Review Question - QID 213518

A 45-year-old man presents to the emergency department for evaluation of headache. His symptoms started 8 hours ago and have not improved with over-the-counter medications. He describes his headache as sudden in onset, reaching maximal intensity in less than a minute. He has neck pain, and states his headache is worsened with movement of his head. This headache does not feel similar to headaches he has had in the past. His temperature is 97.6°F (36.4°C), blood pressure is 154/94 mmHg, pulse is 89/min, respirations are 12/min, and oxygen saturation is 98% on room air. No focal neurologic deficits are noted on exam. Pain is noted with flexion of the neck. A non-contrast CT scan of the head is obtained as shown in Figure A. Which of the following is the most appropriate next step in management?