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What labs are used to make a diagnosis of diabetic ketoacidosis? (at least 2 labs with a value cutoff)
What happens to magnesium level? Phosphate level? Potassium level (both intracellular and extracellular)
"A diagnosis of diabetic ketoacidosis requires the patient's plasma glucose concentration to be above 250 mg per dL (although it usually is much higher), the pH level to be less than 7.30, and the bicarbonate level to be 18 mEq per L or less. Beta-hydroxybutyrate is a better measurement of the degree of ketosis than serum ketones. Intravenous insulin, fluid replacement are the mainstays of therapy, with careful monitoring of potassium levels and giving phosphate and magnesium as well.
Adrogue et al study suggests insulin deficiency as a direct mechanism for the hyperkalemia seen in DKA. (Recall that insulin moves K+ into the intracellular space, so a lack of insulin would cause the K+ to remain in the extracellular space, i.e. in the serum.). the metabolic acidosis present in DKA pulls K+ from the intracellular space to the extracellular space. (Recall that the body adapts to high H+ levels in the serum by moving H+ into the cells in exchange for bringing K+ out of the cells.) The result is low intracellular K+, normal to high serum K+ (i.e. hyperkalemia), and low total body K+.
As reviewed by Trachtenbarg, potassium should be started in patients with DKA as soon as adequate urine output is confirmed and the potassium level is <5 mEq per L. If the serum potassium level is <3.3 mEq per L, potassium replacement should be given immediately and insulin should be held until the potassium level is >3.3 mEq per L.