Inclusion Body Myositis

What is Inclusion Body Myositis?

Inclusion body myositis (IBM) is a slowly progressive inflammatory disorder of muscles. Men over age 50 are most commonly affected. Symptoms include muscle weakness most commonly in the wrist, knees and ankles associated with progressive muscles wasting. One possible symptom is difficulty swallowing. The symptoms start with a gradual onset and affect most muscles in arms and legs. IBM causes no pain and does not shorten one's lifespan.

What causes Inclusion Body Myositis?

The cause of IBM is not certain. Some theories state that IBM is a form of an autoimmune disorder. This means that the immune system abnormalities cause inflammation in the muscles. IBM may also be inherited, although it is rare.

How is Inclusion Body Myositis diagnosed?

The diagnosis of IBM can be made when characteristic changes are seen on a muscle biopsy specimen The results of blood tests, MRIs and EMGs can also help to make the diagnosis.

How is Inclusion Body Myositis treated?

Some patients improve with intravenous gammaglobulin or steroids. However, the overall response to treatment is poor. An impaired mobility and ability to perform ADLs may improve with PT, OT, use of assistive devices.

More Information

Myositis Association of America
Muscular Dystrophy Association