Predictors of poor outcome in patients with posterior reversible encephalopathy syndrome

Posterior reversible encephalopathy syndrome (PRES) is an acute neurotoxic syndrome that, although characteristically reversible, can be fatal or result in long-term disability in a subset of patients. Our aim was to identify factors associated with poor discharge outcome in PRES patients.

We retrospectively reviewed the clinical and radiological records of all patients with PRES admitted at our tertiary care medical center from 2007 to 2014. They were divided based their modified Rankin Score at discharge and compared for their baseline variables, clinical, laboratory and imaging features. Poor outcome was defined by a modified Rankin scale 2-6 and was subdivided based on the primary mechanism that led to poor outcome.

Out of 100 PRES subjects, 36% had poor discharge outcomes. Factors associated with poor outcomes on univariate analysis were history of diabetes mellitus, coma, high Charlson comorbidity index, post-transplantation, autoimmune condition, lack of systolic or diastolic hypertension, elevated blood urea nitrogen and involvement of the corpus callosum. On multivariate analysis, only prior diabetes mellitus odd ratio (OR) = 6.8 (95% CI 1.1-42.1, p = 0.04), corpus callosum involvement (OR = 11.7; 95% CI 2.4-57.4, p = 0.00) were associated with poor outcome. Poor outcome also correlated with increased length of hospital stay (OR = 7.9; 95% CI 1.3-49.7, p = 0.03).

Large prospective studies incorporating serial blood glucose values and advanced imaging studies are required to validate these findings.