Hyponatremia

Differential

• Hypovolemic

  • Hypovolemic hyponatremia due to renal loss

  • Hypovolemic hyponatremia due to extrarenal loss

• Euvolemic

  • SIADH

  • Euvolemic hyponatremia due to diet

• Hypervolemic

  1. Urine sodium < 20

     • HFrEF and HFpEF

     • Cirrhosis

  2. Urine sodium > 20: Renal failure

Sodium Correction

• Methods

  • Initial

    • Stop medications that may be contributing

    • Fluid intake restriction

  • 3% NaCl

• Limit correction to < 12 mmol/L in 24 hours and < 18 mmol/L in 48 hours