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NINDS Inflammatory Myopathies Information Page

Condensed from Inflammatory Myopathies Fact Sheet

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What are Inflammatory Myopathies?

The inflammatory myopathies are a group of diseases, with no known cause, that involve chronic muscle inflammation accompanied by muscle weakness.  The three main types of chronic, or persistent, inflammatory myopathy are polymyositis, dermatomyositis, and inclusion body myositis (IBM).  These rare disorders may affect both adults and children, although dermatomyositis is more common in children.  Polymyositis and dermatomyositis are more common in women than in men.  General symptoms of chronic inflammatory myopathy include slow but progressive muscle weakness that starts in the proximal muscles—those muscles closest to the trunk of the body. Other symptoms include fatigue after walking or standing, tripping or falling, and difficulty swallowing or breathing.  Some patients may have slight muscle pain or muscles that are tender to the touch.  Polymyositis affects skeletal muscles (involved with making movement) on both sides of the body.  Dermatomyositis is characterized by a skin rash that precedes or accompanies progressive muscle weakness.  IBM is characterized by progressive muscle weakness and wasting.  Juvenile myositis has some similarities to adult dermatomyositis and polymyositis. 

Is there any treatment?

The chronic inflammatory myopathies can’t be cured in most adults but many of the symptoms can be treated.  Options include medication, physical therapy, exercise, heat therapy (including microwave and ultrasound), orthotics and assistive devices, and rest.  Polymyositis and dermatomyositis are first treated with high doses of prednisone or another corticosteroid drug.  This is most often given as an oral medication but can be delivered intravenously.  Immunosuppressant drugs, such as azathioprine and methotrexate, may reduce inflammation in people who do not respond well to prednisone. IBM has no standard course of treatment.  The disease is generally unresponsive to corticosteroids and immunosuppressive drugs.

What is the prognosis?

Most cases of dermatomyositis respond to therapy.  The prognosis for polymyositis varies.  Most individuals respond fairly well to therapy, but some people have a more severe disease that does not respond adequately to therapies and are left with significant disability.  IBM is generally resistant to all therapies and its rate of progression appears to be unaffected by currently available treatments. 

What research is being done?

The National Institutes of Health (NIH), through the collaborative efforts of its National Institute of Neurological Disorders and Stroke (NINDS), National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), and National Institute of Environmental Health Sciences (NIEHS), conducts and supports a wide range of research on neuromuscular disorders, including the inflammatory myopathies.  The NINDS and NIAMS are funding DNA analyses using microarrays to characterize patterns of muscle gene expression among adult and juvenile individuals with distinct subtypes of inflammatory myopathies.  Findings will be used to refine disease classification and provide clues to the pathology of these disorders.  Other NIH-funded research is studying prior viral infection as a precursor to inflammatory myopathy.  Other research hopes to determine whether the drug infliximab, which blocks a protein that is associated with harmful inflammation, is safe and effective in treating dermatomyositis and polymyositis.

NIH Patient Recruitment for Inflammatory Myopathies Clinical Trials

Organizations

Column1 Column2
American Autoimmune Related Diseases Association
22100 Gratiot Avenue
Eastpointe, MI   48021-2227
aarda@aarda.org
http://www.aarda.org
Tel: 586-776-3900 800-598-4668
Fax: 586-776-3903

Myositis Association
1737 King Street
Suite 600
Alexandria, VA   22314
tma@myositis.org
http://www.myositis.org
Tel: 703-299-4850 800-821-7356
Fax: 202-466-8940

Arthritis Foundation
P.O. Box 7669
Atlanta, GA   30357
help@arthritis.org
http://www.arthritis.org
Tel: 800-283-7800 404-872-7100 404-965-7888
Fax: 404-872-0457

Muscular Dystrophy Association
3300 East Sunrise Drive
Tucson, AZ   85718-3208
mda@mdausa.org
http://www.mda.org
Tel: 520-529-2000 800-572-1717
Fax: 520-529-5300

National Institute of Arthritis and Musculoskeletal and Skin Diseases Information Clearinghouse
1 AMS Circle
Bethesda, MD   20892-3675
NIAMSinfo@mail.nih.gov
http://www.niams.nih.gov
Tel: 877-22-NIAMS (226-4267) 301-565-2966 (TTY)
Fax: 301-718-6366

National Institute of Environmental Health Sciences (NIEHS)
National Institutes of Health, DHHS
111 T.W. Alexander Drive
Research Triangle Park, NC   27709
webcenter@niehs.nih.gov
http://www.niehs.nih.gov
Tel: 919-541-3345

Related NINDS Publications and Information
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Prepared by:
Office of Communications and Public Liaison
National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892



NINDS health-related material is provided for information purposes only and does not necessarily represent endorsement by or an official position of the National Institute of Neurological Disorders and Stroke or any other Federal agency. Advice on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined that patient or is familiar with that patient's medical history.

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Last updated April 16, 2014