Diagnosis of Polymyalgia Rheumatica
Diagnosis of polymyalgia rheumatica requires ruling out other conditions, such as rheumatoid arthritis (RA), polymyositis, systemic lupus erythematosus, and thyroid problems (Beers 1999; Samanta 2002).
Polymyalgia rheumatica is rare in people less than 50 years, and patients are usually more than 60 years old (Beers 1999). It is twice as common in women as in men (Labbe 1998; Beers 1999). Because polymyalgia rheumatica and giant cell arteritis frequently occur in the same patients, they may represent different aspects of a single condition. Most researchers, however, think polymyalgia rheumatica and giant cell arteritis are different conditions with similar manifestations (Cimmino 1997; Gonzalez-Gay 2004; Cantini 2004; Gonzalez-Gay 2003).
The first step in diagnosing polymyalgia rheumatica is obtaining a clinical history from the patient. The main diagnostic criteria for polymyalgia rheumatica are hip and shoulder pain, coupled with exclusion of other possible causes (Samanta 2002). In addition, a number of blood tests may be used to measure inflammation. For example, patients with polymyalgia rheumatica usually have an elevated erythrocyte sedimentation rate (Beers 1999; Zlonis 1993). C-reactive protein and IL-6 are also elevated in patients with polymyalgia rheumatica (Beers 1999; Samanta 2002). These pro-inflammatory indicators, however, are elevated in response to inflammation anywhere in the body and cannot be used to definitely diagnose polymyalgia rheumatica.
If giant cell arteritis is suspected, a temporal artery biopsy is indicated, although corticosteroid treatment may start without waiting for the biopsy results (Weyand 2003). Other blood vessels (including the aorta) can be visualized with magnetic resonance imaging or ultrasound to determine the extent of inflammation.
Treatment with steroids usually begins promptly. Most patients respond very quickly to corticosteroids. In fact, if symptoms do not resolve rapidly, a physician may want to conduct additional tests to determine whether the diagnosis was correct.