Review Question - QID 108739

This patient presents with diabetic ketoacidosis (DKA). In addition to treatment with intravenous fluids and insulin, patients in DKA should have their potassium levels repleted even if the serum potassium appears normal.

This patient’s acidosis might cause the patient to initially present with normal potassium levels or even hyperkalemia. Patients with DKA undergo osmotic diuresis from the hyperglycemia and lose potassium in their urine. In DKA, insulin deficiency (decreased potassium uptake by cells) and hyperosmolarity (causing intracellular fluid contraction and outward potassium gradient) leads to the increased serum potassium concentration. This elevates the serum potassium level even though total body potassium becomes depleted through urinary losses. Administration of exogenous insulin causes a corresponding rapid intracellular shift of potassium and can lead to hypokalemia. Therefore potassium chloride should be administered alongside insulin in the treatment of DKA. Patient's in DKA should receive IV fluids until the serum anion gap has normalized (less than 12 mEq/L).

Answer 1: Subcutaneous insulin glargine is a long-acting insulin analog that should be administered when the ketoacidosis has resolved before the insulin drip is discontinued. It is not the most important next step in management.

Answer 2: Intravenous isotonic saline is used for vigorous fluid repletion in patients with DKA who are often severely hypovolemic. However, this patient already received 1L of isotonic saline and is hemodynamically stable. Although the patient likely requires more IV fluids, the patient risks hypokalemia if potassium stores are not repleted immediately.

Answer 3: Intravenous sodium bicarbonate administration is controversial and not generally recommended, but it is occasionally administered in cases of severe acidemia.

Answer 5: Intravenous 5% dextrose and 1/2 isotonic saline should be administered when the serum glucose has been reduced to 200mg/dL. Continuous insulin infusion without administering glucose will eventually lead to hypoglycemia. However, repletion of potassium is a more pressing concern at this stage of treatment.

Bullet Summary:
Patients in diabetic ketoacidosis (DKA) often have a normal appearing serum potassium level (secondary to insulin deficiency and hyperosmolarity) despite having low total body potassium levels. Along with IV fluids and an insulin drip, patients in DKA should have their potassium levels repleted.