A 19-year-old man with type 1 diabetes mellitus is brought to the emergency department due to altered mental status, generalized weakness, and recurrent vomiting for the past 24 hours. He recently had a respiratory tract infection. Vital signs show a blood pressure of 90/60 mm Hg, heart rate of 124/min, and respiratory rate of 28/min with deep, sighing breaths. Laboratory results show:
| Test | Value |
|---|---|
| Serum glucose | 580 mg/dL |
| Serum sodium | 132 mEq/L |
| Serum potassium | 3.1 mEq/L |
| Serum bicarbonate | 10 mEq/L |
| Arterial pH | 7.05 |
Arrange the following management steps in the most appropriate chronological order from first to last.
- 1Rapidly administer 1 to 2 liters of intravenous 0.9% normal saline
- 2Administer intravenous potassium chloride
- 3Initiate a continuous intravenous infusion of regular insulin
- 4Add 5% dextrose to the intravenous fluids
- 5Transition to a subcutaneous basal-bolus insulin regimen
Answer
The correct chronological sequence is: 1) Administer intravenous 0.9% normal saline, 2) Administer intravenous potassium chloride, 3) Initiate intravenous regular insulin, 4) Add 5% dextrose to IV fluids, and 5) Transition to subcutaneous insulin.
The correct sequence for DKA management requires addressing the most immediate life-threatening derangements first. Initial resuscitation always begins with isotonic fluids to restore intravascular volume. Next, potassium must be evaluated; because this patient has severe hypokalemia (< 3.3 mEq/L), potassium replacement must precede insulin therapy to avoid lethal arrhythmias. Once potassium is safe (> 3.3 mEq/L), an insulin infusion is started to resolve the ketoacidosis. As glucose levels fall to 200 mg/dL, dextrose is added to the fluids to prevent hypoglycemia while allowing insulin to continue suppressing ketogenesis. Finally, once the anion gap closes and the patient can eat, subcutaneous insulin is initiated.
Step-by-Step Solution
Key Concept
In the management of Diabetic Ketoacidosis (DKA), aggressive fluid resuscitation is the first step. If severe hypokalemia (< 3.3 mEq/L) is present, potassium must be repleted before the initiation of insulin to prevent life-threatening cardiac arrhythmias.