A 70-year-old woman presents with a new headache that she describes as being on one side of her head, primarily in the temple area. The headache is associated with tenderness over her temples and jaw claudication. She also reports blurred vision. What is the likely diagnosis and next steps?
The patient's age, new headache, scalp tenderness, jaw claudication, and visual symptoms are concerning for giant cell arteritis (GCA), also known as temporal arteritis. This is an emergency because untreated GCA can lead to blindness. The next steps should include an immediate ESR and CRP test, which are typically elevated in GCA, and start high-dose glucocorticoid treatment while awaiting biopsy confirmation to prevent further visual loss.