Giant Cell ArteritisEdit
Giant cell arteritis (GCA), also known as temporal arteritis, is a vasculitis that targets large and medium-sized arteries. It most commonly involves the branches of the external carotid artery, especially the temporal artery, but it can affect other cranial vessels and, with longer-standing disease, the aorta. The condition typically presents in adults over 50, with incidence rising with age and a female predominance. It is the most common systemic vasculitis in adults in many Western populations, and it carries a real risk of irreversible vision loss if not recognized and treated promptly. Because vision can be lost within hours to days, urgent assessment and initiation of therapy are standard practice when clinical suspicion is high. GCA frequently coexists with polymyalgia rheumatica (polymyalgia rheumatica), which can complicate both presentation and management.
Epidemiology and pathophysiology
GCA shows a strong age association, most often presenting after age 50 and peaking in the seventh decade. It is more common in people of white descent, particularly those of Northern European ancestry, and less common in many non-white populations. The disease is less about one organ and more about a dysregulated inflammatory response in the walls of large and medium-sized arteries. Histologically, it features granulomatous inflammation with multinucleated giant cells in the vessel wall, typically in the adventitia and media. Inflammation can disrupt the normal elastic architecture, leading to stenosis or occlusion of affected arteries. Imaging findings such as the halo sign on vascular ultrasound of the temporal artery or other affected vessels, and metabolic activity on PET scans, reflect the underlying inflammatory process. Long-standing disease can involve the aorta, giving rise to aneurysm formation and dissection risk later in the disease course.
Clinical presentation
Classic symptoms include new unilateral head pain (often temporal), scalp tenderness, and jaw claudication with chewing. Fever, fatigue, weight loss, and night sweats can accompany the illness. Vision-related symptoms may appear as transient visual obscurations, diplopia, or, in the worst cases, sudden permanent blindness due to occlusion of the ophthalmic artery or its branches. Because symptoms can be nonspecific, especially in older patients, clinicians rely on a combination of history, exam, laboratory tests, and imaging to distinguish GCA from other causes of headache and systemic illness. When PMR coexists, patients may report proximal stiffness and pain in the shoulder or hip girdles, which can lead to delayed recognition of the vasculitis if the cranial features are subtle.
Diagnosis
Diagnosis rests on a combination of clinical suspicion and objective findings. Key laboratory indicators include elevated inflammatory markers such as erythrocyte sedimentation rate (erythrocyte sedimentation rate) and C-reactive protein (C-reactive protein), along with anemia of chronic disease in some patients. Temporal artery biopsy remains a historical gold standard, showing granulomatous inflammation with multinucleated giant cells, although skip lesions can yield false negatives and prior glucocorticoid therapy may reduce diagnostic yield. Imaging has become increasingly important: ultrasound can reveal a halo sign around the temporal artery; MRI or CT angiography can delineate vessel wall inflammation and stenosis; and PET imaging can identify large-vessel involvement beyond the cranial arteries. The choice of diagnostic approach often depends on local expertise, availability, and the urgency of the clinical situation. For suspected GCA, treatment is typically initiated promptly to protect vision, even before biopsy results are available. See also temporal arteritis for common terminology and clinical correlation.
Treatment and prognosis
The immediate priority in suspected GCA is to prevent ischemic complications. High-dose glucocorticoids are the mainstay of therapy, with regimens commonly starting at around 40–60 mg of prednisone daily (or its equivalent) for cranial GCA, and using pulse therapy if vision is threatened. Once symptoms improve, clinicians begin a gradual taper over several months to a year, balancing relapse risk against steroid side effects. Patients require monitoring for adverse effects of long-term corticosteroid use, including osteoporosis, hyperglycemia, hypertension, and increased infection risk; preventive measures such as calcium and vitamin D supplementation and bone-protective strategies are often employed. In recent years, biologic therapies, notably the IL-6 receptor antagonist tocilizumab, have emerged as steroid-sparing options in selected patients, reducing steroid exposure while maintaining disease control. Several guidelines also discuss the role of traditional immunosuppressants like methotrexate or azathioprine in certain circumstances.
Low-dose aspirin has been considered in some patients to reduce ischemic complications, but the evidence is mixed and guidelines vary on its routine use. Decisions about aspirin must weigh potential benefits against bleeding risk, particularly in older patients. Ongoing management also includes assessment and treatment of concomitant PMR symptoms, attention to cardiovascular risk, and consideration of future vascular surveillance given the potential for long-term large-vessel involvement, including aortic aneurysm formation in some individuals.
Relapse is common in GCA, and treatment plans often need adjustment over time. The prognosis depends on promptness of treatment, extent of vessel involvement, and the patient’s comorbid conditions. Long-term surveillance for vascular complications and monitoring of inflammatory activity (via clinical review and laboratory tests) guide ongoing management.
Controversies and debates
- Diagnostic pathways: There is ongoing discussion over the optimal balance between imaging and biopsy. Some centers emphasize rapid imaging to confirm inflammation and guide therapy, while others rely on biopsy to secure a histological diagnosis before committing to prolonged immunosuppression. The reality is that treatment should not be delayed when there is a strong suspicion of GCA, given the risk to vision.
- Steroid-sparing strategies: The emergence of tocilizumab and other immunomodulators has shifted practice toward minimizing corticosteroid exposure. While this can reduce steroid-related harms, access to biologics is expensive, and the long-term safety profile and cost-effectiveness in broad patient populations remain topics of debate among clinicians and payers.
- Use of aspirin: Some clinicians advocate low-dose aspirin to mitigate ischemic risk, while others point to inconsistent evidence and bleeding risks, preferring individualized risk assessment rather than routine universal use.
- Healthcare economics: From a policy standpoint, there is a tension between delivering rapid, high-quality care for a disease where vision can be lost quickly and managing the costs of expensive diagnostics and biologics. Advocates for efficient, evidence-based care emphasize timely treatment and avoidance of unnecessary tests, while critics warn against under-testing in ambiguous cases. The practical goal is to maximize patient outcomes while avoiding wasteful over-treatment.
- Ethnic and geographic disparities: Incidence and presentation can vary by ethnicity and region, which raises questions about screening priorities and resource allocation. Policy discussions often center on ensuring access to appropriate diagnostic modalities and therapies for diverse populations, without letting ideology override clinically guided care.