Euglycemic Diabetic Ketoacidosis Triggered by SGLT2 Inhibitor Use in Undiagnosed Type 1 Diabetes

Sodium-glucose cotransporter 2 inhibitors (SGLT2I) are increasingly used for glycemic control, but their use in type 1 diabetes mellitus (T1DM) is contraindicated due to the risk of diabetic ketoacidosis (DKA). We report a 31-year-old male who initially presented with prediabetes (HbA1c 6.0%) and progressed to overt clinical diabetes (HbA1c 10%, fasting glucose 17 mmol/L, BMI 27 kg/m2) over 2 years. Upon diagnosis, he was commenced on metformin and empagliflozin (SGLT2I) but developed severe euglycemic DKA (blood glucose 4 mmol/L, serum bicarbonate 6 mmol/L, arterial pH 7.1, plasma β-hydroxybutyrate 8.4 mmol/L) within 2 days. Laboratory evaluation revealed elevated anti-glutamic acid decarboxylase (GAD) 65 antibodies (25.6 kU/L) and low-normal C-peptide (0.6 nmol/L), confirming new-onset T1DM. The patient's DKA resolved with intravenous insulin and rehydration, and he was transitioned to a basal-bolus insulin regimen.