What is the management of hyponatremia (low sodium levels)?

From the Guidelines

The management of hyponatremia should prioritize addressing the underlying cause, with fluid restriction and correction of serum sodium levels tailored to the severity and duration of the condition, as well as the patient's volume status, with the goal of correcting serum sodium at a rate of 4-6 mEq/L per 24-hour period, not to exceed 8 mEq/L per 24-hour period to prevent osmotic demyelination syndrome 1.

Key Considerations

• For mild to moderate hyponatremia (sodium >125 mEq/L) without symptoms, addressing the underlying cause is the primary approach, which may involve discontinuing offending medications, treating SIADH, or managing heart failure or cirrhosis.
• Fluid restriction to 800-1000 mL/day is often the first-line treatment for euvolemic hyponatremia, while for hypovolemic hyponatremia, isotonic saline (0.9% NaCl) should be administered to restore volume.
• In hypervolemic states, fluid restriction and loop diuretics like furosemide 20-40 mg IV or PO are indicated.
• For severe symptomatic hyponatremia (sodium <125 mEq/L with neurological symptoms), 3% hypertonic saline should be given at 100-150 mL over 10-20 minutes, which can be repeated 2-3 times until symptoms improve.

Correction Rates and Monitoring

• The correction rate should not exceed 8-10 mEq/L in the first 24 hours and 18 mEq/L in 48 hours to prevent osmotic demyelination syndrome.
• Regular monitoring of serum sodium levels is essential during treatment to ensure appropriate correction rates and prevent complications.

Specific Guidance for Cirrhosis

• Mild hyponatremia (Na 126-135 mEq/L) in cirrhosis without symptoms does not require specific management apart from monitoring and water restriction 1.
• Water restriction to 1,000 mL/day and cessation of diuretics is recommended in the management of moderate hyponatremia (120-125 mEq/L), and a more severe restriction of water intake with albumin infusion is recommended for severe hyponatremia (<120 mEq/L) 1.
• The use of vasopressin receptor antagonists in cirrhosis can raise serum sodium during treatment, but they should be used with caution only for a short term (≤30 days) 1.

From the FDA Drug Label

Removal of excess free body water increases serum osmolality and serum sodium concentrations. All patients treated with tolvaptan, especially those whose serum sodium levels become normal, should continue to be monitored to ensure serum sodium remains within normal limits If hypernatremia is observed, management may include dose decreases or interruption of tolvaptan treatment, combined with modification of free-water intake or infusion.

The management of hyponatremia with tolvaptan involves monitoring serum sodium levels and adjusting the dose as needed to prevent hypernatremia.

• Key considerations:
  • Monitor serum sodium levels closely
  • Adjust tolvaptan dose to prevent hypernatremia
  • Modify free-water intake or infusion as needed 2

From the Research

Management of Hyponatremia

The management of hyponatremia involves treating the underlying cause of the condition and categorizing patients according to their fluid volume status (hypovolemic hyponatremia, euvolemic hyponatremia, or hypervolemic hyponatremia) 3.

• For most patients, the approach to managing hyponatremia should consist of treating the underlying cause.
• Urea and vaptans can be effective treatments for the syndrome of inappropriate antidiuresis and hyponatremia in patients with heart failure, but have adverse effects 3.
• Severely symptomatic hyponatremia (with signs of somnolence, obtundation, coma, seizures, or cardiorespiratory distress) is a medical emergency and should be treated with bolus hypertonic saline to reverse hyponatremic encephalopathy by increasing the serum sodium level by 4 mEq/L to 6 mEq/L within 1 to 2 hours but by no more than 10 mEq/L (correction limit) within the first 24 hours 3, 4.

Treatment Methods

The principles of fluid restriction, which is the mainstay of management of all types of hypotonic hyponatremia, should be clearly understood and followed 5.

• Treatment methods specific to various categories of hyponatremia are available.
• The indications and risks of these treatments should also be well understood.
• Rapid correction of chronic hypotonic hyponatremia may lead to osmotic demyelination syndrome, which has severe clinical manifestations, and may lead to permanent neurological disability or death 5, 4.

Clinical Practice Guidelines

The European Society of Intensive Care Medicine (ESICM), the European Society of Endocrinology (ESE) and the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) have developed clinical practice guidelines on the diagnostic approach and treatment of hyponatremia 6.

• The guidelines focus on patient-positive outcomes and on providing a useful tool for clinicians involved in everyday practice.
• The use of vasopressin receptor antagonists (VRA) is also discussed, which can induce urinary dilution with an aquaresis that leads to an increase in serum sodium concentration 7.