Uzunçakmak Uyanik Handan, Yildiz Fatma Gökçem, Temuçin Çağrı Mesut
Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkiye.
Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkiye.
Turk J Med Sci. 2024 Dec 30;55(1):112-120. doi: 10.55730/1300-0144.5949. eCollection 2025.
BACKGROUND/AIM: Critical illness-associated weakness is a common neuromuscular syndrome that may manifest as critical illness myopathy (CIM), critical illness polyneuropathy (CIP), or an overlapping syndrome known as critical illness polyneuromyopathy (CIPM). Distinguishing between these subtypes can be challenging due to technical issues, patient-related factors such as insufficient cooperation with needle electromyography (EMG) or edema, and the need for sophisticated, time-consuming electrophysiological methods and invasive procedures such as biopsy. This study aimed to contribute to the electrophysiological distinction between CIM and CIPM.
A new index was designed based on distal compound muscle action potential (CMAP) amplitude and negative peak duration values. Comparative and receiver operating characteristic curve analyses were performed on the parameters of patients with CIM and CIPM, as well as between patient groups and controls.
The median and ulnar CMAP index cut-off values for distinguishing between CIM and CIPM were determined to be 0.35 and 0.51, respectively. Values below these cut-off points support a diagnosis of CIPM while higher values indicate CIM. The best parameter for distinguishing both CIM and CIPM patients from healthy controls was the peroneal CMAP index, with a cut-off value of 0.45.
The CMAP index can be easily calculated from CMAP values obtained during routine nerve conduction studies. This index may serve as a practical and guiding method for differentiating between CIM and CIPM, contributing to the electrophysiological diagnosis of critically ill patients, and particularly those with unreliable sensory nerve action potentials and needle EMG examinations.
背景/目的：危重症相关肌无力是一种常见的神经肌肉综合征，可表现为危重症性肌病（CIM）、危重症性多发性神经病（CIP）或一种称为危重症性多神经肌病（CIPM）的重叠综合征。由于技术问题、患者相关因素（如与针极肌电图（EMG）配合不足或水肿）以及需要复杂、耗时的电生理方法和活检等侵入性操作，区分这些亚型具有挑战性。本研究旨在有助于CIM和CIPM之间的电生理鉴别。
基于远端复合肌肉动作电位（CMAP）幅度和负峰持续时间值设计了一个新指标。对CIM和CIPM患者的参数以及患者组与对照组之间进行了比较分析和受试者工作特征曲线分析。
区分CIM和CIPM的正中神经和尺神经CMAP指数截断值分别确定为0.35和0.51。低于这些截断点的值支持CIPM的诊断，而较高的值表明为CIM。区分CIM和CIPM患者与健康对照的最佳参数是腓总神经CMAP指数，截断值为0.45。
CMAP指数可根据常规神经传导研究中获得的CMAP值轻松计算得出。该指数可作为区分CIM和CIPM的实用指导方法，有助于危重症患者的电生理诊断，尤其是那些感觉神经动作电位和针极EMG检查结果不可靠的患者。
