What is the treatment for hypernatremia?

Treatment of Hypernatremia

The treatment of hypernatremia should focus on gradual correction of serum sodium with hypotonic fluids at a rate not exceeding 0.5 mmol/L/hour to prevent neurological complications. 1

Assessment and Classification

• Hypernatremia is defined as a serum sodium concentration greater than 145 mmol/L 1
• Hypernatremia can be classified based on:
  • Duration: acute vs. chronic 1
  • Severity: mild, moderate, or threatening 1
  • Volume status: hypervolemic, hypovolemic, or euvolemic 1

Treatment Based on Volume Status

Hypovolemic Hypernatremia

• Caused by renal or extrarenal water losses exceeding sodium losses 1
• Treatment involves:
  • Initial volume resuscitation with isotonic fluids (0.9% saline) to restore hemodynamic stability 2
  • Followed by administration of hypotonic fluids (0.45% saline or 5% dextrose) to correct the free water deficit 2

Euvolemic Hypernatremia

• Often due to diabetes insipidus (central or nephrogenic) 1
• Management includes:
  • Treating the underlying cause when possible 2
  • Providing free water orally if the patient can drink 2
  • Administering hypotonic IV fluids (D5W) for patients unable to take oral fluids 2
  • For central diabetes insipidus, desmopressin may be indicated 2

Hypervolemic Hypernatremia

• Results from excessive sodium intake (hypertonic saline, sodium bicarbonate) or primary hyperaldosteronism 1
• Treatment approach:
  • Discontinue the source of excessive sodium 1
  • Administer loop diuretics to promote sodium excretion 2
  • Provide free water to correct the deficit 2

Calculation of Water Deficit

• Calculate the free water deficit using the formula:
  • Free water deficit = Total body water × [(current Na⁺/desired Na⁺) - 1] 2
  • Total body water is approximately 0.6 × weight (kg) for men and 0.5 × weight (kg) for women 2

Rate of Correction

• For acute hypernatremia (developed within 48 hours):
  • Correction can be more rapid but should still not exceed 1 mmol/L/hour 1
• For chronic hypernatremia (developed over days):
  • Correction should be slow, not exceeding 0.5 mmol/L/hour or 10-12 mmol/L/day 1, 3
• Overly rapid correction can lead to cerebral edema and neurological complications 1

Monitoring During Treatment

• Check serum sodium levels every 2-4 hours initially during active correction 3
• Monitor for signs of cerebral edema (headache, nausea, seizures, altered mental status) 2
• Assess fluid status regularly through clinical examination and, when necessary, hemodynamic monitoring 4

Special Considerations

• Critically ill patients require careful monitoring as they often have impaired consciousness and cannot regulate their own water intake 4
• Patients with "do not resuscitate" status have higher mortality rates when hypernatremic 3
• Inadequate correction of hypernatremia within 72 hours is associated with increased mortality 3

Common Pitfalls to Avoid

• Correcting hypernatremia too rapidly, which can lead to cerebral edema 1
• Correcting hypernatremia too slowly, which is associated with increased mortality 3
• Failing to identify and treat the underlying cause of hypernatremia 2
• Inadequate monitoring of serum sodium levels during correction 4