Soru

A $45$-year-old woman presents to the emergency department reporting the sudden onset of a severe, diffuse headache that began $18$ hours ago. She describes it as the "worst headache of my life." The headache was accompanied by two episodes of vomiting and sensitivity to light. Her past medical history is significant for hypertension and tobacco use. Her temperature is $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), pulse is $92$/min, blood pressure is $168/95$ mmHg, and respirations are $16$/min. On physical examination, the patient appears uncomfortable and prefers to keep the room lights off. Neurologic examination shows intact cranial nerves, $5/5$ motor strength in all extremities, and normal deep tendon reflexes. Neck flexion produces mild discomfort. A non-contrast computed tomography (CT) scan of the head reveals no evidence of intracranial hemorrhage, mass effect, or midline shift. Which of the following is the most appropriate next step in the diagnostic workup?