Spectrum of giant cell vasculitis.

Giant cell arteritis (GCA) is the commonest primary systemic vasculitis in the United States. Severe outcomes include blindness and stroke, and death may result from aortic dissection. Temporal artery biopsy remains the gold standard for diagnosis. Magnetic resonance imaging (MRI) of involved vessels shows promise as a useful noninvasive method for diagnosis and assessment of disease activity. Corticosteroid therapy is effective but is associated with considerable morbidity. Longitudinal studies with large numbers of patients are required to identify appropriate steroid-sparing agents. New insights into the immunopathogenesis of GCA have allowed us to identify heterogeneous subsets of patients with varying clinical presentations corresponding to specific cytokine profiles. The concept of the involved artery as an active participant in the events leading to luminal obstruction has been realized and provides the opportunity to evaluate novel therapies to modify the course of the disease.