Myopathy

Myopathy is a general term. It refers to any diseases of the muscles. The muscular dystrophies that run in families are one example. Another example are those diseases that produce redness, soreness, and swelling (inflammation) in the muscles.

CAUSES

Myopathies can be acquired or passed down from parent to child (hereditary). It is unknown what causes the myopathies with inflammation. Myopathies can occur at birth or later in life. They may be caused by:

  • Endocrine disorders, such as thyroid disease.

  • Metabolic disorders, which are usually inherited.

  • Infection or inflammation of the muscle. This is often triggered by viruses or an immune system that attacks the muscles.

  • Certain drugs, such as lipid-lowering medicines.

SYMPTOMS

General symptoms include weakness or pain of the limbs. These feelings are usually present close to the center of the body (proximal). Some people report that their myopathy happens during exercise. In some cases, the symptoms decrease as exercise increases. Depending upon the type, one muscle group may be more affected than another. In some cases, people have a myopathy with no symptoms. In the inherited myopathies, some family members may not be affected by symptoms. Other family members may have a range of symptoms.

DIAGNOSIS

Diagnosis is based on your exam and symptoms.

  • Often, blood tests will be done. This is to measure muscle enzyme levels.

  • A test may be done to measure electrical activity of the muscle (electromyography, EMG).

  • A tissue sample (biopsy) of the affected muscle may be taken.

  • A computerized magnetic scan (MRI) may also be performed.

TREATMENT

Treatments vary depending on the type of myopathy. In some cases, treatment to relieve symptoms may be all that is available or needed. Treatment for other forms of myopathy may include medicines. Immunosuppressive drugs and other disease-modifying antirheumatic drugs (DMARDs) may be used. Physical therapy, bracing, or surgery may be needed.

HOME CARE INSTRUCTIONS

  • Certain diets and exercises may be encouraged depending on the type of myopathy.

  • Sun exposure may be discouraged as it can cause rashes.

  • Physical therapy with a muscle strengthening program may be advised.

  • It is important to practice good general health to maintain a normal body weight.

SEEK IMMEDIATE MEDICAL CARE IF:

  • You develop breathing problems.

  • You develop a rash.

  • You have a fever.

FOR MORE INFORMATION

National Institute of Neurological Disorders and Stroke: www.ninds.nih.gov