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Diabetic ketoacidosis — MCCQE Part 1 MCQ

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ModerateNausea/VomitingDiabetic ketoacidosisMCCQE Part 1

19-year-old woman with type 1 diabetes presents with vomiting, abdominal pain and polyuria. Glucose is 28 mmol/L, pH 7.18, bicarbonate is low and ketones are positive. Which of the following is the most appropriate next step?

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Correct answer: C — Start IV fluids, insulin infusion and potassium-guided electrolyte replacement

Start IV fluids, insulin infusion and potassium-guided electrolyte replacement is best because hyperglycaemia, acidosis and ketones define DKA requiring protocolised resuscitation. Wait for confirmatory testing before any stabilisation is suboptimal because resuscitation and time-critical treatment should not wait when instability is present; Discharge once symptoms temporarily improve is suboptimal because temporary improvement can precede deterioration; Give an adjunctive medication as the sole first-line treatment is suboptimal because adjuncts do not replace definitive stabilisation; Delay escalation until cardiac arrest or respiratory failure occurs is suboptimal because early escalation is central to emergency care. Potassium must be checked and managed before and during insulin therapy.

Reference: Diabetes Canada CPG 2025