Polymyositis is a muscle disease that causes the muscle fibers to become inflamed, according to MedicineNet. The disease occurs when white blood cells invade the muscles spontaneously, causing inflammation. As of 2015, the diseaseﾒs cause is unknown.
The muscles closest to the torso or the trunk are typically affected, causing severe weakness, explains MedicineNet. Muscles become progressively weak, although sufferers may experience relapses or flares followed by periods of remission when no symptoms are present. Because the condition can affect other areas of the body, doctors classify polymyositis as a systemic disease related closely to other types of connective tissue diseases, such as rheumatoid arthritis and lupus.
The initial treatment for polymyositis is the administration of corticosteroids in high doses, notes MedicineNet. These medicines work by reducing inflammation in the muscles. If corticosteroids are ineffective in treating the condition, doctors sometimes recommend immunosuppressive medications that suppress the immune systemﾒs response and lessen inflammation. Another treatment option is immunoglobulins infused via an IV, although doctors reserve this treatment for patients who do not respond favorably to other treatments. The prognosis for polymyositis varies. Some people have the condition only briefly without any recurrences, while others go in and out of remission and require more aggressive treatment.