Posterior reversible encephalopathy syndrome

Purpose of review The ophthalmologist may be called upon to evaluate visual loss in a patient with posterior reversible encephalopathy syndrome. Familiarity with presentation and clinical management is imperative, as visual loss is often reversible with prompt treatment directed at causative factors. Recent findings Since its initial description in 1996, the predisposing factors, clinical presentation and radiographic variation of posterior reversible encephalopathy syndrome continue to expand. Case reports of newly uncovered associations of the syndrome appear frequently. Originally considered a subcortical disease of the posterior cerebrum, posterior reversible encephalopathy syndrome has been shown to affect gray matter and can involve both the anterior and posterior cortex, brainstem, cerebellum or even the spinal cord. The pathophysiologic basis of cerebral edema and molecular mechanisms of edema underlying the syndrome are currently being revealed. Summary Acute hypertension, eclampsia, immunosuppressive medication, infection or autoimmune diseases can all result in the clinical syndrome of vasogenic edema in the central nervous system leading to headache, seizure, confusion and frequent visual loss. The biologic basis for the syndrome is likely an insult to cerebral vascular autoregulation. MRI is essential in diagnosing a cerebral cause for visual loss. The ophthalmologist may have the initial opportunity to diagnose the syndrome. Treatment may reverse clinical deficits, and is based on eliminating the etiologic causation.