Polymyositis is an uncommon disease that affects your muscles leaving you with muscle weakness in the muscles closest to your trunk. Polymyositis is one of the myopathies, or illnesses and diseases that affect the muscular system. Some doctors suspect that as with other myopathis, polymyositis, is a result of an autoimmune response in the body.
Polymyositis is a connective tissue disease because of the way it attacks the body. It is most common in people 40-50 years old. It has a higher incidence in black people than whites and more women are affected than men. Interestingly periods of spontaneous remission do happen. Polymyositis is also connected with other connective tissue disease such as lupus erythematosus.
There are diseases that can mimic polymyositis such as some of the muscular dystrophies, drug toxins, metabolic and hormonal disorders and infectious diseases. The signs and symptoms of Polymyositis may appear gradually or rapidly and they may fluctuate over time. Patients experience a progressive symmetrical weakness in the muscles closest to the trunk, trouble swallowing, mild joint and muscle tenderness and fatigue.
The loss of strength will be recognized when patients experience difficulty getting up from a chair, climbing stairs or lifting objects above the shoulders, Fatigue can be pervasive and cause patients lost work time and lost family time. By listening to their bodies and resting when they are tired they may decrease the amount of time they suffer debilitating fatigue.
Polymyositis has a skin component called dermatomyositis that can be present alone or in combination with the systemic disease. The dermatomyositis will present with a purplish discoloration around the eyes or reddish discoloration around the knees and elbows and knuckles. There can also be a reddish rash over the face, neck and upper chest.
When a patient first sees the doctor for polymyositis he will perform a systematic physical exam that accounts for muscle strength and potential involvement of other organ systems. Blood tests may reveal abnormally high levels of muscle enzymes. An EMG is used to exclude other nerve muscle diseases. Imaging with an MRI can show areas of inflammation to help determine a good biopsy site. A muscle biopsy will confirm the type of inflammation typical of polymyositis. The biopsy is usually taken from the quadriceps, biceps or deltoid muscle.
Complications associated with polymyositis include weight loss and pneumonia if the difficulty swallowing becomes so severe that the patient can’t eat or the liquid goes to the lungs instead of the stomach. Patients can develop myocarditis, or inflammation of the heart muscle; congestive heart failure or heart arrhythmias may follow. Interstitial lung disease is also possible with polymyositis. This causes scarring of the lungs leading to a lower elasticity and difficulty breathing. The signs are a dry cough and shortness of breath. Cancer seems to be more common in people with polymyositis but this seems to be even more pronounced in people with dermatomyositis.
Initial treatment is large doses of corticosteroids to help decrease the inflammation in the muscles. Based on the initial response they may be needed for years. In patients that do not respond well to the corticosteroids immunosuppressive medications are considered. Both the corticosteroids and the immunosuppressive therapy have severe side effects from long term use.
Physical therapy is often a part of the treatment plan. Polymyositis often becomes inactive and rehabilitating weakened muscles is a long term concern.
There are several treatments that are currently in trials to determine the long term efficacy of the treatment. These are plamapharesis, IVIG and radiation. These are all treatments used for other illness so long term side effects are known but whether they are effective against Polymyositis is under question.
By having a better knowledge of your disease and the treatment you will have better outcomes and increased success with rehabilitation.