Unusual Complication of Carotid Stenting Delayed Hyperperfusion Syndrome

Cerebral hyperperfusion syndrome (CHS) is a rare syndrome, occurring in three situations: in hypertensive encephalopathy, preeclampsia-eclampsia, and after carotid reperfusion procedures (carotid endarterectomy, carotid artery stenting [CAS]). CHS secondary to carotid revascularization presents with severe ipsilateral headache, seizures, focal neurological deficits, and occasionally intracerebral hemorrhage. A 65-year-old man underwent a right-sided carotid artery procedure and was asymptomatic postprocedure; his blood pressure was controlled. After 2 weeks of the procedure, the patient developed left focal seizures with secondary generalization. His brain magnetic resonance imaging (MRI) showed right temporo-parietal FLAIR hyperintensities without corresponding diffusion restriction or hemorrhage suggestive of edema. He is diagnosed with CHS. Repeat MRI of the brain after 2 months shows resolution of changes. CHS commonly occurs in the 1st week of carotid revascularization. Our patient presented after 2 weeks. We should be careful about this complication beyond the early days after the reperfusion procedure.