frequent in families of patients with NT-LEMS (64%) than in control families (27%) (p=0.002), which was not found in SCLC-LEMS (36%, p=0.53). Affected family members were linked to the NT-LEMS patient through the maternal line in all cases. In conclusion, AIDs were more frequently found in LEMS patients without a tumour and their families, which could not be shown for SCLC-LEMS. This suggests that NT-LEMS shares immunogenetic factors with other AIDs. In families of NT-LEMS, a remarkable preponderance of maternal inheritance was seen, as has been reported previously in myasthenia gravis.     

Practical aspects of 3,4-diaminopyridine treatment of the Lambert-Eaton myasthenic syndrome

3,4-Diaminopyridine (3,4-DAP) given alone or combined with pyridostigmine is the recommended basic therapy in the Lambert-Eaton myasthenic syndrome (LEMS). We present and exemplify our routine test protocol for monitoring drug introduction and treatment regimen of cholinergic drugs in LEMS. The individual drug responses vary and no recommended standard doses exist. Routine electrophysiological repetitive nerve stimulation studies recording amplitude of initial compound muscle action potential (CMAP) in thenar muscles correlate excellently with clinical myasthenic muscle power tests in clinically affected muscle groups. Therefore repetitive clinical muscle power tests, that often are complicated by painful myalgia and activation potentiation, can be replaced by recordings of CMAP in the introduction and clinical follow up of cholinergic drug treatment in LEMS. Also, adverse effects and other treatment problems from the experience of continuous treatment of 19 LEMS patients with 3,4-DAP for up to 10 years are presented.     

Myopathic EMG findings and type II muscle fiber atrophy in patients with Lambert-Eaton myasthenic syndrome

ObjectiveLambert-Eaton myasthenic syndrome (LEMS) is a rare condition, which may mimic myopathy. A few reports have described that EMG in LEMS may show changes compatible with myopathy, and muscle biopsies have been described with type II as well as type I atrophy. The EMG results were, however, based on qualitative EMG examination and the histopathological methods were not always clear. The objective of this study was to investigate if the previous EMG findings could be confirmed with quantitative EMG (QEMG) and to describe muscle histology in LEMS.MethodsQEMG, nerve conduction studies and muscle biopsy were performed in four consecutive LEMS patients.ResultsQEMG showed significantly decreased mean MUP duration and muscle biopsy showed marked type II fiber atrophy.ConclusionEMG and biopsy abnormalities mimicking myopathy may often be found in patients with LEMS.SignificanceLEMS is a debilitating, but treatable disease, which often precedes detection of a malignancy and it is therefore of obvious importance to diagnose these patients with speed and certainty. Hence it is important that neurophysiologists and neurologists are aware that EMG and histological abnormalities mimicking myopathy may be found in LEMS patients so that these findings do not prolong or misdirect the diagnostic process in these patients.     

Paradoxical lid elevation with sustained upgaze: a sign of Lambert-Eaton syndrome

Myasthenia gravis and Lambert-Eaton myasthenic syndrome are causes of acquired extraocular muscle weakness and ptosis. Exacerbation of ptosis after sustained upgaze is a clinically useful sign in the diagnosis of myasthenia gravis. A 54-year-old woman with established Lambert-Eaton myasthenic syndrome exhibited transient improvement of her ptosis after sustained upgaze. We suggest that paradoxical lid elevation after sustained upgaze may be a clinically useful sign in distinguishing Lambert-Eaton myasthenic syndrome from myasthenia gravis.