Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.
Noran Neurological Institute, Minneapolis, Minnesota, USA.
Muscle Nerve. 2021 Jun;63(6):861-867. doi: 10.1002/mus.27219. Epub 2021 Mar 24.
Myokymic discharges are classically associated with nerve injury from prior radiation but may occur in other neuromuscular disorders. Using quantitative analysis we aimed to identify the spectrum of conditions in which myokymic discharges are present and determine if there are electrophysiological features that distinguish postradiation from nonradiation causes of myokymia.
We reviewed the clinical history of all patients examined in our electromyography labs with myokymic discharges recorded from June 2017 to February 2020. Quantitative analysis of each myokymic discharge was performed using a custom MATLAB script, assessing features such as burst frequency, spikes per burst, and burst regularity.
Eighty-eight distinct myokymic discharges (70 patients) were analyzed: 51 postradiation recordings from 35 patients and 37 recordings from 35 nonradiation patients. The diagnostic spectrum of nonradiation cases was diverse, with common causes being median neuropathy (n = 8), cervical (n = 7), and lumbar (n = 5) radiculopathy, and motor neuron disease (n = 5). On quantitative analysis, postradiation myokymia had an increased burst-to-silence ratio (median, 0.29; nonradiation, 0.08) and greater peak number (median, 15; nonradiation, 7). Except for one patient with hereditary peripheral nerve hyperexcitability, all patients who had two or more muscles demonstrating myokymic discharges belonged to postradiation group.
Myokymic discharges can be seen in diverse neuromuscular conditions; most common in our cohort was chronic median neuropathy. Postradiation myokymia appears to have distinguishing morphological features when quantitatively analyzed compared with nonradiation cases.
肌纤维抽搐放电通常与先前辐射引起的神经损伤有关，但也可能发生在其他神经肌肉疾病中。使用定量分析，我们旨在确定存在肌纤维抽搐放电的各种情况，并确定是否存在电生理特征可以区分辐射性和非辐射性肌纤维抽搐的原因。
我们回顾了 2017 年 6 月至 2020 年 2 月期间在我们肌电图实验室检查的所有患者的临床病史，记录了肌纤维抽搐放电。使用自定义的 MATLAB 脚本对每个肌纤维抽搐放电进行定量分析，评估特征包括爆发频率、爆发内的棘波数量和爆发的规律性。
分析了 88 个不同的肌纤维抽搐放电（70 名患者）：51 个来自 35 名患者的放射性记录和 37 个来自 35 名非放射性患者的记录。非放射性病例的诊断范围广泛，常见的原因包括正中神经病变（n=8）、颈（n=7）和腰（n=5）神经根病变以及运动神经元病（n=5）。在定量分析方面，放射性肌纤维抽搐放电的爆发-静止比（中位数，0.29；非放射性，0.08）更高，峰值数量（中位数，15；非放射性，7）更多。除了一名患有遗传性周围神经兴奋性增加的患者外，所有有两个或更多肌肉出现肌纤维抽搐放电的患者都属于放射性组。
肌纤维抽搐放电可见于多种神经肌肉疾病中；在我们的队列中，最常见的是慢性正中神经病变。与非放射性病例相比，放射性肌纤维抽搐放电在定量分析时似乎具有独特的形态特征。
