单纤维肌电图在甲亢伴眼肌型重症肌无力和Graves眼病鉴别诊断中的价值

Utility of single fiber electromyography in the differential diagnosis of hyperthyroidism associated with ocular myasthenia gravis and Graves ophthalmopathy

目的探讨单纤维EMG(SFEMG)技术在甲亢伴眼肌型重症肌无力(OMG)与Graves眼病鉴别诊断中的价值。方法对32例甲亢伴OMG、35例Graves眼病患者进行眼轮匝肌SFEMG测定,分析两组间SFEMG改变的特点。结果在2组患者中,平均颤抖(jitter)值分别为(96. 2±23. 7)、(42. 8±12. 6)μs,jitter> 55μs的百分比M50分别为92%、5%,阻滞所占百分比M50分别为25%、0,纤维密度分别为(1. 9±0. 4)、(1. 7±0. 5)。两组比较,甲亢伴OMG患者各SFEMG参数均明显高于Graves眼病患者组(分别t=15. 56,Z=9. 26,Z=7. 35,均P <0. 01)。结论甲亢伴OMG患者的眼轮匝肌SFEMG均表现为jitter明显增宽,可伴有阻滞,与Graves眼病患者明显不同。眼轮匝肌SFEMG测定有助于甲亢伴OMG和Graves眼病的鉴别诊断。

Objective To assess the utility of single fiber EMG (SFEMG)in the differential diagnosis of hyperthyroidism associated with ocular myasthenia gravis (OMG)and Graves ophthalmopathy.Methods SFEMG was performed in orbicularis oculi muscle of 2 groups of patients.including 32 patients with hyperthyroidism associated with OMG,and 35 patients with Graves ophthalmopathy.The parameters of SFEMG between different groups were compared.Results The mean jitter was (96.2 ± 23.7),(42.8 ± 12.6)μs in hyperthyroidism associated with OMG and patients with Graves Orbitopathy. M50of the percentage of jitter >55 μs was 92% and 5% in the 2 groups respectively.M50of the percentage of block was 25% and 0 in the 2 groups respectively.Fiber density was (1.9 ± 0.4)and (1.7 ± 0.5)in the 2 groups respectively.There was significant difference in those parameters of SFEMG between the patients in 2 groups(t=15.56,Z=9.26,Z=7.35,all P<0.01).Conclusion SFEMG of orbicularis oculi muscle shows significantly increased jitter and block in hyperthyroidism associated with OMG,which can help to differentiate hyperthyroidism associated with OMG from Graves ophthalmopathy.