Myotonie et faiblesse musculaire corrigee par l'exercice — etude clinique et E.M.G. a propos d'un cas

Transient weakness and compound muscle action potential decrement in myotonia congenita

“…The reduced chloride conductance is thought to cause a transient membrane depolarization of the muscle fibers, which results in repetitive activity (the basis of stiffness) when mild and hypoexcitability (the basis of weakness) when severe. 12,[14][15][16]18 The most sensitive method in bringing out the decrement was 10/s for 5 s. All untreated and most of the treated RMC patients, with or without transient weakness, had a decrement ജ25% and usually >50%. The magnitude of decrement usually correlated with the amount of transient weakness.…”

“…Patients with the recessive form of myotonia congenita (RMC), i.e., Becker's recessive generalized myotonia, 2 often suffer from a peculiar transient weakness of their muscles that appears while the muscles are exercised after a period of rest. 1,[3][4][5][8][9][10][11][12][13][14][15][16][17][18]20 Like the symptom of myotonia, the transient weakness virtually disappears with continued exercise. It was first described by Sabouraud et al 17 in a patient with ''Thomsen's disease'' who would now be considered to have RMC.…”