Polymyalgia Rheumatica (PMR)
What is Polymyalgia Rheumatica?
Polymyalgia rheumatica (PMR) is a form of arthritis that typically affects the shoulders and hips, causing joint pain and morning stiffness. PMR can cause symptoms that are similar to rheumatoid arthritis but is considered a distinct disease from rheumatoid arthritis. Blood tests for rheumatoid arthritis are typically negative in PMR.
PMR is often associated with Giant Cell Arteritis (GCA). About 15% of people who have PMR will develop Giant Cell Arteritis; therefore patients with PMR need to be followed by physicians knowledgeable in both diseases. Patients with PMR also need to immediately report new symptoms to their doctors that might indicate the onset of GCA, including headaches or visual changes.
The links between PMR and GCA are of great interest to researchers studying vasculitis. Some investigators think of the two disorders as part of the same disease spectrum, rather than two distinct diseases.
Who gets Polymyalgia Rheumatica?
PMR is relatively uncommon compared to rheumatoid arthritis or osteoarthritis. PMR only affects people older than 50 years of age and especially those older than 65. Women are somewhat more likely to get the disease than men. About 50% of people with GCA will also have PMR.
What causes Polymyalgia Rheumatica?
The cause of PMR is unknown.
How is Polymyalgia Rheumatica diagnosed?
The diagnosis of PMR depends on both clinical signs and symptoms, especially aching and stiffness of the shoulders, hips, torso and neck, often accompanied by fatigue, weight loss, and low grade fever. There is no diagnostic laboratory test for PMR, but at the time of diagnosis, as in GCA, most patients have an elevated erythrocyte sedimentation rate (ESR or “sed rate”), a non-specific blood marker of inflammation, and many patients have anemia. Routine X-rays of affected joints are generally normal for the age of the patient.
How is Polymyalgia Rheumatica treated?
Treatment with prednisone results in improvement of symptoms within a few days. The dose of prednisone is much lower than the dose initially used for GCA, usually between 15 and 20 mg a day, and then slowly reducing the dose. No other drugs have been clearly proven to be of benefit in the treatment of PMR. The average duration of the disease is about 2 ½ years, but this varies greatly among individuals.