A newly diagnosed 9-year-old with DKA has serum potassium of 2.8 mEq/L before any insulin is given. Urine output is adequate. What is the correct approach to insulin and potassium?

• A Start insulin infusion and add potassium 40 mEq/L to fluids simultaneously
• B Start insulin infusion and withhold potassium until serum potassium reaches 5 mEq/L
• C Give a bolus of regular insulin 0.1 unit/kg IV before starting potassium
• D Begin potassium replacement and defer insulin until serum potassium exceeds 3.3 mEq/L ✓

Explanation

Insulin drives potassium into cells and can precipitate fatal arrhythmias when total body potassium is already depleted, even if admission potassium was normal. Guidelines therefore defer insulin until serum potassium is above 3.3 mEq/L, replacing potassium concurrently. Withholding potassium entirely is wrong because DKA always carries a large total body potassium deficit, and insulin boluses are not used in pediatric DKA.

Reference: Nelson Textbook of Pediatrics, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.