What can cause pseudohyponatremia in diabetic patients?

Pseudohyponatremia occurs when the measured sodium concentration is falsely low despite normal serum sodium levels. In diabetic patients, one of the primary causes of pseudohyponatremia is the interference caused by elevated glucose levels during sodium measurement.

Glucose can affect the measurement by altering the osmotic balance in the plasma. Specifically, when blood glucose is elevated, it leads to a shift of water from the intracellular to the extracellular space, diluting serum sodium and resulting in a lower than expected sodium measurement. This phenomenon is particularly relevant in patients with hyperglycemia, such as those with poorly controlled diabetes, which can lead to misleadingly low sodium readings on routine lab tests.

In contrast, while hypotension, insulin resistance, and high bilirubin levels can contribute to various clinical issues in diabetic patients, they do not specifically cause pseudohyponatremia through the same mechanism of interference in sodium measurement. Understanding this relationship is crucial for accurately interpreting laboratory results in the context of managing diabetic patients.