Myositis (inflammatory) is the popular term used to describe a number of inflammatory myopathies:
These diseases cause swelling and loss of muscle. Inflammatory myopathies are thought to be autoimmune diseases, meaning the body's immune system, which normally fights infections and viruses, is misdirected and attacks the body's own normal, healthy tissue through inflammation, or swelling. All of these diseases can cause muscle weakness, but each type is different.
- Muscle weakness, sometimes with muscle pain
- General tiredness and fatigue
- Trouble climbing stairs, standing from a seated position, or reaching up.