Posterior Reversible Encephalopathy Syndrome: Clinical Differences in Patients with Exclusive Involvement of Posterior Circulation Compared to Anterior or Global Involvement.

Introduction Posterior reversible encephalopathy syndrome (PRES) is a clinical–radiologic syndrome not yet fully understood and characterized by transient neurologic symptoms in addition to typical radiological findings. There are only a few articles that describe the clinical differences between patients with PRES that involve carotid and vertebrobasilar circulations. Our study aims to further evaluate the differences between predominantly anterior and posterior circulation PRES. Methods We review 54 patients who had received the diagnosis of PRES from 2009 to 2015. The patients were divided into 2 groups: (1) exclusively in posterior zones; and (2) anterior plus posterior zones or exclusively anterior zones. Several clinical characteristics were evaluated, including the following: age, sex, previous diseases, the neurologic manifestations, the highest blood pressure in the first 48 hours of presentation, highest creatinine level during symptoms, and the neuroimaging alterations in brain magnetic resonance imaging. Results Mean age at diagnosis was 28.5 years old (9 men and 45 women) and mean systolic blood pressure among patients with lesions only in posterior zones was 162.1 mmHg compared to 179.2 mmHg in the anterior circulation. The most common symptoms in the 2 groups were headache and visual disturbances. Discussion PRES may have several radiological features. A higher blood pressure seems to be 1 of the factors responsible for developing widespread PRES, with involvement of carotid vascular territory. This clinical–radiological difference probably occurs because of the larger number of autonomic receptors in the carotid artery in comparison to the vertebral–basilar system.