endocrine and metabolic disorders
Hyponatremia
Key Points
Hyponatremia may occur with normal, increased, or decreased extracellular fluid volume. Common causes include diuretic use, diarrhea, heart failure, liver disease, and renal disease. Hyponatremia is potentially life threatening. The degree, duration, and symptoms of hyponatremia are used to determine how quickly to correct the serum sodium. Treatment varies depending on fluid volume status, but in all cases serum sodium level should be corrected slowly—by ≤ 8 mEq/L (≤ 8 mmol/L) over 24 hours, although fairly rapid correction by 4 to 6 mEq/L using hypertonic saline over the first several hours is frequently needed to reverse severe neurologic symptoms. Osmotic demyelination syndrome may follow too-rapid correction of hyponatremia. 