An inflammatory disorder of the blood vessels in the head that can produce a persisting headache and flu-like symptoms. Because it mainly affects the arteries in the temple, it is sometimes referred to as temporal arteritis. It predominantly affects older adults, usually those over 60, and is more common in women.
Giant cell arteritis (GCA) is often associated with a rheumatic disorder called polymyalgia rheumatica (PMR). PMR causes pain and stiffness in the muscles of the neck, shoulders, and hip area. About 5% to 15% of people with PMR will be diagnosed with GCA at some point in their lives, and about 50% of people with GCA also have PMR.
The most common symptom of GCA is a new headache, typically in the area over the temples. The pain may also occur in the top, front, or back of the head, and the tongue or jaw may be affected as well. The headache may also be accompanied by flu-like symptoms, fatigue, loss of appetite, weight loss, or fever. If GCA affects the blood supply to the eye, it can produce temporary blurring of vision, double vision, or permanent vision loss. (However, if GCA is treated before there is vision loss, the risk of permanent vision loss is very low.)
In diagnosing GCA, doctors use a blood test called the erythrocyte sedimentation rate (“sed rate”) test, which measures inflammation in the body. The sed rate is elevated in most people with GCA, though as other conditions can cause an elevated sed rate, this alone is not sufficient to make the diagnosis. To solidify the diagnosis, doctors generally recommend a biopsy of a small piece of the temporal artery. This procedure is performed on an outpatient basis under local anesthesia and leaves only a small, barely discernible scar at the hairline in front of the ear. The biopsied tissue is then examined under a microscope for signs of inflammation and abnormal cells in the artery wall.
Because of concerns about permanent vision loss, treatment of GCA usually starts early, often before the diagnosis has been confirmed by biopsy. GCA is generally treated with high doses of an oral corticosteroid such as prednisone, and the symptoms usually subside quickly after treatment begins. After one month of high-dose corticosteroids, the dose can usually be reduced gradually over the course of several months, and the drug is typically discontinued completely after 1–2 years. Fortunately, once GCA goes away, it rarely comes back.