Snapshot A 45-year-old woman presents to the emergency room with a severe headache of acute onset. Her headache is significantly more severe than her migraine headaches. Her symptoms began approximately 2 hours ago after she was lifting heavy weights. She denies any head trauma, nausea, or vomiting. Physical examination is unremarkable. A CT head without contrast is normal. An emergency lumbar puncture is done and demonstrates elevated red blood cells that do not diminish from tube 1 to 4. Introduction Definition login to view 1 more bullet Epidemiology login to view 4 more bullets Etiology login to view 3 more bullets Pathogenesis login to view 2 more bullets Presentation Symptoms login to view 7 more bullets Imaging CT head without contrast login to view 4 more bullets Studies Lumbar puncture login to view 5 more bullets Differential Reversible cerebral vasoconstriction syndrome (RCVS) login to view 4 more bullets Treatment Medical login to view 3 more bullets Operative login to view 3 more bullets Complications Arterial vasospasm Hydrocepalus Hyponatremia Cerebral salt wasting login to view 2 more bullets