单纤维肌电图在眼肌型重症肌无力中的应用(附80例报告)

Single Fiber Electromyography in the Diagnosis of Ocular Myasthenia Gravis(Report of 80 Cases)

目的 研究眼肌型重症肌无力 ( OMG)患者的单纤维肌电图 ( SFEMG)及与其他辅助检查的关系 ,期望对临床诊断提供帮助。方法 对 80例 (男 39例 ,女 4 1例 ) OMG患者低频和高频重复神经电刺激 ( RNS)、伸指总肌 (部分额肌 ) SFEMG和血中乙酰胆碱受体抗体 ( ACh RAb)进行测定。结果 伸指总肌 SFEMG示 ,5 0例( 6 2 .5 % )异常 ,表现为颤抖增宽和阻滞。平均颤抖为 ( 4 5 .2± 2 1 .0 )μs,颤抖 >5 5μs所占百分比为 ( 1 8.2± 2 6 .5 ) ,阻滞所占百分比为 ( 8.7± 1 5 .3)。额肌 SFEMG示 ,8例 ( 80 % )异常 ,平均颤抖为 ( 6 6 .3± 2 6 .8)μs,颤抖 >5 5μs所占百分比为 ( 32 .7± 2 8.5 ) ,阻滞所占百分比为 ( 2 8.0± 2 4 .3) ,明显高于正常对照组 ( P<0 .0 0 1 )。 RNS异常率为 2 8.8% ( 2 3/80 )。 ACh RAb滴度增高占 38.8% ( 2 6 /6 7)。 SFEMG的颤抖和阻滞与 RNS递减的程度呈明显的负相关性。 RNS和 ACh RAb异常组平均颤抖明显高于正常组 ( P<0 .0 0 1 )。但 SFEMG正常组仍有 1 3.3% ( 4 /30 ) RNS异常和 2 6 .7% ( 8/30 ) ACh RAb异常。结论 SFEMG在 OMG患者的辅助检查中阳性率最高 ,与 RNS和 ACh RAb具有互补作用 ,三者结合可有助于 OMG的诊断。

Objective To evaluate single fiber electromyography (SFEMG) in the diagnosis of ocular myasthenia gravis (OMG).Methods comparing with repetitive nerve stimulation (RNS) and blood concentration of antibody to the acetylcholine receptor (AChRAb). SFEMG, RNS and AChRAb titration were mesured in 80 patients with OMG (male 39 ,female 41).Results There were remarkble increases of jitter and the ratio of block in frontalis and extensor digitorum communis(EDC)(80% and 62.5% respectively). The mean jitter ranged (45.2±21.0) μs, the ratios of jitter>55 μs and blocking were (18.2±26.5)% and (8.7±15.3)% respectively in EDC.The mean jitter ranged (66.3±26.8)μs, the ratios of jitter>55 μs and blocking were (32.7±28.5)% and (28.0±24.3)% respectively in frontalis.The ratio of abnormal RNS was 28.8%(23/80).There was an increase of AChRAb titration in 26 patiens (38.8%).It was found that increased jitter,and blocking were negatively correlated with maximum decrement to RNS (P<0.01). It was also found that 13.3%(4/30)with abnomal RNS and 26.7%(8/30)with abnormal AChRAb were in the patients with normal SFEMG.Conclusions SFEMG shows the highest sensitive in the diagnosis of OMG. To our knowledge, it suggests that three methods (SFEMG,RNS and AChRAb) have mutual complementary effect in the diagnosis and differential diagnosis of OMG.