A 22-year-old man with a history of type 1 diabetes mellitus is brought to the emergency department due to progressive lethargy, nausea, vomiting, and diffuse abdominal pain over the past 24 hours. He reports having a severe sore throat and fever for the last three days. His temperature is 37.5°C (99.5°F), blood pressure is 92/58 mm Hg, pulse is 128/min, and respirations are 28/min and deep. Physical examination reveals dry mucous membranes, delayed capillary refill, and a fruity breath odor. Laboratory evaluation reveals:
| Laboratory Test | Result |
|---|---|
| Serum glucose | 580 mg/dL |
| Serum sodium | 132 mEq/L |
| Serum potassium | 3.1 mEq/L |
| Serum chloride | 98 mEq/L |
| Serum bicarbonate | 10 mEq/L |
| Blood urea nitrogen | 35 mg/dL |
| Serum creatinine | 1.6 mg/dL |
| Arterial pH | 7.15 |
| Urinalysis | Large ketones, large glucose |
Arrange the following management steps in the most appropriate chronological sequence for this patient.
- 1Administer intravenous 0.9% sodium chloride bolus
- 2Administer intravenous potassium chloride
- 3Initiate continuous intravenous regular insulin infusion
- 4Add 5% dextrose to the intravenous fluids
- 5Administer subcutaneous long-acting insulin
Answer
The correct sequence is: Intravenous 0.9% sodium chloride bolus → Intravenous potassium chloride → Continuous intravenous regular insulin infusion → Add 5% dextrose to intravenous fluids → Subcutaneous long-acting insulin.
The correct sequence prioritizes immediate life-saving interventions while preventing iatrogenic complications. Intravenous fluids (0.9% NaCl) are universally the first step in DKA to restore volume and renal perfusion. Next, because the patient's potassium is critically low (< 3.3 mEq/L), potassium chloride must be given before insulin to prevent life-threatening hypokalemia. Once potassium is confirmed to be ≥ 3.3 mEq/L, an intravenous insulin infusion is started to halt ketogenesis. As glucose levels fall below 250 mg/dL, dextrose is added to the fluids to prevent hypoglycemia while allowing continued insulin administration to close the anion gap. Finally, once the anion gap resolves and the patient can eat, they are transitioned to subcutaneous insulin.
Step-by-Step Solution
Key Concept
In the management of diabetic ketoacidosis, if the initial serum potassium is < 3.3 mEq/L, potassium repletion must precede insulin therapy to prevent severe, potentially fatal insulin-induced hypokalemia.