Giant Cell Arteritis (GCA), also known as temporal arteritis, is a condition where inflammation of the lining of the arteries causes swelling inside the arteries. This can cut off the blood supply to organs and tissues in the body.
The most common arteries affected by the condition are around the head and neck, especially the area around the temples (i.e. temporal arteritis).
Giant Cell Arteritis belongs to a family of arthritic diseases called vasculitis. The word vasculitis means inflammation of blood vessels.
Importance of Early Treatment
New cases of Giant Cell Arteritis are considered a medical emergency that must be treated quickly and aggressively to help prevent serious consequences including blindness and stroke.
Treatment helps reduce damage to the arteries and ensure that important organs and tissues are not cut off from their blood supply.
Who Gets Giant Cell Arteritis
People aged 70 and older are most commonly affected by Giant Cell Arteritis. The condition can also occur in people in their 50s or 60’s, but this is less common. It is about twice as common in women than men. People born in Northern Europe seem to have the highest rates of giant cell arteritis.
The condition is sometimes associated with another rheumatic disease called Polymyalgia Rheumatica. About half of the people who have giant cell arteritis also have Polymyalgia Rheumatica.
Understanding Giant Cell Arteritis
The first signs and symptoms of giant cell arteritis can be hard to pinpoint.
Pain or Tenderness in the Head and Temple Area
The most common initial symptom is persistent pain or tenderness around one or both temples. It is more common to affect a single side of the head.
The affected area can become very sensitive, usually just above the ear on the side of the head (this is over the temporal artery).
People with giant cell arteritis often find it hurts to comb their hair or to lie on a pillow on the side that’s affected. Rarely, the temporal artery can become prominent or very visible.
Other symptoms to watch out for include pain around other areas of the head such as the forehead, scalp, in the jaw when chewing and pain in the tongue or teeth.
Blindness in Severe Cases
When the condition becomes severe, blood flow to areas supplied by the arteries can be cut off. This can lead to symptoms such as vision loss, double vision, and eventually blindness.
People with the condition may start feeling fatigued and generally feel unwell. It often feels like having the flu: headache, fatigue, and muscles may feel sore and achy. A fever and weight loss can also occur.
Association with Polymyalgia Rheumatica
Giant cell arteritis can be accompanied by another condition called Polymyalgia Rheumatica.
It is estimated that up to 70% have Polymyalgia Rheumatica with giant cell arteritis. Polymyalgia Rheumatica results in pain and stiffness in the neck, shoulders, and hip region. This pain and stiffness is much more prominent in the mornings and can last hours.
Giant Cell Arteritis is best diagnosed by a rheumatologist, a type of doctor that specializes in arthritis and autoimmune disease.
To diagnose the condition, doctors will take a careful and complete history and perform a thorough physical examination. Based on this information, they will likely order tests like blood tests, scans, and other types of tests such as a biopsy (tissue sample) to confirm their diagnosis.
Common Tests to Diagnose Giant Cell Arteritis
Biopsy (Tissue Sample)
Biopsy of the Temporal Artery: The best test for diagnosing giant cell arteritis is a biopsy of the temporal artery.
A small piece of the artery is removed in a small operation called a biopsy. The sample is then evaluated under a microscope to see if there is inflammation in the artery wall.
Looking for inflammation: Giant cell arteritis involves inflammation so these tests are expected to have abnormal results.
Common tests include a Complete Blood Count (CBC), Erythrocyte Sedimentation Rate (ESR), and C-Reactive Protein (CRP).
These tests are not specific to giant cell arteritis and only indicate that the body is fighting inflammation somewhere.
Ultrasound and/or Magnetic Resonance Imaging (MRI): Imaging tests can be used to look for evidence of inflammation in the artery walls.
These tests can provide evidence supporting a diagnosis of giant cell arteritis, but are not definitive.
Scientists don’t fully understand what causes giant cell arteritis, but researchers around the world are actively studying this condition to learn more about it.
It’s known that parts of the immune system are activated or (turned on) in people with giant cell arteritis and other types of vasculitis (diseases involving inflamed blood vessels).
One possibility is that the immune system is triggered by an infection and starts to attack the arteries. If this is the case, the source of such an infection has yet to be identified.
Giant Cell Arteritis is sometimes associated with another rheumatic disease called Polymyalgia Rheumatica (PMR). Up to 70% of the people who have giant cell arteritis also have Polymyalgia Rheumatica.
Giant cell arteritis must be treated very quickly and aggressively to help prevent serious consequences including blindness and stroke.
Without effective treatment, inflammation can damage the arteries that supply important organs and tissues in the body, such as the eyes and the brain.
Medications for giant cell arteritis are aimed at controlling inflammation.
In some people, once inflammation is brought under control, the disease can go into remission (an absence of disease activity). When that happens, doses of medicines can sometimes be tapered down and eventually stopped.
In other people, giant cell arteritis behaves more like a chronic (long-term) disease that must be controlled with small doses of medicine on an ongoing basis.
Medications for Giant Cell Arteritis
Corticosteroid medications like prednisone are very effective medications to control the symptoms of giant cell arteritis. They help control inflammation and can prevent long-term damage.
Prednisone is usually started at a high dose (50-100 mg) to quickly bring inflammation under control. Most people start to feel better within a few days of starting prednisone.
Once symptoms have improved and markers of inflammation have come back to normal, the dose can start to be tapered down.
In the short-term, prednisone works very well to control symptoms.
When used for long periods of time, prednisone can have side effects including bone loss (osteoporosis). People taking prednisone should discuss the risks and benefits of the medication with their rheumatologist.
Disease Modifying Anti-Rheumatic Drugs (Methotrexate)
Disease Modifying Anti-Rheumatic Drugs are a type medication that are typically used to treat rheumatoid arthritis and other types of inflammatory arthritis.
Methotrexate is a common example that has been shown effective in treating some people with giant cell arteritis.
Methotrexate will take some time before it starts to work (about 6-12 weeks) so it’s important for people to keep taking it even when they don’t notice effects right away.
Taking methotrexate can help reduce the dose of prednisone that a person with Giant Cell Arteritis needs to keep inflammation under control to reduce the risk of side effects.
Biologics are a class of medications specifically designed to target the immune system.
Blocking a molecule called Interleukin-6 has shown tremendous improvement in the symptoms of giant cell arteritis and reduced the need for prednisone in many patients.
A biologic that blocks Interleukin-6, called Actemra (tocilizumab), is approved for the treatment of this condition and has excellent results.