What is polymyositis?

Polymyositis is an inflammatory disease, of an unknown cause, involving the muscles. With polymyositis, there is inflammation and weakness of your muscles. The muscles of the arms and legs are most commonly affected. These symptoms usually get slowly worse over weeks to months. Polymyositis is more common in women and occurs in people who are 40 to 60 years of age.

What causes polymyositis?

Caregivers do not exactly know what causes polymyositis. Problems with your body's immune system may cause polymyositis. Normally, the immune system helps fight infection in your body. With polymyositis, your body's immune system attacks the muscle tissues for unknown reasons. Germs, called viruses, could also cause polymyositis.

What are the signs and symptoms of polymyositis?

The most common symptom is muscle weakness of the upper arms, thighs and hips. Muscle weakness develops slowly over weeks or months. People with polymyositis often have difficulty with daily activities, such as getting up from a chair. Difficulty in climbing steps, lifting objects, and combing your hair is also common. Polymyositis may also affect the neck muscles, the lungs, and the heart. Other signs and symptoms may include:

  • Feeling more tired than usual.

  • Low grade fever.

  • Lung problems, such as difficulty breathing and infections.

  • Trouble swallowing or talking.

  • Weight loss.

How is polymyositis diagnosed?

You may need one or more of the following tests:

  • Biopsy: Your caregiver will remove a tissue from your muscle, and send it to the lab for tests. Before the tissue is removed, your skin will be cleaned, and medicine may be used to numb the area. After the biopsy, you may need stitches to close the wound. A bandage may cover the biopsy area.

  • Blood tests: Creatine kinase is a substance made by injured muscles. The creatine kinase test checks for the presence of creatine kinase in your blood.

  • Electromyography: This is also called an EMG. An EMG is done to test the function of your muscles and the nerves that control them. Electrodes (wires) are placed on the area of muscle being tested. Needles that enter your skin may be attached to the electrodes. The electrical activity of your muscles and nerves is measured by a machine attached to the electrodes. Your muscles are tested at rest and with activity.

  • Magnetic resonance imaging: This test is also called MRI. An MRI allows caregivers to see inside your body. During the MRI, pictures are taken of your muscles. Caregivers use these pictures to look for muscle changes or injuries.

How is polymyositis treated?

You may have one or more of the following:

  • Immunosuppressives: The immune system may see normal cells as abnormal and attack them. When normal muscle cells are attacked, it causes the symptoms of polymyositis. These medicines may be given to slow down the attack on muscle cells by the immune system. Do not stop taking these medicines without your caregivers OK. Stopping on your own can cause problems.

  • Steroids: This medicine may be given to decrease inflammation.

  • Therapy: A physical therapist and an occupational therapist may exercise your arms, legs, and hands. They may also teach you new ways to do things around the house. A speech therapist may work with you to help you talk or swallow.
With treatment, including medications and physical therapy, you may be able to continue your usual activities for a longer period of time.

Where can I find support and more information?

Polymyositis is a life-changing disease for you and your family. Accepting that you have polymyositis may be hard. You and those close to you may feel angry, depressed, or frightened. These are normal feelings. Talk to your caregivers, family, or friends about your feelings. You may also want to join a support group. This is a group of people who also have polymyositis. Call or write one of the following organizations for more information.

  • Muscular Dystropy Association
    3300 E. Sunrise Drive
    Tucson , AZ 85718
    Phone: 1- 800 - 344-4863
    Web Address: http://www.mdausa.org
  • The Myositis Association
    1233 20th St. NW, Ste 402
    Washington, DC , 20036
    Phone: 1- 202 - 887-0088
    Web Address: http://www.myositis.org

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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