Untreated diabetic ketoacidosis can become fatal within roughly 24 to 72 hours, though the exact timeline depends on age, how severe the acidosis is, and whether another illness is driving it. With prompt emergency care, death is uncommon – under 1% in most adult hospitals – but DKA should always be treated as a 911 emergency. If you or someone with diabetes has rapid breathing, vomiting, confusion, or fruity breath, go to the emergency department immediately.
What Happens Inside the Body
DKA develops when the body has almost no insulin. Without insulin, glucose cannot enter cells, so the body switches to breaking down fat for energy. Fatty acids are converted in the liver into ketone bodies (acetoacetate, beta-hydroxybutyrate, acetone). Ketones are acidic, and when they accumulate faster than the kidneys and lungs can clear them, blood pH drops below 7.30.
At the same time, high glucose causes massive urinary losses of water, sodium, and potassium. A person in full DKA is typically 6 to 9 liters dehydrated. Acidosis impairs heart function, and electrolyte shifts can cause arrhythmias. This is how DKA kills.
The Untreated Timeline
Timelines are approximate, but a common progression in someone who has stopped insulin or is battling an acute illness looks like this:
| Phase | Approximate Time | Signs | Danger Level |
|---|---|---|---|
| Early | 0-12 hours | Thirst, frequent urination, fatigue, nausea, glucose 250+ mg/dL | Reversible with insulin and fluids |
| Moderate | 12-24 hours | Vomiting, abdominal pain, fruity breath, rapid breathing, mild confusion | Urgent ER care needed |
| Severe | 24-48 hours | Deep rapid breathing (Kussmaul), dehydration, low blood pressure, altered consciousness | ICU-level care; real risk of death |
| Critical | 48-72 hours | Coma, shock, cardiac arrhythmias, cerebral edema | High mortality without intensive treatment |
Some patients – especially children, the elderly, and anyone with sepsis or a heart attack – deteriorate far faster. Children with cerebral edema can decline from alert to unconscious in hours.
What Triggers DKA
- Missed insulin doses. The single most common trigger in people with known type 1 diabetes.
- Undiagnosed type 1 diabetes. About 25-40% of first-presentation type 1 cases arrive in DKA.
- Infection or illness. Flu, pneumonia, UTI, gastroenteritis, or COVID-19 raise stress hormones and insulin requirements.
- Heart attack, stroke, pancreatitis. Acute illness can precipitate DKA.
- SGLT2 inhibitors. Drugs like empagliflozin and dapagliflozin can cause euglycemic DKA in both type 1 and type 2 diabetes.
- Pump malfunction. A kinked cannula or empty reservoir stops insulin delivery within hours.
- Severe stress (surgery, trauma).
- Alcohol or cocaine binges.
Warning Signs: When to Call 911
Call 911 or go to the nearest emergency department if a person with diabetes has:
- Glucose over 250 mg/dL with moderate or high ketones
- Rapid deep breathing or “air hunger”
- Fruity or acetone-like breath
- Persistent vomiting (cannot keep fluids down)
- Abdominal pain that mimics appendicitis
- Confusion, extreme drowsiness, or unresponsiveness
- Severe dehydration with dark urine or dizziness standing up
Do not wait to see if it passes. DKA treated at the “mild” stage is almost always resolved within 12-24 hours; DKA treated at the “severe” stage may require a multi-day ICU stay.
Emergency Treatment
Hospital care focuses on three pillars:
- IV fluids. Typically isotonic saline at 1-1.5 liters in the first hour, then maintenance. Fluid alone lowers glucose by dilution and restores kidney perfusion.
- IV insulin. A continuous insulin drip at 0.1 units/kg/hour shuts down ketone production. Subcutaneous insulin is inadequate until DKA resolves.
- Potassium replacement. Total-body potassium is usually depleted even when serum levels look normal. As insulin drives potassium back into cells, serum levels can plummet dangerously without replacement.
Glucose drops faster than acidosis resolves, so once glucose hits 200-250 mg/dL, dextrose is added to the IV while the insulin drip continues until ketones clear and bicarbonate normalizes.
Mortality Rates
According to CDC data and the Kitabchi 2009 consensus, adult DKA mortality in US hospitals is about 0.4-1% in young adults and 2-5% in older adults or those with serious comorbidities. Mortality rises sharply in low-resource settings, in homeless populations, and where treatment is delayed. Cerebral edema causes 21-24% mortality among the 0.5-1% of pediatric DKA cases it affects.
Prevention If You Have Diabetes
Never Stop Insulin
If you are too sick to eat, you still need basal insulin. Glucose rises from stress hormones even without food. Call your clinician for dose adjustment, never for permission to stop insulin.
Sick-Day Rules
- Check glucose every 2-4 hours when ill
- Check ketones (urine or blood) any time glucose exceeds 250 mg/dL or you feel unwell
- Drink 8 ounces of sugar-free fluid every hour
- Take correction insulin per your sick-day plan
- Go to the ER if ketones are moderate or large, vomiting prevents hydration, or symptoms progress
Ketone Monitoring
Blood ketone meters measure beta-hydroxybutyrate – the main DKA ketone – and are more accurate than urine strips. Target: under 0.6 mmol/L. Act on 1.5 mmol/L or higher. Everyone on insulin should own ketone strips.
SGLT2 Precautions
If you take an SGLT2 inhibitor, ketones can climb with a near-normal glucose. Check ketones any time you feel nauseated, short of breath, or unwell, even if glucose looks fine.
Euglycemic DKA: The Hidden Variant
Classic DKA involves glucose over 250 mg/dL, but euglycemic DKA – acidosis with glucose under 200 – is increasingly common and easily missed. Causes include SGLT2 inhibitor use, pregnancy, heavy alcohol use, fasting or low-carb dieting while on insulin, and after gastric bypass. If you feel classically unwell but your meter reads normal, still check ketones.
Who Is Most at Risk
- People with type 1 diabetes, especially adolescents and young adults
- Newly diagnosed people whose diabetes presents in crisis
- People on SGLT2 inhibitors during illness, surgery, or low-carb diets
- People with insulin pumps experiencing undetected pump failure
- People with limited access to insulin for financial reasons
- People with substance use disorders or untreated mental health conditions
After DKA: Follow-Up
Every DKA episode deserves a review of what went wrong. Ask your clinician to revisit your diabetes treatment plan: sick-day rules, insulin-to-carb ratios, ketone testing, and CGM use. Repeated DKA predicts higher mortality and warrants an endocrinology consult and behavioral support if medication adherence is the issue.
The Bottom Line
Diabetic ketoacidosis is a medical emergency with a narrow window. Untreated, death can occur within 24 to 72 hours; treated promptly, survival is the overwhelming norm. The rule is simple: glucose over 250 plus ketones, rapid breathing, vomiting, or confusion equals 911. Keep insulin going during illness, monitor ketones, and never assume DKA will resolve on its own.
