[Horton's giant cell arteritis].

Giant cell arteritis (GCA) is a spontaneous vasculitic syndrome specifically involving the walls of medium and large arteries. While involvement of other arterial beds is occasionally identified, this syndrome is most frequently recognized when symptomatic involvement of the temporal arteries occurs. Vascular lesions are characterized by patchy granulomatous infiltrates composed of T cells, macrophages, histiocytes, and giant cells. A better prognosis depends on early recognition of the clinical symptoms and prompt treatment. Diagnosis was based on the 5 clinical criteria previously used by the American College of Rheumatology (1990): 1) age 50 years or older; 2) new localized headache; 3) temporal artery tenderness or decrease in temporal artery pulse; 4) erythrocyte sedimentation over 50 mm/ hour; 5) abnormal result on artery biopsy. Giant cell arteritis was considered a rare disease under age 50; however, it is now known to be an important and significant cause of morbidity and mortality in elderly people. Therefore early recognition and treatment with corticosteroid are very important. There is no general agreement concerning the initial dosage, 40-65 mg/day are commonly recommended. After a few months the majority of patients can be treated with a low maintenance dosage of prednisolone (5 to 7.5 mg/day). The mean duration of treatment is about 5 years. The literature is reviewed and the clinical implications of this disease are discussed.