Reversible Confluent Deep White Matter Abnormalities: A New Variant of Posterior Reversible Encephalopathy Syndrome

We describe a confluent deep white matter abnormalities variant of PRES, further strengthening the notion that PRES is a disorder of radiological heterogeneity. We present 2 cases of PRES with findings of diffuse but reversible vasogenic edema located in the deep periventricular white matter regions of bilateral hemispheres without a clearly posterior distribution. We feel that this represents a rare variant of PRES on imaging, thus adding to the existing radiological spectrum for this entity. Both of our patients presented with malignant hypertension (mean arterial blood pressure of 200？mmHg) and developed neurological symptoms that included encephalopathy, seizure, headache, and vision changes. Additionally, both patients presented with significant subcortical white matter edema that improved dramatically on follow-up imaging. The clinical and radiological improvement in both patients occurred following successful blood pressure management. It is possible that the deep white matter changes of PRES are seen exclusively in the setting of severe accelerated hypertension. Our case reports reveal that, in patients with hypertensive encephalopathy, a deep white matter pattern of diffuse signal changes may not necessarily indicate chronic ischemic changes and follow-up imaging studies are essential to rule out a diagnosis of PRES. 1. Introduction The clinical manifestations of posterior reversible encephalopathy syndrome (PRES) include encephalopathy, headache, visual disturbance, and seizure. In most cases, symptoms present acutely in the setting of accelerated hypertension, toxemia of pregnancy, autoimmune disorder, immunosuppressive treatment, or cancer chemotherapy. One essential feature of PRES is the presence of reversible subcortical vasogenic edema that has a predominantly posterior distribution on brain imaging [1]. Here we describe 2 cases of PRES with findings of diffuse but reversible vasogenic edema located in the deep periventricular white matter regions of bilateral hemispheres without a clearly posterior distribution. We feel that this represents a rare variant of PRES on imaging, thus adding to the existing radiological spectrum for this entity. 2. Case Description 2.1. Case No. 1 Initially found unresponsive, this 49-year-old hypertensive, hepatitis-C-positive Caucasian man presented to our emergency department with witnessed clonic tonic seizures and postictal confusion. He was treated with midazolam and fosphenytoin, followed by intubation for airway protection. Three months earlier, he presented to our hospital in a hypertensive