From the Guidelines
Pseudohyponatremia in Diabetic Ketoacidosis (DKA) is a condition where laboratory tests show low sodium levels in the blood, but it's not a true reflection of the body's sodium status, due to the high glucose levels in DKA drawing water into the blood and diluting the sodium concentration 1.
Key Points to Consider
- The high glucose levels in DKA cause water to move into the blood, resulting in a dilutional effect on sodium levels, leading to pseudohyponatremia 1.
- To correct for pseudohyponatremia, the serum sodium should be corrected for hyperglycemia by adding 1.6 mEq to the sodium value for each 100 mg/dl glucose above 100 mg/dl 1.
- This correction is crucial to avoid inappropriate treatment and to guide proper management of DKA.
- The corrected sodium level provides a more accurate representation of the body's sodium status, allowing for targeted treatment and management of DKA.
Management Implications
- The choice of fluid replacement therapy in DKA depends on the corrected serum sodium level, with 0.45% NaCl infused at 4–14 ml kg–1 h–1 appropriate if the corrected serum sodium is normal or elevated, and 0.9% NaCl at a similar rate if the corrected serum sodium is low 1.
- Close monitoring of serum osmolality, fluid input/output, and clinical examination is essential to assess the effectiveness of fluid replacement therapy and avoid complications such as cerebral edema 1.
From the Research
Definition of Pseudohyponatremia
- Pseudohyponatremia is a condition where serum sodium levels appear to be low due to an increased mass of nonaqueous components of serum, such as lipids and proteins, rather than an actual decrease in sodium concentration 2.
Relationship to Diabetic Ketoacidosis (DKA)
- DKA is a life-threatening complication of diabetes that can cause a range of electrolyte imbalances, including sodium disturbances 3, 4, 5, 6.
- However, pseudohyponatremia is not directly related to DKA, but rather to the measurement of sodium levels in serum, which can be affected by the presence of hyperlipidemia or hyperproteinemia 2.
Clinical Significance
- Pseudohyponatremia can lead to incorrect diagnosis and treatment of hyponatremia, which can have significant clinical consequences 2.
- In the context of DKA, accurate measurement of sodium levels is crucial for guiding treatment and management of electrolyte imbalances 3, 4, 5, 6.
Measurement of Sodium Levels
- The flame photometry method can give false readings of sodium concentration in whole plasma, whereas a sodium-selective electrode can provide a more accurate measurement of sodium activity in serum water 2.
- Direct potentiometry can provide a more accurate concentration of sodium than indirect potentiometry, which may be affected by the presence of hyperproteinemia or hyperlipidemia 2.