Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiological entity presented with different symptoms such as visual disturbances, headaches, seizures, severe hypertension and altered mental status. It has been recognized in a different pathological conditions, although preeclampsia/eclampsia is the most common cause of PRES. The pathogenesis of PRES is still not fully understood, but it seems that failure of cerebrovascular autoregulation causing vasogenic edema, cerebral vasoconstriction, and disruption of the blood brain barrier plays an important role. Cortical blindness, hypertensive retinopathy, serous retinal detachment (SRD), central retinal artery and vein occlusions, retinal or vitreous hemorrhages, anterior ischemic optic neuropathy (AION) and Purtscher’s retinopathy are ophthalmic disorders that may occur in PRES associated with preeclampsia. Among these, cortical blindness is the best documented complication of preeclampsia. Magnet resonance imaging (MRI) is a gold standard to establish the diagnosis of PRES because clinical findings are not sufficiently specific. Typically, there are bilateral cortical occipital lesions with hyperdensity on T2-weighted MRI. Blindness due to occipital lesions is reversible and the vision loss is usually regained within 4 h to 8 days.
Part of the book: Preeclampsia