Edited by: Joe Hing Kwok Chu
Sodium acts as an important cation of the intracellular fluid. It is necessary for the transmission of nerve impulse and influence the acid-alkaline balance, osmotic pressure, and cellular membrane potential, protecting the against excessive fluid loss, and preserving the normal function of muscle tissue.
Serum levels of Na can be influenced by usage of drugs.
Drugs that can increase the level of serum sodium include: cough medicines, cortisone preparations, antibiotics, laxative, methydopa (Aldomet), hydralazine (Apresoline), reserpine (serpasil).
Drugs that can decrease the level of serum sodium: potent diuretics.
Hypernatremia (high level of sodium):
Deficient water intake or excessive output, severe protracted vomiting or diarrhea, or loss of anti-diutretic hormone (AD) control.
Administering sodium solutions to an unconscious patient. (When a conscious person's serum level is high, he/she will drink water and the serum level is back to normal. (Older people may have be less sensitive to thirst.)
Excessive administration of steroid (mineralocorticoid).
In rare cases hyperglycemia is associated with hypernatremia in hypothalamic lesions, in head injuries, and in hyperosmolar states.
Hyponatremia (low level of sodium)
Associated with absolute sodium loss
Associated with excessive water
Inappropriate anti diuretic hormone syndrome
Intracellular potassium depletion