Giant cell arteritis: an inflammation of the lining of your arteries — the blood vessels that carry oxygen-rich blood from your heart to the rest of your body. Most often, it affects the arteries in your head, especially those in your temples. For this reason, giant cell arteritis is sometimes called temporal arteritis or cranial arteritis.
Giant cell arteritis frequently causes headaches, jaw pain, and blurred or double vision. Blindness and, less often, stroke are the most serious complications of giant cell arteritis.
Prompt treatment with corticosteroid medications usually relieves symptoms of giant cell arteritis and may prevent loss of vision. You should start feeling better within days of starting your treatment.