Giant cell arteritis (GCA) is 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.
Although giant cell arteritis can affect the arteries in your neck, upper body and arms, it occurs most often in 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 is also known as granulomatous arteritis — a reference to a particular type of inflammation.
Giant cell arteritis frequently causes headaches, jaw pain, and blurred or double vision, but the most serious potential complications are blindness and, less often, stroke. These problems can occur when swelling in your arteries impairs blood flow to your eyes or brain.
Adults older than age 50 are at greatest risk of giant cell arteritis. The exact cause isn’t known, but researchers believe that genetic, viral and environmental factors may play roles in the inflammation.
Although there’s no cure for giant cell arteritis, immediate treatment with corticosteroid medications usually relieves symptoms and prevents loss of vision.
The most common symptoms of giant cell arteritis are head pain and tenderness — often severe — that usually occurs in both temples. Some people, however, have pain in only one temple or the front of the head.
Signs and symptoms of giant cell arteritis can vary. For some people, the onset of the condition feels like the flu — with muscle aches (myalgia), fever and fatigue, as well as headache. Other common signs and symptoms include:
- Decreased visual acuity or double vision.
- Scalp tenderness. It may hurt to comb your hair or even to lay your head on a pillow, especially where the arteries are inflamed.
- Jaw pain (jaw claudication) when you chew.
- Pain and stiffness in your neck, arms or hips — usually worse in the morning before you get out of bed. These are often common symptoms of a related disorder, polymyalgia rheumatica. More than one in four people with GCA also have polymyalgia rheumatica.
- Sudden, permanent loss of vision in one eye.
- Unintended weight loss.
If you develop any of these problems, see your doctor without delay. Starting treatment as soon as possible can usually help prevent blindness.
Your arteries are pliable tubes with thick, elastic walls. Oxygenated blood leaves your heart through your body’s main artery, the aorta. The aorta then subdivides into smaller arteries that deliver blood to all parts of your body, including your brain and internal organs.
In giant cell arteritis, some of these arteries become inflamed, causing them to swell. Just what causes these arteries to become inflamed isn’t known.
Although almost any large or medium-sized artery can be affected, swelling most often occurs in the temporal arteries, which are located just in front of your ears and continue up into your scalp. In some cases, the swelling affects just part of an artery, with sections of normal vessel in between.
A potential for blood clots
Wherever it occurs, the swelling narrows the blood vessels, reducing the amount of blood — and therefore oxygen and vital nutrients — that reaches your body’s tissues. In some cases, a blood clot may form in an affected artery, obstructing blood flow completely. Diminished blood flow to your eyes can cause blindness, and an interrupted blood supply to your brain can lead to a stroke.
Sometimes instead of becoming narrower, a blood vessel — especially the aorta or one of its large branches — may weaken and form a bulge (aneurysm), a potentially life-threatening condition.
Even without these serious complications, inflamed blood vessels in your head frequently cause pain and tenderness, especially in your temples.
Although the exact cause of giant cell arteritis isn’t known, several factors can increase your risk, including:
- Age. Giant cell arteritis affects older adults almost exclusively — the average age at onset of the disease is 70, and it rarely occurs in people younger than 50.
- Sex. Women are two to three times more likely to develop giant cell arteritis than men are.
- Race. Although giant cell arteritis can affect people of any race, the vast majority of people affected are white. People of Scandinavian origin are particularly at risk.
- Polymyalgia rheumatica. People with the arthritic condition polymyalgia rheumatica (PMR), which causes stiffness and aching in the neck, shoulders and hips, have an increased risk of giant cell arteritis. Fifteen percent to 25 percent of people with polymyalgia rheumatica also have giant cell arteritis.
Giant cell arteritis can be difficult to diagnose because its early symptoms resemble those of many common conditions. For this reason, your doctor will try to rule out other possible causes of your problem.
In addition to asking about your symptoms and past medical history, your doctor is likely to perform a thorough physical exam, paying particular attention to your temporal arteries. Often, one or both of these arteries are tender, with a reduced pulse and a hard, cord-like feel and appearance.
To help diagnose giant cell arteritis, you may also have some of the following tests:
- Blood tests. If your doctor suspects giant cell arteritis, you’re likely to have a blood test that checks your erythrocyte sedimentation rate — commonly referred to as the sed rate.
This test measures how quickly red blood cells fall to the bottom of a tube of blood. Red cells that drop rapidly may indicate inflammation in your body. You may also have a test that measures C-reactive protein (CRP), a substance your liver produces when inflammation is present. The same tests may be used to follow your progress during treatment.
- Biopsy. Although blood tests can provide your doctor with useful information, the only way to confirm a diagnosis of GCA is by taking a small sample (biopsy) of the temporal artery. Because the inflammation may not occur in all parts of the artery, more than one sample may be needed.
The procedure is performed on an outpatient basis under local anesthesia, usually with little discomfort or scarring. The sample is examined under a microscope in a laboratory. If you have GCA, the artery will often show inflammation that includes abnormally large cells, called giant cells, which give the disease its name.
Unfortunately, a biopsy isn’t foolproof. It’s possible to have GCA and still have a negative biopsy result. If the results aren’t clear, your doctor may advise a biopsy on the other side of your head.
Treatment for GCA 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 should start feeling better within just a few days, but you may need to continue taking medication for one to two years or longer. After the first month, your doctor may gradually begin to lower the dosage until you reach the lowest dose of corticosteroids needed to control inflammation as measured by sed rate and CRP tests. Some of your symptoms may return during this tapering period.
What are corticosteroids?
Corticosteroids are powerful anti-inflammatory drugs whose effects mimic those of hormones produced by your adrenal glands. The drugs can effectively relieve pain, but prolonged use — especially at high doses — can lead to a number of serious side effects.
Older adults, who are most likely to be treated for giant cell arteritis, are particularly at risk because they’re more prone to certain conditions that also may be caused by corticosteroids. These include:
Other possible side effects of cortisone therapy include:
- Weight gain
- Increased blood sugar levels, sometimes leading to diabetes
- Thinning skin and increased bruising
- Decreased function of your immune system
Researchers are trying to find therapies that work as well as corticosteroids but cause fewer side effects.
One drug under investigation is methotrexate, which doctors often use to treat certain cancers and some inflammatory conditions such as rheumatoid arthritis. The hope is that by using both methotrexate and prednisone to treat people with GCA, it would be possible to use less prednisone. Preliminary research results are inconclusive, though.
A small study suggested that azathioprine (Imuran) may be helpful in the treatment of giant cell arteritis when used along with smaller doses of prednisone. Additionally, some case reports suggest that tumor necrosis factor (TNF) blockers, such as etanercept (Enbrel) and infliximab (Remicade), may be helpful. However, larger studies need to be done to confirm the effects of all of these medications.
The most serious complication of GCA is sudden, painless vision loss in one or, in rare cases, both eyes. Unfortunately, blindness is usually permanent. Other rare but possible complications of GCA include:
- Aortic aneurysm. An aneurysm is a bulge in a blood vessel. It can develop in a blood vessel anywhere in your body, but most aneurysms occur in the aorta, the large artery that runs down the center of your chest and abdomen. Aneurysms that develop in the part of the aorta that runs through the abdomen are called abdominal aortic aneurysms. Those that occur in the upper chest are known as thoracic aortic aneurysms.
An aortic aneurysm is a serious condition because it may burst, causing massive and life-threatening internal bleeding. Having giant cell arteritis doubles your risk of aneurysm, which may even occur years after the initial diagnosis.
- Stroke. This serious condition is an uncommon complication of GCA. It occurs when interrupted blood flow deprives part of your brain of necessary oxygen and nutrients.
- Chest pain (angina). In rare cases, some people with GCA have chest pain. This can result from inflammation in the coronary arteries that supply your heart with oxygen and nutrients.