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Myopathy

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Myopathy

What is Myopathy?

The myopathies are a family of neurological diseases in which the primary symptom is muscle weakness due to dysfunction of muscle fiber. Other symptoms of myopathy can include include muscle cramps, stiffness, and spasm. Myopathies can be inherited (such as the muscular dystrophies) or acquired (such as common muscle cramps). Myopathies are grouped as follows:
  • congenital myopathies: characterized by developmental delays in motor skills; skeletal and facial abnormalities are occasionally evident at birth

  • muscular dystrophies: characterized by progressive weakness in voluntary muscles; sometimes evident at birth

  • mitochondrial myopathies: caused by genetic abnormalities in mitochondria, cellular structures that control energy; include Kearns-Sayre syndrome, MELAS and MERRF

  • glycogen storage diseases of muscle: caused by mutations in genes controlling enzymes that metabolize glycogen and glucose (blood sugar); include Pompe's, Andersen's and Cori's diseases
    myoglobinurias: caused by disorders in the metabolism of a fuel (myoglobin) necessary for muscle work; include McArdle, Tarui, and DiMauro diseases

  • dermatomyositis: an inflammatory myopathy of skin and muscle

  • myositis ossificans: characterized by bone growing in muscle tissue

  • familial periodic paralysis: characterized by episodes of weakness in the arms and legs polymyositis, inclusion body myositis, and related myopathies: inflammatory myopathies of skeletal muscle neuromyotonia: characterized by alternating episodes of twitching and stiffness; and stiff-man syndrome, characterized by episodes of rigidity and reflex spasms common muscle cramps and stiffness, and tetany: characterized by prolonged spasms of the arms and legs

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Is there any treatment?

Treatments for the myopathies depend on the disease or condition and specific causes. Supportive and symptomatic treatment may be the only treatment available or necessary for some disorders. Treatment for other disorders may include drug therapy, such as immunosuppressives, physical therapy, bracing to support weakened muscles, and surgery.

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What is the prognosis?

The prognosis for individuals with a myopathy varies. Some individuals have a normal life span and little or no disability. For others, however, the disorder may be progressive, severely disabling, life-threatening, or fatal.

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Organizations

National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)

Muscular Dystrophy Association

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Neuropathy

What is Multifocal Motor Neuropathy?

Multifocal motor neuropathy is a progressive muscle disorder characterized by muscle weakness in the hands, with differences from one side of the body to the other in the specific muscles involved. It affects men much more than women. Symptoms also include muscle wasting, cramping, and involuntary contractions or twitching of the leg muscles. The disorder is sometimes mistaken for amyotrophic laterial sclerosis (ALS, or Lou Gehrig's disease) but unlike ALS, it is treatable. An early and accurate diagnosis allows patients to recover quickly.

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Is there any treatment?

Treatment for multifocal motor neuropathy varies. Some individuals experience only mild, modest symptoms and require no treatment. For others, treatment generally consists of intravenous immunoglobulin (IVIg) or immunosuppressive therapy with cyclophosphamide.

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What is the prognosis?

Improvement in muscle strength usually begins within 3 to 6 weeks after treatment is started. Most patients who receive treatment early experience little, if any, disability. However, there is evidence of slow progression over many years.

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Organizations

American Chronic Pain Association (ACPA)

National Chronic Pain Outreach Association (NCPOA)

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Myopathy