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Temperature‐sensitive repetitive discharges in paramyotonia congenita
Author(s) -
Weiss Michael D.,
Mayer Richard F.
Publication year - 1997
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/(sici)1097-4598(199702)20:2<195::aid-mus9>3.0.co;2-7
Subject(s) - myotonia congenita , electrodiagnosis , medicine , myotonia , myotonic dystrophy
A 47‐year‐old female with paramyotonia congenita was studied with electromyography and showed minimal myotonic discharges but prominent repetitive discharges in hand muscles at room temperature. With cooling the hand, the repetitive discharges ceased as the myotonic potentials became prominent. With exercise and further cooling, the myotonic discharges increased and the strength of the muscle and recruitment pattern decreased. With warming, the myotonic discharges decreased as the repetitive discharges reappeared. This is the first report of repetitive discharges occurring in a patient with temperature‐sensitive sodium channel myotonia. It is postulated that the repetitive discharges as well as the myotonic discharges are the manifestation of muscle membrane hyperexcitability secondary to the abnormal, noninactivating sodium channels. © 1997 John Wiley & Sons, Inc. Muscle Nerve , 20, 195–197, 1997.