What is the treatment for hypernatremia?

Treatment of Hypernatremia

The treatment of hypernatremia should focus on replacing free water deficit and correcting the underlying cause, with a reduction rate of 10-15 mmol/L/24h to avoid cerebral edema, seizures, and neurological injury. 1

Assessment and Diagnosis

Before initiating treatment, determine:

1. Duration of hypernatremia:

   • Acute (<48 hours)
   • Chronic (>48 hours)

2. Volume status:

   • Hypovolemic hypernatremia
   • Euvolemic hypernatremia
   • Hypervolemic hypernatremia

3. Severity of symptoms:

   • Mild: thirst, weakness
   • Severe: confusion, coma, seizures

Treatment Algorithm

Step 1: Determine Correction Rate

• For chronic hypernatremia (>48 hours): Reduce sodium by no more than 8-10 mmol/L/day 2
• For acute hypernatremia (<24 hours): More rapid correction may be considered 2
• ESPGHAN/ESPEN guidelines recommend reduction rate of 10-15 mmol/L/24h 1

Step 2: Calculate Water Deficit

Water deficit (L) = 0.6 × body weight (kg) × [(current Na⁺/140) - 1]

Step 3: Choose Appropriate Fluid

For hypovolemic hypernatremia:

• Initial volume resuscitation with isotonic fluids if hemodynamically unstable
• Then switch to hypotonic fluids (0.45% saline or 5% dextrose) 3, 4

For euvolemic hypernatremia:

• Hypotonic fluids (0.45% saline or 5% dextrose in water)
• For diabetes insipidus: Consider desmopressin 2, 4

For hypervolemic hypernatremia:

• Loop diuretics to promote free water clearance 5
• Hypotonic fluids with caution

Step 4: Monitor and Adjust

• Check serum sodium every 2-4 hours during active correction 6
• Adjust fluid rate based on sodium changes
• Monitor for signs of cerebral edema

Special Considerations

Diabetes Insipidus

• Central diabetes insipidus: Administer desmopressin
• Nephrogenic diabetes insipidus: Treat underlying cause, consider thiazide diuretics

Traumatic Brain Injury

• Prolonged hypernatremia is not recommended to control intracranial pressure in severe TBI patients 1
• The relationship between serum sodium and ICP is weak
• Hypernatremia with disrupted blood-brain barrier may increase cerebral contusions 1

Pediatric Patients

• Children require careful monitoring of electrolytes
• Adjust fluid therapy based on age-specific requirements
• Monitor for signs of cerebral edema during correction 1

Pitfalls and Caveats

1. Avoid overly rapid correction which can lead to cerebral edema, seizures, and neurological injury 1, 2

2. Don't neglect the underlying cause - treating only the sodium level without addressing the cause will lead to recurrence

3. Be cautious with hemodialysis in chronic hypernatremia - while effective for rapid correction in acute cases, it may cause too rapid sodium changes in chronic cases 2

4. Monitor other electrolytes - hypernatremia is often associated with other electrolyte abnormalities that require concurrent management 4

5. Consider ongoing losses when calculating fluid requirements, especially in patients with diabetes insipidus or high insensible losses 4