What Is Giant Cell Arteritis?

Giant cell arteritis develops when the lining of the arteries in the head, typically the temples, becomes inflamed. The condition can affect other large blood vessels, such as those in the arms, neck, and scalp. The inflammation causes the blood vessels to become blocked, resulting in interrupted blood flow.

This article discusses the symptoms, causes, and treatment options for giant cell arteritis.

What Are the Symptoms of Giant Cell Arteritis?

There are many symptoms associated with giant cell arteritis. They are split up into four main subsets, as follows:

• Cranial (affecting the head)
• Extracranial (affecting the outside of the head)
• Systemic
• Polymyalgia rheumatica (affecting the muscles)

In the beginning stages, a person may develop flu-like symptoms such as:

• Fatigue
• Loss of appetite
• Fever

If the inflammation is affecting cranial arteries, or arteries in the head, symptoms include:

• Severe headaches
• Scalp or temple tenderness
• Vision changes such as vision loss or double vision
• Dizziness and issues with balance or coordination
• Pain or tiredness in the jaw when eating or talking
• Sore throat and difficulty swallowing
• Chest pain that comes and goes
• Weight loss and anorexia
• Malaise (general feeling of discomfort)
• Anemia (not having enough healthy red blood cells)
• Elevated inflammatory markers
• Loss of blood flow to the brain that results in brain tissue damage
• Heart attack
• Pain, discomfort, or fatigue in the limbs
• Polymyalgia rheumatica

What Causes Giant Cell Arteritis?

While the exact cause of giant cell arteritis isn’t well understood, it’s thought that the condition is an autoimmune disease. In giant cell arteritis, the immune system attacks healthy cells in the lining of blood vessels, causing inflammation. That inflammation then narrows the blood vessels and causes symptoms and blood flow interruptions.

How Is Giant Cell Arteritis Diagnosed?

The diagnostic process of giant cell arteritis involves discussing symptoms and taking a health history. The gold standard test used for giant cell arteritis is a temporal artery biopsy. This procedure involves removing a part of the artery to be tested for inflammation.

Medical providers will also conduct ESR (erythrocyte sedimentation rate) and CRP (C-reactive protein) tests. These tests determine how much inflammation is in the body. In people with giant cell arteritis, levels are typically above 50 for ESR.

Blood tests will also be performed to check for anemia and elevated levels of liver enzymes. Both can be present in someone with giant cell arteritis. Some imaging tests may also be necessary to diagnose the condition and can include:

• Magnetic resonance imaging (MRI)
• Computed tomography (CT) or positron-emission tomography (PET) scans
• Ultrasounds

How Is Giant Cell Arteritis Treated?

The first-choice treatment option for giant cell arteritis is corticosteroid therapy. Corticosteroids are used to reduce inflammation in the blood vessels. Typically, people will begin on 40–60 milligrams (mg) of prednisone daily for a month and reduce their dose by 10% each month after starting treatment.

Drugs that suppress the immune system, such as Actemera (tocilizumab) and Rasuvo (methotrexate) may also help reduce the damage done by immune cells to the artery lining. However, research has shown that methotrexate may not be effective for giant cell arteritis, so tocilizumab is often the first choice.

Drugs that modulate the immune system, such as Orencia (abatacept), may also treat giant cell arteritis. Research shows it can help reduce the risk of symptoms returning in people with the disease.  

What Is the Prognosis for Giant Cell Arteritis?

People with giant cell arteritis have an excellent prognosis if diagnosed and treated early. Treatment often results in a reduction of symptoms within a few days. When managed, giant cell arteritis rarely affects a person’s life expectancy.

Summary

Giant cell arteritis is inflammation of large blood vessels in the head, neck, scalp, and arms. The artery most likely to be affected is the temporal artery. When people develop giant cell arteritis, they experience many symptoms, with a severe headache being the most pronounced and likely. Healthcare providers will conduct several tests to diagnose giant cell arteritis, including a biopsy and inflammatory marker blood test.

Once medical providers reach a definitive diagnosis, they will start treating with corticosteroids, followed by medications to hinder the overaction of the immune system. Treatment is highly effective for many with giant cell arteritis, and people can manage their disease so effectively that it rarely affects a person's life expectancy.