Management of hyponatraemia in pre-eclampsia with severe features

Pre-eclampsia is a common pregnancy complication with many associated maternal and fetal risks, yet its pathophysiology remains poorly understood. Hyponatraemia is a rarely described finding in pre-eclampsia that has been associated with both maternal and fetal complications and medically indicated delivery. We present a case of hyponatraemia in a patient admitted for induction of labour for gestational hypertension, which developed into pre-eclampsia with severe features requiring magnesium sulfate therapy for seizure prophylaxis. The patient's hyponatraemia resolved with delivery, fluid restriction and serial sodium monitoring. Adjustment to the components of the patient's magnesium sulfate infusion was made to reduce free water intake and avoid further exacerbation of her hyponatraemia. While there is currently no recommendation to routinely monitor sodium levels in hypertensive disorders of pregnancy, careful consideration of this potential finding in cases of pre-eclampsia should be given due to the overlap between symptoms of hyponatraemia and cerebral symptoms of pre-eclampsia.