Examkin

Question

Difficulty: HardEndocrinology and Metabolism

A 19-year-old college student with a history of type 1 diabetes mellitus is brought to the emergency department by roommates after being found profoundly lethargic in his dorm room. Over the past three days, he has experienced progressive polyuria, polydipsia, nausea, and diffuse abdominal pain. He missed several doses of his basal insulin due to a recent upper respiratory tract infection. On examination, he appears acutely ill. Vital signs show a heart rate of 124/min, blood pressure of 88/54 mm Hg, and respiratory rate of 28/min with deep, labored breathing. Mucous membranes are extremely dry, and skin turgor is poor.

Laboratory studies reveal:
Serum chemistry:
Sodium: 131 mEq/L
Potassium: 3.1 mEq/L
Chloride: 95 mEq/L
Bicarbonate: 11 mEq/L
Blood urea nitrogen: 34 mg/dL
Creatinine: 1.5 mg/dL
Glucose: 685 mg/dL

Arterial blood gas analysis on room air demonstrates a pH of 7.12. Urinalysis shows 4+ ketones and 4+ glucose.

Arrange the following therapeutic interventions in the most appropriate chronological sequence for the optimal management of this patient's condition.

  1. 1Administer a rapid intravenous bolus of 0.9% normal saline
  2. 2Administer intravenous potassium chloride
  3. 3Initiate continuous intravenous regular insulin infusion
  4. 4Change intravenous fluids to include 5% dextrose
  5. 5Administer a dose of subcutaneous long-acting insulin

Answer

The correct sequence is: Administer rapid intravenous normal saline, followed by intravenous potassium chloride, then initiate continuous intravenous regular insulin infusion, followed by changing intravenous fluids to include 5% dextrose when glucose drops, and finally administering subcutaneous long-acting insulin when the anion gap closes.
Optimal DKA management follows strict sequential priorities: volume expansion, electrolyte correction, acidosis resolution, and prevention of hypoglycemia. Intravenous isotonic saline is the universal first step to restore perfusion. Crucially, because this patient has severe hypokalemia (K+ = 3.1 mEq/L), potassium replacement must strictly precede insulin administration to prevent fatal arrhythmias from further intracellular potassium shifts. Once potassium is ≥\geq 3.3 mEq/L, continuous intravenous insulin is safely initiated to halt ketogenesis. As glucose levels predictably fall below 200-250 mg/dL during insulin therapy, 5% dextrose is added to the intravenous fluids to prevent hypoglycemia, allowing the continuation of insulin until the anion gap fully closes. Finally, a transition to subcutaneous long-acting insulin is performed once the ketoacidosis resolves and the patient can tolerate oral intake, ensuring sufficient overlap before discontinuing the intravenous insulin drip.

Step-by-Step Solution

1
Assess fluid status and administer 0.9% normal saline
Resolves severe hypovolemia, improves renal perfusion, and lowers counterregulatory hormones
Patients with DKA have profound osmotic diuresis leading to severe volume depletion, which must be addressed immediately as the first priority.
2
Evaluate serum electrolytes and administer intravenous potassium chloride
Restores total body potassium and safely raises serum potassium levels above 3.3 mEq/L
Insulin drives potassium intracellularly; giving insulin to a patient with a starting potassium < 3.3 mEq/L will trigger fatal arrhythmias. Potassium must be replenished first.
3
Initiate targeted therapy for ketoacidosis by starting a continuous intravenous regular insulin infusion
Halts ketogenesis and begins reversing the metabolic acidosis
Insulin is required to suppress lipolysis and ketone body production, effectively addressing the root cause of the high anion gap metabolic acidosis.
4
Monitor glucose response and add 5% dextrose to the intravenous fluids once glucose is < 250 mg/dL
Maintains normoglycemia while allowing continued insulin administration
The metabolic acidosis of DKA typically takes longer to resolve than the hyperglycemia. Adding dextrose prevents hypoglycemia while allowing the insulin drip to stay on until ketones are cleared.
5
Determine resolution of DKA and administer subcutaneous long-acting insulin
Provides basal insulin coverage before the intravenous insulin is stopped
A 1- to 2-hour overlap with subcutaneous insulin is mandatory before discontinuing the intravenous insulin drip to prevent immediate rebound ketoacidosis.

Key Concept

The sequential acute management algorithm for severe Diabetic Ketoacidosis (DKA) complicated by initial severe hypokalemia.
Rate this question

Topics

Endocrinology and Metabolism

More questions from this topic