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Reply To: hyponautremia

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Thanks so much for the question… it is a good one!

The combined effects of hyperglycemia, ketonemia, acidosis and many co-morbid processes often causes significant electrolyte derangements in both DKA and HHS. Hyperglycemia-induced osmotic diuresis results in severe fluid and electrolyte losses. Ketones contribute to the solute diuresis via excretion of ketoanions, which obligates urinary cation excretion of Na, K and ammonium salts. Decreases in Na can also follow hyperglycemia. For each 3.44 mmol/L increase in glu, serum Na decreases by 1 mmol/L. If a patient has severe hyperglycaemia with normal serum sodium, their true sodium is probably high. This formula may underrepresent the effect on Na. Low Na concentrations can also be seen with hypertriglyceridemia, “pseudohyponatremia.” Insulin deficiency also contributes to solute loss as insulin stimulates salt and water reabsorption from both proximal and distal tubules and phosphate from proximal tubules.

In summary, the large increase in glucose in the circulation will draw water into the vasculature from the interstitial fluid and have a dilutional effect on the sodium!

Hope that helps.

Scott x