Hyponatremia is frequently seen accompanying severe hyperglycemia in diabetic dialysis patients. For every increase of 100 mg/dl in the serum glucose concentration, there is corresponding initial decrease of 1.3 mEq/liter in the serum sodium concentration due to osmotic shift of water from the intracellular compartment. Because osmotic diuresis secondary to the hyperglycemia does not occur, the excess plasma water is not excreted and hyponatremia is maintained.