From the Research
Pseudohyponatremia is a laboratory artifact that does not require treatment to address the sodium level, and management should focus on addressing the underlying cause, such as treating hyperproteinemia or managing hyperlipidemia. This condition occurs when there is an increase in the non-aqueous components of plasma, such as lipids (hyperlipidemia) or proteins (hyperproteinemia), which displaces water and sodium in the sample, leading to a falsely low serum sodium measurement 1. Unlike true hyponatremia, patients with pseudohyponatremia typically don't exhibit symptoms of low sodium because the sodium concentration in the water phase of blood remains normal, maintaining proper cellular function.
Key Points to Consider
- Pseudohyponatremia is often linked to conditions like hyperlipidemia or hyperproteinemia, and can mislead clinicians, resulting in misdiagnosis 2.
- Diagnosis involves measuring serum osmolality, which remains normal in pseudohyponatremia (280-295 mOsm/kg) despite the apparently low sodium level.
- Direct ion-selective electrode methods that measure sodium in the water phase of blood can also confirm the diagnosis by showing normal sodium levels 1.
- Management focuses on addressing the underlying cause, rather than correcting sodium levels, and no sodium supplementation is needed since true sodium deficiency doesn't exist.
Clinical Implications
- Healthcare providers should be aware of this phenomenon to avoid unnecessary and potentially harmful sodium correction treatments 1.
- It is essential to recognize and properly differentiate pseudohyponatremia from true hyponatremia to prevent wrong treatments 2.
- Measuring serum sodium with direct potentiometry can help confirm the diagnosis, especially in cases with extreme hypercholesterolemia or hyperlipidemia 3.