重症肌无力的咽喉部临床特点

目的 研究重症肌无力患者咽喉部表现特点及喉肌电图特点.方法 分析30例重症肌无力患者咽喉科的症状、体征和嗓音声学检测、喉肌电图检查及喉神经重频刺激肌电反应检查结果,并与健康对照组比较分析.结果 重症肌无力患者中36.7%(11/30)有声嘶、声低、吞咽费力等咽喉部症状,频闪喉镜下发现16.7%(5/30)患者有声带活动略无力,声门闭合有缝隙.嗓音频谱分析结果:重症肌无力患者嗓音振幅(68.3±14.6)dB(-x±s,以下同),最长发声时间(15.1±4.0)s,均显著低于健康对照;振幅微扰(2.43±1.19)%,标准化噪声能量(-9.6±3.3)dB,均显著高于健康对照.喉肌电图检查结果:重症肌无力患者喉肌肌电干扰型波幅除杓间肌外,均明显低于健康对照,甲杓肌和环甲肌尤为显著,低、中、高调时甲杓肌波幅分别为(215±69)μV、(298±113)μV和(380±153)μV;环甲肌分别为(253±92)μV、(361±116)μV和(486±155)μV;转折数多稍高于健康对照,但差异无统计学意义.喉肌重频刺激反应结果:83.3%(25/30)患者喉肌重频刺激反应阳性,平均受累喉肌数2.2±1.3,平均重频衰减率(27.9±19.2)%.结论 重症肌无力患者虽仅少部分表现出咽喉部症状,但大部分有喉肌受累.对于因声弱声嘶、发音费力而就诊的患者,应将重症肌无力作为一项必要的鉴别诊断.喉肌重频刺激可用于重症肌无力的早期诊断.

Laryngopharyngeal characteristics of myasthenia gravis

OBJECTIVE: To observe the laryngopharynx manifestation and electromyography characteristics of myasthenia gravis (MG) patients. METHODS: Thirty cases of MG were included in this study, their laryngopharynx symptoms and signs, voice acoustic assessment, laryngeal electromyography (LEMG) behaviors and repetitive nerve stimulation test(RNS) were analyzed, and the data was compared with that of normal subjects. RESULTS: About 36.7% of MG patients (11/30) had the symptoms of hoarseness, voice fatigue, disphonia and disphagia. The vocal folds movements of 16.7% of MG patients(5/30) appeared weaker than normal, and their vocal glottic couldn't close completely, while with a seam during phonation. Voice amplitude (68.3 +/- 14.6) dB (x +/- s, same at below), and maximum phonation time (15.1 +/- 4.0) s, were greatly lower than normal; shimmer(2. 43 +/- 1.19)%, and normalized noise energy (-9.6 +/- 3.3) dB, were greatly higher than normal. The amplitudes of interference patterns in MG patients' LEMG markedly decreased, except introarytenoid muscle, during low, normal and high pitch phonation, the amplitudes of thyoiarytenoid muscle were (215 +/- 69) microV, (298 +/- 113) microV and (380 +/- 153) microV, those of cricoarytenoid muscle were (253 +/- 92) microV, (361 +/- 116) microV and (486 +/- 155) RV. The turns increased but had no statistical difference. In the RNS test, 83.3% MG patients (25/30) showed masculine response. There were about 2.20 +/- 1.32 pieces of laryngeal muscles involved, and the reduction rate in amplitude of the compound muscle action potential for RNS was about (27.9 +/- 19.2)%. CONCLUSIONS: Only parts of MG patients had laryngopharyngeal symptoms, but the laryngeal muscles of most of them were involved, appearing as the masculine response for RNS, the decreased synchronization of the laryngeal muscles' interference patterns, the decreased capacity of phonation. MG must be differentiated when a patient has the symptoms of voice weakness, hoarseness and disphonia. Laryngeal RNS test should be used in the early diagnosis of MG.