Internal Medicine Exam Diabetic Ketoacidosis Management 5 — Questions and Answers
Question 1: A patient with DKA has a serum osmolality of 340 mOsm/kg and an altered mental status. What additional diagnosis should be considered?
- Pure DKA with expected mental status change
- Overlapping hyperosmolar hyperglycemic state (mixed DKA/HHS) (Correct answer)
- Hyponatremia-induced encephalopathy
- Addisonian crisis
Correct answer: Overlapping hyperosmolar hyperglycemic state (mixed DKA/HHS)
Serum osmolality >320 mOsm/kg with DKA criteria suggests a mixed DKA/HHS state, which requires attention to osmolarity during fluid replacement.
Question 2: Which of the following is the most common electrolyte abnormality requiring monitoring after DKA resolution?
- Hypernatremia
- Hypokalemia (Correct answer)
- Hypercalcemia
- Hypermagnesemia
Correct answer: Hypokalemia
As insulin drives potassium intracellularly and urinary losses are repleted slowly, hypokalemia is the most common electrolyte complication after DKA treatment.
Question 3: A patient with DKA secondary to new-onset type 1 diabetes is being discharged. Which statement about follow-up insulin management is most accurate?
- A single long-acting insulin dose is sufficient at discharge
- Both basal and prandial insulin regimens should be established prior to discharge (Correct answer)
- Metformin should be added on discharge for glucose control
- Insulin requirements in new-onset type 1 DM are permanent from day one
Correct answer: Both basal and prandial insulin regimens should be established prior to discharge
Patients with new-onset type 1 diabetes should be discharged on a basal-bolus insulin regimen with diabetes education and close follow-up.
Question 4: Which arterial blood gas pattern is most consistent with DKA with appropriate respiratory compensation?
- pH 7.18, PaCO2 40, HCO3 14
- pH 7.22, PaCO2 28, HCO3 11 (Correct answer)
- pH 7.42, PaCO2 40, HCO3 24
- pH 7.50, PaCO2 30, HCO3 23
Correct answer: pH 7.22, PaCO2 28, HCO3 11
DKA causes metabolic acidosis with respiratory compensation (Kussmaul breathing lowers PaCO2); the expected PaCO2 = 1.5 × HCO3 + 8 ± 2.
Question 5: An elderly patient with DKA develops oliguria despite 3 liters of IV fluids. Creatinine rises from 1.2 to 3.8 mg/dL. What complication has occurred?
- Contrast-induced nephropathy
- Acute kidney injury from hypovolemia and hypoperfusion (Correct answer)
- Rhabdomyolysis from insulin therapy
- Diabetic nephropathy exacerbation
Correct answer: Acute kidney injury from hypovolemia and hypoperfusion
Severe dehydration and hypoperfusion in DKA commonly cause prerenal or intrinsic acute kidney injury, which may not reverse promptly with fluid resuscitation.
Question 6: Which of the following triggers is most classically associated with DKA in a previously well-controlled type 1 diabetic who is NOT missing insulin doses?
- Dietary indiscretion
- Occult infection (e.g., UTI, pneumonia) (Correct answer)
- Change in insulin brand
- Psychological stress alone
Correct answer: Occult infection (e.g., UTI, pneumonia)
Infection is the most common medical precipitant of DKA in compliant type 1 diabetic patients, as counter-regulatory hormones from illness increase insulin resistance.
Question 7: Which clinical finding is characteristic of Kussmaul respirations in DKA?
- Shallow, rapid breathing with accessory muscle use
- Deep, slow, labored breathing as respiratory compensation for acidosis (Correct answer)
- Cheyne-Stokes pattern with apneic episodes
- Rapid irregular breathing with pleuritic chest pain
Correct answer: Deep, slow, labored breathing as respiratory compensation for acidosis
Kussmaul respirations are deep, slow, and labored — a compensatory response to metabolic acidosis that lowers PaCO2 to raise pH.
Internal Medicine Exam Diabetic Ketoacidosis Management 5
A patient with DKA has a serum osmolality of 340 mOsm/kg and an altered mental status.
What additional diagnosis should be considered?