A 55-year-old man presents to the emergency department becau…
A 55-year-old man presents to the emergency department because he was experiencing a headache while lifting heavy boxes. The headache was acute in onset, but gradually worsened over several hours. It was associated with nausea. No over-the-counter analgesics alleviated the symptoms. His past medical history is significant for a recent diagnosis of adult polycystic kidney disease. Upon arrival he has a decrease in level of consciousness. Which of the following should be performed first in order to confirm a diagnosis?