Temporal Arteritis and Polymyalgia Rheumatica

In temporal arteritis (sometimes called giant cell arteritis), certain arteries in the head and elsewhere become inflamed. The temporal arteries (located on the temple, beside the eye) are most commonly affected, often causing a throbbing headache. In polymyalgia rheumatica, the lining of some joints (such as those in the neck, shoulders, and hips) becomes inflamed, causing muscle pain and stiffness. Temporal arteritis and polymyalgia rheumatica are separate disorders but closely related. They occur together so often that they may be thought of as Frick and Frack disorders. At least half of people who have temporal arteritis also have polymyalgia rheumatica. And about one fourth of people who have polymyalgia rheumatica develop temporal arteritis.

Temporal arteritis and polymyalgia rheumatica develop only in people over 50, and they become more common as people age. Polymyalgia rheumatica, which affects 7 out of 1,000 people over 50, is more common than temporal arteritis, which affects about 2 out of 1,000 people over 50. Both disorders affect more women than men.

People rarely die of temporal arteritis or polymyalgia rheumatica. But without treatment, the pain these disorders cause, whether they occur together or separately, can make everyday living miserably difficult. If not treated promptly, temporal arteritis can cause blindness.

Causes

No one knows what causes temporal arteritis or polymyalgia rheumatica. However, what happens in the body when the two disorders develop is known. In both disorders, cells that are part of the body's immune system malfunction.

In temporal arteritis, cells of the immune system (mainly certain white blood cells) invade the wall of the arteries that carry blood to the head. These cells cause inflammation in segments of the arteries (arteritis). These segments may become partially or completely blocked. Most often, the temporal arteries are affected. Sometimes other arteries in the head, including those that carry blood to the eyes (ophthalmic arteries) or to the chin, mouth, and nose (facial arteries), are affected, as are arteries in the neck (carotid arteries) and arteries elsewhere in the body. Rarely, a bulge (aneurysm) develops in the body's largest artery, the aorta.

In polymyalgia rheumatica, cells of the immune system enter joints such as those in the neck, shoulders, and hips. These cells cause inflammation of the lining of joints (synovitis). The cells do not invade the muscles, even though polymyalgia rheumatica causes muscle pain more than joint pain.

Symptoms

Temporal arteritis and polymyalgia rheumatica cause the same general symptoms, such as fatigue, slight fever, loss of appetite, and weight loss. People with either of the disorders may have one or more of these symptoms. People may have additional symptoms that are caused only by temporal arteritis. These symptoms vary depending on which arteries are affected. People may also have symptoms caused only by polymyalgia rheumatica.

Temporal arteritis can cause double vision (diplopia) and blurred vision. A person may also be unable to see when looking in one direction. Or a person may completely lose vision in one eye. Loss of vision may be temporary. However, unless temporal arteritis is treated promptly, vision may be lost permanently, sometimes in both eyes.

Many people with temporal arteritis have headaches. Often described as continuous and throbbing, the headaches are usually felt at the temple. The temple may be tender when touched. The temporal artery may bulge because it is inflamed and swollen. It may feel bumpy. Temporal arteritis may cause aching pain in the jaw during chewing or talking (jaw claudication). Some people experience dizziness that feels like spinning (vertigo).

An aneurysm in the aorta due to temporal arteritis often causes no symptoms. But occasionally, an aneurysm leaks or ruptures, causing sudden chest or back pain, weakness, light-headedness, confusion, and even death.

Polymyalgia rheumatica causes muscle pain and stiffness, most often in the neck, shoulders, and hips. The pain tends to be worse in the morning. But pain may awaken a person during the night. Usually, stiffness is more noticeable in the morning and after periods of inactivity. A person may be unable to move the shoulders and hips freely because they are too stiff. Pain may make getting out of bed difficult. Affected muscles may be slightly tender when touched. Less often, mild pain and swelling occur in the wrists, fingers, and knees.

Diagnosis

Doctors may suspect temporal arteritis, polymyalgia rheumatica, or both in a person who has fatigue, fever, loss of appetite, and weight loss. If headaches or sudden changes in vision are also present, temporal arteritis is suspected. Doctors check the temporal artery on each side of the head to see if it is swollen, bulges more than usual, or feels bumpy. If the neck, shoulders, and hips are painful and stiff, polymyalgia rheumatica is suspected.

Blood tests help doctors diagnose both disorders. The most common blood test is measurement of the erythrocyte sedimentation rate (ESR). This test helps determine how much inflammation is present. In most people with either or both disorders, the ESR is much higher than normal. But in a few people, it is normal. If the ESR is normal but symptoms suggest one of these disorders, another blood test—measuring the level of C-reactive protein—may help. The presence of this protein indicates inflammation.

See the figure Arteries Commonly Affected by Temporal Arteritis.

A biopsy of the affected temporal artery is always recommended to confirm a diagnosis of temporal arteritis. For the biopsy, a local anesthetic is injected under the scalp. Then a shallow incision is made directly over the artery, and at least a 1-inch segment of the artery is removed and examined under a microscope. The cut ends of the artery are sewn back together.

No test can confirm a diagnosis of polymyalgia rheumatica. If the diagnosis is uncertain, tests may be done to rule out other disorders as possible causes of the muscle symptoms. For example, a biopsy of a muscle may be done. Occasionally, the electrical activity of different muscles may be measured using small needles inserted into the muscle. This procedure is called electromyography (EMG).

In a person who has temporal arteritis, a chest x-ray may suggest an aneurysm in the aorta. Ultrasonography, computed tomography (CT), or magnetic resonance imaging (MRI) may be done to confirm the diagnosis of an aneurysm.

Treatment and Outlook

When temporal arteritis (alone or with polymyalgia rheu-matica) is suspected and vision is affected, treatment is often begun immediately. It is usually begun even before a biopsy is done to confirm the diagnosis. Any delay in the treatment of temporal arteritis increases the risk that blindness may occur and that blindness, if present, may become permanent. However, when vision is not affected and biopsy results can be obtained in a few days, many doctors wait for biopsy results before starting treatment. Treatment may be given when biopsy results are negative but the results of the physical examination and blood tests strongly suggest temporal arteritis. A biopsy does not always detect temporal arteritis.

Treatment usually consists of a corticosteroid, such as prednisone. Prednisone is taken as a tablet. The starting dose of prednisone for temporal arteritis is much higher than that for polymyalgia rheumatica. If prednisone relieves symptoms in people who are thought to have polymyalgia rheumatica (but do not have temporal arteritis), the diagnosis is supported.

If the biopsy does not show any evidence of temporal arteritis or if prednisone has been tried but has not been effective, doctors look for other causes of the symptoms.

Many people with temporal arteritis (alone or with polymyalgia rheumatica) begin to improve dramatically during the first week of treatment with prednisone. Some improve within 1 day. After only a few days of treatment, headaches from temporal arteritis may subside. After having been barely able to get out of bed because of polymyalgia rheumatica, people may be walking and doing light household chores.

Prednisone is often continued at the starting dose for several weeks to make sure that symptoms are under control. Then, doctors usually slowly and cautiously reduce the dose. They monitor the person's response to the reductions in dose by periodically asking how well prednisone is controlling the symptoms and by measuring the ESR to check for evidence of inflammation. If symptoms worsen or if the ESR increases, doctors usually delay the next reduction in dose or even increase the dose.

The goal is to keep reducing the dose until the person no longer needs to take the drug. This approach is important because prednisone is more likely to cause problems when it is given at a high dose or for a long time. These problems include high blood pressure, thinning of the skin, poor wound healing, osteoporosis, diabetes, and cataracts. Nonetheless, treatment usually must be continued for at least 1 to 2 years and sometimes longer.

If an aneurysm develops in the aorta because of temporal arteritis, the aneurysm may be surgically repaired. Whether an aneurysm is repaired depends on its size and location.

Temporal arteritis and polymyalgia rheumatica rarely cause death. For the most part, problems caused by these disorders can be prevented or effectively treated. Treatment also enables most people who have one or both disorders to regain their ability to function. A complete recovery is the reward for many of the people who faithfully continue treatment as instructed.