Giant cell arteritis can be difficult to diagnose because its early symptoms resemble those of many common conditions. For this reason, your doctor will try to rule out other possible causes of your problem.
To help diagnose giant cell arteritis, you may have some or all of the following tests and procedures:
- Physical exam. In addition to asking about your symptoms and medical history, your doctor is likely to perform a thorough physical exam, paying particular attention to your temporal arteries. Often, one or both of these arteries are tender with a reduced pulse and a hard, cord-like feel and appearance.
Blood tests. If your doctor thinks you might have giant cell arteritis, you're likely to have a blood test that checks your erythrocyte sedimentation rate — commonly referred to as the sed rate. This test measures how quickly red blood cells fall to the bottom of a tube of blood. Red cells that drop rapidly may indicate inflammation in your body.
You may also have a test that measures C-reactive protein (CRP), a substance your liver produces when inflammation is present. The same tests may be used to follow your progress during treatment.
Biopsy. The best way to confirm a diagnosis of giant cell arteritis is by taking a small sample (biopsy) of the temporal artery. The procedure is performed on an outpatient basis during local anesthesia, usually with little discomfort or scarring. The sample is examined under a microscope in a laboratory.
If you have giant cell arteritis, the artery will often show inflammation that includes abnormally large cells, called giant cells, which give the disease its name. It's possible to have giant cell arteritis and still have a negative biopsy result. If the results aren't clear, your doctor may advise another temporal artery biopsy on the other side of your head.
Imaging tests may be used for diagnosing giant cell arteritis and for monitoring your response to treatment. Possible tests include:
Oct. 02, 2015
- Magnetic resonance angiography (MRA). This test combines the use of magnetic resonance imaging (MRI) with the use of a contrast material that produces detailed images of your blood vessels. Let your doctor know ahead of time if you're uncomfortable being confined in a small space because the test is conducted in a tube-shaped machine.
- Doppler ultrasound. This test uses sound waves to produce images of blood flowing through your blood vessels.
- Positron emission tomography (PET). Using an intravenous tracer solution that contains a tiny amount of radioactive material, a PET scan can produce detailed images of your blood vessels and highlight areas of inflammation.
- Borchers AT, et al. Giant cell arteritis: A review of classification, pathophysiology, geoepidemiology and treatment. Autoimmunity Reviews. 2012;11:A544.
- Giant cell arteritis. American College of Rheumatology. http://www.rheumatology.org/I-Am-A/Patient-Caregiver/Diseases-Conditions/Giant-Cell-Arteritis. Accessed Aug. 24, 2015.
- Mukhtyar C, et al. EULAR recommendations for the management of large vessel vasculitis. Annals of Rheumatic Diseases. 2009;68:318. http://ard.bmj.com. Accessed Aug. 24, 2015.
- Unizony S, et al. Inpatient complications in patients with giant cell arteritis: Decreased mortality and increased risk of thromboembolism, delirium and adrenal insufficiency. Rheumatology. 2015;54:1360.
- Weyand CM, et al. Giant-cell arteritis and polymyalgia rheumatica. New England Journal of Medicine. 2014;371:50.
- Smith JH, et al. Giant cell arteritis. Headache. 2014;54:1273.
- Polymyalgia rheumatica and giant cell arteritis. National Institute of Arthritis and Musculoskeletal and Skin Diseases. http://www.niams.nih.gov/Health_Info/Polymyalgia/default.asp. Accessed Aug. 24, 2015.
- Kermani TA, et al. Disease relapses among patients with giant cell arteritis: A prospective, longitudinal cohort study. Journal of Rheumatology. 2015;42:7.
- Singh AG, et al. Visual manifestations in giant cell arteritis: Trend over 5 decades in a population-based cohort. Journal of Rheumatology. 2015;42:2.
- Osteoporosis: Handout on health. NIH Osteoporosis and Related Bone Diseases National Resource Center. http://www.niams.nih.gov/Health_Info/Bone/Osteoporosis/osteoporosis_hoh.asp. Accessed Aug. 25, 2015.
- Mollan SP, et al. Aspirin as adjunctive treatment for giant cell arteritis. Cochrane Database of Systematic Reviews. http://ovidsp.tx.ovid.com/sp-3.16.Ob/ovidweb.cgi. Accessed Aug. 25, 2015.
- Chang-Miller A (expert opinion). Mayo Clinic, Scottsdale, Ariz. Sept. 3, 2015.