National Organization for Rare Disorders, Inc.

It is possible that the main title of the report Neuromyotonia is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • Continuous Muscle Fiber Activity Syndrome
  • Quantal Squander
  • Isaacs-Merten Syndrome
  • Isaacs' Syndrome

Disorder Subdivisions

  • None

General Discussion

Neuromyotonia is a rare neuromuscular disorder characterized by abnormal nerve impulses from the peripheral nerves. These impulses cause continuous muscle fiber activity that may continue, even during sleep. The disorder, which has both inherited and acquired forms, is characterized by muscular stiffness and cramping, particularly in the limbs. Continuous fine vibrating muscle movements (myokymia) can be seen. Muscle weakness may also be present. Muscle relaxation may be difficult especially after physical activity involving the particular muscle(s).


National Institute of Neurological Disorders and Stroke (NINDS)
P.O. Box 5801
Bethesda, MD 20824
Tel: (301)496-5751
Fax: (301)402-2186
Tel: (800)352-9424
TDD: (301)468-5981

Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
TDD: (888)205-3223

Madisons Foundation
PO Box 241956
Los Angeles, CA 90024
Tel: (310)264-0826
Fax: (310)264-4766

For a Complete Report

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc. ® (NORD). A copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see

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