$Unique_ID{BRK04034} $Pretitle{} $Title{Myositis, Inclusion Body} $Subject{Myositis, Inclusion Body IBM Inflammatory Myopathy Dermatomyositis Idiopathic Polymyositis Distal Myopathy Mixed Connective Tissue Disease Oculopharyngeal Muscular Dystrophy } $Volume{} $Log{} Copyright (C) 1989 National Organization for Rare Disorders, Inc. 649: Myositis, Inclusion Body ** IMPORTANT ** It is possible that the main title of the article (Inclusion Body Myositis) is not the name you expected. Please check the SYNONYM listing to find the alternate names and disorder subdivisions covered by this article. Synonyms IBM Disorder Subdivisions: Inflammatory Myopathy Information on the following diseases can be found in the Related Disorders section of this report: Dermatomyositis Idiopathic Polymyositis Distal Myopathy Mixed Connective Tissue Disease Oculopharyngeal Muscular Dystrophy General Discussion ** REMINDER ** The information contained in the Rare Disease Database is provided for educational purposes only. It should not be used for diagnostic or treatment purposes. If you wish to obtain more information about this disorder, please contact your personal physician and/or the agencies listed in the "Resources" section of this report. Inclusion Body Myositis (IBM) is a slowly progressive weakness of muscle groups located either away from the point of origin (distal) or nearest to the trunk or point of origin (proximal). Symptoms Inclusion Body Myositis (IBM) is characterized by a distinct, progressive muscle weakness of the proximal and distal muscles. It is recognized as an inflammatory disease of the skeletal muscles. IBM is not usually associated with skin rash, malignancy, or collagen vascular disease. However, exceptions to each of these general rules has been found in certain patients. Clinically IBM differs from dermatomyositis and polymyositis because it lacks the features of a collagen vascular disease which include symptoms of fever, headache, joint and muscle pain, and weakness. It has a relatively benign and protracted course. In polymyositis and Inclusion Body Myositis there is evidence of macrophages (scavenger cells) which surround, invade, and destroy non- necrotic (living) muscle fibers. Disorder Subdivisions: Inflammatory Myopathy is an inflammation of the muscle groups, which causes progressive muscle weakness. Causes Inclusion Body Myositis seems to be a distinct type of inflammatory muscle disease. It's cause is unknown. A virus or possibly a neurogenic cause (related to or starting in the nervous system) has been suggested, but both theories remain unproven. Affected Population IBM occurs primarily in elderly persons with the average age of onset being 53. However, young adults in their teens have been affected. It seems to affect mostly males. Related Disorders Symptoms of the following disorders can be similar to those of Inclusion Body Myositis. Comparisons may be useful for a differential diagnosis: Dermatomyositis is a systemic connective tissue disorder characterized by inflammatory and degenerative changes in the muscles, subcutaneous tissues and skin. Symptoms may come and go, but the main symptom is muscle weakness, most often in the hip and shoulder, usually accompanied by a rash. There is often underlying cancer in 50% of adult cases. This disorder may possibly be an autoimmune disease. (Autoimmune disorders are caused when the body's natural defenses (antibodies, lymphocytes, etc.), against invading organisms suddenly begin to attack healthy tissue.) (For more information on this disorder, choose "Dermatomyositis" as your search term in the Rare Disease Database). Idiopathic Polymyositis is a systemic connective tissue disorder characterized by inflammatory and degenerative changes in the muscles leading to weakness and some degree of muscle atrophy. The areas primarily affected are the hip, shoulder, and chest. (For more information on this disorder, choose "Polymyositis" as your search term in the Rare Disease Database). Distal Myopathy affects predominantly the small muscles of the extremities. Onset is usually after age 40, with weakness and wasting of small muscles of the hands. Autosomal dominant inheritance is thought to be a cause. Mixed Connective Tissue Disease (MCTD) is a rheumatic disease characterized by overlapping features similar to those of systemic lupus erythematous (SLE), scleroderma and polymyositis. The cause is unknown, but it is suggested that the immune system may be involved. MCTD appears to be more common than polymyositis and less common than scleroderma. Symptoms of MCTD may include Raynaud's phenomena (cold and numbness of fingers), arthritis, swollen hands, inflammatory proximal muscle weakness, dysfunction of the esophagus, and lung disease. MCTD is often used to describe what may be an overlapping group of connective tissue diseases that cannot be diagnosed in more specific terms. (For more information on this disorder, choose "MCTD" as your search term in the Rare Disease Database). Oculopharyngeal Muscular Dystrophy usually occurs in adulthood. Extraocular muscles are involved initially and the muscles used for swallowing tend to become affected. The typical facial appearance, especially drooping of the eyelids, resembles that found in myasthenia gravis. The inheritance pattern often follows an autosomal dominant pattern. However, occasional sporadic cases and cases with autosomal recessive inheritance have occurred. Therapies: Standard Inclusion Body Myositis does not readily yield to treatment with steroids or other immunosuppressive drugs. Researchers are trying to understand the cause of IBM in order to develop more effective therapies. Other treatment is symptomatic and supportive. Therapies: Investigational This disease entry is based upon medical information available through April 1989. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder. Resources For more information on Inclusion Body Myositis, please contact: National Organization for Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 Inclusion Body Myositis Association 1420 Huron Ct. Harrisburg, VA 22801 (703) 433-7935 (write or if calling, between the hours of 9:00-11:30 a.m. and 6:30-7:30 p.m., please) The National Arthritis and Musculoskeletal and Skin Diseases Information Clearinghouse Box AMS Bethesda, MD 20892 (301) 495-4484 Muscular Dystrophy Association, National Office 3300 E. Sunrise Dr. Tucson, AZ 85718 (602) 529-2000 References MENDELIAN INHERITANCE IN MAN, 8th ed.: Victor A. McKusick; Johns Hopkins University Press, 1986. Pp. 427. ONOCLONAL ANTIBODY ANALYSIS OF MONOCUCLEAR CELLS IN MYOPATHIES. V: IDENTIFICATION AND QUANTITATION OF T8+ CYTOTOXIC AND T8+ SUPPRESSOR CELLS. K. Arahata, et. al; Ann. Neurol. (May, 1988, issue 23 (5)). Pp. 493-9. INCLUSION BODY MYOSITIS: A CHRONIC PERSISTENT MUMPS MYOSITIS? S.M. Chou; Hum. Pathol. (August, 1986, issue 17(8)). Pp. 765-77. INCLUSION BODY MYOSITIS AND SYSTEMIC LUPUS ERYTHEMATOSUS. R.A. Yood, et. al; J. Rheumatol. (June, 1985, issue 12(3)). Pp. 568-70.