What is the treatment for hypernatremia?

Treatment of Hypernatremia

The treatment of hypernatremia should focus on correcting the underlying cause while safely restoring normal sodium levels through appropriate fluid administration, with correction rates tailored to the acuity of onset. 1, 2

Classification and Assessment

• Hypernatremia is defined as plasma sodium concentration greater than 145 mmol/L 2
• Classify hypernatremia based on:
  • Duration: acute (<48 hours) vs. chronic (>48 hours) 2
  • Severity: mild, moderate, or severe 2
  • Volume status: hypervolemic, hypovolemic, or euvolemic 2

Treatment Based on Volume Status

Hypovolemic Hypernatremia

• Caused by renal or extrarenal fluid losses 2
• Treatment: Replace both water and sodium deficit with hypotonic fluids (0.45% saline or 5% dextrose) 1, 3
• For severe cases, begin with isotonic fluids to restore hemodynamic stability before switching to hypotonic solutions 3

Euvolemic Hypernatremia

• Often due to diabetes insipidus (central or nephrogenic) 2
• Treatment:
  • Central diabetes insipidus: Desmopressin (Minirin) administration 3
  • Nephrogenic diabetes insipidus: Address underlying cause (e.g., discontinue lithium, correct hypokalemia) 2
  • Provide hypotonic fluids (5% dextrose or free water) 1, 3

Hypervolemic Hypernatremia

• Caused by excessive sodium intake (hypertonic saline, sodium bicarbonate) or primary hyperaldosteronism 2
• Treatment:
  • Loop diuretics to promote sodium excretion 3
  • Hypotonic fluid replacement 1
  • Address underlying cause (e.g., manage primary hyperaldosteronism) 2

Correction Rate Guidelines

• For acute hypernatremia (<24 hours):

  • Faster correction is safer as brain cells haven't had time to adapt 2
  • Consider hemodialysis for rapid normalization in severe cases 3

• For chronic hypernatremia (>48 hours):

  • Correct sodium at a rate not exceeding 8-10 mmol/L/day 3
  • Target correction rate of no more than 0.4 mmol/L/hour 2
  • Too rapid correction can lead to cerebral edema and neurological damage 3

Monitoring and Adjustments

• Monitor serum sodium levels frequently during correction (every 2-4 hours initially) 3
• Adjust fluid therapy based on serial sodium measurements 3
• For patients requiring continuous renal replacement therapy (CRRT), adjust dialysate/replacement fluid sodium concentration in a step-wise manner 4

Special Considerations

• Critically ill patients often develop hypernatremia due to impaired thirst mechanism and inability to access water 5
• In intensive care settings, careful attention to sodium and water balance is essential as hypernatremia is an independent risk factor for increased mortality 5
• When initiating renal replacement therapy in patients with chronic hypernatremia, be cautious to avoid too rapid sodium correction 3

Common Pitfalls to Avoid

• Correcting chronic hypernatremia too rapidly (>8-10 mmol/L/day) 3
• Failing to identify and address the underlying cause 2
• Inadequate monitoring during correction 3
• Overlooking hypernatremia in sedated or unconscious patients 5