In diabetic ketoacidosis, there is increased acid in the extracellular space. According to FA there is a transcellular shift due to decreased insulin that leads to more H+ entering the cell in exchange for K+. This leads to hyperkalemia with depleted intracellular stores of K+. There is also osmotic diuresis that leads to increased K+ loss in the urine and total body K+ depletion. The question asks that is most likely to decrease with insulin therapy: serum potassium concentration will decrease as K+ is now exchanged for H+ inside the cell.
This explanation is faulty. Insulin causes K to go inside via upregulating NaKATPase activity. Nothing to with H+ exchange as far as Insulin is concerned.
H and K exchange is separate from this.
I agree that Serum K decrease is the better answer, but wouldn't Urine K also decrease once blood sugar goes down with insulin treatment (i.e. osmotic diuresis would lessen)?
submitted by โan_improved_me(91)
@blackcoffee;
Insulin does play a role in bringing back K+ into cells via modulation of K+/H+ exchange. This is because it helps to address the ketoacidotic state of the patient. By bringing pH closer to baseline, there is return of K+ into the cells, while H+ comes back out of the cells.