Rebound ketoacidosis in a patient with diabetic ketoacidosis using ultra-long-acting insulin

Background/objective: A 26-year-old Taiwanese woman with type 1 diabetes mellitus developed diabetic ketoacidosis after missing a premixed insulin dose. The case is notable for recurrent ketosis and hyperglycemia despite a 6-h overlap during the transition from intravenous to subcutaneous insulin therapy. The objective of this report is to describe the challenges of transitioning insulin regimens with ultra-long-acting insulin. Case presentation: A 26-year-old woman presented with severe diabetic ketoacidosis, confirmed by laboratory findings of blood glucose at 520 mg/dL, pH 7.14, bicarbonate 8 mmol/L, and serum ketones 5.9 mmol/L. She received intravenous insulin for 48 hours before transitioning to subcutaneous IGlar-300 with a 6-h overlap. Despite initial improvement, ketones rebounded to 4.2 mmol/L with hyperglycemia 7 hours after intravenous insulin discontinuation. Reintroduction of intravenous insulin for 48 hours and subsequent doses of IGlar-300 stabilized her condition, allowing discharge with resolved ketosis and improved glycemic control. Discussion: This case underscores the challenges of transitioning to ultra-long-acting insulin during management of diabetic ketoacidosis. The pharmacokinetics of basal insulin analogs like IGlar-300 may necessitate extended overlap with intravenous insulin to maintain stable glycemic control and prevent rebound ketosis. Conclusion: This case highlights the need for careful management during the transition from intravenous to subcutaneous ultra-long-acting insulin to prevent rebound ketosis. Although not specifically addressed in current guidelines, an extended overlap with intravenous insulin may be required in similar cases. Clinical Relevance: This case underscores the importance of tailored DKA management when using ultra-long-acting insulins, highlighting the need for extended overlap durations to ensure ketone clearance and avoid rebound ketoacidosis.