From the Guidelines
Treatment of Severe Hyponatremia
Severe hyponatremia should be treated with cautious administration of hypertonic saline and correction of the underlying cause.
- For symptomatic patients, 3% hypertonic saline may be administered at a rate of 1-2 mL/kg/hour, with a goal of increasing serum sodium by 4-6 mEq/L within the first 4-6 hours 1.
- Asymptomatic patients may be managed with fluid restriction and oral sodium supplements, such as sodium chloride tablets 1-2 grams orally three times daily, to gradually correct the sodium level over 24-48 hours 1.
Key Considerations
- Close monitoring of serum sodium levels and clinical status is essential to avoid overcorrection or worsening of hyponatremia 1.
- Hypovolemic hyponatremia requires plasma volume expansion with saline solution and correction of the causative factor 1.
- Hypervolemic hyponatremia requires attainment of a negative water balance, and fluid restriction to 1-1.5 L/day may be reserved for those who are clinically hypervolaemic with severe hyponatraemia (serum sodium <125 mmol/L) 1.
- Hypertonic sodium chloride administration should be limited to severely symptomatic hyponatremia, and serum sodium should be slowly corrected to avoid the risk of central pontine myelinolysis 1.
From the Research
Treatment for Severe Hyponatremia
The treatment for severe hyponatremia typically involves correcting the underlying cause of the condition and managing the patient's fluid volume status.
- For patients with severely symptomatic hyponatremia, bolus hypertonic saline is recommended to increase the serum sodium level by 4-6 mEq/L within 1-2 hours, but not exceeding a correction limit of 10 mEq/L within the first 24 hours 2, 3, 4.
- The rate of correction depends on the duration, degree of hyponatremia, and the presence or absence of symptoms 4.
- In patients with acute, severe, and symptomatic hyponatremia, hourly oral sodium chloride can be used as an alternative to intravenous 3% NaCl, with careful monitoring of the serum sodium concentration 5.
- Concurrent administration of desmopressin and hypertonic saline can also be used to correct severe hyponatremia, with a predicted increase in serum sodium level and minimal risk of overcorrection 6.
Management Strategies
- Restricting free water and hypotonic fluid intake is recommended for all patients with hyponatremia, regardless of their volume status 4.
- Vasopressin antagonists can be used to normalize the serum sodium concentration on a chronic basis, but their use is limited by practical considerations 3.
- Urea and vaptans can be effective treatments for the syndrome of inappropriate antidiuresis and hyponatremia in patients with heart failure, but have adverse effects such as poor palatability and gastric intolerance with urea, and overly rapid correction of hyponatremia and increased thirst with vaptans 2.