What Is Myositis?

By kara

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Myositis is the term given to conditions that cause muscle inflammation. The disorder is typically chronic and progressive in nature and can be difficult to diagnose. This condition is rare. Onset is typically gradual, though for some it occurs rapidly.

Approximately 50,000-70,000 people in the United States are currently living with the disorder, and between 1,600 and 3,200 new cases are identified annually. There are five types and for all but one, females are more likely to get the disease than males. Myositis can impact people of any age, depending on the type.

1. Causes: Infection and Inflammation

Infections can lead to myositis. The most common cause is a viral infection, but bacterial and fungal causes are not unheard of. In the viral-induced form, the pathogen itself may directly damage the muscle tissue, or it may release a chemical that finds its way into the muscles.

Systemic inflammation can also lead to myositis. In most cases, the cause of the inflammation is related to autoimmune disorders. These types are severe and result in the body’s tissue, including the muscle, attacking itself. Polymyositis, dermatomyositis and inclusion body myositis are all inflammatory forms of the disease.