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Difficulty: HardEndocrinology and Metabolism

A 2424-year-old woman with a history of type 1 diabetes mellitus is brought to the emergency department due to altered mental status, nausea, and vomiting that has progressively worsened over the past 2424 hours. She recently had a urinary tract infection and missed several doses of her basal insulin. Her temperature is 37.4∘C37.4^\circ\text{C} (99.3∘F99.3^\circ\text{F}), blood pressure is 90/6090/60 mmHg, pulse is 122122/min, and respirations are 2828/min (deep and rapid). Physical examination reveals dry mucous membranes and delayed capillary refill. Laboratory results are as follows:

TestResult
Serum glucose580580 mg/dL
Arterial pH7.057.05
Serum bicarbonate99 mEq/L
Serum potassium2.82.8 mEq/L
Serum sodium132132 mEq/L
Serum creatinine1.61.6 mg/dL
Serum ketonesPositive

Arrange the following steps in the correct sequential order for the most appropriate acute management of this patient's condition.

  1. 1Administer rapid intravenous fluid resuscitation with 0.9%0.9\% normal saline
  2. 2Administer intravenous potassium chloride and withhold insulin
  3. 3Initiate a continuous intravenous regular insulin infusion
  4. 4Add 5%5\% dextrose to the intravenous fluid regimen
  5. 5Transition to a subcutaneous basal-bolus insulin regimen

Answer

The correct sequence is: (1) Administer rapid intravenous fluid resuscitation with 0.9%0.9\% normal saline, (2) Administer intravenous potassium chloride and withhold insulin, (3) Initiate a continuous intravenous regular insulin infusion, (4) Add 5%5\% dextrose to the intravenous fluid regimen, (5) Transition to a subcutaneous basal-bolus insulin regimen.
The management of diabetic ketoacidosis (DKA) requires a rigorous, stepwise approach. First, profound fluid deficits must be addressed with isotonic saline to restore perfusion. Second, electrolyte derangements must be evaluated. In DKA, total body potassium is depleted due to osmotic diuresis and vomiting. Even if initial serum potassium is normal or high, it will rapidly fall with insulin administration. If the initial potassium is <3.3<3.3 mEq/L (as seen in this patient with 2.82.8 mEq/L), insulin MUST be strictly withheld while aggressive intravenous potassium is administered to prevent arrhythmias. Once potassium is ≥3.3\geq 3.3 mEq/L, a continuous intravenous insulin infusion is started to halt ketogenesis. When glucose falls to ≤200\leq 200 mg/dL, dextrose is added to the fluids to prevent hypoglycemia while continuing the insulin required to close the anion gap. Finally, once the anion gap closes and the patient can eat, a transition to subcutaneous insulin is performed.

Step-by-Step Solution

1
Evaluate hemodynamic status and initiate volume resuscitation.
Rapid intravenous fluid administration with 0.9%0.9\% normal saline is initiated.
Severe osmotic diuresis leads to profound dehydration in diabetic ketoacidosis, making volume expansion the most critical first step.
2
Evaluate serum potassium prior to insulin administration.
Potassium chloride is administered and insulin is held.
The patient has severe hypokalemia (2.82.8 mEq/L). Giving insulin immediately would drive potassium into cells, risking fatal cardiac arrhythmias. Potassium must be replenished to ≥3.3\geq 3.3 mEq/L first.
3
Start intravenous insulin therapy once potassium levels are safe.
Continuous intravenous regular insulin is initiated.
Insulin is required to suppress ketogenesis and resolve the high anion gap metabolic acidosis.
4
Monitor blood glucose and adjust maintenance fluids.
5%5\% dextrose is added to the fluids when glucose reaches ≤200\leq 200 mg/dL.
Insulin must be continued until the anion gap closes, but adding dextrose prevents hypoglycemia as serum glucose typically falls faster than ketones clear.
5
Transition to maintenance therapy once the crisis resolves.
Subcutaneous insulin is started.
After the acidosis resolves and the patient can tolerate oral intake, intravenous insulin is switched to a long-term subcutaneous regimen.

Key Concept

Stepwise management of Diabetic Ketoacidosis (DKA) in the setting of severe hypokalemia
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Topics

Endocrinology and Metabolism

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