What is the appropriate treatment for a patient with hyponatremia?

From the Guidelines

The most appropriate treatment for a patient with hyponatremia is a slow infusion of hypertonic saline, with the goal of correcting serum sodium levels by no more than 8 mmol/L per day, as recommended by the most recent guidelines 1. Hyponatremia is a condition characterized by abnormally low sodium levels in the blood, typically below 135 mEq/L. When treating hyponatremia, it's crucial to correct sodium levels gradually to prevent osmotic demyelination syndrome, a serious neurological complication that can occur with rapid sodium correction.

Key Considerations

• Hypertonic saline (typically 3% NaCl) provides concentrated sodium to raise serum levels.
• The infusion must be administered slowly, usually at rates that increase serum sodium by no more than 8-10 mEq/L in 24 hours for chronic hyponatremia, or up to 4-6 mEq/L in the first 6 hours for severe symptomatic cases.
• Patients receiving hypertonic saline require close monitoring of serum sodium levels, neurological status, and fluid balance.
• Rapid infusion or using hypotonic solutions would be contraindicated as they could worsen hyponatremia or cause dangerous fluctuations in sodium levels.

Treatment Approach

• For hypovolaemic hyponatremia, plasma volume expansion with saline solution and correction of the causative factor is necessary 1.
• For hypervolemic hyponatremia, attainment of a negative water balance is required, and non-osmotic fluid restriction may be helpful in preventing further decrease in serum sodium levels 1.
• Hypertonic sodium chloride administration should be reserved for severely symptomatic patients with acute hyponatremia, and serum sodium should be slowly corrected 1.

Monitoring and Management

• Close monitoring of serum sodium levels, neurological status, and fluid balance is essential for patients receiving hypertonic saline.
• Albumin infusion may improve serum sodium concentration, but more information is needed 1.
• Midodrine may be considered for refractory ascites on a case-by-case basis, but the quality of evidence is low 1.

From the Research

Treatment Approaches for Hyponatremia

The treatment of hyponatremia depends on the severity and symptoms of the condition, as well as the underlying cause. The following approaches are recommended:

• For symptomatic hyponatremia, the rapid intermittent administration of hypertonic saline is preferred 2, 3, 4, 5.
• In asymptomatic mild hyponatraemia, an adequate solute intake with an initial fluid restriction (FR) of 500 ml/day adjusted according to the serum sodium (sNa) levels is preferred 2.
• For patients with the syndrome of inappropriate antidiuretic hormone (SIADH), urea and tolvaptan are considered the most effective second-line therapies 2.
• Oral urea is considered to be a very effective and safe treatment for mild and asymptomatic hyponatraemia 2.
• Specific treatment with vaptans may be considered in either euvolaemic or hypervolaemic patients with high ADH activity 2.

Correction Rates and Monitoring

The correction of hyponatremia should be done gradually to avoid overcorrection, which can lead to osmotic demyelination. The recommended correction rates are:

• 4-6 mmol/L increase in serum sodium concentration in the first 1-2 hours for severely symptomatic patients 5.
• 6-8 mmol/L in 24 hours, 12-14 mmol/L in 48 hours, and 14-16 mmol/L in 72 hours 4.
• Frequent monitoring of the serum sodium concentration and urine output are mandatory to avoid overcorrection 3, 4.

Special Considerations

• In patients with severe symptoms, such as somnolence, obtundation, coma, seizures, or cardiorespiratory distress, bolus hypertonic saline is recommended to reverse hyponatremic encephalopathy 5.
• In patients with hypovolemic hyponatremia, treatment should focus on correcting the underlying cause of volume depletion 5.
• In patients with euvolemic or hypervolemic hyponatremia, treatment should focus on correcting the underlying cause of water retention 5.