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Difficulty: HardMonitoring and Treatment Evaluation

A 24-year-old woman with a history of type 1 diabetes mellitus is admitted to the intensive care unit for the management of diabetic ketoacidosis (DKA). On presentation, she has a serum glucose of 580 mg/dL580 \text{ mg/dL}, an anion gap of 24 mEq/L24 \text{ mEq/L}, and a serum potassium of 4.8 mEq/L4.8 \text{ mEq/L}. She has received an initial intravenous fluid bolus of 0.9% sodium chloride.

Arrange the following monitoring and therapeutic steps in the correct chronological sequence required for the safe resolution of her DKA and transition to maintenance therapy.

  1. 1Initiate continuous intravenous regular insulin infusion after confirming serum potassium is ≥3.3 mEq/L\geq 3.3 \text{ mEq/L}.
  2. 2Add 5% dextrose to the intravenous fluids when the serum glucose concentration decreases to 200 mg/dL200 \text{ mg/dL}.
  3. 3Administer the first dose of subcutaneous long-acting insulin once the serum anion gap closes (≤12 mEq/L\leq 12 \text{ mEq/L}) and the patient is able to eat.
  4. 4Discontinue the continuous intravenous regular insulin infusion 1 to 2 hours1 \text{ to } 2 \text{ hours} after the administration of subcutaneous insulin.

Answer

The correct sequence for DKA management is: 1) Initiate continuous intravenous regular insulin infusion after confirming serum potassium is ≥3.3 mEq/L\geq 3.3 \text{ mEq/L}. 2) Add 5% dextrose to the intravenous fluids when the serum glucose concentration decreases to 200 mg/dL200 \text{ mg/dL}. 3) Administer the first dose of subcutaneous long-acting insulin once the serum anion gap closes (≤12 mEq/L\leq 12 \text{ mEq/L}) and the patient is able to eat. 4) Discontinue the continuous intravenous regular insulin infusion 1 to 2 hours1 \text{ to } 2 \text{ hours} after the administration of subcutaneous insulin.
The management of DKA requires strict sequential monitoring and therapeutic adjustments. Insulin is the cornerstone of treatment but drives potassium intracellularly; therefore, serum potassium must be verified as ≥3.3 mEq/L\geq 3.3 \text{ mEq/L} prior to initiation. As insulin clears ketones, it also lowers glucose rapidly. To allow continuous insulin administration until the anion gap closes without causing hypoglycemia, 5% dextrose is added to IV fluids when glucose reaches 200 mg/dL200 \text{ mg/dL}. Once the anion gap normalizes (≤12 mEq/L\leq 12 \text{ mEq/L}), DKA has resolved, and subcutaneous insulin can be administered. Finally, a 1 to 2 hour1 \text{ to } 2 \text{ hour} overlap is mandatory before stopping the IV insulin drip to allow the subcutaneous depot to absorb and prevent rebound ketoacidosis.

Step-by-Step Solution

1
Identify the prerequisite for initiating insulin therapy.
Potassium must be ≥3.3 mEq/L\geq 3.3 \text{ mEq/L}.
Insulin causes intracellular shifts of potassium; administering it in the presence of profound hypokalemia can cause fatal arrhythmias.
2
Determine the monitoring threshold for adjusting intravenous fluids.
Add 5% dextrose when glucose reaches 200 mg/dL200 \text{ mg/dL}.
Insulin must be continued to clear ketones and close the anion gap. Adding dextrose prevents hypoglycemia during this prolonged metabolic correction.
3
Identify the criteria for transitioning to subcutaneous insulin.
Anion gap ≤12 mEq/L\leq 12 \text{ mEq/L} and patient tolerating oral intake.
A closed anion gap indicates the resolution of ketoacidosis, making it safe to transition the patient off the intravenous insulin drip.
4
Determine the protocol for stopping the intravenous insulin infusion.
Stop the continuous infusion 1 to 2 hours1 \text{ to } 2 \text{ hours} after giving subcutaneous insulin.
Subcutaneous insulin takes time to absorb. Stopping the drip immediately without an overlap will lead to a rapid drop in circulating insulin levels and rebound DKA.

Key Concept

Monitoring and sequential treatment adjustment in diabetic ketoacidosis (DKA)
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Topics

Monitoring and Treatment Evaluation

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