Polymyositis, also known as idiopathic inflammatory myopathy, is one of a handful of related rare inflammatory muscle diseases. The disease is typified by chronic inflammation and weakness in muscles surrounding your chest and abdomen, including those in your upper arms, shoulders, hips and thighs. It is twice as common in women than in men. Polymyositis is a progressive disease, but treatment can help many patients recover.


The primary symptom of polymyositis is progressive muscle weakness, first starting with the muscles surrounding your chest and abdomen, including your upper arms, shoulders, hips and thighs. In some cases, the condition may also affect muscles in the lower arms, hands, lower legs and feet. You might find it hard to stand up from a chair or to get up after a fall. Symptoms of the disease can include:

  • Arthritis
  • Difficulty speaking
  • Fatigue
  • Heart arrhythmia
  • Pain or tenderness in chest, upper arms or thighs
  • Shortness of breath
  • Trouble swallowing
  • Weakness

Inflammation of the heart (inflammatory cardiomyopathy) can also lead to inflammation of the lung tissues. These symptoms and trouble swallowing are the most serious and need careful observation.


Because the cause of polymyositis is unknown, there is currently no way to prevent the condition.

Risk Factors

It’s still unclear what causes polymyositis, but it is thought to be related to autoimmune reactions and may have a genetic component. Women are twice as likely to develop the disease; it is also more common among African Americans than people of other races. Most patients are between the ages of 30 and 60.

Some people develop an autoimmune myositis after viral infections like HIV, HTLV-1 or Coxsackie B. Exposure to drugs such as carbimazole, carticaine, cimetidine, human growth hormone, interferon-alpha, penicillamine and phenytoin have also been linked to some cases.


After a physician assesses your medical history and current symptoms, you will have a complete physical exam. This may also include:

Bloodwork. It is important to find out the level of creatine kinase (CK), as a high number is consistent with damage to muscle fibers. Your doctor may also test for antibodies that are consistent with autoimmune muscle disease.

Electromyogram. This test uses tiny needles inserted into the muscles to check patterns of electric activity when the muscles are used.

Muscle biopsy. A small piece of muscle is removed for examination to see how healthy the cellular structure is or is not.



Treatment for polymyositis will vary depending on your age and underlying health conditions, as well as the progress of the disease.

Corticosteroids. Treatment to reduce inflammation will likely start with doses of prednisone or a similar drug, taken either orally or intravenously, for four to six weeks.

Immunosuppressant drugs. Drugs like azathioprine, cyclosporine, cyclophosphamide or methotrexate may be used if the corticosteroids are not improving the inflammation or if their side effects are intolerable.

Intravenous immunoglobulin (IVIg). Some patients have found relief in IVs of immunoglobulin, which contains antibodies from donated plasma.

Follow-up Care

  • A physician will monitor you and provide medications to help reduce inflammation.
  • Physical therapy and exercise therapy are usually recommended to help patients build their strength. Aquatic therapy is also often suggested.

Why Choose UK HealthCare for Neuromuscular Disorders?

If you or a loved one is living with a neuromuscular disorder, neuromuscular doctors with Kentucky Neuroscience Institute can offer the latest and most sophisticated care options. UK HealthCare’s ALS Multidisciplinary Clinic earned accreditation as a Certified Treatment Center of Excellence from the ALS Association. This honor is awarded to facilities that demonstrate competency meeting the clinical care and treatment standards set forth by the ALS Association. These facilities must also take part in ALS research and a comprehensive site review.

Additionally, the Kentucky Neuroscience Institute is ranked 44th in the country by U.S. News & World Report, and our physicians are regularly named to the Best Doctors in America List.