Giant Cell Arteritis
(Temporal Arteritis; Cranial Arteritis; Horton Disease)
(See also Overview of Vasculitis.)
Giant cell arteritis is chronic inflammation of large and medium arteries of the head, neck, and upper body. Typically affected are the temporal arteries, which run through the temples and provide blood to part of the scalp, the jaw muscles, and optic nerves.
The cause is unknown.
Typically, people have a severe and often throbbing headache, pain in the scalp when they brush their hair, and pain in facial muscles when they chew.
Without treatment, blindness can result.
Symptoms and results of a physical examination suggest the diagnosis, but biopsy of the temporal artery is done to confirm it.
Prednisone (a corticosteroid) and aspirin are usually effective treatments.
Giant cell arteritis is a relatively common form of vasculitis in the United States and Europe. Women are affected more often than men. Giant cell arteritis typically affects people over age 55, often at about age 70. About 40 to 60% of people with giant cell arteritis also have polymyalgia rheumatica. The cause of these disorders is unknown.
Symptoms may begin gradually over several weeks or abruptly. People may have fever and feel tired and generally unwell. They may lose weight unintentionally and sweat more than usual. Symptoms vary, depending on which arteries are affected.
Typically, the large arteries to the head are affected, causing a severe, sometimes throbbing headache at the temples or back of the head to develop for the first time. Arteries in the temple may be tender to the touch and feel swollen and bumpy. The scalp may feel painful when touched or when the hair is brushed.
Double or blurred vision, large blind spots, sudden blindness in one eye that resolves within a few minutes, or other eye problems may develop. The greatest danger is permanent blindness, which can occur suddenly if the blood supply to the optic nerve is blocked. Complete blindness in both eyes is uncommon if people are treated as soon as the diagnosis is suspected but can occur without treatment. Over the past 50 years, the number of visual disturbances has gone down while recovery rates have gone up, most likely because giant cell arteritis is diagnosed earlier and treated before the eyes are affected.
Doctors suspect the diagnosis based on symptoms and results of a physical examination. Doctors feel the temples to see whether the temporal arteries feel hard, bumpy, or tender. Blood tests are done. Results can support the diagnosis. For example, anemia, a very high erythrocyte sedimentation rate (ESR), and a high level of C-reactive protein indicate inflammation. A biopsy of the temporal artery (in the temple) is done to confirm the diagnosis (see Table: Biopsy of the Temporal Artery).
The diagnosis is also more likely if the patient also has signs of polymyalgia rheumatica.
If giant cell arteritis is suspected in very large arteries, such as the aorta and its major branches, magnetic resonance angiography may be done to confirm the diagnosis.
Biopsy of the Temporal Artery
With treatment, most people recover fully, but the disorder may recur.
Treatment is started as soon as giant cell arteritis is suspected because without treatment, blindness can develop. Treatment is usually started even before a biopsy is done. Treatment does not affect the biopsy results as long as the biopsy is done within 2 weeks after starting treatment. Prednisone, a corticosteroid, is effective. Initially, the dose is high to stop the inflammation in the blood vessels and prevent vision loss. After several weeks, doctors gradually reduce the dose if people are improving. Most people need to take prednisone for at least 2 years to control symptoms and prevent blindness.
Doctors recommend people take a low dose of aspirin daily to help prevent strokes.