What is the treatment for hypernatremia (high sodium levels)?

Treatment of Hypernatremia

The treatment of hypernatremia should focus on addressing the underlying cause while carefully administering hypotonic fluids to gradually correct the sodium imbalance, with the goal of decreasing serum sodium by no more than 8-10 mmol/L per 24-hour period to prevent neurological complications.

Classification and Initial Assessment

Hypernatremia (serum sodium >145 mmol/L) requires careful assessment before treatment. The approach depends on:

1. Volume status assessment:

   • Hypovolemic hypernatremia
   • Euvolemic hypernatremia
   • Hypervolemic hypernatremia

2. Acuity of development:

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

3. Presence of neurological symptoms:

   • Mild: weakness, irritability, lethargy
   • Severe: seizures, altered consciousness, coma

Treatment Algorithm

1. Hypovolemic Hypernatremia (most common)

This occurs due to water loss exceeding sodium loss:

• First step: Volume resuscitation with hypotonic fluids 1

  • Initial fluid: 0.45% saline or 5% dextrose in water (D5W)
  • Calculate water deficit: Water deficit = 0.6 × body weight (kg) × [(measured Na⁺/140) - 1]
  • Rate of correction: No more than 8-10 mmol/L per 24 hours 2

• Monitor: Serum sodium every 2-4 hours initially, then every 4-6 hours

  • Adjust fluid rate based on sodium correction rate
  • Watch for signs of cerebral edema if correction is too rapid

2. Euvolemic Hypernatremia

Often due to diabetes insipidus or impaired thirst mechanism:

• Treatment: Replace free water deficit
  • D5W is preferred if patient can tolerate glucose load
  • 0.45% saline if some sodium replacement is also needed
  • Treat underlying cause (e.g., DDAVP for central diabetes insipidus)

3. Hypervolemic Hypernatremia

Rare condition with excess total body sodium:

• Treatment: Remove excess sodium
  • Loop diuretics (furosemide) with hypotonic fluid replacement
  • Consider hemodialysis in severe cases or renal failure

Special Considerations

Rate of Correction

• Chronic hypernatremia (>48 hours): Correct at maximum rate of 8 mmol/L/day 2

  • Too rapid correction can lead to cerebral edema
  • Target correction over 48-72 hours

• Acute hypernatremia (<48 hours): Can be corrected more rapidly (10-12 mmol/L/day) 2

  • Still requires careful monitoring

Calculating Fluid Requirements

For a 70 kg patient with serum sodium of 160 mmol/L:

1. Water deficit = 0.6 × 70 × [(160/140) - 1] = 6 liters
2. Add ongoing losses and maintenance fluids
3. Distribute correction over 48-72 hours

Monitoring During Treatment

• Serum sodium levels (every 2-4 hours initially)
• Neurological status
• Fluid input/output
• Hemodynamic parameters
• Urine output

Complications to Watch For

• Cerebral edema: Can occur with overly rapid correction

  • Signs: Headache, nausea, vomiting, altered mental status, seizures
  • Management: Slow or temporarily halt correction, consider hypertonic saline if severe symptoms develop

• Persistent hypernatremia: May indicate ongoing water losses or inadequate replacement

  • Reassess volume status and adjust treatment plan

Pitfalls to Avoid

1. Correcting too rapidly: Never exceed 10 mmol/L/day decrease in chronic hypernatremia 2

2. Failing to identify and treat the underlying cause: Address diabetes insipidus, excessive fluid losses, or medication effects

3. Using incorrect fluids: Avoid using isotonic fluids as primary treatment as they won't effectively lower sodium

4. Inadequate monitoring: Frequent electrolyte checks are essential during correction

5. Overlooking comorbidities: Renal failure, heart failure, and liver disease may complicate management

By following this structured approach to hypernatremia management with careful attention to the rate of correction and underlying causes, you can effectively treat this potentially dangerous electrolyte disorder while minimizing the risk of neurological complications.