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  • 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. Caregivers do not exactly know what causes polymyositis. It is thought that a problem in the immune system or certain viruses may cause polymyositis.
  • Signs and symptoms include muscle weakness that develops slowly over weeks or months. Other symptoms, such as muscle shortening, fever, feeling more tired than usual, and joint pains may be seen. Polymyositis may also affect other body parts. You may have heart problems and trouble swallowing or breathing. Tests such as a muscle biopsy, an electromyogram, an magnetic resonance imaging (MRI), and blood tests may be done to diagnose polymyositis. Treatment includes steroids and immunosuppressants. Physical, occupational, and swallowing therapies may also be helpful. With treatment, including medications and physical therapy, you may be able to continue your usual activities for a longer period of time.


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.


If left untreated, your symptoms of polymyositis may worsen and affect most of your daily activities. Other conditions, such as difficulty in swallowing or breathing and heart problems, may be serious and life threatening. Ask your caregiver if you have questions on your polymyositis, medicines, and treatments.


Informed consent

is a legal document that explains the tests, treatments, or procedures that you may need. Informed consent means you understand what will be done and can make decisions about what you want. You give your permission when you sign the consent form. You can have someone sign this form for you if you are not able to sign it. You have the right to understand your medical care in words you know. Before you sign the consent form, understand the risks and benefits of what will be done. Make sure all your questions are answered.

Deep breathing:

This exercise should be done once an hour to keep you from getting a lung infection. Deep breathing opens the tubes going to your lungs. Slowly take a deep breath and hold the breath as long as you can. Then let out your breath. Take 10 deep breaths in a row every hour while awake. You may be asked to use an incentive spirometer to help you with this. Put the plastic piece into your mouth and slowly take a breath as deep and as long as you can. Hold your breath as long as you can. Then, let out your breath.

Heart monitor:

This is also called an ECG or EKG. Sticky pads placed on your skin record your heart's electrical activity.


You may have the following:

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


You may need the following:

  • 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.

Treatment options:

  • Eating and swallowing: Your doctor may ask a swallowing therapist to work with you if you have trouble swallowing. This person has special training to help people learn safer ways to swallow. The swallowing therapist will also help you learn which foods and liquids are safe to eat and drink.
    • You may be fed by an IV or a nasogastric (NG) tube if your swallowing problems are very bad. An NG tube is put in through your nose and goes down into your stomach. The tube may also go directly from the outside of your body into your stomach. This is called a gastrostomy tube.
    • You may be given thickened liquids to drink because they may be easier for you to swallow. A special powder is used to thicken liquids. You may also be able to eat softer (mashed) foods. You may be able to eat what you usually eat when your swallowing gets better.
  • Physical therapy: You may need to see a physical therapist to teach you special exercises. These exercises help improve movement and decrease pain. Physical therapy can also help improve strength and decrease your risk for loss of function.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Learn more about Polymyositis (Inpatient Care)

Associated drugs

Micromedex® Care Notes