Myositis refers to a number of muscle diseases
that involve a break down and degeneration of muscle tissue and
cells. Myositis is a rare and debilitating disease, that is an
inflammation of the muscles. As it runs its course, muscle cells
and fibers in different parts of the body are damaged and destroyed.
The result is increasing fatigue, loss of muscle strength and
the patient may have difficulty performing routine tasks, eventually
basic physical activities are nearly impossible.
Myositis usually involves a breakdown of muscle tissues, but it can also injure the heart muscle, the lungs, skin areas and the colon. In some cases, the muscles affected may be in only one arm or leg, or a specific muscle group. Patients that have chronic muscle pain and tenderness and fatigue, can take blood tests used to measure the amount of muscle tissue released. The tests include a creatine kinase (CK) or creatine phosphokinase (CPK). People with elevated CK or CPK levels will be evaluated for myositis or rhabdomyolysis.
Other related muscle disorders or "inflammatory myopathies" are called dermatomyositis, polymyositis, and inclusion body myositis.
Doctors do not know how myositis develops,
but many scientists believe it is an autoimmune disease in which
the body attacks itself. Myositis is significant disorder that
is a very high risk factor for the development of rhabdomyolysis,
and kidney failure.