Zusammenfassung
Die Neuromyotonie ist ein durch Hyperexzitabilität peripherer Nerven verursachtes Syndrom spontan auftretender Muskelaktivität und Ursache sichtbarer, generalisierter Myokymien und muskulärer Krämpfe. Elektromyographisch finden sich neben hochfrequenten Doublet- und Triplettentladungen singulärer motorischer Einheiten auch myokyme und neuromyotone Entladungen sowie Fibrillationen und Faszikulationen. In bis zu 90% ist die Neuromyotonie autoimmun erworben (Isaac-Syndrom) und geht mit Antikörpern gegen präsynaptische, spannungsabhängige Kaliumkanäle einher. Einzelne Patienten mit autoimmun bedingter Neuromyotonie zeigen auch Symptome des autonomen (Hyperhidrose) und zentralen Nervensystems im Sinne einer limbischen Enzephalitis, wofür dann die Bezeichnung Morvan-Syndrom verwendet wird. Wir berichten über einen Patienten mit Isaac-Syndrom und stellen anhand der klinischen und elektrophysiologischen Charakteristika die Pathophysiologie, die Diagnose und die Differenzialdiagnose der Neuromyotonie vor.
Summary
Neuromyotonia is a clinical and electrophysiological syndrome of spontaneous muscle fiber activity due to hyperexcitability of peripheral nerve origin causing generalised, visible myokymia and muscular cramps. Electromyography shows abnormal doublet and triplet discharges of high intraburst frequency as well as myokymic and neuromyotonic discharges. Fasciculations and fibrillation potentials are common. Most commonly, neuromyotonia is an acquired immune-mediated disorder (Isaacs’ syndrome) showing elevated antibody levels against presynaptic, voltage-gated, potassium channels. Some of these patients have additional autonomic (hyperhidrosis) and/or CNS symptoms similar to those from limbic encephalitis (referred to then as Morvan’s syndrome). We report on a patient with Isaacs’ syndrome and discuss the clinical and electrophysiological features, pathophysiology, diagnosis, and differential diagnosis of diseases with peripheral nerve hyperexcitability.
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Fischer, D., Schröder, R. Isaac-Syndrom. Nervenarzt 75, 531–535 (2004). https://doi.org/10.1007/s00115-003-1619-x
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DOI: https://doi.org/10.1007/s00115-003-1619-x
Schlüsselwörter
- Neuromyotonie
- Morvan-Syndrom
- Myokymie
- Hyperexzibilität peripherer Nerven
- Antikörper gegen präsynaptische Kaliumkanäle