Giant cell arteritis and Takayasu arteritis are large-vessel vasculitides that share multiple common features but also have significant differences in epidemiology, demographics, clinical presentation, evaluation, and treatment. Giant cell arteritis is more common in elderly patients of Caucasian descent versus Takayasu arteritis, which is more prevalent in younger patients of Asian descent. Although traditionally age has been the main criterion for differentiating the 2 etiologies, modifications in the diagnostic criteria have recognized the overlap between the 2 conditions. In this monograph, we review the diagnostic criteria for both conditions and describe the epidemiology, pathogenesis, histology, evaluation, and management for large-vessel vasculitis in ophthalmology. Additionally, we describe ocular imaging techniques that may be utilized by ophthalmologists to identify manifestations of large-vessel vasculiti- des in patients. Lastly, we compare and contrast the key clinical, laboratory, and pathologic features that might help ophthalmologists to differentiate the 2 entities.

Giant cell arteritis (GCA) is the most common vasculitis in adults, and patients with GCA often present with vision loss that may progress to permanent blindness. For this reason, empirical treatment with corticosteroids is initiated when there is reasonable suspicion of GCA. Corticosteroids have remained the mainstay of treatment for GCA for the past 70 years due to their profound immunosuppressive effects. However, not all patients tolerate or respond adequately to corticosteroids, and prolonged dosages increase the risk for adverse side effects. There have also been recent advances and investigations into alternative immunosuppressive therapies for GCA; specifically, interleukin 6 inhibitors and other alternatives have been approved by the American College of Rheumatology and European League Against Rheumatism for adjunctive use with corticosteroids or for refractory GCA. However, it is unclear whether current immunosuppressive alternatives can conclusively replace corticosteroids in the treatment of GCA and prevention of vision loss. This article reviews the robust immunosuppressive mechanisms of corticosteroids and summarizes clinical investigations of alternative therapies for GCA.