Department of Clinical Neurophysiology, King's College Hospital, London, UK.
Queen Square Centre for Neuromuscular Diseases, University College London, London, UK.
Muscle Nerve. 2022 May;65(5):581-585. doi: 10.1002/mus.27465. Epub 2021 Dec 6.
The aim of this study was to evaluate the sensitivity of the long exercise test (LET) in the diagnosis of periodic paralysis (PP) and assess correlations with clinical phenotypes and genotypes.
From an unselected cohort of 335 patients who had an LET we analyzed 67 patients with genetic confirmation of PP and/or a positive LET.
32/45 patients with genetically confirmed PP had a significant decrement after exercise (sensitivity of 71%). Performing the short exercise test before the LET in the same hand confounded results in four patients. Sensitivity was highest in patients with frequent (daily or weekly) attacks (8/8, 100%), intermediate with up to monthly attacks (15/21, 71%) and lowest in those with rare attacks (9/16, 56%) (p = .035, Mann-Whitney U-test). Patients with a positive LET without confirmed PP mutation comprised those with typical PP phenotype and a group with atypical features.
In our cohort, the LET is strongly correlated with the frequency of paralytic attacks suggesting a role as a functional marker. A negative test in the context of frequent attacks makes a diagnosis of PP unlikely but it does not rule out the condition in less severely affected patients.
本研究旨在评估长时运动试验（LET）在周期性瘫痪（PP）诊断中的敏感性，并评估其与临床表型和基因型的相关性。
我们对 335 例接受 LET 的患者进行了分析，其中 67 例患者的 PP 得到了基因证实，或 LET 阳性。
45 例经基因证实的 PP 患者中有 32 例在运动后有明显的减退（敏感性为 71%）。在同一只手上先进行短运动试验会使 4 例患者的结果产生混淆。在每日或每周发作的患者中（8/8，100%），敏感性最高；每月发作一次的患者敏感性次之（15/21，71%）；而发作频率较低的患者敏感性最低（9/16，56%）（p=0.035，Mann-Whitney U 检验）。在 LET 阳性但未证实有 PP 基因突变的患者中，包括具有典型 PP 表型的患者和一组具有非典型特征的患者。
在我们的队列中，LET 与瘫痪发作的频率密切相关，提示其可作为一种功能性标志物。在频繁发作的情况下，阴性试验不太可能提示为 PP，但并不能排除在病情较轻的患者中不存在该疾病。
