Internal Medicine Exam Diabetic Ketoacidosis Management 4

Question 1

In DKA, the serum potassium is initially high despite total body potassium depletion. What is the primary mechanism?

Accepted Answer

Acidosis-driven transcellular shift of potassium out of cells

Answer

Metabolic acidosis causes H⁺ to shift into cells in exchange for K⁺ moving out, raising serum potassium despite total body depletion.

Question 2

A patient with DKA has serum phosphate of 0.8 mg/dL. In which clinical scenario would phosphate replacement be most strongly indicated?

Accepted Answer

Symptomatic hypophosphatemia with cardiac dysfunction or respiratory failure

Answer

Phosphate replacement is indicated in DKA when hypophosphatemia is symptomatic or associated with cardiac/respiratory dysfunction.

Question 3

Which finding best differentiates DKA from hyperglycemic hyperosmolar state (HHS)?

Accepted Answer

Anion gap metabolic acidosis with significant ketonemia

Answer

DKA is characterized by significant ketonemia and anion gap acidosis, whereas HHS has minimal or no ketosis.

Question 4

What is the expected rate of glucose decline per hour with appropriate insulin therapy in DKA?

Accepted Answer

50–75 mg/dL/hr

Answer

Optimal insulin therapy lowers blood glucose by 50–75 mg/dL per hour; faster drops risk cerebral edema especially in children.

Question 5

A patient with DKA on insulin infusion develops glucose of 180 mg/dL but still has an anion gap of 20. What is the appropriate management?

Accepted Answer

Add dextrose to IV fluids and continue insulin infusion

Answer

When glucose reaches 200–250 mg/dL but the anion gap remains elevated, add dextrose to maintain glucose while continuing insulin to clear ketones.

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