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

From the Guidelines

Management of symptomatic hyponatremia requires careful correction of serum sodium levels to prevent neurological complications, with the goal of raising sodium by 4-6 mEq/L in the first 6 hours to alleviate acute symptoms, and not exceeding 8-10 mEq/L in 24 hours or 18 mEq/L in 48 hours to prevent osmotic demyelination syndrome, as recommended by recent guidelines 1. For patients with severe symptoms like seizures or altered mental status, administer 3% hypertonic saline as a 100-150 mL bolus over 10-20 minutes, which can be repeated 1-2 times if symptoms persist.

• The use of hypertonic saline should be reserved for severely symptomatic patients, especially if a transplant is imminent, and serum sodium should be slowly corrected to prevent central pontine myelinolysis 1.
• For less severe symptoms, a slower correction is appropriate using fluid restriction (typically <1-1.5 L/day) and addressing underlying causes.
• Specific pharmacologic options include tolvaptan (starting at 15 mg daily) for SIADH, with close monitoring of sodium levels, as it has been shown to be effective in improving serum sodium concentration in patients with hypervolemic hyponatremia 1.
• Loop diuretics like furosemide (20-40 mg IV or oral) may help in hypervolemic hyponatremia, but should be used with caution to avoid worsening fluid overload.
• Throughout treatment, frequent monitoring of serum sodium (every 2-4 hours initially in severe cases) is essential to guide therapy.
• The underlying cause of hyponatremia must be identified and treated simultaneously, whether it's medications, endocrine disorders, heart failure, or other conditions.
• Fluid management should be tailored to the patient's volume status: restriction for euvolemic/hypervolemic states and isotonic saline for hypovolemic patients, as recommended by recent guidelines 1.

From the FDA Drug Label

The dose of tolvaptan could be increased at 24-hour intervals to 30 mg once daily, then to 60 mg once daily, until either the maximum dose of 60 mg or normonatremia (serum sodium >135 mEq/L) was reached Fluid restriction was to be avoided if possible during the first 24 hours of therapy to avoid overly rapid correction of serum sodium, and during the first 24 hours of therapy 87% of patients had no fluid restriction. 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 symptomatic hyponatremia with tolvaptan involves:

• Initiating treatment with 15 mg once daily and increasing the dose at 24-hour intervals to 30 mg once daily, then to 60 mg once daily, until normonatremia is reached or the maximum dose is attained 2
• Avoiding fluid restriction during the first 24 hours of therapy to prevent overly rapid correction of serum sodium 2
• Monitoring serum sodium levels to prevent hypernatremia and adjusting the dose or treatment as needed 2 Key considerations:
• Monitoring serum sodium levels closely to avoid overly rapid correction or hypernatremia
• Adjusting the dose of tolvaptan based on serum sodium levels and clinical response
• Modifying free-water intake or infusion as needed to manage hypernatremia 2

From the Research

Management of Symptomatic Hyponatremia

• Symptomatic hyponatremia is a serious condition that requires prompt treatment, as it can lead to severe neurological damage or even death 3, 4, 5, 6, 7.
• The treatment approach depends on the severity of symptoms, with severely symptomatic patients requiring immediate attention 3, 4, 5, 6, 7.
• Hypertonic saline is the recommended treatment for severely symptomatic hyponatremia, with a goal of increasing serum sodium levels by 4-6 mEq/L within 1-2 hours, but not exceeding 10 mEq/L within the first 24 hours 3, 4, 5, 6, 7.

Treatment Options

• 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.
• Hypertonic saline can be administered as a bolus injection or continuous infusion, with the choice depending on the severity of symptoms and the patient's response to treatment 5, 7.
• Desmopressin can be used concomitantly with hypertonic saline to prevent rapid correction of serum sodium levels and reduce the risk of osmotic demyelination 6, 7.

Monitoring and Prevention of Overcorrection

• Frequent monitoring of serum sodium levels and urine output is essential to avoid overcorrection and prevent iatrogenic brain damage 4, 5, 6, 7.
• The risk of overcorrection is higher in patients with severe symptoms, and reducing the bolus volume and reevaluating before repeating the bolus infusion may help prevent overcorrection 5.
• Diuresis should be monitored, as symptoms caused by hypovolemia can be misinterpreted as severely symptomatic hyponatremia 5.