Tengan C H, Antunes A C, Gabbai A A, Manzano G M
Division of Neurology, Department of Neurology and Neurosurgery, Universidade Federal de São Paulo, Brazil.
J Neurol Neurosurg Psychiatry. 2004 Mar;75(3):497-9. doi: 10.1136/jnnp.2003.013870.
To evaluate exercise test responses in hypokalaemic periodic paralysis (HPP), to determine its value as a diagnostic tool and the factors that could affect the responses.
22 subjects were studied from two families with HPP caused by R528H mutation, four patients with thyrotoxic periodic paralysis, 15 normal controls, and four controls with hyperthyroidism. All family members were submitted to clinical evaluation, electrophysiological exercise testing, and DNA analysis. Patients with thyrotoxic periodic paralysis had exercise tests before and after treatment of their hyperthyroidism.
Abnormal responses to the exercise tests were obtained only in subjects with recent attacks of weakness. They were not correlated with genotype, as asymptomatic carriers were unaffected. Patients with thyrotoxic periodic paralysis showed pronounced impairment while they were hyperthyroid, but improved when they were euthyroid. One patient with HPP and chronic KCl use had an increase in amplitude potentials over approximately 20 minutes, possibly related to alteration of potassium homeostasis.
The exercise test is a useful diagnostic test for periodic paralysis, but in the absence of recent weakness negative results must be viewed with caution. It has advantages over the DNA test in being a non-invasive functional test that can provide insights into abnormalities of muscle excitability.
评估低钾性周期性麻痹（HPP）患者的运动试验反应，确定其作为诊断工具的价值以及可能影响反应的因素。
对来自两个因R528H突变导致HPP的家族的22名受试者、4名甲状腺毒症性周期性麻痹患者、15名正常对照者以及4名甲状腺功能亢进对照者进行了研究。所有家庭成员均接受了临床评估、电生理运动试验和DNA分析。甲状腺毒症性周期性麻痹患者在甲亢治疗前后进行了运动试验。
仅在近期有肌无力发作的受试者中获得了运动试验的异常反应。这些反应与基因型无关，因为无症状携带者未受影响。甲状腺毒症性周期性麻痹患者在甲亢时表现出明显的功能损害，但在甲状腺功能正常时有所改善。一名长期使用氯化钾的HPP患者在大约20分钟内动作电位幅度增加，可能与钾稳态改变有关。
运动试验是周期性麻痹的一种有用诊断试验，但在近期无肌无力的情况下，阴性结果必须谨慎看待。它作为一种非侵入性的功能试验，相对于DNA检测具有优势，能够深入了解肌肉兴奋性异常。
