MRCP2-3022

A 50-year-old man arrives at the emergency department complaining of the most severe headache he has ever experienced. He explains that he was sitting with his wife when he suddenly felt excruciating pain at the back of his head. The pain quickly escalated to a 10/10 intensity, and he also feels nauseous, although he has not vomited yet.

The patient has a medical history of adult dominant polycystic kidney disease and hypertension, for which he takes ramipril. Upon examination, his Glasgow coma scale is 15/15, and there is no focal neurology.

Due to concerns of an intracranial bleed, a non-contrast CT head is ordered, which reveals hyperdensity in the subarachnoid space and ventricles.

What is the most appropriate definitive intervention for this diagnosis?