Diagnosing Giant Cell Arteritis

Featuring Dr. John Wade, MD, FRCPC, Rheumatologist

Duration: 5 minutes, 8 seconds

Giant cell arteritis is a clinical diagnosis. One has to suspect it. And once one suspects the diagnosis, there are blood tests, and investigations you can go on and do to confirm the diagnosis.

The first investigation one would do is do some blood tests. On the blood test, the patient will often have a mild anemia or low hemoglobin. In addition, almost invariably there are markers of inflammation that are elevated in the blood.

So the most common blood test that one would do is an ESR, or a C-reactive protein. And if one or both of those are elevated, it increases the likelihood of having the diagnosis of giant cell arteritis.

It’s very important to try and confirm the diagnosis, because the treatments are quite significant, and one wants to have certainty if one can that it truly is giant cell arteritis. The best way to diagnose it is to either do a biopsy of the temporal artery, or to do an imaging study of the arteries that are branching out from the heart or the aorta.

The temporal artery biopsy is a simple outpatient procedure. It takes about 10-15 minutes to do. It’s a local anesthetic, you do not have to be put to sleep, and the surgeon will do a little minor cut in the area of the right side or the left side of the head, and do a few little sutures.

It’s a very safe operation, typically they’ll do one side, not both sides. Very occasionally, your doctor might recommend a biopsy of the other side if the biopsy of one side is negative.

The biopsy results are pretty good, and if the biopsy is positive, then you have a confirmed diagnosis of giant cell arteritis, and you will treat. The difficulty is, is if you have a high suspicion of giant cell arteritis, and you do the biopsy and the biopsy is negative, then it’s sometimes a challenge to know what to do.

So your specialist may then do a biopsy of the other side, or your specialist may then want to go on and do some more advanced imaging. The two advanced imaging tests that they would do would be either a CT angiogram of the vessels that go out from the heart, or an MR angiogram, which is another, more precise way of looking at the artery wall.

So both of these tests can increase the sensitivity and the specificity that a likelihood of making the diagnosis by doing these further tests. There is one further test that some people are currently doing, called an ultrasound or Doppler test.

And currently it’s in early days, but some centres in North America and Europe are becoming quite good about doing a simple ultrasound of the temporal artery and the arteries in the neck to determine whether there’s inflammation in those arteries.

And those can be equally effective in confirming a diagnosis of giant cell arteritis, if the centre that’s doing it has expertise. Unfortunately, there’s still a lot of learning to do with doing the ultrasound test for giant cell arteritis, and presently in most centres it’s not definitive, but it can certainly help you then go on and decide whether you might do other imaging, or whether you might do a biopsy of the temporal artery.

If there are any visual symptoms, referring to an ophthalmologist can be very helpful. An eye doctor who has expertise in this area can recognize some of the symptoms of giant cell arteritis, and make sure that any visual complaints are attributed to giant cell arteritis vs. any other condition.

If you have any other concerns or questions about the diagnosis of giant cell arteritis, speak to your healthcare provider or your specialist.

Presenter: Dr. John Wade, Rheumatologist, Vancouver, BC

Local Practitioners: Rheumatologist