A 24-year-old man with a history of type 1 diabetes mellitus is brought to the emergency department with nausea, vomiting, and confusion. Blood pressure is 95/60 mm Hg, and heart rate is 120/min. Laboratory studies show:
| Test | Result |
|---|---|
| Serum glucose | 520 mg/dL |
| Arterial pH | 7.15 |
| Serum bicarbonate | 10 mEq/L |
| Serum potassium | 3.8 mEq/L |
| Serum anion gap | 22 mEq/L |
Arrange the following interventions in the correct chronological sequence for the optimal acute management of this patient's condition.
- 1Administer a rapid bolus of intravenous 0.9% normal saline
- 2Add potassium chloride to the intravenous fluids
- 3Initiate a continuous intravenous infusion of regular insulin
- 4Add 5% dextrose to the intravenous fluids once serum glucose reaches 200-250 mg/dL
- 5Transition to a subcutaneous insulin regimen once the anion gap normalizes and the patient can eat
Answer
The correct sequence is: (1) Intravenous fluids, (2) Potassium replacement, (3) Intravenous insulin, (4) Addition of dextrose to fluids, (5) Transition to subcutaneous insulin.
The acute management of diabetic ketoacidosis (DKA) strictly follows this chronological sequence to minimize mortality and complications. Step 1 is aggressive fluid resuscitation with 0.9% normal saline to correct the profound dehydration caused by osmotic diuresis. Step 2 requires evaluating serum potassium. Because insulin drives potassium intracellularly, a patient with a 'normal' potassium level (like 3.8 mEq/L) will rapidly become hypokalemic once insulin is started; thus, potassium must be added to the fluids prior to or concurrent with insulin. Step 3 is initiating the intravenous regular insulin infusion to suppress ketogenesis and resolve the high anion gap acidosis. Step 4 involves adding 5% dextrose to the fluids when the serum glucose drops to 200-250 mg/dL, preventing hypoglycemia while continuing the insulin needed to completely clear the ketones. Finally, Step 5 is transitioning the patient to a subcutaneous insulin regimen once the anion gap has closed, acidosis has resolved, and the patient is able to tolerate oral intake.
Step-by-Step Solution
Key Concept
Diabetic ketoacidosis requires a stepwise management approach prioritizing aggressive fluid resuscitation, followed by careful potassium assessment and replacement, before initiating continuous intravenous insulin therapy to correct the underlying acidosis.