Diagnosing Polymyalgia Rheumatica

What is polymyalgia rheumatica?

Polymyalgia rheumatica is an inflammatory condition that affects large muscle groups. It causes muscle pain and stiffness, especially in the shoulders and hips. Approximately 15% of individuals with polymyalgia rheumatica also have giant cell arteritis (aka, temporal arteritis, a serious inflammatory condition that damages the arteries). Fifty percent of people diagnosed with giant cell arteritis also have polymyalgia rheumatica.

Diagnostic process

While one specific test cannot definitively diagnose polymyalgia rheumatica, several tests can be used to identify inflammation due to polymyalgia rheumatica while alsoeliminating the possibility of other similar conditions.

The diagnostic process typically begins with a thorough medical history and physical exam. During the physical exam, the neck, arms and legs are checked for range of motion. Any swelling in the small joints of the hands and feet are also noted, which may indicate a diagnosis of rheumatoid arthritis rather than polymyalgia rheumatica.

Diagnostic tests

Based on the information from the physical exam and medical history, one or more of the following tests may be ordered:

• Erythrocyte sedimentation rate (ESR or sed rate)
  An ESR blood test measures inflammation levels in the body. An abnormally high rate may suggest polymyalgia rheumatica.
• C-reactive protein (CRP) level
  A CRP blood test checks the levels of a certain protein in the body. High levels are another indicator of inflammation in the body.
• Ultrasound
  Ultrasound technology may be used to check the soft tissues in and around the joints. Signs of inflammation may indicate a diagnosis of polymyalgia rheumatica.
• Magnetic resonance imaging (MRI)
  An MRI may be ordered to eliminate the possibility of other health conditions that may be causing pain.
• Biopsy
  If giant cell arteritis, or temporal arteritis, is suspected in addition to polymyalgia rheumatica, a biopsy of an artery in the temple may be ordered. During this procedure, a local anesthetic is applied and a small sample of an artery is removed and studied for signs of inflammation. This test is only needed if symptoms such as headaches, scalp pain, jaw pain, or vision changes are present in addition to symptoms of polymyalgia rheumatica.