Giant Cell Arteritis (GCA or Temporal Arteritis)

• Giant cell arteritis is a result of inflammation of arteries.
• Giant cell arteritis can lead to blindness and/or stroke.
• Giant cell arteritis is detected by a biopsy of an artery.
• Giant cell arteritis is treated with high-dose cortisone medications.

Giant cell arteritis, also called temporal arteritis or cranial arteritis, is a serious disease characterized by inflammation of the walls of the blood vessels (vasculitis). The vessels affected are the arteries (hence the name "arteritis"). Giant cell arteritis occurs in 10%-15% of patients with polymyalgia rheumatica. The age of affected patients is over 50 years of age, identical to that of polymyalgia rheumatica. The onset of giant cell arteritis may be years before, after, or without accompanying polymyalgia rheumatica. Giant cell arteritis is abbreviated GCA.

The cause of giant cell arteritis is not known. Recent research is looking into possible infectious causes, and some information suggests a possible relationship to the microbe chlamydia. This will require further studies for verification.

Because giant cell arteritis is commonly due to inflammation of the arterial blood vessels affecting the head, it frequently leads to headaches, pain in the jaw when repetitively chewing, and tenderness of the scalp (usually over the inflamed arteries of the sides of the head). It is also commonly associated with fatigue, low-grade fevers, and weight loss. The muscle aching of polymyalgia rheumatica is seen in nearly half of the patients with giant cell arteritis, either before, during, or after the onset of the arteritis.

When the arteries affected by giant cell arteritis become inflamed, they can narrow to the degree that the blood flow through them is limited. This can cause serious deficiency of oxygen supply to the tissues normally supplied by these arteries. Inadequate oxygenation of the eyes or brain can lead to impaired or double vision, blindness, or stroke. Less commonly, inflammation of the blood vessels supplying the arms can lead to arm pain when the arms are working.

The diagnosis of giant cell arteritis is suspected when a patient over the age of 50 (usually over 60) develops symptoms above and/or suddenly develops blindness or stroke. The diagnosis is supported by signs of inflammation in the blood indicated by an elevation in the erythrocyte sedimentation rate and/or C-reactive protein.

The diagnosis is confirmed with a biopsy of an artery, usually an artery on the side of the scalp called the temporal artery. This biopsy is performed under local anesthesia in an outpatient setting. It requires an incision into the scalp over the artery in the skin. The tissue of this area is supplied by blood from many vessels and does just fine after removal of the piece of the artery.

The goal of the treatment of giant cell arteritis is to suppress the inflammation within the arteries. When giant cell arteritis is diagnosed, high doses of cortisone medications, either intravenously or by mouth are necessary. The high doses required to quiet the inflamed arteries frequently are associated with side effects, including sweats, weight gain, bruising, puffiness of the face, erratic emotions, insomnia, and others.

Also, in order to maintain optimal blood flow, low-dose aspirin is often given to optimize circulation of blood and prevent unwarranted blood clotting within diseased arteries. Studies have shown that low-dose aspirin can reduce the risk of stroke and visual loss in patients with giant cell arteritis.

Because the cortisone medications are associated with potential bone toxicity, causing osteoporosis, patients should consider calcium and vitamin D supplementation. Appropriate patients should have bone mineral density testing, and osteoporosis medications, such as estrogen, alendronate (Fosamax), and risedronate (Actonel), are considered.

Giant cell arteritis usually runs a self-limited course, over months to years. Rarely, the inflammation may not respond to high doses of cortisone, and stronger medications that suppress the immune system have been tried, such as methotrexate (Rheumatrex, Trexall). In most patients, the cortisone medications can gradually be tapered according to the symptoms while the ESR blood test is monitored.

The effects of the arteritis depend not only on the amount of inflammation in the arteries but also on the location of the arteries in various body tissues. Research scientists studying arteritis have discovered that the location of the inflamed arteries in the body and whether it is associated with polymyalgia rheumatica seem to relate to different features of specialized white blood cells (T cells) that are infiltrating the artery walls. If these T cell differences can be further classified according to the patterns of inflammation in patients, this could lead to a new era of "customized" treatments for giant cell arteritis.

There is no prevention for giant cell arteritis. Prevention measures focus on preventing side effects of medications used to treat giant cell arteritis.

Giant cell arteritis can lead to blindness and/or stroke. This is because, in some patients with giant cell arteritis, inflammation of the arteries that supply oxygen to the eyes and brain can impair the circulation to these organs.

Additional complications can result from medications used to treat giant cell arteritis. These include cataracts, bruising of skin, weight gain, and osteoporosis from cortisone medications. Therefore, the lowest possible doses of medications and countermeasures are used to minimize long-term risks.