Questions and Answers about Polymyalgia Rheumatica and Giant Cell Arteritis
Who Is at Risk for These Conditions?
Caucasian women over the age of 50 have the highest risk of
developing polymyalgia rheumatica and giant cell arteritis. While women are
more likely than men to develop the conditions, research suggests that men with
giant cell arteritis are more likely to suffer potentially blinding eye
involvement. Both conditions almost exclusively affect people over the age of
50. The incidence of both peaks between 70 and 80 years of age.
Polymyalgia rheumatica and giant cell arteritis are both quite
common, according to the National Arthritis Data Work Group. In the United
States, it is estimated that 700 per 100,000 people in the general population
over 50 years of age develop polymyalgia rheumatica. An estimated 200 per
100,000 people over 50 years of age develop giant cell arteritis.
How Are Polymyalgia Rheumatica and Giant Cell Arteritis Diagnosed?
A diagnosis of polymyalgia rheumatica is based primarily on the
patient’s medical history and symptoms, and on a physical examination. No
single test is available to definitively diagnose polymyalgia rheumatica.
However, doctors often use lab tests to confirm a diagnosis or rule out other
diagnoses or possible reasons for the patient’s symptoms.
The most typical laboratory finding in people with polymyalgia
rheumatica is an elevated erythrocyte sedimentation rate, commonly referred to
as the sed rate. This test measures inflammation by determining how quickly red
blood cells fall to the bottom of a test tube of unclotted blood. Rapidly
descending cells (an elevated sed rate) indicate inflammation in the body.
While the sed rate measurement is a helpful diagnostic tool, it alone does not
confirm polymyalgia rheumatica. An abnormal result indicates only that tissue
is inflamed, but this is also a symptom of many forms of arthritis and other
Before making a diagnosis of polymyalgia rheumatica, the doctor
may order additional tests. For example, the C-reactive protein test is another
common means of measuring inflammation. There is also a common test for
rheumatoid factor, an antibody (a protein made by the immune system) that is
sometimes found in the blood of people with rheumatoid arthritis. While
polymyalgia rheumatica and rheumatoid arthritis share many symptoms, those with
polymyalgia rheumatica rarely test positive for rheumatoid factor. Therefore, a
positive rheumatoid factor might suggest a diagnosis of rheumatoid arthritis
instead of polymyalgia rheumatica.
As with polymyalgia rheumatica, a diagnosis of giant cell
arteritis is based largely on symptoms and a physical examination. The exam may
reveal that the temporal artery is inflamed and tender to the touch, and that
it has a reduced pulse.
Any doctor who suspects giant cell arteritis should order a
temporal artery biopsy. In this procedure, a small section of the artery is
removed through an incision in the skin over the temple area and examined under
a microscope. A biopsy that is positive for giant cell arteritis will show
abnormal cells in the artery walls. Some patients showing symptoms of giant
cell arteritis will have negative biopsy results. In such cases, the doctor may
suggest a second biopsy.