Periphere Nervenübererregbarkeit – Krampf-Faszikulationssyndrom, Neuromyotonie und Morvan Syndrom

Zusammenfassung

Periphere Nervenübererregbarkeitssyndrome sind seltene Erkrankungen die sich je nach Schweregrad und Ausprägung durch verschiedene klinische und elektrophysiologische Befunde auszeichnen. Bei dem Krampf-Faszikulationssyndrom (KFS) finden sich entsprechend Muskelkrämpfe und Faszikulationen, die sich auch elektromyografisch nachweisen lassen. Die Neuromyotonie (NMT) ist klinisch durch Muskelkrämpfe, Muskelzuckungen, Myokymien, verzögerte Muskelrelaxation, Parästhesien und vermehrtes Schwitzen gekennzeichnet und elektromyografisch finden sich neben Doublets, Triplets und Multiplets die charakteristischen hochfrequenten neuromyotonen Entladungen. Das Morvan Syndrom erweitert die Neuromyotonie um Dysautonomie, Veränderungen der Kognition und des Verhaltens. Autoantikörper, die nicht gegen die VGKC selbst gerichtet sind, sondern gegen Proteine, die mit den VGKC einen Komplex bilden (Contactin-2, CASPR-2 und LGI-1) finden sich in bis zu 25% beim KFS, in bis zu 50% bei der NMT und bis zu 90% beim Morvan Syndrom. NMT und Morvan Syndrom kommen als paraneoplastische Syndrome vor, vor allem assoziiert mit Thymom oder kleinzelligem Bronchuskarzinom. Bei paraneoplastischen Formen kann die Behandlung des Tumors zu Besserungen der neuromyotonen Symptome führen. Zur symptomatischen Behandlung werden Na-Kanal Blocker wie z. B. Carbamazepin eingesetzt, zur Behandlung autoimmuner Formen intravenöse Immunglobuline oder Plasmapharese.

Abstract

Syndromes of peripheral nerve hyperexcitability represent a group of rare syndromes with distinct clinical and electrophysiological features. The mildest form, the cramp-fasciculation syndrome (CFS) is characterised by muscle cramps and fasciculations which are also seen on electromyographic recordings (EMG). In neuromyotonia (NMT) patients complain about cramps, fasciculations, muscle stiffness, paraesthesia and increased sweating. EMG shows typical high-frequency neuromyotonic discharges, doublets, triplets and multiplets. Features of Morvan’s syndrome are neuromyotonia, dysautonomia and behavioural and cognitive changes. Antibodies against proteins which interact with voltage-gated potassium channels (Contactin-2, CASPR-2 und LGI-1) are found in up to 25, 50 and 90% in patients with CFS, NMT and Morvan’s syndrome. NMT and Morvan’s syndrome can occur as paraneoplastic syndromes associated with thymoma and small-cell lung cancer. Paraneoplastic hyperexcitability disorders can respond to successful treatment of the tumour, autoimmune forms may respond to plasma exchange or intravenous immunoglobulins. Sodium channel blocking agents, e. g., carbamazepine, are used as symptomatic treatment.

Schlüsselwörter

Kaliumkanal - paraneoplastisch - Myokymie

Key words

VGKC - paraneoplastic - myokymia

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