Cerebral hyperperfusion syndrome: a novel presentation of internal carotid artery dissection.

Cervical artery dissection (CeAD) occurs preferentially in the middle-aged, and its annual incidence rate is 2.6 to 3.0 per 100,000.(1) Manifestations of internal carotid artery dissection (ICAD) include ischemic stroke and TIA (>70% of patients), headache, neck pain, Horner syndrome, cranial nerve palsy, pulsatile tinnitus, and, rarely, subarachnoid hemorrhage.(2) Cerebral hyperperfusion syndrome is known to occur after carotid artery revascularization procedures and it is thought to result from the combination of several factors that impair cerebral vascular autoregulatory mechanisms.(3.)