Dilutional hyponatremia in pre-eclampsia.

Abstract

The objective of this report is to describe a defect in water metabolism, characterized by hyponatremia, in patients with pre-eclampsia-induced nephrotic syndrom. This was an observational study of 3 women. Hyponatremia was observed in 3 women with pre-eclampsia characterized by various extrarenal manifestations, as well as by nephrotic syndrome with normal or nearly normal renal function. Restriction in water intake partially corrected hyponatremia before delivery in each case, and no complications were observed in the neonates. The mechanism of impaired excretion of water in these patients is proposed to involve persistent and inappropriate production of vasopressin through stimulation of the nonosmotic mechanism for vasopressin secretion in response to a reduction in effective plasma volume. These results indicate for the first time that women with pre-eclampsia are, at least when nephrotic, at risk for development of dilutional hyponatremia, which can cause neurologic complications that simulate those of eclampsia.