Giant Cell Arteritis is the most common form of vasculitis in older adults. Vasculitis is a general term for a group of diseases that are characterized by the inflammation of blood vessels. In GCA, the body’s immune system launches an attack on the walls of its own arteries. While it can affect the aorta and its other large branches, it has a strong predilection for the arteries in the head and neck, particularly the temporal arteries, which run along the temples on either side of the forehead.

A helpful analogy is to think of your arteries as a system of large, flexible hoses that deliver oxygen-rich blood to your vital organs.

• In GCA, the body’s immune system mistakenly attacks the walls of these hoses themselves.
• This inflammation causes the hose wall to become very thick, swollen, and inflamed, which severely narrows the inside opening.
• This “clogged hose” drastically reduces blood flow to the critical organs it supplies. When this happens in the temporal artery, it causes a severe headache. When it happens in the arteries supplying the jaw muscles, it causes pain with chewing. Most critically, when it affects the ophthalmic artery supplying the eye, it can starve the optic nerve of oxygen, leading to blindness.

The condition gets its name “Giant Cell Arteritis” from its appearance under a microscope. When a piece of an inflamed artery is biopsied, a pathologist will see that the vessel wall is filled with inflammatory cells, including abnormally large cells called “giant cells.”

In my experience, patients often describe a new, persistent headache, sometimes with scalp tenderness or vision changes which raises an immediate red flag for temporal arteritis.

The exact cause of GCA is unknown. It is considered an autoimmune/inflammatory condition. The current leading theory is that in a genetically susceptible older individual, an environmental trigger, most likely a viral or bacterial infection, sets off a dysregulated and overactive immune response. This immune response, for reasons not yet understood, then begins to target specific proteins within the walls of the arteries, leading to the damaging inflammation that defines the disease.

Clinically, it’s believed to result from an autoimmune process that causes the immune system to attack arterial walls, leading to inflammation and narrowing.

GCA is not contagious and cannot be passed from person to person. It is a condition that develops based on a combination of risk factors, most of which are outside of an individual’s control.

The primary risk factors for developing GCA are:

• Age: GCA is a disease of aging. It almost never occurs in people under the age of 50, and the risk increases with each subsequent decade. The average age of onset is around 75.
• Gender: It is two to three times more common in women than men.
• Ancestry: It is most common in individuals of Northern European, particularly Scandinavian, descent. However, it can and does affect people of all races and ethnic backgrounds.
• Having Polymyalgia Rheumatica (PMR): There is an extremely strong link between GCA and another inflammatory condition called Polymyalgia Rheumatica. Up to 50% of people with GCA also have the symptoms of PMR (widespread stiffness and pain in the shoulders and hips).

In my experience, although the exact cause remains unclear, I often associate it with aging and have seen a strong link to polymyalgia rheumatica in many patients.

The symptoms of GCA can be divided into specific “red flag” head and neck symptoms, and more general, systemic symptoms.

The “Red Flag” Symptoms of GCA

These are the most specific and urgent signs of the disease. Any person over the age of 50 who develops these symptoms should seek immediate medical care.

• A New, Persistent Headache: This is the most common symptom. It is often a severe, throbbing headache that is different from any headache the person has had before. It is usually located in temples.
• Scalp Tenderness: The scalp can become so tender that it hurts to brush your hair, wear glasses, or even rest your head on a pillow. The temporal artery itself may feel thickened or cord-like to the touch.
• Jaw Claudication: This is a hallmark and highly specific symptom. It is a deep, aching pain and fatigue in the jaw muscles that occurs specifically while chewing food, particularly tough foods like meat. The pain gets better once the person stops chewing.
• Visual Disturbances: This is a true medical emergency. Any new visual problem can be a sign that the blood supply to the optic nerve is compromised. This can include:
  • Sudden, painless loss of vision in one eye (amaurosis fugax).
  • Blurred vision.
  • Double vision (diplopia).
  • If not treated immediately, this vision loss can become permanent and irreversible.

Systemic and Other Symptoms

Many people with GCA also feel generally unwell.

• Symptoms of Polymyalgia Rheumatica (PMR): Widespread, symmetrical aching and severe morning stiffness in the neck, shoulders, and hips.
• Constitutional Symptoms: Unexplained low-grade fever, drenching night sweats, profound fatigue, and unintentional weight loss.
• Less commonly, GCA can affect the aorta, leading to an aneurysm.

Clinically, I watch for systemic signs like fever, fatigue, weight loss, and elevated inflammatory markers. Vision loss is the most feared complication and can occur rapidly.

A diagnosis of GCA is considered a medical emergency due to the risk of blindness. A doctor, usually a rheumatologist, will make a presumptive diagnosis based on a combination of the patient’s age, their characteristic symptoms, and initial blood tests.

The “Treat First, Biopsy Later” Principle

If a doctor has a high clinical suspicion for GCA, especially if the patient is experiencing any visual symptoms, they will start treatment with high-dose steroids immediately. They will not wait for final biopsy results. This is because the treatment can save a person’s sight, and waiting a few days for a biopsy could lead to irreversible vision loss.

The diagnostic process includes:

• Clinical Evaluation: The doctor will listen for the classic story of a new headache, jaw claudication, and scalp tenderness in a person over 50.
• Blood Tests for Inflammation: A blood test will be drawn to check the levels of inflammatory markers. In GCA, the Erythrocyte Sedimentation Rate (ESR) and the C-Reactive Protein (CRP) will be very highly elevated.
• Temporal Artery Biopsy: This is the gold standard for confirming the diagnosis. It is a minor surgical procedure, usually performed by a general or vascular surgeon under local anesthesia.
  • The surgeon makes a small incision at the temple and removes a small piece (about 1-2 cm) of the temporal artery.
  • The tissue is then sent to a pathologist, who examines it under a microscope. The presence of inflammation and the characteristic “giant cells” in the artery wall confirms the diagnosis of GCA.
• Imaging: In some centers, a Doppler ultrasound of the temporal arteries may be performed, which can show a characteristic “halo sign” of inflammation around the vessel. Advanced imaging like a CT or PET scan may be used to look for inflammation in the aorta.

In my experience, prompt diagnosis is critical. Even if biopsy is pending, I start treatment based on clinical suspicion to prevent irreversible complications like blindness.

The goals of treatment are to immediately suppress the inflammation to prevent organ damage (especially blindness), to relieve the painful symptoms, and to manage the long-term course of the disease.

1. High-Dose Corticosteroids

This is the emergency, sight-saving, and cornerstone of treatment. As soon as GCA is suspected, the patient is started on a high dose of an oral corticosteroid, usually prednisone (typically 40-60 mg per day). The response is often rapid and dramatic, with the headache and other symptoms improving within one to three days.

2. The Long, Slow Taper

Once the symptoms and inflammatory markers have been brought under control, the doctor will begin a very slow and gradual reduction (taper) of the prednisone dose. This process is highly individualized and must be done very carefully to prevent the disease from flaring up again. The total duration of steroid treatment is often one to two years, and sometimes longer.

3. Steroid-Sparing Agents

Because long-term treatment with high-dose steroids carries a risk of significant side effects (such as weight gain, diabetes, osteoporosis, and cataracts), a second medication is now often used to help control the disease and allow the steroid dose to be tapered more quickly and safely.

• Tocilizumab (Actemra®): This is a newer biologic medication that has been shown to be highly effective in treating GCA. It works by blocking a key inflammatory protein called IL-6. It is given as a regular injection and is now often considered a first-line agent to be used in combination with steroids.
• Methotrexate: This is an older immunosuppressive medication that can also be used as a steroid-sparing agent.

4. Low-Dose Aspirin

Patients with GCA are often advised to take a low-dose aspirin each day to help reduce the risk of vision loss or stroke caused by blood clots forming in the inflamed arteries.

Clinically, I sometimes use tocilizumab in steroid-resistant cases or to help reduce long-term steroid exposure especially in patients at high risk for side effects.

Giant Cell Arteritis, or temporal arteritis, is a serious inflammatory disease of the arteries affecting older adults. It is a true medical emergency, where the clock is ticking against the threat of sudden and permanent blindness. The key to preventing this devastating outcome is patient and physician awareness of the classic “red flag” symptoms: a new headache in a person over 50, tenderness of the scalp, and pain in the jaw when chewing. Anyone experiencing these symptoms, especially if accompanied by any visual changes, must seek immediate medical care. While the diagnosis is frightening, GCA is a very treatable condition. In my experience, early recognition and immediate treatment of temporal arteritis can prevent permanent vision loss, which is often the presenting concern.

American College of Rheumatology. (2023). Giant Cell Arteritis. Retrieved from https://rheumatology.org/patients/giant-cell-arteritis

The Mayo Clinic. (2023). Giant cell arteritis. Retrieved from https://www.mayoclinic.org/diseases-conditions/giant-cell-arteritis/symptoms-causes/syc-20372758

The Vasculitis Foundation. (n.d.). Giant Cell Arteritis. Retrieved from https://www.vasculitisfoundation.org/education/forms/giant-cell-arteritis/