Giant Cell Arteritis: Symptoms, Diagnosis & Treatment Guide

What Is Giant Cell Arteritis?

Giant cell arteritis (GCA) is an inflammatory disease of the blood vessels, specifically affecting medium and large arteries. It primarily involves the temporal arteries at the temples but can affect other arteries including the aorta. The inflammation narrows blood vessels, reducing blood flow to critical structures including the eyes, which can cause permanent blindness if untreated.

Giant cell arteritis gets its name from the characteristic "giant cells" seen when examining affected artery tissue under a microscope. These are large, abnormal cells formed by the fusion of immune cells during the inflammatory process. The condition is also called temporal arteritis because the temporal arteries running along the temples are most commonly affected, though this name can be misleading since GCA can involve arteries throughout the body.

The disease occurs almost exclusively in people over 50 years of age, with peak incidence between ages 70 and 80. Women are affected two to three times more often than men. Geographic and ethnic variations exist, with the highest rates occurring in people of Northern European descent, particularly those from Scandinavian countries. The condition is relatively rare in Asian and African populations.

GCA belongs to a group of conditions called vasculitis, which means inflammation of blood vessels. It specifically falls into the category of large vessel vasculitis. The underlying cause remains incompletely understood, but the disease appears to involve an abnormal immune response where the body's defense system mistakenly attacks its own blood vessel walls.

The Relationship Between GCA and Polymyalgia Rheumatica

Giant cell arteritis has a close relationship with another inflammatory condition called polymyalgia rheumatica (PMR). These two conditions frequently occur together and may represent different manifestations of the same underlying disease process. Approximately 40-60% of patients with GCA also have symptoms of PMR, while about 10-15% of patients initially diagnosed with PMR will eventually develop GCA.

Polymyalgia rheumatica causes stiffness and aching in the muscles of the shoulders, upper arms, hips, and thighs. The symptoms are typically worse in the morning and improve with activity throughout the day. Both conditions respond well to corticosteroid treatment, though GCA requires higher doses initially due to the risk of vision loss.

Why Early Treatment Is Critical

The most serious complication of giant cell arteritis is irreversible vision loss, which occurs when inflammation blocks blood supply to the optic nerve (anterior ischemic optic neuropathy). This devastating complication affects 15-20% of untreated patients and can occur suddenly, sometimes without warning. Once vision loss occurs from GCA, it is almost always permanent.

The good news is that vision loss is largely preventable with prompt treatment. Studies show that starting corticosteroid therapy before visual symptoms develop almost completely eliminates the risk of blindness. This is why GCA is considered a medical emergency requiring immediate treatment, often before diagnostic tests are complete.

What Are the Symptoms of Giant Cell Arteritis?

The most common symptoms of giant cell arteritis include severe new-onset headache (especially in the temples), scalp tenderness, jaw pain when chewing (jaw claudication), vision problems, and general symptoms like fever, fatigue, and weight loss. Symptoms typically develop over weeks but can appear suddenly. Vision changes require immediate medical attention.

Giant cell arteritis produces a distinctive pattern of symptoms that, when recognized, should prompt immediate medical evaluation. The symptoms result from inflammation narrowing blood vessels and reducing blood flow to various structures. Understanding these warning signs can be life-saving because early recognition and treatment prevent permanent vision loss.

The symptoms of GCA can be grouped into three main categories: symptoms related to inflammation of the temporal and other cranial arteries, symptoms related to systemic inflammation throughout the body, and symptoms related to polymyalgia rheumatica when both conditions are present together. Many patients experience symptoms from multiple categories simultaneously.

Headache and Temporal Artery Symptoms

The most characteristic symptom is a new type of severe headache, typically located in the temple region on one or both sides. Patients often describe this as different from any headache they have experienced before. The headache may be constant or throbbing and can be severe enough to interfere with sleep. The temporal area may be visibly swollen, and the temporal artery may appear prominent or cord-like.

Scalp tenderness is another hallmark symptom, with many patients reporting pain when brushing their hair or laying their head on a pillow. The tenderness usually occurs over the temporal arteries but can affect broader areas of the scalp. Some patients notice that their temporal arteries feel harder than normal or that the pulse in these arteries is reduced or absent.

Jaw Claudication - A Key Diagnostic Feature

Jaw claudication refers to pain, fatigue, or cramping in the jaw muscles that occurs during chewing and resolves with rest. This symptom is highly specific for giant cell arteritis, meaning that when present, it strongly suggests the diagnosis. The discomfort typically begins after chewing for a minute or so and worsens with continued eating, forcing patients to take breaks during meals.

The mechanism behind jaw claudication is the same as claudication in the legs from peripheral artery disease - the muscles don't receive enough blood flow to meet their increased demands during activity. In GCA, inflammation narrows the arteries supplying the chewing muscles, causing this distinctive symptom.

Vision Symptoms - A Medical Emergency

Visual symptoms in giant cell arteritis require immediate medical attention because they can precede permanent vision loss. Patients may experience blurred vision, double vision (diplopia), or transient episodes of vision loss affecting part or all of the visual field (amaurosis fugax). These warning symptoms sometimes occur hours to days before complete vision loss, providing a critical window for intervention.

Complete or partial loss of vision can occur suddenly in one or both eyes. The vision loss is typically painless and may be described as a curtain or shadow coming down over the vision. When one eye is affected, the other eye remains at high risk without treatment - about 50% of untreated patients will lose vision in the second eye within weeks.

Systemic Symptoms

Many patients with giant cell arteritis experience general symptoms of inflammation that may be mistaken for other conditions. These systemic symptoms include fever (usually low-grade), fatigue, loss of appetite, unintentional weight loss, night sweats, and a general feeling of being unwell (malaise). Some patients experience significant weight loss of 10 pounds or more before diagnosis.

These nonspecific symptoms can make diagnosis challenging, especially when more characteristic symptoms like headache or jaw claudication are absent. Some patients present primarily with fever of unknown origin, and GCA should be considered in the evaluation of unexplained fever in older adults.

When Should You See a Doctor for Giant Cell Arteritis?

Seek immediate medical care if you are over 50 and experience sudden vision changes, new severe headache with scalp tenderness, or jaw pain when chewing. These symptoms suggest giant cell arteritis, which is a medical emergency. Treatment should begin before diagnostic tests are complete if vision is threatened. Do not delay seeking care - permanent blindness can occur within hours.

Giant cell arteritis is unique among medical conditions in that treatment is often started before the diagnosis is confirmed. This urgency exists because the consequences of delayed treatment - permanent blindness - are so devastating and largely preventable with prompt corticosteroid therapy. Understanding when to seek care can literally save your sight.

The decision about how urgently to seek medical attention depends on which symptoms are present. Visual symptoms always constitute an emergency requiring immediate care. Other symptoms warrant urgent evaluation but allow slightly more time. In all cases, if you suspect GCA based on your symptoms, err on the side of seeking care sooner rather than later.

Emergency Situations

Some symptoms of giant cell arteritis require emergency medical attention, typically at an emergency department where treatment can begin immediately. These emergency situations include any sudden change in vision (blurred vision, double vision, partial or complete vision loss), symptoms suggesting a stroke (sudden weakness, speech difficulty, confusion), and severe, unrelenting headache with signs of systemic illness.

If you experience any visual symptoms and are over 50 years old with risk factors for GCA (female sex, Northern European ancestry, history of PMR), call emergency services or go directly to an emergency department. Time is critical - vision loss can become permanent within hours if the blood supply to the optic nerve is interrupted.

Urgent Situations

Other symptoms warrant urgent medical evaluation within 24-48 hours but may not require emergency room care. These include new persistent headache in the temple area, scalp tenderness, jaw claudication without vision symptoms, unexplained fever or weight loss in someone over 50, and symptoms of polymyalgia rheumatica (shoulder and hip stiffness) in combination with headache.

Contact your primary care physician or rheumatologist immediately if you experience these symptoms. Many healthcare systems have rapid access pathways for suspected GCA that allow same-day or next-day evaluation. If your regular physician cannot see you quickly, urgent care or emergency department evaluation is appropriate.

What Causes Giant Cell Arteritis?

The exact cause of giant cell arteritis is not fully understood, but it involves an abnormal immune response where the body attacks its own blood vessel walls. Genetic factors, aging, and possibly viral infections contribute to susceptibility. The immune system creates chronic inflammation in the arterial walls, leading to thickening that narrows or blocks blood flow.

Giant cell arteritis develops when the immune system, which normally protects the body from infections and foreign substances, mistakenly attacks the walls of blood vessels. This autoimmune process leads to inflammation that thickens the vessel walls, progressively narrowing the channel through which blood flows. In severe cases, the vessel can become completely blocked, cutting off blood supply to downstream tissues.

The triggering event that initiates this abnormal immune response remains unknown. Researchers have proposed several theories, including viral infections, environmental factors, and breakdown of the normal barriers between blood and vessel wall tissue that occurs with aging. It's likely that multiple factors combine in genetically susceptible individuals to cause the disease.

Genetic Factors

Genetic susceptibility plays a significant role in giant cell arteritis. Studies of twins and families show that first-degree relatives of GCA patients have increased risk of developing the condition. The strongest genetic associations involve genes in the HLA (human leukocyte antigen) system, particularly HLA-DRB1*04, which is involved in immune system regulation.

The geographic and ethnic distribution of GCA also points to genetic influences. The condition is most common in populations of Northern European descent, particularly Scandinavian countries, and is rare in Asian and African populations. These patterns persist even when people migrate to different regions, suggesting genetic rather than environmental explanations.

The Role of Aging

Aging appears to be essential for GCA development - the condition virtually never occurs before age 50, and risk increases with advancing age. Several age-related changes may contribute: the immune system becomes more prone to autoimmune reactions (immunosenescence), blood vessels become stiffer and more prone to damage, and accumulated lifetime exposures may eventually trigger disease in susceptible individuals.

The structure of blood vessel walls changes with age in ways that may make them vulnerable to immune attack. The elastic fibers in arterial walls degrade over time, exposing proteins that are normally hidden from the immune system. These exposed proteins may trigger the immune response that leads to GCA in genetically predisposed individuals.

Environmental Triggers

Several environmental factors have been investigated as potential triggers for giant cell arteritis, though none have been definitively proven. Viral infections, particularly varicella zoster virus (which causes chickenpox and shingles), have been found in some GCA tissue samples, but other studies have not confirmed this association. The observation that GCA may occur in seasonal clusters suggests infectious triggers, but the specific agents remain unidentified.

How Is Giant Cell Arteritis Diagnosed?

Giant cell arteritis is diagnosed using a combination of symptoms, blood tests showing elevated inflammation markers (ESR and CRP), imaging studies (ultrasound or PET-CT), and temporal artery biopsy. Blood tests typically show ESR above 50 mm/hour and elevated CRP. The gold standard is temporal artery biopsy showing characteristic giant cells, but treatment often starts before biopsy results are available.

Diagnosing giant cell arteritis requires integrating clinical symptoms, laboratory tests, and often imaging or tissue biopsy. Because treatment should not be delayed when GCA is suspected, diagnosis is typically a two-step process: an initial assessment that leads to starting treatment, followed by confirmatory testing. The goal is to have high confidence in the diagnosis while not delaying potentially sight-saving treatment.

No single test can definitively diagnose or exclude GCA. Instead, physicians use the overall clinical picture - the combination of symptoms, patient age, and test results - to estimate the probability of disease and guide treatment decisions. In cases of uncertainty, the potential consequences of missing the diagnosis (blindness) typically favor treatment while awaiting further information.

Blood Tests for Inflammation

Laboratory tests for inflammatory markers are essential in evaluating suspected GCA. The two most important tests are erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). In GCA, ESR is typically markedly elevated, often above 50 mm/hour and sometimes exceeding 100 mm/hour. CRP is also usually elevated, often significantly above normal levels.

While elevated inflammatory markers support the diagnosis of GCA, normal values do not exclude it. Approximately 5-10% of patients with biopsy-proven GCA have normal or only slightly elevated ESR. This is why clinical judgment remains paramount - if symptoms strongly suggest GCA, treatment should proceed even if blood tests are normal.

Other blood tests may show mild anemia (normocytic, normochromic anemia of chronic disease), elevated platelet count (thrombocytosis), and abnormal liver function tests, particularly elevated alkaline phosphatase. These findings are nonspecific but add to the overall clinical picture suggesting systemic inflammation.

Imaging Studies

Imaging has become increasingly important in diagnosing GCA, particularly ultrasound of the temporal arteries. Doppler ultrasound can reveal the "halo sign" - a dark area around the artery representing swelling of the vessel wall. When performed by experienced operators, temporal artery ultrasound has good sensitivity and specificity for GCA and can provide rapid, non-invasive diagnostic information.

For patients with suspected large vessel involvement (affecting the aorta or its branches), PET-CT scanning can detect increased metabolic activity in inflamed vessel walls. MRI angiography is another option for visualizing inflammation in larger arteries. These advanced imaging techniques are particularly valuable when temporal artery disease is absent or when monitoring response to treatment.

Temporal Artery Biopsy

Temporal artery biopsy remains the gold standard for confirming GCA diagnosis. The procedure involves removing a small segment (typically 1-2 cm) of the temporal artery under local anesthesia. The tissue is examined microscopically for characteristic findings: inflammation of the vessel wall, destruction of the elastic layer, and the presence of giant cells (large multinucleated cells that give the disease its name).

A positive biopsy definitively confirms GCA, but a negative biopsy does not rule it out. GCA can affect arteries in a patchy distribution (skip lesions), meaning inflammation may not be present in the specific segment that was sampled. For this reason, many experts recommend bilateral biopsies or repeat biopsy if the initial result is negative but clinical suspicion remains high.

How Is Giant Cell Arteritis Treated?

Giant cell arteritis is treated with high-dose corticosteroids (typically prednisone 40-60 mg daily) started immediately upon diagnosis. If vision is threatened, intravenous methylprednisolone may be given first. The steroid dose is gradually reduced over 1-2 years based on symptoms and blood tests. Tocilizumab (an IL-6 inhibitor) is often added to reduce steroid requirements and prevent relapse.

Treatment for giant cell arteritis has three main goals: prevent vision loss and other serious complications, control symptoms, and minimize treatment-related side effects. Corticosteroids remain the cornerstone of therapy and are remarkably effective - most patients experience dramatic symptom improvement within 24-72 hours of starting treatment. However, the need for long-term steroid therapy and its associated side effects has driven development of steroid-sparing strategies.

Treatment typically continues for one to two years or longer, depending on individual response. Disease relapses are common when steroids are reduced too quickly, requiring careful monitoring and gradual dose reduction. Regular follow-up with blood tests and symptom assessment guides treatment adjustments throughout the course of therapy.

Initial High-Dose Corticosteroid Therapy

Treatment begins with high-dose prednisone (or equivalent corticosteroid), typically 40-60 mg daily for most patients. This dose is effective at rapidly suppressing the inflammation that threatens vision and causes symptoms. Higher doses or intravenous administration may be used when visual symptoms are present or imminent, as these situations require the most aggressive treatment approach.

If vision is already affected or seems threatened, many physicians start with three days of intravenous methylprednisolone (1000 mg daily) before transitioning to oral prednisone. While there is limited evidence that this approach improves visual outcomes compared to high-dose oral steroids alone, it may provide more rapid suppression of inflammation in critical situations.

The response to corticosteroids is typically dramatic and swift. Headache, scalp tenderness, and systemic symptoms like fever and fatigue usually improve within one to three days. Blood inflammatory markers (ESR and CRP) begin to fall within the first week. Failure to respond to high-dose steroids should prompt reconsideration of the diagnosis.

Steroid Tapering

After initial symptom control, corticosteroid doses are gradually reduced over many months to minimize long-term side effects while maintaining disease control. Various tapering schedules exist, but most involve reducing the dose by 10% every one to two weeks initially, with slower reductions as doses decrease. The goal is to reach the lowest dose that maintains remission.

Relapses are common during steroid tapering, occurring in 40-60% of patients. Signs of relapse include return of symptoms (headache, scalp tenderness, jaw claudication) or rise in inflammatory markers. When relapse occurs, the steroid dose is increased to regain control, then tapering resumes at a slower pace. Some patients require low-dose steroids for extended periods.

Tocilizumab: A Steroid-Sparing Option

Tocilizumab is an injectable medication that blocks interleukin-6 (IL-6), a key inflammatory molecule in GCA. Clinical trials have shown that adding tocilizumab to corticosteroid therapy significantly increases the chance of achieving remission while reducing the total steroid dose required. This translates to fewer steroid-related side effects.

Tocilizumab is administered by subcutaneous injection, typically once weekly or every two weeks. It is generally well-tolerated but can increase infection risk and may mask inflammatory markers like CRP, requiring adjusted monitoring strategies. Current guidelines recommend considering tocilizumab for most GCA patients, particularly those at high risk for steroid side effects.

Managing Long-Term Treatment Side Effects

Long-term corticosteroid therapy carries significant risks that require proactive management. Key concerns include osteoporosis, diabetes, hypertension, cataracts, weight gain, mood changes, and increased infection risk. Preventive measures typically include calcium and vitamin D supplementation, bone density monitoring, blood sugar monitoring, and sometimes medications to prevent bone loss.

Regular follow-up appointments allow monitoring for both disease activity and treatment side effects. Blood tests typically include inflammatory markers, blood counts, blood sugar, and occasionally other tests depending on symptoms. Many patients benefit from seeing multiple specialists (rheumatologist, ophthalmologist, primary care) as part of a coordinated care team.

What Are the Complications of Giant Cell Arteritis?

The most serious complication is permanent vision loss, occurring in 15-20% of untreated patients. Other complications include stroke, aortic aneurysm and dissection, jaw necrosis (rare), and scalp necrosis (rare). Long-term corticosteroid treatment also causes complications including osteoporosis, diabetes, and infections. Regular monitoring can detect and manage most complications.

Giant cell arteritis can cause serious complications affecting the eyes, blood vessels, and other organs. The most feared complication is permanent blindness, which can be largely prevented with prompt treatment. Other vascular complications may develop during or after the acute phase of illness. Additionally, the medications used to treat GCA - particularly long-term corticosteroids - carry their own set of potential complications.

Vision Loss

Permanent vision loss is the most devastating complication of giant cell arteritis and the primary reason the condition is considered a medical emergency. Vision loss occurs when inflammation blocks blood flow to the optic nerve, causing a condition called anterior ischemic optic neuropathy. The optic nerve tissue, deprived of oxygen, dies rapidly and cannot regenerate.

Vision loss from GCA is typically sudden, painless, and permanent. It may affect all or part of the visual field in one or both eyes. Without treatment, vision loss occurs in 15-20% of patients; with prompt corticosteroid treatment, this risk drops to less than 1%. Once vision loss has occurred, it rarely improves even with treatment, emphasizing the importance of prevention through early therapy.

Aortic Complications

Giant cell arteritis can affect the aorta (the body's largest artery), leading to aortic aneurysm (abnormal widening) or aortic dissection (tearing of the aortic wall). These complications may develop during active disease or years after the initial diagnosis, even in patients who are otherwise in remission. Regular monitoring with imaging studies is often recommended, particularly in the years following diagnosis.

Treatment-Related Complications

Long-term corticosteroid use causes a range of side effects that require monitoring and management. Osteoporosis and fractures are major concerns, as steroids accelerate bone loss. Steroid-induced diabetes or worsening of existing diabetes requires blood sugar monitoring. Cardiovascular effects include hypertension and unfavorable changes in cholesterol levels. Weight gain, muscle weakness, and skin fragility are common. Mood changes, including depression and anxiety, may occur.

How Can You Live Well with Giant Cell Arteritis?

Living well with GCA involves taking medications as prescribed, attending regular follow-up appointments, recognizing signs of relapse or complications, maintaining bone health through exercise and supplements, managing steroid side effects proactively, and staying informed about your condition. Most patients achieve good disease control and maintain their quality of life with proper management.

A diagnosis of giant cell arteritis requires significant lifestyle adjustments, particularly during the first year of treatment when medication doses are highest. However, most patients successfully manage their condition and maintain good quality of life with appropriate medical care and self-management strategies. Understanding what to expect and how to optimize your health during treatment helps many patients navigate this challenging period.

Medication Adherence and Monitoring

Taking medications exactly as prescribed is crucial for both disease control and minimizing side effects. Corticosteroids should not be stopped suddenly, as this can cause dangerous withdrawal effects and disease flare. Set reminders for medication times and refill prescriptions before running out. If you experience side effects that make you want to stop treatment, discuss alternatives with your physician rather than discontinuing independently.

Recognizing Relapse and Complications

Learning to recognize signs of disease relapse or complications allows early intervention. Warning signs of relapse include return of headache, scalp tenderness, jaw claudication, or visual symptoms. New symptoms like chest pain, shortness of breath, or back pain may indicate aortic involvement. Contact your healthcare team promptly if any concerning symptoms develop.

Bone Health and Exercise

Protecting bone health is essential during long-term corticosteroid therapy. Weight-bearing exercise (walking, jogging, dancing) and resistance training help maintain bone density. Take calcium and vitamin D supplements as recommended. Avoid smoking and excessive alcohol, both of which accelerate bone loss. Regular bone density scans help monitor for osteoporosis.