Myopathies

Diseases of skeletal muscle (the muscles of arms and legs and respiration) are known as myopathies. Myopathies often are hereditary, but viruses, medications, environmental toxin, and other substances can also cause them.

Patients with myopathies usually are weak, but they may also have muscle cramps, pain, twitching or wasting; exercise intolerance; or, particularly after fasting or exercise, a reddish discoloration of their urine.

Some myopathies respond to a change in diet or dietary supplements, others to medications. Diagnosis begins with a careful history and then proceeds to blood tests, electrical studies (EMG), and, sometimes, muscle biopsy.

For additional information about myopathies, we suggest starting with the website of the Muscular Dystrophy Association, which sponsors research and patient services for these diseases.