CT: computed tomography; SAH: subarachnoid hemorrhage; ICH: intracerebral hemorrhage; RCVS: reversible cerebral vasoconstriction syndrome; MR: magnetic resonance; LP: lumbar puncture; CSF: cerebrospinal fluid; MRI: magnetic resonance imaging; MRV: magnetic resonance venogram; ECG: electrocardiogram.
* Additional vascular imaging may be warranted to exclude SAH if initial head CT is normal and LP is nondiagnostic (eg, traumatic tap, symptoms >2 weeks prior). Refer to the UpToDate topic on the diagnosis of aneurysmal subarachnoid hemorrhage for details.