Giant cell arteritis: a systemic vascular disease.

Giant cell arteritis (GCA) is increasingly being recognized as a systemic vascular disease, not confined to the cranial arteries. Epidemiological studies have shown that almost one-third of the patients with GCA develop serious peripheral vascular complications during long-term follow up, and there is growing evidence that unrecognized extracranial involvement may be even more common. GCA of large- and medium-sized peripheral arteries typically leads to long tapering and occlusion of the arterial lumen due to concentric intimal thickening, sometimes accompanied by spontaneous dissection. Depending on the extent of the arterial obliteration and on the anatomy of the involved arterial segment, this may result in severe ischemia of the limbs during the acute phase of the disease. GCA of the aorta usually remains asymptomatic for many years, and leads to a markedly increased risk of aneurysms and dissections, particularly of the thoracic aorta. Evolving vascular imaging techniques such as duplex ultrasound, computer tomography (CT), magnetic resonance imaging (MRI), and fluorine-18-desoxyglucose positron emission tomography (18F-FDG-PET) have greatly improved our ability to detect and study arterial changes in large-artery vasculitis. Boosted by these advances in vascular imaging, vascular specialists are increasingly involved in the early diagnosis, follow-up and treatment of patients with large-vessel vasculitis.