A Very High Glucose with Ketones Present
This combination is an emergency and needs assessing today, not at the next appointment. There is one version that catches people out: on SGLT2 inhibitors the same dangerous process can run while the glucose sits close to normal, so a reassuring glucose does not exclude it when the symptoms are there.
The pattern on your report
- Glucose High · marked Key
- Ketones High · marked Key
- Bicarbonate Low · moderate Key
- Potassium High-normal Key
Printed as: Bicarbonate in mmol/Lor mEq/L— Labeled bicarbonate, HCO3 or total CO2.Ketones in mmol/L— Blood ketone meters report beta-hydroxybutyrate in mmol/L. Urine strips measure a different ketone and lag behind, so they under-report a fast-moving situation.Glucose in mmol/Lor mg/dL— An eighteenfold difference. In this pattern the glucose is the least reliable of the numbers, because it can be near normal on SGLT2 inhibitors.Potassium in mmol/Lor mEq/L— The same figure either way. In this situation the measured value understates the depletion.
Why the numbers look like this
Without enough insulin, cells cannot take glucose in, and the body concludes it is starving in the middle of plenty. The liver pours out more glucose and switches to burning fat, and the fat arrives as ketones, which are acids. Bicarbonate is consumed neutralizing them, which is the falling number on this panel.
Meanwhile the glucose itself, above the kidney's threshold, drags water and electrolytes out in the urine. The result is a body that is dehydrated and depleted of potassium even while the blood potassium reads normal or high, because acidosis shifts potassium out of cells into the plasma being measured. That is why the measured value overstates the stores, and why it falls quickly once insulin starts and the shift reverses.
Not being flagged is not the same as normal
No single glucose value defines this condition: the diagnosis rests on ketones plus acidosis, usually with a raised glucose, and on SGLT2 inhibitors the glucose can sit near normal while the rest proceeds. Home blood ketone meters measure beta-hydroxybutyrate, and readings around 3 mmol/L and above belong to emergency care rather than to another correction dose; urine strips lag hours behind the blood and under-report a fast-moving situation.
What else on the report can hide this
Bicarbonate and the anion gap grade the acidosis, and the blood gas confirms what the panel suggests. Potassium is watched rather than checked once, for the reason above. The trigger hunt runs alongside treatment, not after it: an infection screen, a review of insulin doses and pump equipment, and in an older person an ECG, because a silent cardiac event can be the precipitant. Once stable, GAD antibodies and a C-peptide settle which type of diabetes this is, which shapes everything afterward.
What usually causes it
Listed from most to least common — not from most to least serious.
- Very common
New type 1 diabetes
Frequently the first presentation, particularly in children and young adults, with weeks of thirst, weight loss and passing large volumes of urine beforehand.
- Very common
Missed insulin doses or pump failure
The commonest trigger in someone already diagnosed. A blocked cannula or a failed pump can do it within hours.
- Very common
Infection or another acute illness
Raises insulin requirement sharply. Chest and urinary infections are the usual ones, and the illness may be the only symptom noticed first.
- Common
SGLT2 inhibitors
Cause ketoacidosis with a glucose that can be near normal. Vomiting and abdominal pain on one of these drugs is the presentation, and the normal glucose is what delays recognition.
- Common
Steroids or other drugs raising glucose
Corticosteroids in particular, and they can precipitate this in someone whose diabetes was previously stable.
- Uncommon
A heart attack or stroke
The stress response raises insulin requirement. Worth actively excluding in an older person, since the cardiac event may be silent.
- Uncommon
Alcoholic ketoacidosis
Heavy drinking with little food. Ketones and acidosis with a glucose that is normal or low, which is a different treatment pathway.
- Rare
Pancreatitis or pancreatic disease
Destroys insulin-producing tissue. Abdominal pain that came first rather than as a consequence.
What is usually checked next
- Immediate assessment, not a repeat blood test This is the answer rather than a step toward it. Everything below happens in that assessment.
- Blood ketones, bicarbonate and a blood gas Confirms ketoacidosis and grades severity, which determines how it is treated.
- Potassium, before and during treatment The measured level misrepresents total body stores and falls sharply once insulin starts, which is why it is followed rather than checked once.
- A search for the trigger Infection screen, an ECG, and a review of doses and equipment. Treating the numbers without finding the cause leaves it to recur.
- GAD antibodies and C-peptide, once stable Establishes the type of diabetes, which determines lifelong treatment. Done after the emergency, not during it.
When to seek care sooner
- Emergency Deep rapid breathing, or breathlessness at rest
- Emergency Vomiting, abdominal pain, or a sweet smell on the breath
- Emergency Drowsiness, confusion, or difficulty waking
- Emergency Vomiting and abdominal pain on an SGLT2 inhibitor, even with a normal glucose
- Emergency Unable to keep fluids down with a high glucose
- Emergency Ketones rising on home testing despite correction doses
Questions worth bringing to your appointment
- Should I be assessed today rather than waiting?
- I take an SGLT2 inhibitor. Could this be ketoacidosis despite my glucose?
- What triggered it, and has that been looked for?
- How should I check ketones at home, and at what point do I call for help?
- Do I need testing to establish which type of diabetes I have?