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Difficulty: MediumEndocrinology and Metabolism

A 24-year-old man with a history of type 1 diabetes mellitus is brought to the emergency department with altered mental status, vomiting, and diffuse abdominal pain. His blood pressure is 90/60 mmHg, heart rate is 125/min, and respiratory rate is 28/min with deep, rapid breaths. Laboratory studies reveal a blood glucose of 650 mg/dL, arterial pH of 7.12, serum bicarbonate of 10 mEq/L, and a high anion gap. Urinalysis is strongly positive for ketones. Arrange the following steps in the management of this patient's condition in the most appropriate chronological order.

  1. 1Administer a rapid intravenous bolus of 0.9% normal saline
  2. 2Verify serum potassium concentration is > 3.3 mEq/L
  3. 3Initiate a continuous intravenous infusion of regular insulin
  4. 4Add 5% dextrose to the maintenance intravenous fluids
  5. 5Administer subcutaneous long-acting basal insulin

Answer

The correct sequence is: Administer 0.9% normal saline -> Verify potassium > 3.3 mEq/L -> Initiate IV regular insulin -> Add 5% dextrose to fluids -> Administer subcutaneous basal insulin.
The management of diabetic ketoacidosis follows a strict, step-wise algorithm designed to safely correct volume depletion, hyperglycemia, and ketoacidosis while preventing fatal electrolyte shifts. First, severe fluid deficit is addressed with isotonic 0.9% normal saline. Second, because insulin drives potassium intracellularly, one must verify the serum potassium is greater than 3.3 mEq/L to prevent arrhythmias. Third, an intravenous insulin infusion is started to halt ketone production. Fourth, as blood glucose falls below 200-250 mg/dL, 5% dextrose is added to the fluids so insulin can continue running to close the anion gap without causing hypoglycemia. Finally, once the anion gap is closed, the patient is transitioned to subcutaneous insulin.

Step-by-Step Solution

1
Restore intravascular volume.
Administer a rapid intravenous bolus of 0.9% normal saline.
Patients with DKA have profound osmotic diuresis and volume depletion. Aggressive fluid resuscitation is the immediate priority to restore perfusion.
2
Assess for potential electrolyte derangements prior to insulin administration.
Verify serum potassium concentration is > 3.3 mEq/L.
Insulin shifts potassium intracellularly. If given to a hypokalemic patient, it can trigger life-threatening arrhythmias.
3
Halt ketogenesis and lower blood glucose.
Initiate a continuous intravenous infusion of regular insulin.
Insulin stops lipolysis and ketone body production, correcting the metabolic acidosis.
4
Prevent hypoglycemia during acidosis correction.
Add 5% dextrose to the maintenance intravenous fluids.
Blood glucose often drops faster than the anion gap closes. Adding dextrose allows insulin to be continued without causing hypoglycemia.
5
Transition to maintenance therapy.
Administer subcutaneous long-acting basal insulin.
Once the anion gap normalizes and the patient can eat, subcutaneous insulin is administered at least 2 hours before discontinuing the IV insulin drip.

Key Concept

The sequential management of diabetic ketoacidosis (DKA) prioritizes volume resuscitation, followed by potassium assessment, continuous insulin administration, glucose supplementation as levels fall, and finally transition to subcutaneous insulin.
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Topics

Endocrinology and Metabolism

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