- Unconsciousness, seizure, or abnormal responsiveness in a person with diabetes is a medical emergency—call emergency services immediately.
- Do not give food, drink, sugar, or medicine by mouth to an unconscious person because of choking risk.
- Diabetic coma can result from severe hypoglycemia, diabetic ketoacidosis (DKA), or hyperosmolar hyperglycemic state (HHS).
Medically reviewed by: Dr. Ruden Cakoni, MD, Endocrinologist & Diabetologist
Endocrinologist, Catholic Hospital “Our Lady of Good Counsel”; University Faculty Member; member of the European Society of Endocrinology.
Last medically reviewed: July 2026
A diabetic coma means that a person with diabetes has become unconscious because of a severe metabolic emergency. It can happen when blood glucose becomes dangerously low, or during severe diabetic ketoacidosis or hyperosmolar hyperglycemic state.
Quick Answer
A person with diabetes who is unconscious, having a seizure, or not responding normally needs emergency medical help immediately. Call your local emergency number. Do not put sugar, food, liquid, or medicine into an unconscious person’s mouth because they may choke. If the person is breathing, place them on their side. Give prescribed glucagon only if severe hypoglycemia is suspected and you know how to use it.
What Is a Diabetic Coma?
“Diabetic coma” is a general description, not one single diagnosis. It refers to loss of consciousness caused by a severe diabetes-related emergency. The three principal causes are severe hypoglycemia, diabetic ketoacidosis (DKA), and hyperosmolar hyperglycemic state (HHS).
Loss of consciousness is usually a late and dangerous sign. Many people develop warning symptoms first, although symptoms can be missed, especially during sleep or when hypoglycemia awareness is reduced.
Three Conditions That Can Cause Diabetic Coma
1. Severe hypoglycemia
Blood glucose falls so low that the brain cannot function normally. Causes may include too much insulin or diabetes medication, a missed meal, unexpected exercise, alcohol, illness, or a mismatch between medication and carbohydrate intake.
2. Diabetic ketoacidosis
DKA develops when there is not enough effective insulin. The body breaks down fat and produces acidic ketones. It is more common in type 1 diabetes, but it can occur in type 2 diabetes, including with illness or certain SGLT2 medicines.
Important exception: DKA does not always cause extremely high blood sugar. Euglycemic DKA can occur with glucose below 200 mg/dL (11.1 mmol/L), particularly in some people taking SGLT2 medicines. Nausea, vomiting, abdominal pain, deep or difficult breathing, marked weakness, or positive ketones still require urgent assessment even when the glucose number does not look extremely high.
3. Hyperosmolar hyperglycemic state
HHS usually develops over days as very high glucose causes profound dehydration and rising blood concentration. It is more common in older adults with type 2 diabetes and is often triggered by infection, missed treatment, stroke, heart attack, or another illness.
DKA and HHS can overlap, so a person may have features of both conditions rather than fitting neatly into one category. Both require urgent hospital assessment, laboratory testing, fluids, electrolyte monitoring, and insulin treatment. They cannot be treated safely as home remedies.
Warning Signs Before Consciousness Is Lost
| Emergency | Possible warning signs | How it may develop |
|---|---|---|
| Severe hypoglycemia | Shaking, sweating, hunger, palpitations, dizziness, blurred vision, confusion, unusual behavior, weakness, seizure, or unconsciousness. | Often develops quickly, although the pattern varies. |
| DKA | Thirst, frequent urination, nausea, vomiting, abdominal pain, dehydration, fruity-smelling breath, deep or difficult breathing, fatigue, confusion, or reduced consciousness. | Often develops over hours, but it may progress rapidly. |
| HHS | Extreme thirst, frequent urination followed by worsening dehydration, dry mouth, profound weakness, visual or neurological changes, confusion, seizures, or unconsciousness. | Usually develops over several days. |
If you are awake and able to test, check your glucose promptly. Follow your prescribed hypoglycemia or sick-day plan. If you have symptoms of DKA, check ketones when this is part of your plan. Learn more about severe hypoglycemia and dangerous blood sugar levels.
What Should You Do If a Person With Diabetes Is Unconscious?
- Call emergency services immediately. Tell the dispatcher that the person has diabetes if you know this.
- Check breathing and follow the dispatcher’s instructions. Begin CPR if the person is not breathing normally and you are trained, or as directed by the dispatcher.
- If breathing normally, place the person on their side in the recovery position, unless you suspect a serious neck or spinal injury.
- Give nothing by mouth. Do not place sugar, honey, juice, tablets, food, or liquid under the tongue or inside the mouth.
- Use glucagon if available, prescribed, and you know how to give it when severe hypoglycemia is suspected. Emergency help is still necessary. Glucagon may be less effective after prolonged fasting or heavy alcohol use.
- Stay with the person. If they wake and can swallow safely, follow their hypoglycemia plan and the instructions from emergency professionals.
How Is a Diabetic Coma Treated?
The treatment depends on the cause. Emergency professionals measure glucose and assess breathing, circulation, neurological status, medication history, ketones, electrolytes, kidney function, acid–base balance, infection, and other possible triggers.
- Severe hypoglycemia: glucagon outside the hospital when appropriate, or intravenous glucose from trained medical professionals.
- DKA: carefully monitored fluids, insulin, potassium and other electrolyte management, plus treatment of the trigger.
- HHS: carefully monitored fluid replacement, electrolyte management, insulin when indicated, and treatment of the underlying illness.
These treatments require close monitoring. Giving insulin, potassium, or large volumes of fluid without medical supervision can be dangerous.
Can Diabetic Coma Be Prevented?
Not every episode is preventable, but planning can reduce risk. I advise you to:
- Know your personal glucose targets and review unexplained highs and lows with your diabetes team.
- Take insulin and other medicines exactly as prescribed; never stop basal insulin in type 1 diabetes unless your medical team directs you.
- Keep fast-acting carbohydrate available and ask whether you should have ready-to-use glucagon.
- Teach family members, friends, school staff, or colleagues how to recognize severe hypoglycemia and use glucagon.
- Follow a written sick-day plan, maintain hydration, and know when to check ketones.
- Wear medical identification and keep an updated medication list.
- Seek help early for persistent vomiting, breathing difficulty, high ketones, confusion, severe dehydration, or glucose that remains dangerously high.
Related Questions
Can someone wake up from a diabetic coma?
Yes. Recovery is possible when the underlying cause is recognized and treated promptly, but diabetic coma is a medical emergency and the outcome depends on the cause, severity, duration, and the person's overall health. Call emergency services immediately rather than waiting for the person to wake up.
At what blood sugar level does coma occur?
There is no single glucose level at which everyone becomes unconscious. Severe hypoglycemia can cause seizure or unconsciousness, while DKA and HHS can cause altered consciousness at very high glucose levels. DKA can also occasionally occur with glucose below 200 mg/dL (11.1 mmol/L), particularly with SGLT2 medicines. Symptoms and the person's condition matter more than one glucose number.
Should I give insulin to an unconscious person with diabetes?
No. Do not give insulin unless specifically directed by emergency medical professionals. You may not know whether the person is unconscious from severe hypoglycemia, DKA, HHS, stroke, seizure, or another emergency. Call emergency services immediately and give nothing by mouth.
Is diabetic coma the same as DKA?
No. DKA is one possible cause of diabetic coma. Severe hypoglycemia and hyperosmolar hyperglycemic state (HHS) can also cause loss of consciousness. A person does not need to be in a coma to have DKA or HHS; both should be treated before consciousness deteriorates.
Related Resources
References
- Hyperglycemic Crises in Adults With Diabetes: A Consensus Report. Diabetes Care. 2024.
- Diabetic Ketoacidosis. Centers for Disease Control and Prevention.
- Hypoglycemia (Low Blood Glucose). American Diabetes Association.
- Low Blood Sugar (Hypoglycaemia). NHS.