以发声困难为首发症状的重症肌无力患者的临床特点

Clinical characteristics of myasthenia gravis with dysphonia as the initial symptom

目的探讨以发声困难为首发症状的重症肌无力患者的临床特征,提高早期诊断率,减少误诊。方法报告以发声困难为首发症状的重症肌无力患者31例,观察和分析其临床症状和体征以及疾病的发展和转归过程。结果患者早期症状包括发声无力9例,不能发高音1例,不能维持正常的音量或音调3例,声音嘶哑18例,均有病态性发声疲劳反复发作。纤维喉镜检查喉部表现为一侧或双侧声带内收、外展受限,声带松弛,声带麻痹,声门不能完全闭合,梨状窝积液等。新斯的明试验发声困难症状及喉部体征均有改善。19例患者检测血液中乙酰胆碱受体抗体,5例高于正常参考值。所有患者经过治疗其症状均改善或消失,但在疾病的进程中,均相继出现全身肌无力和球肌麻痹症状。结论嗓音变化可能是某些重症肌无力患者早期惟一症状,对临床具有晨轻暮重,病态疲劳性发声困难的患者应注意采用新斯的明试验或检测血液中乙酰胆碱受体抗体,以除外重症肌无力。

Objective To identify clinical features and diagnostic tests that would alert the otolaryngologist to consider myasthenia gravis （MG） in the differiential diagnosis of dysphonia, we reviewed the clinical characteristics of MG whose initial symptom is dysphonia. Methods 31 patients who presented with dysphonia as their initial and primary complaint are reported, their symptoms and signs are observed and analyzed. Results Patients with dysphonia as their initial symptom of MG may complain of vocal fatigue, difficulty sustaining or projecting their voices, breathy voice or intermittent hoarsness. These symptoms are characterized by fluctuating weakness and abnomal fatigability. Flexible fibroendoscopic examination revealed that patients had incomplete adduction of the vocal folds, fatigue of the tensors of the vocal fold, incomplete glottic closure, vocal cord paralysis, saliva pooling over the bilateral or unilateral pyriform sinus. Neostigmine test revealed dramatic improvement in all patients. Serum levels of anti-Ach-R antibodies were tested in 19 cases, only 5 cases were abnormality. All patients had improved after treatment. Conclusions Voice changes can be the first sign of early MG. Based on fluctuating weakness or weak voice at the end of the day, a positive neostigmine test, significantly higher circulating antibody to acetylcholine receptor, a diagnosis of MG could definitively be made.