Koshy Kiren G, Iype Thomas, Panicker Praveen
Neurology, Medical College Trivandrum, Trivandrum, IND.
Cureus. 2023 Sep 20;15(9):e45643. doi: 10.7759/cureus.45643. eCollection 2023 Sep.
Peripheral nerve hyperexcitability is an uncommon but treatable condition in neurology. Voltage-gated potassium channelopathies, especially contactin-associated protein-like 2 (CASPR2) antibody, are commonly implicated. We present the case of a 16-year-old boy with tremulousness of both feet and twitching of muscles all over the body for three months. Examination revealed irregular, arrhythmic, small-amplitude twitching movements of the toes along with fasciculations in both thighs. Nerve conduction studies were within normal limits. F-wave studies showed a prolonged polyphasic large-amplitude discharge following the compound muscle action potential and obscuring the F waves. Electromyography showed extensive myokymic discharges. The serum autoimmune antibody profile showed strong positivity for CASPR2. He started lacosamide as a symptomatic treatment. In view of the good symptomatic response, further immunomodulation was deferred and he remains on follow-up. We present this case to highlight the role of motor afterdischarges as a diagnostic clue to peripheral nerve hyperexcitability and to review the literature on this interesting finding.
周围神经兴奋性增高是神经病学中一种罕见但可治疗的病症。电压门控钾通道病，尤其是接触蛋白相关蛋白样2（CASPR2）抗体相关的疾病，通常与之相关。我们报告一例16岁男孩，双脚震颤和全身肌肉抽搐3个月。检查发现脚趾有不规则、无节律、小幅度的抽搐动作，双侧大腿有肌束震颤。神经传导研究结果在正常范围内。F波研究显示，复合肌肉动作电位后出现多相大振幅放电延长，F波模糊。肌电图显示广泛的肌束震颤放电。血清自身免疫抗体谱显示CASPR2呈强阳性。他开始使用拉科酰胺进行对症治疗。鉴于有良好的对症反应，推迟了进一步的免疫调节治疗，他仍在接受随访。我们展示这个病例以突出运动后放电作为周围神经兴奋性增高诊断线索的作用，并回顾关于这一有趣发现的文献。
