Giant cell arteritis (GCA) is a form of uncommon condition involving certain arteries in a person's body that become inflamed. The condition is sometimes referred to as, 'temporal arteritis,' or, 'cranial arteritis,' because if often affects the arteries in a person's scalp, near to their temples. The condition may; however, also involve additional arteries in a person's head, neck, and arms, as well as other areas on occasion. Microscopic examination of the cells that narrow or block the person's arteries reveal characteristic, 'giant,' cells which deprive the downstream tissues of an adequate blood supply.
GCA affects mainly people who are over the age of fifty, with the average age of affected person's being seventy. The cause of GCA is unknown to medical science. The condition occurs twice as often in women as it does in men, with the white population presenting a stronger predisposition for the disease. Black and Asian Americans rarely develop GCA. Another high-risk group includes people with polymyalgia rheumatica, another condition that is not well-understood and is characterized by pain, morning stiffness, as well as tenderness in the hips, shoulders and neck. Approximately fifty-percent of people who experience GCA also have polymyalgia; ten-percent of those with polymyalgia develop arteritis.
GCA involves an inflammation of the lining of a person's arteries, the very blood vessels that carry oxygen-rich blood to a person's heart and the rest of their body as well. GCA commonly causes a person to experience jaw pain, headaches, and blurred or doubled vision. People with GCA can experience blindness, or less often, stroke, as complications of the condition.
Causes of GCA
A person's arteries are essentially pliable tubes with thick, elastic walls. Oxygenated blood leaves a person's heart through their body's main artery, the aorta. Their aorta subdivides into smaller arteries that deliver blood to every part of their body, to include their brain and internal organs. When a person has GCA, some of their arteries become inflamed and swell. The reasons why are not known.
While almost any of a person's large or medium-sized arteries may be affected by GCA, the swelling associated with is most often associated with the person's temporal lobes, located right in front of their ears and continuing up into their scalp. For some people, the swelling affects just a portion of an artery, with sections of regular vessel in-between. The exact cause of GCA is not known, although there are a number of factors that can increase a person's risk. These factors can include:
Age:GCA affects older adults almost exclusively. The average age at onset of the disease is 70; it rarely occurs in people younger than 50.
Gender: Women are two to three times more likely to develop GCA than men are.
Race: Although giant cell arteritis may affect people of any race, the 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. Up to 15 percent of people with polymyalgia rheumatica also have giant cell arteritis.
Symptoms of GCA
GCA may produce symptoms that include jaw muscle pain when the person talks or eats, tenderness over inflamed vessels in the person's temples, and severe headaches. When blood vessels that nourish the person's eyes become involved, the person can suddenly develop blindness in one or both of their eyes. Up to thirty-percent of people affected by temporal arteritis develop blindness in one of their eyes. Administration of prednisone in order to suppress inflammation offers a level of relief of symptoms and can prevent blindness and additional disabilities such as stroke. People with GCA who experience any vision problems should inform their physician at once. In general, the symptoms of GCA include:
Unintended weight loss
Jaw pain when you chew
Persistent head pain and tenderness
Decreased visual acuity or double vision
Pain and stiffness in your neck, arms or hips
Sudden, permanent loss of vision in one eye
The most serious complication of GCA is blindness. The swelling associated with GCA narrows a person's blood vessels and reduces the amount of blood, and therefore the amount of oxygen and nutrients, that reaches the tissues in their body. A diminished blood supply to a person's eyes may cause sudden and painless vision loss in one, or rarely, both of the person's eyes. Unfortunately, the loss of vision is usually permanent.
Another complication of GCA is that it doubles a person's risk of aneurysm. An aneurysm is a bulge that forms in a weakened blood vessel, commonly an aorta, the large artery which runs through the center of a person's chest and abdomen. An aortic aneurysm is a serious condition; it has the potential to burst and cause life-threatening internal bleeding. An aortic aneurysm has the potential to occur years after a person has received a diagnosis of GCA. It is important that people who have been diagnosed with GCA receive monitoring by their doctor regarding the health of their aorta through annual chest X-rays or additional imaging test such a CT scan, MRI, or ultrasound.
Still another complication of GCA is the potential for stroke. In some people with GCA, a blood clot can form in an affected artery and obstruct their blood flow completely. When this happens it deprives part of their brain of the oxygen and nutrients it needs completely and causes a stroke.
GCA may also cause chest pain or, 'angina.' While rare, some people with GCA experience chest pain. The pains can result from inflammation in their coronary arteries that supply their heart with oxygen and nutrients.
A diagnosis of GCA is confirmed by a biopsy of the person's temporal artery. Large doses of cortisone-like medications, such as prednisone, suppress inflammation in the person's artery walls. As the inflammation subsides, the dosage is reduced and the medication may be discontinued, although treatment many times continues for a year or more.
GCA may be hard to diagnose because the early symptoms associated with it resemble those of a number of common conditions. There are various tests a doctor might order in an attempt to rule out other potential causes. These tests may include the following:
Physical examination:In addition to asking about your symptoms and past medical history, a doctor is likely to perform a thorough physical exam, paying particular attention to the person's temporal arteries. Often, one or both of these arteries are tender, with a reduced pulse and a hard, cord-like feel and appearance.
Blood tests: If a doctor suspects giant cell arteritis, they are likely to order a blood test that checks the person's erythrocyte sedimentation rate.
Biopsy: While blood tests and blood vessel imaging tests, such as MRI angiography and cerebral angiography, may provide a doctor with useful information, the only way to confirm a diagnosis of GCA is by taking a biopsy of the temporal artery. Because the inflammation may not occur in all parts of the artery, more than one sample may be needed.
Treatment of GCA
Prednisone is a main form of treatment for GCA. While prednisone does have side-effects, the high risk of permanent blindness and additional problems related to blood vessel blockages does justify its use in people who are diagnosed with GCA. The side-effects of high-dose use of prednisone taken over long periods of time include weight gain, fluid accumulation, redistribution of body fat, mood swings, depression, thin skin and easy bruising. The more serious complications of long-term use of prednisone may include stomach ulcers, otseoporosis, diabetes, high blood pressure, as well as an increased risk of infections. A physician will monitor the person taking prednisone who has GCA closely to check for side-effects and decrease the dose of the medication to safer levels as soon as possible.
Another form of treatment for GCA is the use of low-doses of the anticancer medication, 'methotrexate,' combined with prednisone. Promptly treating GCA with corticosteroid medications usually relieves the symptoms the person is experiencing and can prevent the loss of their vision. The fact that vision loss is such a risk in association with GCA finds many doctors starting medication treatment even before confirming the diagnosis with a biopsy.