Hypoalbuminemia and preclampsia

Esme12, ASN, BSN, RN · Feb 10, 2012

Although the presence of edema is not necessary for the diagnosis, sudden weight gain, with edema of the feet, hands, and face, is a common presenting symptom in preeclampsia. Salt loads are excreted more slowly than in normal pregnancy. The edema of preeclampsia is unlike that in congestive heart failure, hepatic cirrhosis, and nephrotic syndrome, where low effective circulating volume leads to high plasma renin and aldosterone concentrations and secondary renal sodium retention ("underfill" edema). Instead, renin and aldosterone concentrations are suppressed relative to normal pregnancy. The edema of preeclampsia thus resembles the "overfill" edema of acute glomerulonephritis or of acute ischemic renal failure in which GFR is decreased out of proportion to the drop in renal plasma flow and in which glomerular-tubular imbalance has been invoked as a cause of salt retention.

Decreased GFR, increased capillary permeability, and hypoalbuminemia may contribute to the edema formation. Albumin-bound Evan's blue dye disappears more quickly from the intravascular space in preeclamptic women compared with normal pregnant women, suggesting endothelial permeability is increased. However, this phenomenon is also seen in non-pregnant patients with heart failure and the nephrotic syndrome. Hypoalbuminemia is common and may contribute to edema. However, correction of hypoalbuminemia with albumin infusions in preeclampsia patients usually does not produce a diuresis, suggesting that the hypoalbuminemia alone is not responsible for the edema.Kidney International - Preeclampsia: A renal perspective