Polymyalgia rheumatica is a rare inflammatory disease characterized by muscle pain (myalgia), stiffness, and additional generalized systemic symptoms such as fatigue, low-grade fever, and/or a general feeling of ill health (malaise). Polymyalgia rheumatica can be a relatively benign condition that is extremely responsive to treatment. In some rare cases, permanent muscle weakness, degeneration and loss (atrophy) of muscle mass, and disability may occur. The exact cause of polymyalgia rheumatica is unknown, although immunological factors and familial tendencies (genetic predisposition) have been mentioned in the medical literature.
Polymyalgia rheumatica is closely related to giant cell arteritis, another inflammatory disorder. Giant cell arteritis is characterized by progressive inflammation of many arteries of the body. These two disorders have been described in the medical literature as possible variants of the same disease process. Some researchers believe they represent different ends of a disease continuum. The exact nature of the association is not fully understood.
In most cases, the symptoms of polymyalgia rheumatica begin abruptly (acutely). However, symptoms may develop slowly (insidiously) during a period of several weeks or months. Symptoms may include muscle pain (myalgia) and stiffness in the neck, shoulders, upper arms, lower back, hips, and/or thighs. The lower arms, hands, lower legs, and feet (distal extremities) are not usually affected by this disorder. Stiffness and pain, which typically occur on both sides of the body (bilateral), are most severe in the morning (morning stiffness) and after long periods of rest or inactivity (gel phenomenon). In most cases, the shoulder girdle is the first area affected. However, in other cases, the neck or hips may show the first signs of the disorder. Pain or discomfort usually begins on one side of the body before affecting the other side as well.
Additional symptoms of polymyalgia rheumatica may include muscle tenderness and weakness, low-grade fever, loss of appetite, weight loss, fatigue, a general feeling of ill health (malaise), and/or depression. In some cases, fever or weight loss may be the initial symptoms of polymyalgia rheumatica.
About 30 percent of people with polymyalgia rheumatica develop symptoms that are characteristic of rheumatoid-like arthritis including joint swelling, pain (arthralgia), and degenerative changes in some joints. Low levels of circulating red blood cells (anemia, nonhemolytic type) may also develop in some people with this disorder.
The symptoms associated with polymyalgia rheumatica often disappear for periods of time (remission) and then reappear (exacerbation). These episodes may continue for about six months or up to six years. However, severe impairment or permanent disability, even after months or years, is rare. In most cases, individuals with polymyalgia rheumatica do not experience loss of muscle strength.
The exact cause of polymyalgia rheumatica is not known. The immune system has been implicated in some studies, but a direct relationship has not been established. Autoimmune disorders are caused when the body’s natural defenses against “foreign” or invading organisms (e.g., antibodies) begin to attack healthy tissue for unknown reasons. In addition, because the disorder occurs in older individuals, polymyalgia rheumatica may be related to the aging process.
A small percentage of cases of polymyalgia rheumatica seem to run in families (familial aggregation), and some people may inherit a genetic predisposition (possibly HLA-DR4) to this disorder. A genetic predisposition means that a person may carry a gene for a disease but it may not be expressed unless something in the environment triggers the disease. Although HLA-DR4 is associated with more cases of polymyalgia rheumatica than chance alone would explain, the exact nature of the relationship is not fully understood.
Polymyalgia rheumatica is a rare disorder that affects twice as many females as males. Affected individuals are usually over the age of 50 years. This disorder occurs at the rate of about 50 per 100,000 in people over 50 years of age. Polymyalgia rheumatica is estimated to affect 450,000 individuals in the United States.
The disease occurs with greater frequency in Caucasians and has higher incidence rates in the United States and northern Europe than in the rest of the world. Most individuals with this disorder eventually experience total recovery from the symptoms of polymyalgia rheumatica.
The diagnosis of polymyalgia rheumatica may be confirmed by a thorough clinical examination including a detailed patient history and specialized blood testing that demonstrates an abnormally elevated sedimentation rate. Other substances in the blood, such as serum albumin, globulins, and fibronogen, may also be elevated. Microscopic and laboratory examination of muscle tissue samples (biopsy) from affected individuals does not usually reveal any muscle abnormality. Some people with this disorder may also be anemic. Rheumatoid factor is not present in the blood of people with this disorder.
Nonsteroidal antiinflammatory drugs (NSAIDs) may be used to treat those people with polymyalgia rheumatica who do not have vascular symptoms or signs (e.g., recurring headaches indicative of giant cell arteritis). Some affected individuals respond well to treatment with aspirin, which relieves pain and reduces inflammation.
If these medications are not effective, low to moderate doses of corticosteroid drugs (e.g., prednisone) may be prescribed. Most affected individuals treated with corticosteroids experience rapid improvement within a few days. After the symptoms resolve, the dosage may then be lowered and a maintenance dose may be prescribed for a few months or up to several years. Periodic medical evaluation is essential to screen for potential side effects of corticosteroid drugs.
Individuals with polymyalgia rheumatica who also have other symptoms such as recurring headaches that may be suggestive of giant-cell arteritis, are usually placed on high-doses of corticosteroid drugs (e.g., prednisone). Other treatment for polymyalgia rheumatica is symptomatic and supportive.
The corticosteroid drug deflazacort is being studied for treatment of polymyalgia rheumatica. Deflazacort may be an effective alternative to prednisone and may also have fewer side effects. More studies are needed to determine the long-term safety and effectiveness of this drug for the treatment of polymyalgia rheumatica.
Researchers are studying the effects of immunosuppressants such as methotrexate in the treatment of individuals with polymyalgia rheumatica. Clinical trials are necessary to determine the long-term safety and effectiveness of this potential treatment for individuals with polymyalgia rheumatica.
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