Shukla Garima, Gupta Salil, Goyal Vinay, Singh Sumit, Srivastava Achal, Behari Madhuri
Department of Neurology, All India Institute of Medical Sciences, New Delhi 110029, India.
Clin Neurol Neurosurg. 2013 Feb;115(2):179-86. doi: 10.1016/j.clineuro.2012.05.013. Epub 2012 Jun 5.
Patients with myasthenia gravis, especially those in crises, are not infrequently observed to demonstrate wide fluctuation in heart rate and blood pressure.
This study was conducted to assess autonomic function in patients with myasthenia gravis.
Patients with myasthenia gravis diagnosed on the basis of typical clinical details, edrophonium or neostigmine test, decremental response on repetitive nerve stimulation testing and anti acetyl choline receptor antibody testing, were compared with age and gender matched controls. Apart from detailed clinical evaluation, all subjects underwent tests of autonomic function, viz. heart rate and blood pressure response on orthostatic tests and isometric handgrip test, Valsalva maneuver, R-R interval variation (RRIV) and the sympathetic skin response (SSR). Results were compared with those in the control group using repeated measures ANOVA and the paired t-test.
Sixty-four patients (27 males, 37 females) with a mean age of 40.5 ± 17 years) with myasthenia gravis of an average 3 ± 4 years duration, and 241 normal controls were enrolled. On the orthostatic tests, patients showed rise in heart rate, systolic and diastolic blood pressure, as did controls, however, the rate and the duration of rise was significantly higher than in the controls (p < 0.01). Similar difference between patients and controls, in rate of rise of these parameters was observed on the isometric hand grip test. No significant difference was observed between the two groups on tests of parasympathetic function (Valsalva ratio, RRIV). These effects could also partially be due to pyridostigmine, which all patients were receiving.
This study suggests sympathetic hyper-reactivity in patients with myasthenia gravis, which could be responsible for serious hemodynamic instability in patients in crisis.
重症肌无力患者，尤其是处于危象期的患者，常出现心率和血压的大幅波动。
本研究旨在评估重症肌无力患者的自主神经功能。
根据典型临床症状、依酚氯铵或新斯的明试验、重复神经电刺激试验的递减反应以及抗乙酰胆碱受体抗体检测确诊的重症肌无力患者，与年龄和性别匹配的对照组进行比较。除详细的临床评估外，所有受试者均接受自主神经功能测试，即直立试验和等长握力试验时的心率和血压反应、瓦尔萨尔瓦动作、R-R间期变异性（RRIV）以及交感神经皮肤反应（SSR）。使用重复测量方差分析和配对t检验将结果与对照组进行比较。
纳入64例平均年龄为40.5±17岁、重症肌无力病程平均为3±4年的患者（27例男性，37例女性）以及241名正常对照者。在直立试验中，患者与对照组一样，心率、收缩压和舒张压均升高，但升高的幅度和持续时间显著高于对照组（p<0.01）。在等长握力试验中，患者和对照组在这些参数的升高速率上也观察到类似差异。两组在副交感神经功能测试（瓦尔萨尔瓦比值、RRIV）方面未观察到显著差异。这些影响也可能部分归因于所有患者均在服用的吡啶斯的明。
本研究提示重症肌无力患者存在交感神经过度反应，这可能是导致危象期患者严重血流动力学不稳定的原因。
