Open AccessRepetitive compound muscle action potentials in electrophysiological diagnosis of congenital myasthenic syndromes: A case report and review of literature
Author(s) -
Rajinder Kumar,
Anju Kuruvilla
Publication year - 2010
Publication title -
annals of indian academy of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 31
eISSN - 1998-3549
pISSN - 0972-2327
DOI - 10.4103/0972-2327.64645
Subject(s) - congenital myasthenic syndrome , medicine , compound muscle action potential , neuromuscular junction , neuromuscular transmission , electrophysiology , neuroscience , stimulus (psychology) , repetitive nerve stimulation , electromyography , physical medicine and rehabilitation , acetylcholine receptor , psychology , receptor , psychotherapist
Congenital myasthenic syndromes (CMSs) are a heterogeneous group of disorders, characterized by dysfunction of neuromuscular junction (NMJ) transmission. These syndromes are genetically inherited and are present since birth. Some have characteristic clinical or electrodiagnostic features but in many cases determination of the specific form requires genetic studies or specialized morphological and electrophysiological studies on muscle tissue. We report a case of a 4-year-old boy with progressive ptosis and limitation of ocular movements who was diagnosed as slow-channel CMS based on the characteristic electrodiagnostic features. Repetitive compound muscle action potentials (R-CMAPs) were recorded after single nerve stimulus, with decremental response after repetitive trains performed at 3 Hz. CMSs are at times clinically difficult to distinguish from acquired myasthenia. The characteristic clinical and electrodiagnostic features help in the diagnosis and enable rational therapy. In this article we discuss the characteristics of synaptic R-CMAPs.