Risk factors for posterior reversible encephalopathy syndrome in hypertensive pregnant women presenting with seizures

Pregnant women developing generalised tonic–clonic seizures in the absence of a prior neurological disorder are often diagnosed as eclamptic. Posterior reversible encephalopathy syndrome (PRES) is a distinct neuroimaging condition associated with long-term sequelae, which may occur in pregnancy. Some reports suggested PRES to be the pathophysiological process leading to eclampsia, whereas others observed PRES and eclampsia to have varying clinical severity and risk factors. In this case–control study, risk factors associated with PRES were compared to those for eclampsia in women with hypertension presenting with seizures who had undergone neuroimaging. PRES was noted to occur in 22.5% (51/227) hypertensive pregnant women presenting with seizures that otherwise would have been classified as eclampsia. An additional 51 women with eclampsia underwent neuroimaging. Women who had PRES had higher systolic (155.3 vs 144.5, p = 0.04), diastolic (99.2 vs 93.4, p = 0.006) and mean (117.9 vs 110.4, p = 0.001) blood pressure at admission compared to those with eclampsia. Eclampsia and PRES may occur through a similar pathophysiological mechanism, resulting in the same spectrum of neurological complications of preeclampsia, with PRES being the severest form of the disease process. PRES is difficult to differentiate from eclampsia based on clinical and laboratory investigation, except for high blood pressures, without adjunctive MRI/CT neuroimaging. Future studies should assess the role of biomarkers as well as long-term neurological sequelae in pregnant women with a diagnosis of PRES.