＜シンポジウム（3）―4―4＞電気診断の復権
電気診断の復権；筋チャネロパチーの電気生理学的診断
有村 由美子1）, 中村 友紀1）, 吉村 道由1）, 上原 明子1）, 有村 公良1）2）, 迫田 俊一1）, 髙嶋 博1）
1）鹿児島大学大学院医歯学総合研究科神経病学講座神経内科・老年病学〔〒890―8520 鹿児島市桜ヶ丘8丁目35―1〕
2）三州会大勝病院
The periodic paralysis (PP) and myotonic syndromes have been recognized as muscle ion channelopathies (MIC) consequent to the discovery of genetic abnormalities of muscle ion channels. Genetic studies are therefore indispensable in the diagnosis of MIC. However, it is not practical to examine all muscle ion channels immediately upon identification of clinical symptoms. Clinical symptoms of MIC occur due to the abnormal excitability of the muscle membrane which is in turn related to abnormal ion channel genes. Therefore, a series of electrophysiologic tests is useful in examining the characteristics of abnormal excitability and predicting the abnormal ion channel Needle EMG studies can detect myotonic discharges while the prolonged exercise test can distinguish between primary and secondary PP. For myotonia, pattern I which includes the repeated short exercise test at room temperature or at cold skin temperature is specific for paramyotonia congenita, pattern II is characteristic for myotonia congenita, and pattern III is useful for Na channel myotonia. The decrement of CMAP with 10 Hz repetitive stimulation is related to mutation type in myotonia congenita. Thus, these electrophysiological tests may be of use in screening for MIC to narrow down the diagnosis and the selection of candidates for gene analysis.
Full Text of this Article in Japanese PDF (197K)
(臨床神経, 52：1252－1255, 2012)
key words：筋チャネロパチー，電気生理学的検査，prolonged exercise test，repeated short exercise test，repetitive stimulation
（受付日：2012年5月25日）
