What is the treatment for pseudo hyponatremia?

Treatment of Pseudohyponatremia

Pseudohyponatremia requires no specific sodium correction as it represents a laboratory artifact rather than a true sodium deficit, and treatment should focus on addressing the underlying cause.

Understanding Pseudohyponatremia

Pseudohyponatremia is a laboratory phenomenon characterized by falsely low serum sodium measurements despite normal effective plasma osmolarity. It occurs in specific clinical scenarios:

• Pseudohyponatremia results from laboratory artifact when sodium is measured by flame photometry or other methods that don't directly measure sodium activity in the water phase of plasma 1
• It commonly occurs in conditions with extreme hyperlipidemia or hyperproteinemia (such as multiple myeloma) 2, 1
• Unlike true hyponatremia, patients with pseudohyponatremia typically don't exhibit symptoms related to low sodium levels 3

Diagnostic Approach

Proper identification of pseudohyponatremia is essential to avoid inappropriate treatment:

• Measure serum osmolality - normal or elevated osmolality with low reported sodium suggests pseudohyponatremia 3
• Consider using ion-selective electrode measurement of sodium, which provides accurate readings even in the presence of hyperlipidemia or hyperproteinemia 2, 1
• Evaluate for conditions associated with pseudohyponatremia:
  • Severe hyperlipidemia
  • Hyperproteinemia (multiple myeloma, Waldenstrom's macroglobulinemia)
  • Hyperglycemia (which causes a different form of laboratory artifact) 3

Treatment Principles

The management of pseudohyponatremia differs fundamentally from true hyponatremia:

• No sodium correction is needed as the actual sodium concentration in the water phase of plasma is normal 1, 4
• Focus treatment on the underlying cause of hyperlipidemia or hyperproteinemia 3
• Avoid inappropriate administration of hypertonic saline or other sodium-raising interventions that could lead to true hypernatremia 1

Common Pitfalls to Avoid

• Misdiagnosing pseudohyponatremia as true hyponatremia and initiating unnecessary fluid restriction or sodium correction 1
• Failing to recognize the laboratory method used for sodium measurement in your facility 1
• Not considering pseudohyponatremia in patients with conditions associated with extreme hyperlipidemia or hyperproteinemia 2, 4
• Overlooking the need to measure serum osmolality to differentiate between true and pseudo-hyponatremia 3

Special Considerations

• In multiple myeloma patients, pseudohyponatremia may resolve with treatment of the underlying disease, as demonstrated by normalization of sodium levels after chemotherapy 2
• Alternative methods to assess true sodium status include:
  • Measuring serum water content through osmometry before and after dilution 4
  • Chloride measurement before and after ultrafiltration 4
  • Direct ion-selective electrode measurement 2, 1

Remember that pseudohyponatremia is a laboratory artifact rather than a physiological disturbance, and treating it as true hyponatremia could lead to harmful consequences.