Review Question - QID 216750

A 60-year-old woman presents to the emergency department for severe headache. The headache began early in the day and was accompanied by dizziness and ringing in her ears. The headache worsened over the following 3 hours and is currently rated as 10/10 in severity. While in the emergency department, she has an episode of emesis. She denies recent head trauma. She takes amlodipine, metformin, glipizide, and atorvastatin. She has a 45-pack-year smoking history. She is an avid tennis player. The patient is given a single medication to treat her acute headache. Later in the emergency department, she begins complaining of visual problems. The patient’s temperature is 98.9°F (37.2°C), blood pressure is 154/84 mmHg, pulse is 90/min, and respirations are 18/min. Exam reveals bilateral conjugate upward gaze. She is unable to look down on command, but is alert and oriented. The rest of the cranial nerve exam is unremarkable. What is the most likely cause of this patient’s symptoms?