Abstract:

Objective To compare the sensitivity and specificity of ice test, neostigmine test and single fiber electromyography (SFEMG) in the diagnosis of ocular myasthenia gravis (OMG), so as to establish an appropriate process for the diagnosis of OMG. Methods A total of 116 patients with newly onset ptosis and/or diplopia were detected by ice test, neostigmine test and SFEMG. Patients were followed up for 6 months to observe the disease changes and experimental treatment effects. Results Apart from patients whose diagnosis was in doubt or lost to follow - up, and who were diagnosed as generalized myasthenia gravis (GMG), the definite diagnosis was finally made in 81 patients, including 21 OMG patients and 60 patients with ptosis and/or diplopia caused by other diseases. The sensitivity of ice test for diagnosis of OMG was 95.24% (20/21), and specificity was 98.33%(59/60). The sensitivity of neostigmine test for diagnosis of OMG was 90.48% (19/21), and specificity was 85% (51/60). The sensitivity of SFEMG for diagnosis of OMG was 95.24% (20/21), and specificity was 80% (48/60). Among 3 tests, only specificity was found significant difference (χ² = 5.232, P = 0.022). The specificity of ice test was better than that of neostigmine test (χ² = 5.707, P = 0.017) and SFEMG (χ² = 6.023, P = 0.014). Conclusions The ice test achieved high sensitivity and specificity in the diagnosis of OMG. The combination of ice test, neostigmine test and SFEMG may have important clinical value for the early diagnosis of OMG.

Key words: Myasthenia gravis, Blepharoptosis, Diplopia, Ice test (not in MeSH), Neostigmine, Electromyography

摘要：

目的 比较冰试验、新斯的明试验、单纤维肌电图（SFEMG）诊断眼肌型重症肌无力的敏感性和特异性，以期建立益于临床开展的诊断流程。方法 共116 例新发眼睑下垂和（或）复视患者，进行冰试验、新斯的明试验和SFEMG，经随访6 个月观察病情变化和试验性治疗效果而最终明确诊断。结果 剔除最终诊断不明、失访和随访期间进展为全身型重症肌无力的患者，最终纳入81 例患者［包括眼肌型重症肌无力21 例和其他疾病引起的眼睑下垂和（或）复视60 例］，冰试验诊断眼肌型重症肌无力的灵敏度为95.24%（20/21）、特异度为98.33%（59/60），新斯的明试验分别为90.48%（19/21）和85%（51/60），SFEMG 分别为95.24%（20/21）和80%（48/60），3 种诊断方法仅特异性差异有统计学意义（χ² = 5.232，P = 0.022），且冰试验的特异度高于新斯的明试验（χ² = 5.707，P = 0.017）和SFEMG（χ² = 6.023，P = 0.014）。结论 冰试验诊断眼肌型重症肌无力的敏感性和特异性均较高，结合新斯的明试验和SFEMG对眼肌型重症肌无力的早期诊断具有重要临床意义。

关键词: 重症肌无力, 眼睑下垂, 复视, 冰试验（非MeSH 词）, 新斯的明, 肌电描记术