This study will evaluate subjects with adult- and childhood-onset myositis to learn more about their cause and the immune system changes and medical problems associated with them. Myositis is an inflammatory muscle disease that can damage muscles and other organs, resulting in significant disability.

Children or adults with polymyositis or dermatomyositis or a related condition may be evaluated under this study. Healthy children or adults will also be enrolled as "controls," for comparison of test results.

All patients will undergo a complete history (including completing some questionnaires) and physical examination, review of medical records, and blood and urine tests. Patients may then choose to participate in an additional 1- to 5-day evaluation, which will include some or all of the following diagnostic, treatment or research procedures:

1. Standardized muscle strength testing, range of motion of joints and walking (gait) analysis by a physiotherapist; completion of a questionnaire regarding ability to perform daily tasks
2. Skin assessment, possibly including photographs of lesions and a skin biopsy (removal of a small skin sample under local anesthetic)
3. Magnetic resonance imaging (scans that use magnetic fields to visualize tissues) of leg muscles
4. Swallowing studies, including a physical examination and questionnaire on swallowing ability, studies of tongue strength, and ultrasound imaging during swallowing, and possibly, a modified barium swallow
5. Voice and speech assessment, possibly including computerized voice analysis and laryngoscopy-analysis of the larynx (voice box) using a small rigid scope with a camera placed in the mouth to view and record vocal cord function
6. Pulmonary function tests (measurement of air moved into and out of the lungs, using a breathing machine) to evaluate lung function and, possibly, chest X-ray
7. Electrocardiogram (measurement of the electrical activity of the heart) and, possibly, echocardiogram (ultrasound imaging of the heart)
8. Endocrine evaluation
9. Eye examination, in patients with vision loss or other eye symptoms
10. Nutrition assessment to evaluate muscle mass and muscle wasting, including tape measurements or bioelectric impedance testing, a painless procedure in which wires are attached to the extremities with a sticky paste.
11. Muscle ultrasound.
12. Electromyography (record of the electrical activity of muscles)
13. Muscle or skin biop...

This study will evaluate subjects with adult- and childhood-onset myositis to learn more about their cause and the immune system changes and medical problems associated with them. Myositis is an inflammatory muscle disease that can damage muscles and other organs, resulting in significant disability.

Children or adults with polymyositis or dermatomyositis or a related condition may be evaluated under this study. Healthy children or adults will also be enrolled as "controls," for comparison of test results.

All patients will undergo a complete history (including completing some questionnaires) and physical examination, review of medical records, and blood and urine tests. Patients may then choose to participate in an additional 1- to 5-day evaluation, which will include some or all of the following diagnostic, treatment or research procedures:

1. Standardized muscle strength testing, range of motion of joints and walking (gait) analysis by a physiotherapist; completion of a questionnaire regarding ability to perform daily tasks
2. Skin assessment, possibly including photographs of lesions and a skin biopsy (removal of a small skin sample under local anesthetic)
3. Magnetic resonance imaging (scans that use magnetic fields to visualize tissues) of leg muscles
4. Swallowing studies, including a physical examination and questionnaire on swallowing ability, studies of tongue strength, and ultrasound imaging during swallowing, and possibly, a modified barium swallow
5. Voice and speech assessment, possibly including computerized voice analysis and laryngoscopy-analysis of the larynx (voice box) using a small rigid scope with a camera placed in the mouth to view and record vocal cord function
6. Pulmonary function tests (measurement of air moved into and out of the lungs, using a breathing machine) to evaluate lung function and, possibly, chest X-ray
7. Electrocardiogram (measurement of the electrical activity of the heart) and, possibly, echocardiogram (ultrasound imaging of the heart)
8. Endocrine evaluation
9. Eye examination, in patients with vision loss or other eye symptoms
10. Nutrition assessment to evaluate muscle mass and muscle wasting, including tape measurements or bioelectric impedance testing, a painless procedure in which wires are attached to the extremities with a sticky paste.
11. Muscle ultrasound.
12. Electromyography (record of the electrical activity of muscles)
13. Muscle or skin biopsy (removal of a small piece of muscle tissue for microscopic examination)

All patients may have only a one-time evaluation or may return for one follow-up evaluations (either the 1-day or 3- to 5-day evaluation) over a 1-year period.

Healthy children will undergo a medical history and brief physical examination; blood and urine tests; speech and swallowing studies including questionnaires and physical examination, tongue strength, and ultrasound study; and bioelectric impedance testing. Children 8 to 18 years old may also have exercise testing.

• Dermatomyositis
• Polymyositis
• Idiopathic Inflammatory Myopathy
• Healthy

• Rider LG. Outcome assessment in the adult and juvenile idiopathic inflammatory myopathies. Rheum Dis Clin North Am. 2002 Nov;28(4):935-77. Review.
• Rider LG, Giannini EH, Brunner HI, Ruperto N, James-Newton L, Reed AM, Lachenbruch PA, Miller FW; International Myositis Assessment and Clinical Studies Group. International consensus on preliminary definitions of improvement in adult and juvenile myositis. Arthritis Rheum. 2004 Jul;50(7):2281-90. Review.
• Huber AM, Feldman BM, Rennebohm RM, Hicks JE, Lindsley CB, Perez MD, Zemel LS, Wallace CA, Ballinger SH, Passo MH, Reed AM, Summers RM, White PH, Katona IM, Miller FW, Lachenbruch PA, Rider LG; Juvenile Dermatomyositis Disease Activity Collaborative Study Group. Validation and clinical significance of the Childhood Myositis Assessment Scale for assessment of muscle function in the juvenile idiopathic inflammatory myopathies. Arthritis Rheum. 2004 May;50(5):1595-603.

• Recruiting by Invitation Only

INCLUSION CRITERIA:

All patients admitted to the study must satisfy the following criteria:

1. Meet probable or definite criteria for IIM by Bohan and Peter.
2. Ability of Patient or parent/guardian to give informed consent to all or part of the study after full information has been provided.
3. Selected patients with undefined illnesses who may have weakness, myalgias, or an elevated CK may be evaluated to establish a diagnosis and, if they are found to have IIM, would be offered the opportunity to enter the study.

EXCLUSION CRITERIA:

1. Severe medical diseases requiring intensive care or any other conditions in which drawing the amount of blood required or undergoing procedures needed for the study is not deemed medically appropriate by the treating physician or the principal investigator.