What IV fluid is used to treat hyponatremia?

IV Fluid Treatment for Hyponatremia

For treating hyponatremia, isotonic saline (0.9% NaCl) is the appropriate IV fluid for most cases of hypovolemic hyponatremia, while 3% hypertonic saline is indicated for severe symptomatic hyponatremia regardless of volume status. 1, 2

Treatment Based on Volume Status and Symptom Severity

Hypovolemic Hyponatremia

• Isotonic saline (0.9% NaCl) is the first-line treatment for hypovolemic hyponatremia to restore intravascular volume 1
• Discontinue diuretics that may be contributing to hyponatremia 1
• For severe dehydration with neurological symptoms, consider hypertonic saline with careful monitoring 1

Euvolemic Hyponatremia (SIADH)

• Fluid restriction (<1 L/day) is the first-line treatment for mild to moderate asymptomatic SIADH 1
• For severe symptoms (seizures, coma) or sodium <120 mEq/L, administer 3% hypertonic saline 1, 3
• 3% hypertonic saline can be administered as:
  • Bolus infusion (100 mL, repeated up to three times) which produces faster initial elevation of serum sodium than continuous infusion 3
  • Continuous infusion at a controlled rate 3

Hypervolemic Hyponatremia

• Implement fluid restriction to 1-1.5 L/day for serum sodium <125 mmol/L 1
• Consider albumin infusion for patients with cirrhosis 1
• Avoid hypertonic saline unless life-threatening symptoms are present, as it may worsen edema and ascites 1

Correction Rate Guidelines

• For severe symptoms (seizures, coma), aim to increase sodium by 4-6 mmol/L in the first 6 hours or until symptoms improve 1, 3
• Total correction should not exceed 8 mmol/L in 24 hours to prevent osmotic demyelination syndrome 1, 4
• Patients with advanced liver disease, alcoholism, malnutrition, or prior encephalopathy require more cautious correction (4-6 mmol/L per day) 1

Special Considerations

• Hypotonic fluids may be required in specific situations:
  • Patients with significant renal concentrating defects (e.g., nephrogenic diabetes insipidus) 5
  • Patients with voluminous diarrhea or severe burns 5
  • Correction of hypernatremia 5
• In pediatric patients, the American Academy of Pediatrics recommends isotonic solutions with appropriate KCl and dextrose for maintenance IV fluids to prevent hyponatremia 5
• Frequent monitoring of serum sodium is essential during treatment, especially with hypertonic saline 1, 3
• If overcorrection occurs, consider relowering with electrolyte-free water or desmopressin 1, 4

Common Pitfalls to Avoid

• Overly rapid correction exceeding 8 mmol/L in 24 hours can lead to osmotic demyelination syndrome 1, 6
• Using fluid restriction in cerebral salt wasting can worsen outcomes 1
• Inadequate monitoring during active correction 1
• Failing to recognize and treat the underlying cause 1
• Using hypertonic saline in hypervolemic hyponatremia without life-threatening symptoms 1

Monitoring During Treatment

• For severe symptoms: monitor serum sodium every 2 hours during initial correction 1
• Watch for signs of osmotic demyelination syndrome (dysarthria, dysphagia, oculomotor dysfunction, quadriparesis) typically occurring 2-7 days after rapid correction 1, 4
• If patients receiving isotonic maintenance IVFs develop hyponatremia, evaluate for other sources of free water or possible SIADH and/or adrenal insufficiency 5