What is the recommended management for severe hyponatremia?

From the Guidelines

The recommended management for severe hyponatremia involves water restriction, cessation of diuretics, and consideration of vasopressin receptor antagonists or hypertonic saline for symptomatic cases. According to the 2021 practice guidance by the American Association for the Study of Liver Diseases 1, severe hyponatremia (<120 mEq/L) requires a more severe restriction of water intake, and albumin infusion may be recommended.

Key Considerations

• Water restriction to 1,000 mL/day and cessation of diuretics is recommended for moderate hyponatremia (120-125 mEq/L) 1.
• Vasopressin receptor antagonists can raise serum sodium during treatment but should be used with caution only for a short term (≤30 days) 1.
• Hypertonic saline is reserved for short-term treatment of patients with symptomatic or severe hyponatremia or those with imminent liver transplant (LT) 1.
• The goal rate of increase of serum sodium is 4-6 mEq/L per 24-hour period, not to exceed 8 mEq/L per 24-hour period to ameliorate the risk of osmotic demyelination syndrome (ODS) 1.

Management Approach

• For severe hyponatremia, initial treatment should focus on raising serum sodium by 4-6 mEq/L in the first 24 hours, with frequent monitoring to avoid overcorrection.
• Concurrent treatment of the underlying cause is essential, which may include discontinuing offending medications, addressing SIADH, or treating volume depletion.
• Fluid restriction (typically 800-1000 mL/day) is important for euvolemic or hypervolemic patients.
• In cases of chronic hyponatremia with minimal symptoms, a slower correction rate is preferred.

From the FDA Drug Label

Tolvaptan tablets should be initiated and re-initiated in patients only in a hospital where serum sodium can be monitored closely. Too rapid correction of hyponatremia (e.g., > 12 mEq/L/24 hours) can cause osmotic demyelination resulting in dysarthria, mutism, dysphagia, lethargy, affective changes, spastic quadriparesis, seizures, coma and death. Patients requiring intervention to raise serum sodium urgently to prevent or to treat serious neurological symptoms should not be treated with tolvaptan tablets.

The recommended management for severe hyponatremia is to initiate and re-initiate treatment in a hospital where serum sodium can be closely monitored. Tolvaptan should not be used to treat patients who require urgent intervention to raise serum sodium to prevent or treat serious neurological symptoms.

• The dose of tolvaptan should be increased gradually, with a starting dose of 15 mg once daily, to a maximum of 60 mg once daily, as needed to achieve the desired level of serum sodium.
• Monitoring of serum sodium concentrations and neurologic status is crucial, especially during initiation and after titration.
• Slower rates of correction may be advisable in susceptible patients, including those with severe malnutrition, alcoholism, or advanced liver disease 2.

From the Research

Management of Severe Hyponatremia

The management of severe hyponatremia is a critical aspect of treating this condition. According to the studies, the following approaches are recommended:

• For severely symptomatic hyponatremia, treatment with bolus hypertonic saline is recommended 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 within the first 24 hours 3, 4.
• The use of urea and vaptans can be effective in managing the syndrome of inappropriate antidiuresis and hyponatremia in patients with heart failure, but have adverse effects 3.
• Hourly oral sodium chloride can provide an attractive alternative to intravenous 3% NaCl for selected patients with severe hyponatremia 5.
• Continuous versus bolus infusion of hypertonic saline in the treatment of symptomatic hyponatremia caused by SIAD has been studied, and the results suggest that 3% saline bolus causes more rapid elevation of pNa at 6 hours, with a concomitant improvement in Glasgow Coma Scale (GCS) at 6 hours 6.

Treatment Approaches

The treatment approaches for severe hyponatremia include:

• Intravenous administration of 3% hypertonic saline solution 7.
• Hourly oral sodium chloride tablets 5.
• Continuous infusion of low-dose 3% saline 6.
• Bolus infusion of 3% saline 6.

Important Considerations

When managing severe hyponatremia, it is essential to consider the following:

• The rate of correction of serum sodium concentration should not exceed 10 mEq/L within the first 24 hours to avoid osmotic demyelination syndrome 3, 4.
• Frequent electrolyte monitoring and judicious intervention with dDAVP are required to prevent overcorrection with bolus therapy 6.
• The underlying cause of hyponatremia should be identified and treated, if possible 3, 4.