Clinical scenario: DKA | Protocol started | Glucose level decreased
A 12-year-old girl with known type 1 diabetes mellitus is admitted with severe diabetic ketoacidosis. On admission, she is drowsy but arousable. Her weight is 38 kg.
Initial investigations:
- Blood glucose: 31 mmol/L (558 mg/dL)
- Venous pH: 6.98
- Serum bicarbonate: 5 mmol/L
- Serum sodium: 128 mmol/L
- Serum potassium: 5.4 mmol/L
- Blood urea nitrogen: 10 mmol/L
- Effective serum osmolality: 305 mOsm/kg
She receives appropriate fluid resuscitation and is started on intravenous insulin at 0.05 units/kg/hour. Four hours later, her blood glucose has fallen to 14 mmol/L (252 mg/dL), but the venous pH remains 7.02 and bicarbonate is 7 mmol/L. She remains clinically dehydrated but is hemodynamically stable.
What is the most appropriate next step in management?
A. Discontinue insulin infusion and begin subcutaneous rapid-acting insulin
B. Increase insulin infusion to 0.1 units/kg/hour to correct acidosis faster
C. Add dextrose to the intravenous fluids while continuing the insulin infusion
D. Administer intravenous sodium bicarbonate because severe acidosis persists
E. Reduce intravenous fluids to prevent cerebral edema
Correct answer & Explanation:
Correct Answer: C. Add dextrose to the intravenous fluids while continuing the insulin infusion
Explanation
The endpoint of DKA treatment is resolution of ketoacidosis, not normalization of blood glucose.
As plasma glucose falls to approximately 250–300 mg/dL (14–17 mmol/L), intravenous dextrose should be added to the maintenance fluids while the insulin infusion is continued. Insulin is required to suppress ketogenesis, reduce free fatty acid production, and clear ketoacids. Stopping insulin prematurely allows ketosis to recur despite an apparently acceptable glucose concentration.
Why the other options are incorrect
A. Discontinue insulin infusion
- Incorrect. Insulin should continue until ketoacidosis has resolved (pH >7.30, bicarbonate >15–18 mmol/L, and clinical improvement).
B. Increase insulin infusion
- Incorrect. There is no evidence that increasing insulin above the recommended rate hastens recovery, and it increases the risk of hypoglycemia and hypokalemia.
C. Add dextrose while continuing insulin
- Correct. This allows ongoing insulin administration to resolve ketosis without causing hypoglycemia.
D. Sodium bicarbonate
- Incorrect. Routine bicarbonate therapy is contraindicated in pediatric DKA because it has not shown clinical benefit and may increase the risk of cerebral injury and worsen hypokalemia. It is reserved only for exceptional circumstances such as life-threatening hyperkalemia or profound acidosis causing cardiovascular compromise.
E. Reduce intravenous fluids
- Incorrect. Fluids should continue according to the DKA protocol. Simply reducing fluids because of concern for cerebral edema is inappropriate. If cerebral edema is suspected, immediate treatment with hypertonic saline or mannitol is indicated while continuing appropriate supportive care.
Board Pearls
- Continue IV insulin until ketoacidosis resolves, not until glucose normalizes.
- Add 5–10% dextrose when glucose falls to 250–300 mg/dL (14–17 mmol/L).
- Resolution of DKA is defined by improvement in pH, bicarbonate, anion gap/ketosis, and clinical status, not glucose alone.
- Routine bicarbonate therapy is not recommended in pediatric DKA.
- Cerebral edema is the leading cause of DKA-related mortality in children; early warning signs include headache, declining consciousness, bradycardia, hypertension, and cranial nerve palsies.
