Posterior reversible encephalopathy syndrome: a review.

Encephalopathy due to reversible cerebral edema is an important cause of neurologic morbidity accompanying many disorders. Although controversy remains concerning the pathophysiologic trigger, the mechanism of this disorder ultimately depends on failure of the blood-brain barrier to maintain the compartmentalization of intravascular fluid. This failure of the blood-brain barrier depends primarily on the capillary hydrostatic pressure, under the influence of the systemic blood pressure, and on the integrity of the structures that make up the blood-brain barrier, most importantly the vascular endothelium, under the influence of various diseases and toxic medications. Although typical clinical contexts and presentations have been well defined, many patients have atypical features that pose a diagnostic challenge. Therefore, awareness of this clinical variability is important for prompt diagnosis. This review discusses the history and pathophysiology of posterior reversible encephalopathy syndrome and then addresses its clinical diagnosis and management.