How does hypertonic hyponatremia present?

Updated: Jun 17, 2019
  • Author: Eric E Simon, MD; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Answer

Patients with hypertonic hyponatremia have normal total body sodium and a dilutional drop in the measured serum sodium due to the presence of osmotically active molecules in the serum, which causes a water shift from the intracellular compartment to the extracellular compartment.

Glucose produces a drop in the serum sodium level of 1.6 mEq/L for each 100 mg/dL of serum glucose greater than 100 mg/dL. This relationship is nonlinear, with greater reduction in plasma sodium concentrations with glucose concentrations over 400 mg/dL, making 2.4 mEq/L for each 100 mg/dL increase in glucose over 100 mg/dL a more accurate correction factor when the glucose is greater than 400 mg/dL. [17]

Other examples of osmotically active molecules include mannitol (often used to treat brain edema) or maltose (used with intravenous immunoglobulin administration).


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