Myotonia is a medical term that refers to a neuromuscular condition in which the relaxation of a muscle is impaired. It can affect any muscle group. Repeated effort will be needed to relax the muscle, although the condition usually improves after the muscles have warmed-up. Individuals with myotonia may have trouble releasing their grip on objects or may have difficulty rising from a seated position. They may walk with a stiff, awkward gait. Myotonia is caused by an abnormality in the muscle membrane, and is often associated with inherited neurological disorders. Myotonia is commonly seen in individuals with myotonic muscular dystrophy, myotonia congenita, and in people who have one of a group of neurological disorders called the channelopathies, which are inherited diseases that are caused by mutations in the chloride sodium or potassium channels that regulate the muscle membrane. Myotonia may also be triggered by exposure to cold.
Treatment for myotonia may include mexelitine, quinine, phenytoin, and other anticonvulsant drugs. Physical therapy and other rehabilitative measures may help muscle function.
Myotonia is a chronic disorder. Symptoms may improve later in life.
The National Institute of Neurological Disorders and Stroke supports and conducts an extensive research program on neuromuscular disorders. The goals of this research are to learn more about these disorders and to find ways to treat, prevent, and cure them.
National Institute of Arthritis and
Musculoskeletal and Skin Diseases (NIAMS)
National Institutes of Health, DHHS
31 Center Dr., Rm. 4C02 MSC 2350
Bethesda, MD 20892-2350
Muscular Dystrophy Association
Voluntary health agency that fosters neuromuscular disease research and provides patient care funded almost entirely by individual private contributors. MDA addresses the muscular dystrophies, spinal muscular atrophy, ALS, Charcot-Marie-Tooth disease, myasthenia gravis, Friedreich's ataxia, metabolic diseases of muscle, and inflammatory diseases of muscle, for a total of more than 40 neuromuscular diseases.
National Office - 222 S. Riverside Plaza
Chicago, IL 60606