What is the recommended treatment for severe symptomatic hyponatremia using 3% (three percent) saline?

From the Guidelines

For severe symptomatic hyponatremia, the recommended treatment is 3% hypertonic saline, which may improve hyponatremia at the cost of worsening fluid overload, and is best reserved for those with severely symptomatic acute hyponatremia, especially if a transplant is imminent 1.

Key Considerations

• The goal is to raise serum sodium by up to 5 mmol/L in the first hour, with a limit of 8–10 mmol/L every 24 hours thereafter, until the serum sodium concentration reaches 130 mmol/L 1.
• Administration of 3% saline should be done with caution, as it may worsen fluid overload, and patients should be closely monitored in an ICU setting with frequent neurological checks.
• The underlying cause of hyponatremia should be identified and treated simultaneously.

Treatment Approach

• Initial treatment with 3% hypertonic saline can be administered as an IV bolus, with the goal of raising serum sodium levels to relieve acute symptoms.
• After initial bolus therapy, a slower continuous infusion of 3% saline can be used, with frequent monitoring of serum sodium levels.
• Patients with severe symptomatic hyponatremia require close monitoring and individualized treatment to balance the risk of too-rapid correction and prevent osmotic demyelination syndrome.

Important Considerations

• The use of 3% saline is generally recommended for patients with severely symptomatic acute hyponatremia, especially if a transplant is imminent 1.
• Other treatments, such as fluid restriction and diuretics, may be considered in patients with cirrhosis and ascites, but the use of 3% saline is specifically recommended for severe symptomatic hyponatremia 1.

From the Research

Treatment of Severe Symptomatic Hyponatremia

• The recommended treatment for severe symptomatic hyponatremia is bolus hypertonic saline 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 2.
• Hypertonic saline (3%) infusion is usually used to obtain rapid correction of symptomatic hyponatremia 3, 4, 5.
• The European guidelines recommend bolus-wise administration of 150 mL of 3% hypertonic saline for the treatment of symptomatic hyponatremia 5.
• Treatment target is defined as an increase in serum sodium by 5-10 mEq/L within the first 24 hours and a maximum of 8 mEq/L during subsequent 24 hours 5.
• Overly rapid correction of hyponatremia may cause osmotic demyelination, a rare but severe neurological condition, which can result in parkinsonism, quadriparesis, or even death 2, 3, 4.

Administration and Monitoring

• Frequent monitoring of the serum sodium concentration and urine output are mandatory during treatment with hypertonic saline 4, 5.
• Administration of desmopressin to terminate an unwanted water diuresis is an effective strategy to avoid or reverse overcorrection 4.
• Reducing bolus-volume and reevaluation before repeating bolus infusion might prevent overcorrection 5.
• Diuresis should be monitored to avoid misinterpreting symptoms caused by hypovolemia as severely symptomatic hyponatremia 5.

Risks and Complications

• Overcorrection of hyponatremia risks iatrogenic brain damage 2, 3, 4.
• The risks of brain myelinolysis can be largely reduced by limiting the correction level to < or = 15 mEq/1/24 h 3.
• Demyelinization is also observed in hypernatremia but it follows a greater (50%) increase in serum sodium than from hyponatremic baseline 3.