The causes of hyponatremia are so varied. In general, hyponatremia can be described as an excess of body water relative to serum sodium levels, often identified as a serum sodium concentration <135 mEq/L. It is associated with decreased serum osmolality resulting from changes in total body water, rather than from changes in body sodium content. These changes are regulated primarily by thirst, vasopressin, and the kidney.
Hyponatremia may be depletional, resulting from electrolyte losses in excess of water (depletional hyponatremia), or dilutional, resulting from retained water (dilutional hyponatremia). Dilutional hyponatremia is often associated with an excessive secretion of vasopressin.
In children, hyponatremia is most commonly due to water intoxication. But, then why would the child be taking in so many fluids? This case may require the child being seen by some pediatric specialists.
thanks for your reply. This child is always thristy and has excessive urination. His blood work shows that he also has low chloride, ferritin and alk phos levels. He also has an elevated lymphocyte level. It is just a guessing game at this point and test after test ruling out possibilites.