Giant cell arteritis.

Giant cell, or temporal, arteritis is a vasculitis of the medium and large arteries that preferentially involves vessels originating from the arch of the aorta. Classically, this disease manifests in an older individual with new-onset persistent headache, an abnormal temporal artery on examination, and increased serum inflammatory markers. The level of clinical suspicion for giant cell arteritis should be based upon patient age, clinical symptoms, and laboratory evaluation. However, the diagnostic gold standard is achieved by histologic confirmation by temporal artery biopsy. Prompt treatment with corticosteroids is essential in order to minimize the frequency of permanent sequelae such as visual loss and stroke.