Giant Cell Arteritis
Giant cell arteritis (GCA), also called temporal arteritis, is an inflammatory disease with predilection for the arms (upper extremity branches of the aorta) and head (cranial arteries). All the layers of the artery wall are affected. Microscopic examination reveals infiltration of the wall by inflammatory cells (lymphocytes and macrophages). one type of inflammatory cell, macrophages, can fuse together to form giant cells, thus the name giant cell arteritis. The disease follows a “skip” pattern, meaning that involved segments alternate with normal ones. The temporal artery located on the temple of the head can be hardened (indurated), tender, and can “roll” when touched (palpated).
Specific substances in the blood (antigens) involved in triggering the disease process have not been identified. Research has focused on increased prevalence in Caucasian people of northern European origin and possible seasonal variations suggesting as yet undetermined environmental agents as precipitating factors.
Giant Cell Arteritis is a relatively rare disease. It occurs almost exclusively in individuals older than 50 years. The average age of onset is 70 years. The disease incidence increases with age. Women are affected about twice as frequently as men. In Olmstead County, Minnesota, a prevalence rate of 1 per 500 persons aged 50 or older was reported.
The clinical features of Giant Cell Arteritis are extremely variable. The onset can be gradual over a few weeks, or abrupt. Characteristically, patients have pervasive bodily symptoms including progressive tiredness; decreased appetite and weight loss are common. Many patients describe new moderate to severe headache in the side (temporal region) or back (occipital region) of the head. Scalp tenderness is reported with combing, wearing eyeglasses, or sleeping on the affected side. In some cases, the headache can be reproduced by pressure over the temporal artery. More than half of the patients have low-grade fevers that oftentimes lead to extensive investigations aimed at ruling out infection or cancer. Other symptoms may include: pain in the masticatory muscles when chewing meat or solid foods, pain in the tongue precipitated by talking, and/or pain in one or more extremities with repetitive use. Some patients experience short episodes of visual loss; initially these episodes are short and vision is regained. Unfortunately, these episodes of loss of vision are warning signs for the irreversible loss of vision. Polymyalgia rheumatica (PR) can be associated with Giant Cell Arteritis. Patients affected by this condition report morning stiffness and pain in the shoulder, neck, and hip area, severe enough to limit their activities and oftentimes confine them to bed. Patients with Giant Cell Arteritis are more likely to have abnormal expansion of large blood vessels in the chest (dilatation of the thoracic aorta) than patients without the disease. As a consequence, routine chest radiographs (x-rays) to look for enlargement of the space between the lungs (mediastinum) should be performed yearly in Giant Cell Arteritis patients. If such a finding is noted, a computed tomography (CT) of the chest to evaluate the size of the aorta is indicated.
Laboratory data indicate inflammation. Tests indicating active disease process, the erythrocyte sedimentation rate (ESR), and the C-reactive protein (CRP) are usually markedly elevated. Anemia (low red blood cell count) is often present. Platelet count can be elevated. The liver function tests can be slightly abnormal. The artery in the temple area, the temporal artery, one of the most common affected areas, can be easily biopsied to confirm the diagnosis. Temporal artery biopsy should be done, if possible, before treatment is initiated. When transient visual symptoms are present, treatment should be initiated immediately.
Once the diagnosis of Giant Cell Arteritis is established, steroids, or a related medication, should be started at a dose between 40 and 60 mg per day. This dose can be reduced gradually in the following months as clinical response is attained. The erythrocyte sedimentation rate and C-reactive protein can be followed monthly. As markers of inflammation, these tests are expected to parallel the clinical improvement and tend to normal as the inflammatory process is under control. The majority of patients develop side effects from steroid therapy such as: osteoporosis with increased risk for fractures, diabetes, cataract, glaucoma, high blood pressure, obesity, acne, breakdown of the major hip-bone joint (aseptic osteonecrosis of the femoral head), and infections. Occasionally, in those who need prolonged therapy with high doses of steroid, the side effects from treatment may be worse than the disease itself. The goal is to gradually decrease the steroid to the lowest dose that controls the disease. The average duration of therapy is about 2 years and many patients are able to get off steroids completely. Although most patients initially do well, relapses occur and steroids should be restarted or increased and then tapered at a slower rate.
Addition of immunosuppressive medication such as methotrexate has failed to show a decrease in the number of relapses. Methotrexate can be an option in those who do not tolerate, or who develop significant side effects from steroids. There are a few promising case reports of resistant (refractory) Giant Cell Arteritis treated with the medications etanercept or infliximab. These drugs are biologic agents that target one of the mediators of the inflammatory process. At this time though, more studies are needed to confirm their usefulness in Giant Cell Arteritis.
SEE ALSO: Cardiovascular disease, Headache
- Cantini, F., & Niccoli, L. (2001). Treatment of longstanding active giant cell arteritis with infliximab: Report of four cases. Arthritis and Rheumatism, 44, 2933-2935.
- Hoffman, S. G., Cid, M. C., Hellman, D. B., et al. (2002). A multicenter, randomized, double-blind, placebo-controlled trial of adjuvant methotrexate treatment for giant cell arteritis. Arthritis and Rheumatism, 16, 1309-1318.
- Hunder, G., & Valente, R. M. (2002). Giant cell arteritis: Clinical aspects. In G. S. Hoffman & C. M. Weyland (Eds.), Inflammatory diseases of blood vessels (pp. 425-441). New York: Marcel Dekker.
- Salvarani, C., Cantini, F., Boiardi, L., & Hunder, G. G. (2002). Polymyalgia rheumatica and giant-cell arteritis. New England Journal of Medicine, 347, 261-271.