Most authors define hyponatremia as a serum sodium concentration below the lower limit of normality, lower than 135 meq/L1, but there is still a discussion on best values of reference .
Characterized as a hydroelectrolytic disorder, hyponatremia is very common in elderly, hospitalized individuals and may be commonly associated with neoplasms, liver cirrhosis, heart failure and renal failure. Physiologically, it is inferred that the increase of water triggers hyponatremia and not a direct sodium low, even in situations of hypovolemic hyponatremia .
Thus, excess water leads to an increase in serum sodium dilution, and as a negative feedback under normal conditions,the level of antidiuretic hormone (ADH) decreases, so that the kidney collecting tubules become impermeable to water and It can be excreted in urine. However, in pathological situations, there may be a decompensation in this functioning, with several etiologies related to inadequate ADH secretion, such as antidepressant medications use .
Published on: Jul 13, 2017 Pages: 41-43