Giant Cell Arteritis (GCA): A Practical Guide to a Serious but Treatable Condition

Written By R. Michelle Koolaee

Why is it important to be aware of Giant Cell Arteritis (GCA)?

Giant cell arteritis (GCA) is one of the few rheumatologic conditions where early recognition can prevent irreversible complications—especially irreversible blindness.

At the same time, treatment options have evolved significantly in recent years, allowing for better outcomes and less reliance on long-term steroids.

What exactly is Giant Cell Arteritis?

GCA is a type of vasculitis. These are diseases that cause inflammation of blood vessels and can sometimes be very serious.

There are different types of vasculitis depending on the size of the vessels involved:

  • Small vessel

  • Medium vessel

  • Large vessel

GCA affects large arteries, particularly:

  • The temporal arteries (on the sides of the head)

  • Larger vessels like the aorta and its branches

Why is GCA considered urgent?

Because inflammation in these arteries can reduce blood flow.

If untreated, this can lead to:

  • Permanent vision loss

  • Aortic complications

  • Rarely, life-threatening outcomes

The key principle:
👉 We treat first when suspicion is high—we don’t wait.

Who is at risk?

GCA almost exclusively affects:

  • Adults over age 50

  • Most commonly in their 60s–80s

If someone younger presents with similar symptoms, we typically look for other causes first.

What symptoms should I not ignore?

Classic symptoms

  • A new type of headache

    • Persistent

    • Different from prior headaches

    • Not responding to usual medications

  • Scalp tenderness

  • Jaw pain when chewing (a very specific and important clue)

  • Fatigue and low-grade fevers

Vision symptoms (urgent)

  • Blurred vision

  • Double vision

  • Sudden vision loss

👉 These require immediate medical attention

Can it present in less obvious ways?

Yes—and this is where diagnosis can be delayed.

Some patients have:

  • General fatigue

  • Weight loss

  • Low-grade fevers

  • Chest or abdominal discomfort

Others may have symptoms of polymyalgia rheumatica (PMR):

  • Shoulder and hip stiffness

  • Difficulty getting out of bed in the morning

How is GCA diagnosed?

When GCA is suspected based on clinical history and bloodwork showing inflammation (such as elevated ESR and/or CRP), the next step is confirmation while starting treatment promptly. A temporal artery biopsy is considered the gold standard, demonstrating inflammation within the vessel wall, although a negative result does not fully exclude the diagnosis.

What are other modalities used to diagnose GCA?

Depending on the situation, additional imaging may be used:

  • Ultrasound of the temporal arteries: looks for the “halo sign,” a dark, thickened ring around the artery representing inflammation of the vessel wall.

  • CT angiography (CTA) or MR angiography (MRA): can show vessel wall thickening, contrast enhancement, and areas of narrowing in larger arteries such as the aorta and its branches.

  • PET scan: detects increased metabolic activity along blood vessel walls, helping identify inflammation in large vessels beyond the temporal arteries.

  • MRI brain with vessel wall imaging: an emerging technique that can directly visualize inflammation and enhancement of the temporal arteries; ongoing work from centers like the University of Pennsylvania is helping define its role.

Modern practice increasingly incorporates imaging early in the evaluation, not just biopsy, to improve diagnostic accuracy and assess the full extent of disease.

What happens if my doctor suspects GCA?

Treatment starts immediately. Because of the serious risk of vision loss and organ damage if left untreated, we do not wait for the temporal artery biopsy to start treatment, if clinical suspicion is high. 

First step: high-dose corticosteroids

  • This reduces inflammation quickly

  • Most importantly, it helps protect vision

Diagnostic testing (biopsy or imaging) follows shortly after—but treatment is not delayed.

What are the current treatment options?

1. Corticosteroids are still the backbone of initial therapy.

However, long-term steroid use has real risks:

  • Weight gain

  • Bone loss

  • Diabetes

  • Infection risk

So we now aim to minimize steroid exposure when possible.

2. Targeted (steroid-sparing) therapies

Tocilizumab (Actemra)

  • Targets the IL-6 pathway

  • The first FDA-approved therapy specifically for GCA

3. Upadacitinib (Rinvoq)

  • A JAK inhibitor

  • FDA approved in 2025 for GCA

How long does treatment last?

  • Typically at least 1–2 years

  • Often longer depending on the individual

GCA has a high relapse rate, so treatment decisions are careful, gradual and personalized. 

What should I do if I’m concerned about GCA?

Do not wait or delay your care.

  • Seek care urgently

  • Ask for evaluation of inflammation markers

  • Request referral to a rheumatologist

What is the long-term outlook?

With early diagnosis, appropriate therapy, and close monitoring:

👉 Most patients do very well

The difference between good and poor outcomes is often timing and expertise.

If you’re experiencing symptoms that raise concern for GCA, this is not something to delay evaluating.

This condition requires:

  • Careful assessment

  • Prompt treatment

  • Ongoing monitoring

Having a physician who is familiar with current treatment strategies and evolving data can make a meaningful difference in both short- and long-term outcomes.

Additional References:

1. The GiACTA Trial (Landmark Treatment Trial)

Stone JH, Tuckwell K, Dimonaco S, et al. Trial of Tocilizumab in Giant-Cell Arteritis. N Engl J Med. 2017;377(4):317-328. doi:10.1056/NEJMoa1613849

This is the pivotal randomized controlled trial that led to FDA approval of tocilizumab (Actemra) for GCA in 2017. It demonstrated that 56% of patients on weekly tocilizumab achieved sustained remission at 52 weeks, compared to only 18% on prednisone alone, while significantly reducing cumulative steroid exposure. 

2. ACR/Vasculitis Foundation Management Guideline

Maz M, Chung SA, Abril A, et al. 2021 American College of Rheumatology/Vasculitis Foundation Guideline for the Management of Giant Cell Arteritis and Takayasu Arteritis. Arthritis Care Res. 2021;73(8):1071-1087. doi:10.1002/acr.24632

This is the current U.S. clinical practice guideline for GCA management, covering diagnosis (including temporal artery biopsy and imaging), glucocorticoid therapy, and the use of steroid-sparing agents like tocilizumab and methotrexate. 

3. ACR/EULAR Classification Criteria

Ponte C, Grayson PC, Robson JC, et al. 2022 American College of Rheumatology/EULAR Classification Criteria for Giant Cell Arteritis. Arthritis Rheumatol. 2022;74(12):1881-1889. doi:10.1002/art.42325

These are the most up-to-date classification criteria for GCA, incorporating modern imaging modalities (ultrasound, PET) alongside traditional features like temporal artery biopsy and ESR. The criteria use a points-based scoring system with 87% sensitivity and 95% specificity. 

4. NEJM Clinical Practice Review

Weyand CM, Goronzy JJ. Clinical Practice: Giant-Cell Arteritis and Polymyalgia Rheumatica. N Engl J Med. 2014;371(1):50-57. doi:10.1056/NEJMcp1214825

This is a widely cited comprehensive clinical review from the New England Journal of Medicine covering the pathophysiology, diagnosis, and treatment of GCA and polymyalgia rheumatica, including glucocorticoid dosing, tapering strategies, and monitoring recommendations.

R. Michelle Koolaee
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