Atypical Hyperperfusion Encephalopathy in Post-Carotid Stenting

Hyperperfusion encephalopathy (HPE) is a condition due to increased perfusion of the brain which is clinically characterized by headache, seizures, and other neurologic signs associated with increased (or not) systemic blood pressures and edema in the subcortical white matter (predominantly in the occipital lobe). Patients with critical carotid stenosis treated with endarterectomy or carotid artery stenting may develop a HPE syndrome of the ipsilateral hemisphere which closely resembles the unilateral HPE and that usually involves the vascular area subjected ipsilaterally to the carotid stenosis. We present here a case of a 62-year-old woman who developed atypical hyperperfusion syndrome after a carotid stenting for high-grade carotid artery stenosis. In our patient, the HPE involved bilaterally both hemispheres, even though the treatment of the carotid stenosis was unilaterally. Some authors have hypothesized that a high dose of contrast, in combination with an unidentified personal vulnerability, may result in the rupture of the blood-brain barrier, carrying the CA into the cerebral parenchyma (both hemispheres), leading to the encephalopathy. The course and prognosis of HPE in post-carotid stenting are excellent with conservative treatment and full recovery usually occurs within 24 to 48 hours.