[Giant cell arteritis].

Giant cell arteritis is a medium- and large-vessel vasculitis, the most prevalent systemic vasculitis in subjects over age 60. Clinical features are miscellaneous and sometimes misleading. Elevated acute-phase responses, such as a high erythrocyte sedimentation rate and increased levels of C-reactive protein, are important clues to the diagnosis, which is ensured by a positive temporal artery biopsy. Non invasive imaging techniques such as colour duplex ultrasonography, high resolution tomodensitometry, magnetic resonance imaging, and positron emission tomography (or 18-fluorodeoxyglucose scintigram) assist meaningfully the diagnosis in patients with aortitis and/or aortic arch syndrome. The frequent and fearsome visual complications (monocular or even binocular blindness) highlight the urgency of treatment, based mainly on prolonged corticosteroid treatment, with its frequent, at times severe, side effects. These patients can often become free of treatment, in 2 to 3 years in average, but are prone to develop lately vascular complications such as ischemic heart disease or aortic aneurysm so that a close follow-up far beyond the clinical recovery is needed.