A patient presents with a chief complaint of the “worst head…

A patient presents with a chief complaint of the “worst headache of my life,”nausea, and vomiting. A noncontrast computed tomography scan of the head is completed and appears normal. Given concern for underlying pathology, you decide to perform a lumbar puncture, which has elevated opening pressure as well as elevated red blood cell count in three separate tubes. What is the most likely diagnosis?