The clinical and radiological spectrum of posterior reversible encephalopathy syndrome: the retrospective Berlin PRES study

The aim of the study was to characterize the clinical and radiological spectrum of posterior reversible encephalopathy syndrome (PRES) in a large cohort. The radiological report data bases of the authors' university hospitals were searched for patients with PRES. Various imaging features at onset of symptoms and on follow-up as well as clinical and paraclinical data were tabulated in those patients fulfilling the criteria for PRES. Exploratory univariate analyses were performed. A total of 96 patients with PRES were included into the study. Wide differences in lesion location, diffusivity, distribution pattern, edema severity, hemorrhage, underlying diseases, symptoms, mean arterial pressure (MAP) and coagulation status were encountered. Hemorrhage occurred significantly more frequently in patients with altered coagulation state and was significantly associated with higher edema grades and with the presence of cytotoxic edema. There was a significant difference in MAP between toxic associations with higher MAP in infection, eclampsy and autoimmune disorders, while lower MAP was found in chemotherapy and immunsupression. In 82% of patients complete or near complete resolution of edema was noted during follow-up. Higher MAP levels were associated with incomplete edema resolution. In 43% of patients residual lesions were seen with a relatively even distribution between focal gliosis, infarction, posthemorrhagic residua, atrophy and laminar necrosis. PRES in this large hospital-based retrospective study comprises a wide radiological and clinical spectrum. Residual lesions were encountered more frequently than commonly expected. Our results point towards a differential contribution of high blood pressure to the course of PRES in different underlying etiologies.