Internal Medicine Exam Diabetic Ketoacidosis Management 2 — Questions and Answers
Question 1: A patient with DKA has a serum potassium of 3.2 mEq/L on arrival. What is the correct next step before starting insulin?
- Begin insulin infusion immediately
- Replace potassium to ≥3.5 mEq/L before starting insulin (Correct answer)
- Give sodium bicarbonate to correct acidosis first
- Administer glucagon to stabilize glucose
Correct answer: Replace potassium to ≥3.5 mEq/L before starting insulin
Insulin drives potassium intracellularly, so potassium must be ≥3.5 mEq/L before insulin is started to prevent life-threatening hypokalemia.
Question 2: Which of the following best describes the anion gap in uncomplicated DKA?
- Normal anion gap metabolic acidosis
- Elevated anion gap metabolic acidosis (Correct answer)
- Respiratory alkalosis with compensatory metabolic acidosis
- Mixed anion gap and non-anion gap metabolic acidosis
Correct answer: Elevated anion gap metabolic acidosis
DKA causes elevated anion gap metabolic acidosis due to accumulation of beta-hydroxybutyrate and acetoacetate.
Question 3: A 28-year-old with type 1 diabetes presents with DKA. Blood glucose is 520 mg/dL. After 1 hour of insulin infusion, glucose drops to 250 mg/dL. What should be added to IV fluids?
- Stop insulin and switch to subcutaneous
- Add dextrose to IV fluids and continue insulin (Correct answer)
- Double the insulin infusion rate
- Administer IV sodium bicarbonate
Correct answer: Add dextrose to IV fluids and continue insulin
Dextrose is added to IV fluids when glucose reaches 200–250 mg/dL to allow continued insulin infusion and ketone clearance.
Question 4: Which laboratory finding is most consistent with resolution of DKA and readiness to transition to subcutaneous insulin?
- Blood glucose < 200 mg/dL
- Serum bicarbonate ≥ 18 mEq/L and anion gap ≤ 12 (Correct answer)
- Urine ketones negative
- Serum pH > 7.30
Correct answer: Serum bicarbonate ≥ 18 mEq/L and anion gap ≤ 12
Resolution criteria include anion gap ≤12 mEq/L, serum bicarbonate ≥18 mEq/L, and pH >7.3 — all three should be met before transitioning.
Question 5: A patient is transitioning from insulin drip to subcutaneous insulin after DKA resolution. How long should the insulin drip overlap with the first subcutaneous dose?
- No overlap needed — stop drip when subQ is given
- 1–2 hour overlap (Correct answer)
- 4–6 hour overlap
- 12 hour overlap
Correct answer: 1–2 hour overlap
The insulin drip should overlap with subcutaneous insulin for 1–2 hours to prevent rebound hyperglycemia and ketoacidosis.
Question 6: A patient with DKA has a measured serum sodium of 128 mEq/L. Blood glucose is 600 mg/dL. What is the corrected sodium?
- 128 mEq/L (no correction needed)
- 132 mEq/L
- 136 mEq/L (Correct answer)
- 140 mEq/L
Correct answer: 136 mEq/L
Corrected sodium = measured Na + 1.6 × [(glucose − 100)/100]; here: 128 + 1.6 × 5 = 136 mEq/L.
Question 7: Which precipitating factor accounts for the majority of DKA cases in known diabetics?
- New diagnosis of diabetes
- Infection or illness
- Medication non-compliance (Correct answer)
- Excessive alcohol use
Correct answer: Medication non-compliance
Insulin omission or non-compliance with insulin therapy is the most common precipitant of DKA in patients with known diabetes.
Internal Medicine Exam Diabetic Ketoacidosis Management 2
A patient with DKA has a serum potassium of 3.2 mEq/L on arrival.
What is the correct next step before starting insulin?