Afterdischarges in Myasthenia Gravis

Li Yang; Shougang Guo; Xiuying Chen

doi:10.3389/fneur.2021.599744

Afterdischarges in Myasthenia Gravis

Front Neurol. 2021 Apr 13:12:599744. doi: 10.3389/fneur.2021.599744. eCollection 2021.

Authors

Li Yang¹, Shougang Guo², Xiuying Chen¹

Affiliations

¹ Electromyography Room, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China.
² Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China.

Abstract

Introduction: This study aimed to analyze the clinical features of myasthenia gravis (MG) in combination with the afterdischarges and compare the characteristics of afterdischarges in MG with different serum antibodies. Methods: Ninety-two patients with MG were analyzed retrospectively. The afterdischarges were investigated using motor nerve conduction examination, F-wave examination, and repetitive nerve stimulation (RNS). Results: Afterdischarges were observed after the M wave in 14 of 92 patients. Three of these 14 patients tested positive for the muscle-specific tyrosine kinase antibody (MuSK-Ab), and 11 patients tested positive for the acetylcholine receptor antibody (AchR-Ab). The characteristics of the afterdischarges on RNS differed distinctly between the two antibody groups. The afterdischarges occurred on the first stimulation, but decreased on the second and subsequent stimulations in patients with MuSK-MG, while the afterdischarges continued to occur on each stimulation in patients with AchR-MG. Discussion: The characteristics of the afterdischarges on RNS enabled easy identification of their synaptic or neurogenic nature.

Keywords: MuSK; Myasthenia Gravis; acetylcholine receptor; afterdischarge; peripheral nerve hyperexcitability; repetitive nerve stimulation.