Giant-cell arteritis is a condition that involves inflammation of arteries. It is more common with older age and rarely occurs before age 60 years. Another name for the condition is temporal arteritis because it most often involves the temporal arteries. The temporal arteries are located on the sides of the forehead. Inflammation of the arteries can cause them to narrow and can block normal blood flow to areas of the body that the arteries serve. Symptoms of giant-cell arteritis include head, face, jaw, or scalp pain; fever; fatigue; and loss of appetite. A serious complication of giant-cell arteritis is loss of vision. Timely diagnosis and treatment with steroid medications can prevent this. However, the high doses of steroid medications necessary to treat giant-cell arteritis can have side effects, so doctors want to be certain that patients have the condition before prescribing a long course of treatment. Treatment after loss of vision occurs will not restore normal vision but can prevent further vision loss. Unfortunately, giant-cell arteritis can be difficult to diagnose without doing a biopsy of the temporal artery. A biopsy is a minor surgical procedure that allows doctors to obtain a piece of tissue to examine under a microscope. Some reports have suggested that ultrasound tests of the temporal artery can be helpful in diagnosing giant-cell arteritis, but the role of ultrasonography in diagnosing this condition remains uncertain. Ultrasonography involves using sound waves to take special pictures.