Morvan's syndrome: clinical, laboratory, and in vitro electrophysiological studies.
Morvan's syndrome is a rare disorder characterized by neuromyotonia, hyperhidrosis, and central nervous system dysfunction. We report a patient with features of this syndrome, but who initially presented with breathing difficulties. Concentric needle electromyography showed an abundance of myokymic and neuromyotonic discharges. Exercise tests and repetitive nerve stimulation showed a decrement-increment response of compound muscle action potentials. Antibodies against voltage-gated potassium channels were not detected on repeated testing, but the presence of oligoclonal bands in the cerebrospinal fluid (CSF) suggested an autoimmune etiology. At follow-up over 3 years, no cancer was found. Electrophysiological in vitro studies of effects of patient serum and CSF on rat nerves provided no evidence of altered voltage-gated sodium or potassium conductances. We conclude that putative humoral factors do not block ion channels acutely but may cause channel dysfunction with chronic exposure.
Löscher
Wolfgang N
WN
Department of Neurology, University of Innsbruck, Anichstrasse 35, A-6020 Innsbruck, Innsbruck, Austria. wolfgang.loescher@uibk.ac.at
Wanschitz
Julia
J
Reiners
Karlheinz
K
Quasthoff
Stefan
S
D000200:Action Potentials; D000293:Adolescent; D000818:Animals; D001323:Autoantibodies / Q000032:analysis; D004553:Electric Conductivity; D004568:Electrodiagnosis; D004576:Electromyography; D005080:Exercise Test; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000503:physiopathology; D020385:Myokymia / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000503:physiopathology; D043025:Oligoclonal Bands / Q000134:cerebrospinal fluid; D010543:Peroneal Nerve / Q000503:physiopathology; D024642:Potassium Channels, Voltage-Gated / Q000276:immunology / Q000378:metabolism; D051381:Rats; D015222:Sodium Channels / Q000378:metabolism; D013497:Sural Nerve / Q000503:physiopathology
D001323:Autoantibodies; D043025:Oligoclonal Bands; D024642:Potassium Channels, Voltage-Gated; D015222:Sodium Channels