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Pump Failure DKA — RACP Adult Medicine MCQ

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ModerateEndocrinology & DiabetesPump Failure DKARACP Adult Medicine

A 35-year-old woman with type 1 diabetes on an insulin pump develops a site infection. Her pump is delivering insulin lispro. She removes the pump. Within 4 hours, she develops ketoacidosis (pH 7.22, ketones 4.5 mmol/L). Why does DKA develop so rapidly after pump discontinuation?

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Correct answer: D — She has insulin antibodies

Insulin pumps deliver continuous subcutaneous infusion of rapid-acting insulin analogue (no long-acting insulin depot). When the pump is removed, there is no circulating basal insulin within 3–5 hours (the duration of action of rapid-acting insulin). Without basal insulin, lipolysis and ketogenesis commence rapidly, leading to DKA much faster than in patients on basal-bolus MDI regimens (where the long-acting insulin provides several hours of background coverage). Pump users must have an emergency plan with pen insulin.

Reference: ADS – 2024 – Insulin Pump Therapy; eTG – 2025 – Endocrinology