The answer, step by step

1. 1Glucose is flushed out in the urineThe kidney stops taking glucose backBlood glucose falls — even when insulin is shortWhy? →
2. 2Insulin falls tooLower glucose, so the body makes less insulinIllness, fasting or a cut in insulin lowers it furtherWhy? →
3. 3Fat is burned, ketones build upWithout enough insulin, the body breaks down fatFat breakdown makes acidic ketonesWhy? →
4. 4DKA — with a glucose that doesn’t look highOnly moderately raised glucose, so it’s easy to missRare, but it can be fatalWhy? →

What to do

• UrgentUnwell on an SGLT2 inhibitor? Test ketonesNausea, vomiting, abdominal pain, fast deep breathing, sleepinessTest for raised ketones even if glucose is near-normal
• Do thisStop it if DKA is suspectedDiscontinue the SGLT2 inhibitorDon’t restart any SGLT2 inhibitor unless another cause was found and resolved
• Do thisPause it for major surgery or serious illnessInterrupt treatment in hospitalMonitor blood ketones; restart when ketones are normal and the patient is stable