Inflammatory Myopathies are a group of rare muscle diseases that result in the degeneration and inflammation of skeletal muscle tissue, resulting in discernible muscle weakness. The muscle weakness may develop slowly over weeks to months and often years. Inflammatory Myopathies are thought be autoimmune in nature as the inflammatory cells surround, invade and destroy healthy muscle fibers as though they were foreign to the body.
Inflammatory Myopathies include Dermatomyositis (DM), Juvenile Myositis (JM/JDM) or Polymyositis (PM) and Inclusion Body Myositis (IBM). Each different disease results in muscle weakness though each has its own characteristics, development and treatment.
Myositis diseases are very rare and affect about 10 out of one million people each year. It is estimated that about 50,000 people in the U.S. may have this type of disease. Many cases go undiagnosed for years. Dermatomyositis (DM) which has a skin rash and Polymyositis (PM) affects mostly women in their 40-50's but can show up in men and in children, some at a very young age. In children this disease is called Juvenile Myositis (JM) or Juvenile Dermatomyositis (JDMS), one common characteristic of JDMS is the formation of calcium deposits in the muscle. Inclusion Body Myositis (IBM) is mostly found in men after the age of 50-60. It is quite different from the other Myositis diseases as it doesn't respond well to drug therapy. Treatment options vary depending on the type of Myositis and its severity.
Early signs of Myositis are extreme fatigue after prolonged walking or standing, difficulty rising from a chair, lifting the arms above the head or climbing stairs. DM & PM mostly affect the muscles that are proximal (close) to and within the trunk. Muscles affected are the neck, back, hip, thighs and buttocks as well as the shoulders and upper arm muscles. In some cases the throat muscles can be affected making swallowing difficult. Rare cases involve heart and lung involvement. IBM involves a wider range of muscles, often affecting the hands and feet.
Treatments for the DM & PM usually start with drug therapy and physical therapy. Prednisone (cortisone), Methotrexate, Cellcept, Immuran and sometimes Intravenous Immune Globulin (IVIG) are often tried alone or in various combination. Placquinil is commonly prescribed for the skin rash associated with Dermatomyositis. There are many new and exciting drugs being researched and tried in certain cases. Embrel, Remicade and other monoclonal anti-body drugs are showing some promise but are still being tested. When making a diagnosis your doctor may include the use of physical exam, special blood work, E.M.G. and a muscle biopsy.
It is important to find a doctor that knows about the Myositis diseases as early treatment in most cases will be beneficial. One or more specialist, a Rheumatologist, Dermatologist or a Neurologist may work together in managing your disease. Physical & Occupational Therapy could be helpful and don't forget your MENTAL health.