II. Definition
- Hyponatremia with measured Serum Osmolality = 280-300
III. Pathophysiology
IV. Causes
- Pseudohyponatremia (Isotonic)
- Hyperlipidemia (Serum Triglycerides >1500 mg/dl)
- Hyperproteinemia (Serum Protein > 10 g/dl)
- Isotonic (Sodium-free) infusion
V. Labs
- Pseudohyponatremia is not an issue when Serum Sodium is measured by Sodium electrode
- In this case, measured Sodium is the true Sodium concentration
- Many labs in U.S. (as of 2015) use Sodium electrode to measure Serum Sodium
VI. Management
- Pseudohyponatremia
- In Pseudohyponatremia, Sodium does not need to be managed specifically
- Evaluate and treat underlying cause
- Hyperlipidemia
- Hyperproteinemia (e.g. Multiple Myeloma - consider SPEP, UPEP)
- Isotonic Infusion
- Reflects true Hyponatremia and requires correction
VII. References
- Kone in Tisher (1993) Nephrology, p. 87-100
- Levinsky in Wilson (1991) Harrison's IM, p. 281-84
- Rose (1989) Acid-Base and Electrolytes, p. 601-38
- Braun (2015) Am Fam Physician 91(5): 299-307 [PubMed]
- Miller (2023) Am Fam Physician 108(5): 476-86 [PubMed]
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Related Studies
| Concepts | Finding (T033) |
| SnomedCT | 237843009 |
| English | Hyponat+normal/incr serum osmo, pseudohyponatremia, pseudohyponatremia (diagnosis), Hyponatraemia with normal or increased serum osmolality, Hyponatremia with normal or increased serum osmolality, Pseudohyponatraemia, Pseudohyponatremia, Pseudohyponatremia (disorder) |
| Czech | Pseudohyponatrémie, Pseudo-hyponatrémie |
| Dutch | pseudohyponatriëmie |
| French | Pseudo-hyponatrémie |
| German | Pseudohyponatraemie |
| Hungarian | Pseudo-hyponatremia, Pseudo-hyponatraemia |
| Italian | Pseudoiponatremia |
| Spanish | Seudohiponatremia, seudohiponatremia (trastorno), seudohiponatremia |
| Japanese | ｷﾞｾｲﾃｲﾅﾄﾘｳﾑｹﾂｼｮｳ, ｷﾞｾｲﾃｲﾅﾄﾘｳﾑｹｯｼｮｳ, 偽性低ナトリウム血症 |
| Portuguese | Pseudo-hiponatremia |
