Giant Cell Arteritis

An adult aged 50 or older with a new headache, jaw or tongue claudication, scalp tenderness, polymyalgia rheumatica symptoms, or visual change may have giant cell arteritis (GCA) until assessed. The first clinical decision is whether cranial ischemia is threatening the eye or brain. Transient visual dimming or a curtain-like loss that resolves is amaurosis fugax, not reassurance; it signals ischemia and requires emergency treatment. New diplopia, persistent visual loss, or stroke symptoms carry the same urgency. When suspicion is strong, begin high-dose glucocorticoids immediately and arrange diagnostic testing in parallel. In a patient without threatened vision, this usually means high-dose oral prednisone or prednisolone. With threatened or new visual loss, urgent ophthalmology assessment and pulse intravenous methylprednisolone are required. In Canadian practice, temporal and axillary artery ultrasound is generally the first-line imaging test when experienced operators are available; biopsy is reserved for cases in which imaging and the clinical picture do not settle the diagnosis. A normal ESR or CRP lowers probability but cannot overrule a convincing presentation, and IL-6 blockade can make these markers falsely reassuring.