An 80-year-old woman presents to the clinic with a 2-week history of a continuous, throbbing, right-sided temporal headache. She reports that brushing her hair has become extremely painful, and her jaw aches when chewing tough foods like meat. Yesterday, she experienced a 10-minute episode of painless, transient visual loss in her right eye, which she describes as a “dark curtain” falling over her vision. Over the past month, she has also felt profoundly fatigued and noticed pronounced morning stiffness in her shoulders and hips, making it difficult to get dressed. Her past medical history is notable for well-controlled hypertension managed with amlodipine, and for osteoporosis for which she takes a biphosphonate. She appears distressed and frequently rubs the right side of her head. She is afebrile. Her blood pressure is 135/85 mmHg with a heart rate of 82 bpm.