Giant cell arteritis.

Giant cell arteritis (GCA) is an immune-mediated vasculitis affecting individuals over 50 years of age. It is characterised by granulomatous inflammation that affects medium-sized and large arteries. The wide spectrum of clinical manifestations can be divided into those related to tissue ischemia from vascular lesions and those related to a systemic inflammatory response. The pathogenesis of these groups also appears distinct, with vascular lesion formation thought to be an adaptive immune response, and the systemic inflammatory reaction an innate immune response. Clinical suspicion of GCA must remain especially high in those with neurological or visual symptoms and if warranted, prompt treatment with high-dose corticosteroids is invaluable in halting disease progression.