How is hypernatremia treated?

Treatment of Hypernatremia

Hypernatremia should be treated primarily with water replacement using hypotonic fluids, with the rate of correction based on the chronicity of the condition and avoiding rapid correction to prevent neurological complications. 1

Diagnosis and Assessment

Before initiating treatment, proper assessment is crucial:

1. Confirm true hypernatremia - Exclude pseudohypernatremia 2
2. Determine volume status - Assess whether the patient is hypovolemic, euvolemic, or hypervolemic 2
3. Determine chronicity - Acute (<48 hours) or chronic (>48 hours) 2
4. Evaluate urine osmolality and sodium - Helps identify the underlying cause 2
5. Assess for symptoms - Altered mental status, weakness, seizures indicate severity 1

Treatment Algorithm

1. Emergency Management of Hypernatremic Dehydration

For patients with NDI (Nephrogenic Diabetes Insipidus) presenting with hypernatremic dehydration:

• Avoid salt-containing solutions, especially 0.9% NaCl - These increase renal osmotic load 3
• Use 5% dextrose in water - Preferred for intravenous rehydration 3
• Calculate initial fluid rate based on physiological demand:
  • Children: First 10 kg: 100 ml/kg/24h; 10-20 kg: 50 ml/kg/24h; remaining: 20 ml/kg/24h
  • Adults: 25-30 ml/kg/24h 3

2. Treatment Based on Volume Status

Hypovolemic Hypernatremia:

• Initial stabilization with isotonic fluids if hemodynamically unstable
• Followed by hypotonic fluids (5% dextrose or 0.45% saline) 1, 2
• Address underlying cause of fluid loss (diarrhea, vomiting, etc.)

Euvolemic Hypernatremia:

• Free water replacement orally if possible
• 5% dextrose intravenously if oral intake not possible 2
• Treat diabetes insipidus if present:
  • Central DI: Desmopressin
  • Nephrogenic DI: Thiazide diuretics, low salt diet, prostaglandin synthesis inhibitors 3

Hypervolemic Hypernatremia:

• Loop diuretics to promote sodium excretion
• Free water replacement 2

3. Rate of Correction

• Acute hypernatremia (<48 hours): Can correct more rapidly, up to 1 mEq/L/hour
• Chronic hypernatremia (>48 hours): Correct at maximum rate of 8-10 mEq/L/day 2, 4
• Monitor sodium levels every 2-4 hours during active correction 4

Special Considerations

Nephrogenic Diabetes Insipidus Management

• Low salt diet (≤6 g/day) and protein restriction (<1 g/kg/day) 3
• Thiazide diuretics may be considered based on patient preference 3
• Discontinue prostaglandin synthesis inhibitors in adults or when continence is achieved 3
• Prostaglandin synthesis inhibitors are contraindicated in pregnancy 3

Critically Ill Patients

• More frequent monitoring of electrolytes
• Higher risk of mortality with hypernatremia 4
• Careful fluid management as many patients have impaired consciousness 4

Pitfalls and Caveats

1. Avoid overly rapid correction - Can lead to cerebral edema and neurological complications 2, 4
2. Don't use isotonic saline for NDI patients - Can worsen hypernatremia as it increases renal osmotic load 3
3. Don't neglect ongoing losses - Continue to replace ongoing fluid losses during correction 2
4. Regular monitoring is essential - Serum sodium, urine output, and clinical status 2
5. Underlying cause must be addressed - Treatment is not complete without addressing the etiology 1, 2

Follow-up

For patients with chronic conditions like NDI:

• Regular monitoring of electrolytes (Na, K, Cl, HCO3)
• Ultrasound of urinary tract every 2-3 years
• More frequent follow-up for patients with CKD 3