How to manage hyponatremia?

From the Guidelines

Managing hyponatremia requires a careful approach, prioritizing the correction of the underlying cause and sodium levels, with the goal of improving morbidity, mortality, and quality of life. The management of hyponatremia depends on the severity, symptoms, and whether the condition developed acutely or chronically. For mild to moderate asymptomatic hyponatremia, fluid restriction to 800-1000 mL/day is often sufficient 1, especially in cases of SIADH or heart failure. For symptomatic or severe hyponatremia (sodium <120 mEq/L), hypertonic 3% saline may be administered intravenously at 1-2 mL/kg/hr, with the goal of increasing sodium by 4-6 mEq/L in the first 24 hours to relieve symptoms 1. Correction must be carefully monitored to avoid exceeding 8-10 mEq/L per day, as rapid correction risks osmotic demyelination syndrome. Some key points to consider in the management of hyponatremia include:

• For hypovolemic hyponatremia, isotonic saline (0.9% NaCl) can restore volume while correcting sodium levels 1.
• Specific medications include vasopressin receptor antagonists like tolvaptan (starting at 15 mg daily) for euvolemic or hypervolemic hyponatremia, and loop diuretics like furosemide for hypervolemic states 1.
• Underlying conditions such as adrenal insufficiency may require hormone replacement with hydrocortisone.
• Regular monitoring of serum sodium (every 2-4 hours initially in severe cases) is essential to ensure appropriate correction rates and prevent neurological complications 1. It is also important to note that 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. Additionally, the use of hypertonic saline is reserved for short-term treatment of patients with symptomatic or severe hyponatremia or those with imminent LT 1. When correction of chronic hyponatremia is indicated in patients with cirrhosis, the goal rate of increase of serum (Na) is 4-6 mEq/L per 24-hour period, not to exceed 8 mEq/L per 24-hour period to ameliorate the risk of ODS 1. Overall, the management of hyponatremia requires a careful and individualized approach, taking into account the underlying cause, severity, and symptoms of the condition, as well as the patient's overall health status and risk factors for complications.

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.

Management of Hyponatremia:

• Monitor serum sodium levels
• Use of tolvaptan to remove excess free body water and increase serum sodium concentrations
• Modify free-water intake or infusion as needed
• Dose decreases or interruption of tolvaptan treatment if hypernatremia is observed 2 2

Note: The provided drug labels do not offer a comprehensive guide to managing hyponatremia, but rather provide information on the use of tolvaptan in treating the condition.

From the Research

Management of Hyponatremia

Hyponatremia is a common electrolyte disorder that affects approximately 5% of adults and 35% of hospitalized patients 3. The management of hyponatremia depends on the underlying cause, severity, and symptoms of the condition.

Approach to Management

• The approach to managing hyponatremia should consist of treating the underlying cause 3.
• Clinicians should categorize patients according to their fluid volume status (hypovolemic hyponatremia, euvolemic hyponatremia, or hypervolemic hyponatremia) 3, 4.
• 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.
• Vasopressin receptor antagonists provide prompt and effective water diuresis and increase in serum sodium concentration in both euvolemic and hypervolemic hyponatremia 4.

Treatment of Symptomatic Hyponatremia

• Severely symptomatic hyponatremia (with signs of somnolence, obtundation, coma, seizures, or cardiorespiratory distress) is a medical emergency that requires urgent treatment with bolus hypertonic saline to reverse hyponatremic encephalopathy 3, 4, 5, 6.
• The goal of treatment is to increase the serum sodium level by 4-6 mEq/L within 1-2 hours, but by no more than 10 mEq/L within the first 24 hours 3, 5.
• Overly rapid correction of chronic hyponatremia may cause osmotic demyelination, a rare but severe neurological condition 3, 5, 7, 6.

Considerations for Treatment

• The therapeutic strategy should guide optimal treatment of hyponatremia, requiring attention to the patient's volume status, presence or absence of symptoms, duration of hypo-osmolality, and presence or absence of risk factors for neurologic complications 7.
• Planning therapy to achieve a 6 mEq/L daily increase in the serum sodium concentration can avoid iatrogenic brain damage by staying well clear of correction rates that are harmful 5.
• Administration of desmopressin to halt a water diuresis can help prevent overcorrection; if overcorrection occurs, therapeutic relowering of the serum sodium concentration is supported by data in experimental animals and was found to be safe in a small observational clinical trial 5.