Symptomatic Cerebral Hyperperfusion After Cerebral Vasospasm Associated with Aneurysmal Subarachnoid Hemorrhage

Background: Cerebral hyperperfusion syndrome, which carries a potential risk of intracranial hemorrhage, is a rare and overlooked condition in the setting of subarachnoid hemorrhage (SAH). Case Description: A 72-year-old female presenting with SAH underwent clipping of a ruptured aneurysm of the left middle cerebral artery. On post-SAH day 7, the patient exhibited motor aphasia due to cerebral vasospasm of the left middle cerebral artery. After recovery from symptomatic cerebral vasospasm, the patient became restless and suffered from right hemiparesis on post-SAH day 12. Initially, recurrence of cerebral vasospasm was suspected; however, cerebral blood flow measurement using single-photon emission computed tomography revealed apparently increased perfusion in the same territory of the left middle cerebral artery. Hypertensive therapy was not induced during the postoperative period. Her neurologic symptoms and signs of cerebral hyperperfusion gradually improved with intensive blood pressure lowering. Conclusions: This is the first report to describe postischemic cerebral hyperperfusion syndrome after symptomatic vasospasm detected using sequential single-photon emission computed tomography during the acute stage of SAH. Early diagnosis of this rare phenomenon is crucial given the necessity to lower blood pressure for preventing hemorrhagic complications, which is contrary to the usual management of patients with vasospasm.