What is the most appropriate initial step in managing diabetic ketoacidosis (DKA) in addition to intravenous fluid administration?

Management of Diabetic Ketoacidosis in a 20-Month-Old Child

The most appropriate initial step after intravenous fluid administration is continuous intravenous regular insulin infusion at 0.1 units/kg/hour, which for this 7.8 kg child would be approximately 0.78 units/hour. 1

Why Regular Insulin IV is the Correct Answer

Continuous intravenous regular insulin is the standard of care for critically ill and mentally obtunded patients with DKA. 2, 1 This child meets criteria for severe DKA based on:

• Profound metabolic acidosis (pH 7.15, bicarbonate 8 mEq/L) 1
• Lethargy and altered mental status 1
• Severe dehydration (weight below 3rd percentile, tachycardia, tachypnea) 3

The insulin infusion should begin at 0.1 units/kg/hour (with or without an initial 0.1 units/kg bolus) for moderate to severe DKA. 1 For this 7.8 kg child, this translates to approximately 0.78 units/hour of regular insulin. 1

Why the Other Options Are Incorrect

Long-acting insulin is inappropriate because it cannot be titrated rapidly in response to changing glucose levels and does not address the acute metabolic crisis. 1 Long-acting insulin is only given 2-4 hours before stopping IV insulin during the transition phase, not as initial therapy. 1, 4

Insulin pump therapy is contraindicated in acute DKA management because it uses subcutaneous delivery, which is unreliable in severely dehydrated patients with poor tissue perfusion. 1 Pumps are for outpatient maintenance therapy, not acute crisis management.

Sodium bicarbonate is not recommended because multiple studies demonstrate it makes no difference in resolution of acidosis or time to discharge. 2, 1 The acidosis will correct with insulin therapy, fluid resuscitation, and resolution of ketoacidosis.

Total parenteral nutrition is irrelevant to acute DKA management and would worsen hyperglycemia. 2 The priority is correcting the metabolic derangements, not providing nutrition.

Critical Management Steps Beyond Insulin

Potassium Monitoring and Replacement

• Check potassium before starting insulin and delay insulin if K+ <3.3 mEq/L to prevent fatal cardiac arrhythmias. 4
• This child's potassium is 3.6 mEq/L, which is acceptable to start insulin but requires immediate supplementation. 1
• Add 20-30 mEq/L potassium to IV fluids once urine output is confirmed, targeting serum potassium 4-5 mEq/L throughout treatment. 1, 4
• Insulin drives potassium intracellularly, potentially causing life-threatening hypokalemia despite normal initial levels. 1

Glucose Management During Treatment

• Monitor blood glucose every 1-2 hours initially, expecting glucose to fall 50-75 mg/dL per hour. 4
• When glucose falls to 250 mg/dL, add dextrose 5% to IV fluids while continuing insulin infusion. 1, 5 This is critical because ketonemia takes longer to clear than hyperglycemia. 5
• Never stop insulin when glucose normalizes—this is the most common error leading to persistent or worsening ketoacidosis. 1, 5
• Target glucose between 150-200 mg/dL until DKA resolution. 1, 5

Monitoring Requirements

• Check electrolytes, glucose, BUN, creatinine, and venous pH every 2-4 hours until stable. 1, 5
• Venous pH adequately monitors acidosis resolution and avoids repeated arterial punctures in this young child. 5

DKA Resolution Criteria

DKA is resolved only when ALL of the following are met: 1, 5

• Glucose <200 mg/dL
• Serum bicarbonate ≥18 mEq/L
• Venous pH >7.3
• Anion gap ≤12 mEq/L

Transition to Subcutaneous Insulin

Once DKA resolves and the child can tolerate oral intake:

• Administer basal insulin 2-4 hours BEFORE stopping IV insulin to prevent rebound hyperglycemia and recurrence of ketoacidosis. 1, 4
• Start a multiple-dose regimen combining rapid-acting and long-acting insulin. 1, 5
• Continue IV insulin for 1-2 hours after starting subcutaneous insulin to ensure adequate plasma levels. 5

Common Pitfalls to Avoid

• Never discontinue IV insulin without prior basal insulin administration—this causes immediate DKA recurrence. 1, 4
• Never stop insulin when glucose normalizes—continue until all resolution criteria are met. 1, 5
• Inadequate potassium monitoring can lead to fatal cardiac arrhythmias, especially in young children. 1, 4
• Overly aggressive glucose correction without dextrose supplementation causes hypoglycemia. 5