Posterior reversible encephalopathy syndrome in preeclampsia and eclampsia: The role of hypomagnesemia

•Hypomagnesemia frequently occurs in the acute phase of obstetric PRES.•Hypomagnesaemia may play a role in triggering obstetric PRES by regulating blood pressure and inflammation failure.•Magnesium supplementation might be helpful for obstetric PRES patients. Posterior reversible encephalopathy syndrome (PRES), defined by its clinical and imaging manifestations, is a critical maternal complication. The specific pathophysiological mechanism of PRES has not been fully elucidated and remains controversial. Recently, several case studies reported that hypomagnesemia is present in the acute phase of PRES regardless of its etiology. Moreover, magnesium sulfate is a conventional treatment for preeclampsia (PE) and eclampsia; therefore, we hypothesized that hypomagnesemia might play an important role in the cascades involved in PRES in PE or eclampsia. We consecutively collected PE and eclampsia patients who were examined via magnetic resonance imaging (MRI) and tested for magnesium levels between January 2013 and January 2017. All patients were grouped into PRES and non-PRES groups based on MRI results. Demographic data, magnesium levels and imaging features were collected retrospectively. A total of 72 patients met the inclusion criteria; these participants were sorted into PRES (n = 38) and non-PRES (n = 34) groups. Twenty-four patients (63%) in the PRES group and 2 patients (6%) in the non-PRES group presented hypomagnesemia. Moreover, magnesium levels were significantly lower in the PRES group during both the acute phase (p < 0.001) and the post-phase (p = 0.04) than in the non-PRES group. However, there was no correlation between magnesium levels and edema severity during the acute phase. These results demonstrate that hypomagnesemia frequently occurs in the acute phase of obstetric PRES and suggest a potential relationship between them. Such a connection would support the application of magnesium sulfate in PE and eclampsia patients to prevent PRES. However, additional randomized trials are needed.