Treatment

The main treatment for giant cell arteritis consists of high doses of a corticosteroid drug such as prednisone. Because immediate treatment is necessary to prevent vision loss, your doctor is likely to start medication even before confirming the diagnosis with a biopsy.

You'll likely begin to feel better within a few days of beginning treatment. If you have visual loss before starting treatment with corticosteroids, it's unlikely that your vision will improve. However, your unaffected eye might be able to compensate for some of the visual changes.

You may need to continue taking medication for one to two years or longer. After the first month, your doctor might gradually begin to lower the dosage until you reach the lowest dose of corticosteroids needed to control inflammation.

Some symptoms, particularly headaches, may return during this tapering period. This is the point at which many people also develop symptoms of polymyalgia rheumatica. Such flares can usually be treated with slight increases in the corticosteroid dose. Your doctor might also suggest an immune-suppressing drug called methotrexate (Trexall).

Corticosteroids can lead to serious side effects, such as osteoporosis, high blood pressure and muscle weakness. To counter potential side effects, your doctor is likely to monitor your bone density and might prescribe calcium and vitamin D supplements or other medications to help prevent bone loss.

The Food and Drug Administration recently approved tocilizumab (Actemra) to treat giant cell arteritis. It's given as an injection under your skin. Side effects include making you more prone to infections. More research is needed.