Rare Case of Severe Preeclampsia-Associated Severe Hyponatremia in a Parturient With Twin Gestation
Abstract Number: F-31
Abstract Type: Case Report/Case Series
Preeclampsia in pregnancy is associated with a multitude of well known complications, including coagulation disorders, pulmonary edema, HELLP syndrome, and uterine hypoperfusion. Severe hyponatremia is however a very rare complication. To our knowledge, there are 8 cases previously reported in the literature. We report on a ninth case and discuss the pathophysiologic characteristics and management of severe hyponatremia in preeclampsia.
Patient is a 34 year old otherwise healthy woman, G2P1A1, at 32 weeks gestation. She was admitted after presenting to her Obstetrician's office with persistent elevation in blood pressures, and persistent proteinuria, over several days. Blood pressures were 140/90, in comparison to her baseline 90/50. Urine protein was 1.94g/24 hours. There were no other manifestations of preeclampsia.
The patient's serum sodium concentration on presentation was 129 meq/L, and reached a nadir of 123 meq/L two days after admission. Her established baseline is normal. The value was too low to be explained by the reset osmostat of pregnancy. Urine osmolality and urine sodium were low, and all other urine and serum chemistry values were unremarkable. She is a heavy water drinker, at about 4L per day. The nephrologist agreed with our impression that the mechanism of the hyponatremia was either euvolemic or hypervolemic, with possible contribution from excessive water intake.
Management of this parturient necessitated careful coordination between MFM, Nephrology, Obstetrics, Neonatal ICU, and Anesthesia teams. To avoid severe neonatal hyponatremia, the NICU team recommended a maternal serum sodium cut off of 125 meq/L. Demeclocycline, Conivaptan, and Furosemide are mainstays of treatment for SIADH that are best avoided in pregnancy due to potential danger to the fetus. The nephrologist treated the patient with one 2 gram dose of sodium chloride instead, and placed her on 1000ml fluid restriction/24h. There was also frequent monitoring of electrolytes and neonatal status, and frequent assessment for signs of hypovolemia, to avoid uterine hypoperfusion. Despite some improvement of serum sodium to 132 meq/L, a non-reassuring BPP on twin A, and worsening proteinuria 6.6g/24h, led to the decision to proceed with delivery by urgent cesarean section. This was done under spinal anesthesia without complications on day 3 of L and D stay. Patient and the twin neonates did very well after delivery, and maternal serum sodium normalized on POD 3. Patient was discharged on postop day 4 without lasting sequelae.
Severe hyponatremia in preeclampsia can be very dangerous to parturient and fetus, and is associated with an increased risk of maternal seizures, fetal jaundice, fetal tachypnea, fetal seizures, and polyhydramnios. Regardless of the etiology, prompt diagnosis and treatment are of utmost importance.
1. Sandhu G, Ramaiyah S, Chan G, Meisels I. Pathophysiology and Management of Preeclampsia. Am J Kidney Dis. 2010;55(3):599-603