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Guidelines on clinical presentation and management of nondystrophic myotonias.
- Source :
-
Muscle & nerve [Muscle Nerve] 2020 Oct; Vol. 62 (4), pp. 430-444. Date of Electronic Publication: 2020 May 27. - Publication Year :
- 2020
-
Abstract
- The nondystrophic myotonias are rare muscle hyperexcitability disorders caused by gain-of-function mutations in the SCN4A gene or loss-of-function mutations in the CLCN1 gene. Clinically, they are characterized by myotonia, defined as delayed muscle relaxation after voluntary contraction, which leads to symptoms of muscle stiffness, pain, fatigue, and weakness. Diagnosis is based on history and examination findings, the presence of electrical myotonia on electromyography, and genetic confirmation. In the absence of genetic confirmation, the diagnosis is supported by detailed electrophysiological testing, exclusion of other related disorders, and analysis of a variant of uncertain significance if present. Symptomatic treatment with a sodium channel blocker, such as mexiletine, is usually the first step in management, as well as educating patients about potential anesthetic complications.<br /> (© 2020 Wiley Periodicals, Inc.)
- Subjects :
- Acetazolamide therapeutic use
Age of Onset
Carbonic Anhydrase Inhibitors therapeutic use
Chloride Channels genetics
Electrodiagnosis
Electromyography
Genetic Testing
Humans
Lamotrigine therapeutic use
Mexiletine therapeutic use
Myotonia Congenita drug therapy
Myotonia Congenita genetics
Myotonia Congenita physiopathology
Myotonic Disorders genetics
NAV1.4 Voltage-Gated Sodium Channel genetics
Practice Guidelines as Topic
Ranolazine therapeutic use
Sodium Channel Blockers therapeutic use
Voltage-Gated Sodium Channel Blockers therapeutic use
Fatigue physiopathology
Muscle Weakness physiopathology
Muscle, Skeletal physiopathology
Myalgia physiopathology
Myotonic Disorders physiopathology
Subjects
Details
- Language :
- English
- ISSN :
- 1097-4598
- Volume :
- 62
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Muscle & nerve
- Publication Type :
- Academic Journal
- Accession number :
- 32270509
- Full Text :
- https://doi.org/10.1002/mus.26887