GIANT CELL ARTERITIS

GCA is a type of vasculitis or arteritis, a group of diseases whose main feature is inflammation of blood vessels. In GCA, the vessels most often involved are the arteries of the scalp and head, especially the arteries over the temples, which is why another term for GCA is “temporal arteritis.”

GCA can overlap with polymyalgia rheumatica (PMR). At some point, 5 – 15% of patients with PMR will have a diagnosis of GCA. About 50 percent of patients with GCA have symptoms of PMR. The two conditions may occur at the same time or on their own. It also affects the same types of patients as does PMR. It occurs only in adults, usually over age 50, in women more than men, and in whites more than non-whites.

The most common symptom (what you feel) of GCA is a new headache, usually around the temples, but headache due to GCA can occur anywhere, including the front, top and back of the skull. Almost as common are symptoms such as fatigue, loss of appetite, weight loss or a flu-like feeling. There may be pain in the jaw with chewing. Sometimes the only sign of GCA is unexplained fever. Less common symptoms include pains in the face, tongue, or throat.

If GCA spreads to the blood supply of the eye, eyesight can be affected. Problems with vision can include temporary blurring, double vision or blindness. Permanent loss of vision in GCA can occur suddenly, but proper treatment can prevent this complication. In fact, if a patient’s vision is fine at when they start treatment, the risk of later loss of sight is 1 in 100, or less. It is vital that patients who have active or inactive PMR report any symptoms of new headache, changes in vision or jaw pain right away to their doctors.

As with PMR, the cause of GCA is not known.

There is no simple blood test or noninvasive way to confirm the diagnosis of GCA. The erythrocyte sedimentation rate (or sed rate) is a blood test that measures inflammation by checking to see how the rate at which red blood cells (erythrocytes) sediment (or fall) within an hour. This rate is high in most people with GCA. Because other diseases can cause high sedimentation rates, doctors cannot rely on this finding alone as proof of GCA.

In some cases, an ultrasound of the temporal arteries on the side of head can be done. If positive this can be suggestive of active GCA. A negative test, however, does not rule out GCA and biopsy would need to be done.

It is common to do a biopsy – or surgical removal – of a small piece of the temporal artery and study it under a microscope for signs of inflammation. This biopsy is an outpatient procedure, done under local anesthesia (numbing of that site while you are awake). It leaves just a small scar that usually cannot be seen at the hairline in front of the ear. In GCA, the biopsy shows inflammation of the artery. If there is doubt about the diagnosis based on the first biopsy, your doctor may do a biopsy of the temporal artery on the other side of your head.

The treatment for GCA should begin as soon as possible because of the risk of loss of vision. If your doctor strongly suspects GCA, treatment can start before you get the results of a temporal artery biopsy. Unlike the treatment for PMR, which requires only low-dose corticosteroids (also called glucocorticoids), GCA treatment usually involves high doses of corticosteroids. Typically, the dose is 40-60 milligrams (mg) per day of prednisone (Deltasone, Orasone, etc.). Headaches and other symptoms quickly decrease with treatment, and the sedimentation rate declines to a normal range.

The high dose of corticosteroids usually continues for a month, and then the dose is slowly decreased. The speed at which your doctor lowers the dose may change if you have recurring symptoms of GCA or large increases in the sedimentation rate. In most cases, though, the prednisone dose can be reduced to about 5 – 10 mg per day over a few months. Patients are usually tapered off this medicine by one to two years. GCA rarely returns after treatment.

In May 2017, tocilizumab (Actemra) was approved for the treatment of GCA. This medication can be given as an intravenous medication, monthly, or as a subcutaneous injection, self-administered by the patient, every one or two weeks. Tocilizumab was shown to provide a greater number of patients to be in remission from GCA with one year of treatment and to require less total amounts of prednisone.

As would be expected, side effects are more common with higher doses of corticosteroids. For example, corticosteroid treatment can cause bone loss, so your doctor may want you to get a bone density test and suggest you take supplements of calcium and vitamin D to protect against osteoporosis and the risk of fractures (broken bones). Your doctor also may suggest you take a prescription medicine to protect your bones. These include the bisphosphonates: risedronate (Actonel), alendronate (Fosamax), ibandronate (Boniva), or zoledronic acid (Reclast).

Some of the other side effects from high-dose corticosteroids are jittery moods, weight gain, fluid retention, and poor sleep. These can be unpleasant but are reversible. These should improve as the drug dose is tapered. Steroids also raise the risk of infections, muscle weakness, cataracts, glaucoma, avascular necrosis of bone, and skin thinning or bruising, so patients should see their doctor often to watch for and treat these problems. Most steroid side effects are temporary and can be managed. See your doctor often to check for side effects.