Summary

• Giant cell arteritis (GCA) is a common form of vasculitis in people aged 50 years or older. The extracranial branches of the carotid artery are usually affected.
• Irreversible blindness is the most common serious consequence. Aortic aneurysms and large vessel stenoses may occur as a long-term complication.
• Temporal artery biopsy is the definitive test to establish diagnosis.
• Patients with jaw claudication, diplopia, and an abnormal temporal artery on examination are more likely to have a temporal artery biopsy that is positive for GCA. GCA is unlikely if levels of inflammatory markers are normal.
• Prednisone is highly effective therapy. Treatment should not be delayed while awaiting biopsy.