What is the treatment for hyponatremia (low sodium level of 122 mEq/L) in the Emergency Department (ED)?

From the Guidelines

For a patient with a sodium level of 122 mEq/L in the Emergency Department, the most appropriate treatment approach is to focus on careful correction while avoiding overly rapid sodium increases, with a goal to raise sodium by 4-6 mEq/L in the first 24 hours, as recommended by the American Association for the Study of Liver Diseases in 2021 1. The initial management includes fluid restriction to 1-1.5 L/day for hyponatremic patients who are euvolemic or hypervolemic, as suggested by the Clinical and Molecular Hepatology guidelines in 2018 1.

• Key considerations in the treatment of hyponatremia include:
  • Identifying and addressing underlying causes such as SIADH, heart failure, cirrhosis, or medication effects
  • Regular monitoring of serum sodium levels (every 2-4 hours initially for symptomatic patients, then every 4-6 hours) to ensure appropriate correction rates
  • Consultation with nephrology is recommended for complex cases, especially when hypertonic saline is being administered or the etiology is unclear For symptomatic patients (those with seizures, altered mental status, or severe neurological symptoms), administering 3% hypertonic saline at 100-150 mL over 10-20 minutes, which can be repeated 2-3 times if symptoms persist, is a recommended approach 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. It is essential to note that severe hyponatremia (<120 mEq/L) at the time of liver transplantation increases the risk of osmotic demyelination syndrome, and multidisciplinary coordinated care may mitigate this risk 1.

From the FDA Drug Label

Tolvaptan tablets are indicated for the treatment of clinically significant hypervolemic and euvolemic hyponatremia (serum sodium <125 mEq/L or less marked hyponatremia that is symptomatic and has resisted correction with fluid restriction) The usual starting dose for tolvaptan tablets is 15 mg administered once daily without regard to meals. Increase the dose to 30 mg once daily, after at least 24 hours, to a maximum of 60 mg once daily, as needed to achieve the desired level of serum sodium. 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.

Treatment of Hyponatremia: Tolvaptan is used to treat clinically significant hypervolemic and euvolemic hyponatremia.

• The goal is to increase serum sodium levels, but too rapid correction can cause serious neurologic sequelae.
• The starting dose is 15 mg once daily, which can be increased to a maximum of 60 mg once daily as needed.
• Monitoring of serum sodium and volume status is crucial during initiation and titration of tolvaptan therapy 2.

From the Research

Sodium 122 Treatment in the ED

• The treatment of hyponatremia, including Sodium 122, depends on the underlying cause and severity of the condition 3, 4.
• For patients with severely symptomatic hyponatremia, 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 3.
• In cases of hyponatremic encephalopathy, a 3% sodium chloride protocol has been shown to be effective in reversing symptoms without producing neurologic injury related to cerebral demyelination 5.
• 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, 6.
• Treatment options for hyponatremia also include isotonic saline, water restriction, long loops diuretics, and vaptans, and the choice of treatment depends on the individual patient's condition and the underlying cause of the hyponatremia 4, 7.

Treatment Approaches

• Hypovolemic hyponatremia is treated with normal saline infusions 4.
• Euvolemic hyponatremia is treated with restricting free water consumption or using salt tablets or intravenous vaptans 4.
• Hypervolemic hyponatremia is treated primarily by managing the underlying cause and free water restriction 4.

Important Considerations

• Overly rapid correction of chronic hyponatremia can cause osmotic demyelination, a rare but severe neurological condition 3, 4.
• The correction limit for serum sodium level is 10 mEq/L within the first 24 hours 3.
• Patients with a history of hyponatremia are at increased risk of falls and fractures, and cognitive impairment 3.