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Normoosmolar Hyponatremia
Aka: Normoosmolar Hyponatremia, Iso-Osmolar Hyponatremia, Pseudohyponatremia
- See Also
- Hyponatremia
- Definition
- Hyponatremia with measured Serum Osmolality = 280-300
- Pathophysiology
- Water normally comprises 92-94% of serum
- Lipids or proteins decrease water fraction
- Causes
- Pseudohyponatremia (Isotonic)
- Hyperlipidemia (Serum Triglycerides >1500 mg/dl)
- Hyperproteinemia (Serum Protein > 10 g/dl)
- Isotonic (sodium-free) infusion
- Glucose
- Mannitol
- Glycine (used in some urologic procedures)
- Post-Transurethral prostatic resection syndrome
- Large volume intraoperative hypotonic irrigation
- Neurologic and cardiopulmonary signs
- Management
- Pseudohyponatremia
- Pseudohyponatremia does not need to be treated
- Evaluate and treat underlying cause (e.g. lipids)
- Isotonic Infusion
- Reflects true Hyponatremia and requires correction
- 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