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Inflammatory Myopathies
Inflammatory myopathies are a group of muscle diseases that cause inflammation and degeneration of the skeletal muscle tissues. The cause of these diseases is unknown, however, they are thought to be autoimmune disorders (disorders that cause the body's tissues to be attacked by its own immune system.) For people with inflammatory myopathies, inflammatory cells surround, invade and destroy normal muscle fibers as though they were defective or foreign to the body. This eventually results in noticeable muscle weakness. This muscle weakness usually affects both sides of the body and may develop over weeks, months or even years. Inflammatory myopathies affect women nearly twice as often as they affect men.
Dermatomyositis (PM/DM)Dermatomyositis is one of a group of muscle diseases that involve inflammation of the muscles or associated tissues; the inflammatory cells of the immune system attack the blood vessels that supply muscles and skin. The cause of Dermatomyositis is unclear, however, it is suspected that viruses or exposure to certain drugs might trigger the misdirected immune response. The gradual progression of the disease usually begins to onset from childhood to adulthood. Distinctive reddish or purplish rashes are common symptoms as well as rough, scaly skin. Patients also often have hard, painful calcium nodules under the skin. Weakening of the muscles of the hips, thighs, upper arms, top part of the back, shoulders and muscles that move the neck also occur. Heart and respiratory problems are not uncommon. Immunosuppressant medications often effectively control symptoms.
Polymyositis (PM)Polymyositis, like Dermatomyositis, is not a genetic disease, though a genetic predisposition may exist. Also one of a group of muscles diseases that involve inflammation of the muscles or associated tissues, polymyositis has no clear cause. Researchers suspect viruses or exposure to certain drugs might trigger the misdirected immune system. The disease can trigger anywhere from childhood to early adulthood and is more commonly found in females than males. Symptoms include weakness of the muscles of the hips, thighs, upper arms, top part of the back, shoulders and muscles that move the neck. Respiratory complications are also not uncommon. Immunosupressive drugs often help to control symptoms.
Inclusion Body Myositis (IBM)Onset: after age 50.
