Low level of sodium in the blood is called hyponatremia. The normal level is 140 meq/lL. Hyponatremia is seen when there is loss of sodium or excess water in the body which dilutes the sodium.
- Loss of sodium as in diarrhea.
- Loss of sodium from the kidney as with diuretics.
- Excess water retention as seen in heart or kidney failure.
- SIADH (Syndrome of Inappropriate ADH (hormonal) production)
Hypernatremia is characterized by increased sodium level in the blood. It is more a disorder of water metabolism and is seen when the ratio of solutes to water in the body is increased.
Causes of Hypernatremia
- Impaired thirst e.g. coma.
- Presence of osmotic substances in the urine which cause excessive water loss, e.g. glucose, mannitol administartion, diabetic ketoacidosis.
- Excess loss of water from the kidney as in diabetes insipidus.
- Excess loss of water from the skin: e.g. sweating, burns.