Hyponatremia; Current Diagnosis and Treatment

Hyponatremia is the most common electrolyte abnormality encountered in clinical practice. The symptoms of hyponatraemia are largely dependent on the rapidity of the development of hyponatraemia. Acute symptomatic hyponatremia is a serious clinical situation. The pathogenesis of hyponatremia has been found to occur secondary to the nonosmotic secretion of ADH in over 95% of cases. In other words, hyponatremia caused by more water imbalance than sodium imbalance in the majority of cases. Pseudohyponatremia(elevation of lipids or proteins in plasma causing artifactual decrease in serum sodium concentration) and translocational hyponatremia(the additional solutes in plasma such as glucose, mannitol and radiographic contrast agent causing osmotic shift of water from intracellular fluid to extracellular fluid) that are not associated excess are excluded on the first step in the differential diagnosis of hyponatraemia. While only fluid restriction is sufficient for treatment of asymptomatic patients, emergency treatment should be given in symptomatic patients. Recently ADH receptor antagonists have been used as an alternative treatment of saline infusion in the treatment of euvolemic and hypervolemic hyponatremia. Correction rate of sodium should be 0,5-1mEq/L/h in the treatment of hyponatremia. Rapidly correction should be avoided in hyponatraemia, because it can lead to celebral hemorrhage and central pontine myelinolysis.