why does fluid overload cause hyponatremia
Hyponatremia means that the sodium level in the blood is below normal. Your body needs sodium for fluid balance, blood pressure control, as well as the nerves and muscles. The normal blood sodium level is 135 to 145 milliequivalents/liter (mEq/L). Hyponatremia occurs when your blood sodium level goes below 135 mEq/L.yponatremia can be the result of illnesses and medications. Some causes that may be related to kidney disease include: 1  Kidney failure-the kidneys cannot get rid of extra fluid from the body. 2  Congestive heart failure-excess fluid builds up in the body.