Clinical predictors and differential diagnosis of posterior reversible encephalopathy syndrome.

The aim of our study is to determine the clinical predictors and the differential diagnosis of posterior reversible encephalopathy syndrome (PRES) in patients presenting with acute neurological symptoms and risk factors for PRES. Using the diagnostic algorithm for PRES from Fugate and Rabinstein (Lancet Neurol 14(9):914-925, 1), we carried out a retrospective study on 220 patients, presenting with acute neurological symptoms such as seizures, encephalopathy, headache, visual disturbances or other focal neurological signs that appear in the clinical setting of risk factors such as hypertension/blood pressure fluctuations, chemotherapy, renal failure, autoimmune disorders, or eclampsia, in whom imaging of the brain was performed to exclude PRES. Seventeen percent of patients had a radiologically confirmed diagnosis of PRES. Univariable logistic regression showed a significant association between PRES and epileptic seizures, encephalopathy, hypertension, chemotherapy and renal failure. Multivariable logistic regression of acute neurological symptoms and risk factors showed a significant association of epileptic seizures, encephalopathy, visual disturbances, hypertension and chemotherapy with PRES. Using these variables to predict PRES yielded a discriminative ability (AUC) equal to 0.793. Diagnoses when PRES was not confirmed included primary or secondary headaches (26%), toxic-metabolic encephalopathy (21%), vascular pathology (12%) and other less frequent disorders. Epileptic seizures, encephalopathy, visual disturbances, hypertension, renal failure and chemotherapy were the best clinical predictors of PRES, while headache, immune suppression and autoimmune disease were not useful for the clinical diagnosis of PRES in our study.