American Medical Association Family Medical Guide - American Medical Association [634]
Symptoms
The main symptom of polymyositis is muscle weakness, especially in the shoulders, upper arms, hips, and thighs. The muscle weakness may occur suddenly, without warning, or develop gradually over weeks or months. As the muscles weaken, you become less able to perform routine activities such as bathing, dressing, getting up from a chair, climbing stairs, or walking. Other symptoms of the disorder include muscle pain, joint pain and swelling, fever, fatigue, and weight loss. If polymyositis affects the lungs, it can cause shortness of breath and a persistent cough. If the disorder affects the muscles of the throat and esophagus, you can have difficulty swallowing and speaking. In addition to the characteristic symptoms of polymyositis, dermatomyositis produces a reddish rash on the face, shoulders, elbows, knuckles, knees, and ankles. In many cases, the symptoms of polymyositis and dermatomyositis come and go.
Diagnosis
To diagnose polymyositis or dermatomyositis, your doctor will ask about your symptoms, take a health history, and perform a physical examination. The doctor may recommend a muscle biopsy, in which a sample of muscle tissue is surgically removed and examined under a microscope. Blood tests that measure the levels of specific enzymes (proteins that promote or accelerate chemical reactions in the body) and antibodies produced by people with the disorder are also helpful in making a diagnosis. The doctor will probably order an electromyogram (an evaluation of the electrical activity of the muscles) and, in some cases, screening tests for cancer. He or she also may recommend an examination by a rheumatologist (a doctor who specializes in treating disorders of the joints, muscles, and connective tissues) or a neurologist (a doctor who specializes in treating disorders of the nervous system) to rule out other disorders.
Treatment
In some cases, polymyositis or dermatomyositis disappears on its own without treatment and does not return. However, in most cases, a doctor has to treat the disorder with high doses of a corticosteroid medication such as prednisone (taken by mouth) to relieve the inflammation, swelling, and pain. As the symptoms improve, the doctor will gradually reduce the dose, but most people will need to take low doses of corticosteroids for many years and, in some cases, for the rest of their lives to control the disorder. Corticosteroids usually are not an effective treatment for polymyositis or dermatomyositis that has been triggered by cancer.
If treatment with corticosteroids does not work, the doctor will probably prescribe immune-suppressing drugs (drugs that curb the abnormal activity of the immune system), such as methotrexate or azathioprine, in combination with or instead of the corticosteroids. If corticosteroids and immune-suppressing drugs are not effective in relieving the symptoms, the doctor may prescribe gamma globulin (the pooled antibodies of healthy donors) given intravenously (through a vein).
Your doctor will recommend that you get plenty of rest and limit activity when your symptoms flare up. He or she will work with you to develop a program of regular moderate exercise to help improve and maintain your flexibility, strength, and endurance.
Raynaud’s Disease and Raynaud’s Phenomenon
Raynaud’s disease is a disorder in which the capillaries (the smallest blood vessels) in the skin constrict, reducing blood flow to the fingers and toes. In some cases, the nose, lips, and earlobes are also affected. The cause of Raynaud’s disease is unknown, but doctors think it may be an autoimmune