Dysnatremia in Renal Failure

Proximal salt reabsorption in the hypertrophied tubules in the early phase of chronic renal failure (CRF) would be diminished according to the inhibited expression of proximal salt-transporting molecules, which may be facilitated by the inhibition of Na-K-ATPase expression. Results from animal models suggest that patients with early-phase CRF would easily develop hyponatremia and, in contrast, patients showing developed CRF would be more likely to show dehydration or hypernatremia. Several large-scale studies of individuals with chronic kidney disease (CKD) revealed that hyponatremia is much more common than hypernatremia in patients with earlier stages of CKD. However, patients with end-stage renal disease (ESRD) more frequently show hypernatremia than hyponatremia. These clinical trends in CKD and CRF patients are in agreement with the results of animal experiments, suggesting that salt loss might be a principal pathological setting in the early stages of CKD and that water loss could overcome the salt loss in ESRD.