Review Question - QID 213686

A 67-year-old man presents to the emergency department with a headache that has persisted for the past 5 hours. The headache is right-sided, throbbing in quality, and associated with photophobia and nausea. He denies any recent head strike, changes in his vision, or unilateral weakness or sensory changes. He has a medical history of coronary artery disease with stent placement, chronic obstructive pulmonary disease, migraine headaches, type 2 diabetes mellitus, and atrial fibrillation. He is currently on aspirin, warfarin, metformin, propranolol. His temperature is 98.0°F (36.7°C), blood pressure is 155/85 mmHg, pulse is 90/min, respirations are 17/min, and oxygen saturation is 98% on room air. On neurological examination, the patient has full visual fields, equally reactive pupils, symmetric face with activation, and full strength in the bilateral upper and lower extremities with intact sensation to light touch. There is no evidence of neck stiffness. Laboratory studies are notable for an INR of 2.9. A CT head without IV contrast is shown in Figure A. Which of the following is the most appropriate next step in management?