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Difficulty: HardEndocrinology and Metabolism

A 22-year-old woman with a history of type 1 diabetes mellitus is brought to the emergency department due to a 2-day history of worsening nausea, vomiting, and diffuse abdominal pain. She recently had an upper respiratory tract infection and missed several doses of her basal insulin. Her temperature is 37.4°C (99.3°F), blood pressure is 92/60 mm Hg, pulse is 124/min, and respirations are 28/min and deep. Her mucous membranes are dry. Initial laboratory results show:

TestResult
Serum glucose540540 mg/dL
Serum sodium132132 mEq/L
Serum potassium4.94.9 mEq/L
Serum bicarbonate1010 mEq/L
Blood urea nitrogen3232 mg/dL
Serum creatinine1.41.4 mg/dL
Arterial blood pH7.127.12

Arrange the following interventions in the most appropriate chronological sequence for the management of this patient's condition, from initial presentation in the emergency department to the resolution of the acute crisis.

  1. 1Initiate rapid intravenous infusion of 0.9%0.9\% sodium chloride.
  2. 2Commence continuous intravenous regular insulin infusion.
  3. 3Incorporate potassium chloride into maintenance intravenous fluids.
  4. 4Add 5%5\% dextrose to the intravenous fluids.
  5. 5Administer subcutaneous basal insulin and discontinue the intravenous insulin infusion 2 hours later.

Answer

The correct chronological sequence is: 1) Initiate 0.9% sodium chloride, 2) Commence continuous intravenous insulin, 3) Incorporate potassium chloride, 4) Add 5% dextrose, 5) Administer subcutaneous basal insulin.
The correct sequence reflects the standard physiological priorities in DKA management: volume expansion, cessation of ketogenesis, electrolyte replacement, prevention of hypoglycemia, and transition to maintenance therapy. Fluid resuscitation is the critical first step to correct hypovolemia. Insulin is then initiated to stop ketone production. Because insulin drives potassium intracellularly, potassium supplementation is required once levels drop into the normal range. When glucose falls to 200200-250250 mg/dL, dextrose is added to prevent hypoglycemia while insulin continues to close the anion gap. Finally, once the acidosis resolves, a transition to subcutaneous insulin is made with an overlapping period to prevent rebound DKA.

Step-by-Step Solution

1
Diagnose the acute condition based on the clinical presentation and laboratory values.
The patient has Diabetic Ketoacidosis (DKA), evidenced by hyperglycemia (540540 mg/dL), high anion gap metabolic acidosis (pH 7.127.12, HCO3 1010 mEq/L, calculated anion gap of 2222), and hypovolemia.
Accurate diagnosis is required to initiate the specific stepwise management protocol for DKA.
2
Determine the most critical initial intervention for hemodynamic stability.
Intravenous fluid resuscitation with isotonic (0.9%0.9\%) saline is selected as the first step.
Patients with DKA have profound total body water deficits due to osmotic diuresis. Volume replacement restores renal perfusion, clearing some glucose, and stabilizes blood pressure.
3
Determine the next step to correct the underlying metabolic derangement.
Continuous intravenous regular insulin infusion is initiated.
Insulin is required to stop ketone production and correct the acidosis. Because the patient's initial potassium is 4.94.9 mEq/L (above the 3.33.3 mEq/L threshold), it is safe to start insulin immediately after fluids.
4
Anticipate the electrolyte shift caused by the initial treatments.
Potassium chloride must be added to the intravenous fluids.
Insulin drives potassium intracellularly, and fluids dilute the serum concentration. To prevent severe hypokalemia, potassium is added once levels drop below 5.25.2 mEq/L and urine output is confirmed.
5
Identify the threshold for altering fluid composition as glucose levels drop.
5%5\% dextrose is added to the intravenous fluids when serum glucose reaches 200200-250250 mg/dL.
During DKA treatment, glucose drops faster than ketones clear. Dextrose prevents hypoglycemia, allowing insulin administration to continue until the acidosis (anion gap) fully resolves.
6
Determine the criteria for transitioning to maintenance therapy.
Subcutaneous basal insulin is administered, and the IV infusion is stopped 2 hours later.
Once the anion gap is closed (≤12\leq 12 mEq/L) and the patient tolerates oral intake, IV insulin can be stopped. A 2-hour overlap with subcutaneous insulin prevents a gap in insulin coverage and rebound ketoacidosis.

Key Concept

The stepwise management of Diabetic Ketoacidosis (DKA) prioritizes volume resuscitation, followed by insulin therapy to halt ketogenesis, meticulous electrolyte (potassium) replacement, addition of dextrose to prevent hypoglycemia, and overlapping transition to subcutaneous insulin.
Estimated Time:2m 0s
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Topics

Endocrinology and Metabolism

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