A Rare Case of Euglycemic Diabetic Ketoacidosis: Triad of Influenza A, Methicillin-Susceptible Staphylococcus aureus Pneumonia, and Sodium-Glucose Co-transporter 2 Inhibitor Use

Euglycemic diabetic ketoacidosis (euDKA) is a rare but life-threatening complication of diabetes characterized by ketoacidosis with only mildly elevated or normal blood glucose levels. Sodium-glucose co-transporter 2 (SGLT2) inhibitors are recognized precipitants, particularly during acute illness. We report, to our knowledge, a previously unreported triad: euDKA precipitated by influenza A with secondary methicillin-susceptible Staphylococcus aureus pneumonia in a 66-year-old man with type 2 diabetes on long-term SGLT2 inhibitor therapy. Despite near-normal glycemia on presentation and a history of previously tolerated mild respiratory infections on this regimen, he was found to have high anion gap metabolic acidosis (pH: 7.27) with markedly elevated serum ketones. He was managed with intravenous insulin, dextrose, fluids, and concurrent treatment of influenza and bacterial pneumonia, resulting in full recovery. This case underscores that life-threatening ketoacidosis can develop despite near-normal glucose and prior tolerance of acute illness and highlights the importance of early recognition, standardized treatment, and "sick day" precautions for patients taking SGLT2 inhibitors.