Diabetes affects the way the body regulates blood glucose. Most people with diabetes manage their condition successfully day to day, but sometimes blood glucose can become dangerously low or high and urgent help may be needed.
The two situations people most often associate with diabetic emergencies are hypoglycaemia, where blood glucose falls too low, and hyperglycaemia, where it rises too high.
These conditions can look very different, and the correct first aid response depends on whether the person is conscious, able to swallow safely and showing signs of serious deterioration.
This guide explains how to recognise possible diabetic emergencies, what first aid to give and when to call 999.
A diabetic emergency can happen when a person's blood glucose becomes too low or too high.
Someone with diabetes may carry useful clues such as:
Do not assume unusual behaviour is caused by alcohol, tiredness or anxiety. Confusion and altered behaviour can be signs of dangerously low blood glucose.
| Condition | What it means | Typical pattern |
|---|---|---|
| Hypoglycaemia | Blood glucose is too low. | Can develop quickly and may cause sweating, shaking, hunger, confusion and reduced responsiveness. |
| Hyperglycaemia | Blood glucose is too high. | Often develops more gradually and may cause thirst, frequent urination, tiredness and, if severe, serious illness such as diabetic ketoacidosis. |
Hypoglycaemia, often called a hypo, happens when blood glucose becomes too low.
In people with diabetes it can happen for reasons such as:
A hypo can develop quickly, so recognising it early is important.
Possible signs of hypoglycaemia include:
Severe hypoglycaemia can cause seizures or loss of consciousness.
If you suspect hypoglycaemia and the person is awake, responsive and able to swallow safely, help them sit down and give them a fast-acting source of sugar.
Suitable options can include:
If the person manages their diabetes themselves, follow their usual hypo treatment plan where possible.
Stay with them and monitor how they respond.
The exact amount can vary according to the person's diabetes plan and the product being used.
UK diabetes guidance commonly uses approximately 15 to 20 grams of fast-acting carbohydrate for an adult hypo, followed by reassessment after around 10 to 15 minutes.
If the person has their own glucose meter or continuous glucose monitor and is able to use it, they can check their blood glucose according to their normal plan.
If their glucose remains low or symptoms continue, further fast-acting carbohydrate may be needed.
Once the person's symptoms improve and their blood glucose has recovered, they may need a longer-acting carbohydrate source to help prevent the glucose level dropping again.
Depending on their own diabetes plan, this could include:
Stay with them until they have recovered properly.
A person with low blood glucose may become confused, irritable or uncooperative.
If they are still fully conscious and can swallow safely, help them take their usual hypo treatment.
Do not force food or drink into someone's mouth if their level of consciousness is deteriorating or if you are not confident that they can swallow safely.
If they are not improving promptly, become increasingly confused or you are concerned about their condition, call 999 or 112.
Do not give anything by mouth to an unconscious or significantly unresponsive person.
Food, drinks or glucose gel placed in the mouth could cause choking or aspiration.
If they are unconscious:
See our First Aid for an Unconscious Person and Recovery Position Explained guides for more information.
Glucagon is a medicine that can be prescribed for people at risk of severe hypoglycaemia. It raises blood glucose by helping the liver release stored glucose.
If the person has prescribed glucagon available and you have been shown how to use it, follow the product instructions and their emergency plan.
NHS guidance advises calling 999 if a person with very low blood sugar is not responding normally or is unconscious and:
Do not delay emergency help while trying to find medication you are not trained or confident to use.
Severe hypoglycaemia can sometimes cause a seizure.
If this happens:
For more detailed guidance, see our First Aid for Seizures guide.
Hyperglycaemia means blood glucose is higher than it should be.
Possible causes include:
Unlike a hypo, high blood glucose often develops more gradually.
Possible symptoms include:
Very high blood glucose can lead to serious complications, including diabetic ketoacidosis or hyperosmolar hyperglycaemic state.
Diabetic ketoacidosis (DKA) is a serious complication caused by a lack of insulin, leading to a build-up of harmful substances called ketones in the blood.
It is most commonly associated with type 1 diabetes but can also occur in some people with type 2 diabetes.
DKA can sometimes be the first sign that someone has diabetes.
Possible warning signs include:
DKA is life-threatening and requires urgent hospital treatment.
Call 999 or go to A&E if someone with suspected high blood glucose is becoming seriously unwell.
NHS guidance highlights emergency symptoms including:
If someone has symptoms suggesting DKA but has never been diagnosed with diabetes, call 999 or seek emergency assessment.
This is a common first aid question.
If a person with diabetes is conscious, able to swallow safely and shows typical symptoms of a hypo, fast-acting sugar may be appropriate.
However, if you are uncertain what is happening, the safest course is to assess the person's overall condition, check their glucose if they can do so themselves, and seek urgent medical advice if symptoms are significant or worsening.
Do not give food or drink to anyone who is drowsy, unresponsive or unable to swallow safely.
No. Do not independently administer insulin to another person unless this forms part of an established care plan and you are specifically trained and authorised to do so.
Insulin doses are individual and incorrect administration can cause severe hypoglycaemia.
A person who is conscious and capable may manage their own prescribed insulin according to their diabetes plan.
No. Do not change, omit or increase someone's diabetes medication unless this has been advised by their healthcare team or forms part of their established sick-day or emergency plan.
If blood glucose remains high despite usual treatment, the person should follow advice from their diabetes team or NHS 111.
Children with diabetes can experience both high and low blood glucose.
A child's hypo may present as:
Children often have an individual diabetes management plan setting out exactly how their hypo should be treated.
Schools, nurseries, sports clubs and other settings caring for a child with diabetes should make sure relevant staff understand that plan and know where the child's emergency supplies are kept.
If a child becomes unconscious or has a seizure, give nothing by mouth and call 999.
A colleague with diabetes may choose to tell relevant people about their condition and what help they might need during an emergency.
Where appropriate, workplace arrangements may include:
Employers should avoid making assumptions about what a person with diabetes requires and should consider individual needs as part of appropriate workplace arrangements.
Exercise can lower blood glucose, particularly in people who use insulin or certain diabetes medicines.
A person with diabetes may plan food, insulin and glucose monitoring around activity according to advice from their healthcare team.
Coaches and first aiders should know how to recognise signs of hypoglycaemia and where the person's fast-acting glucose is kept if an agreed plan is in place.
See our Sports First Aid guide for broader sports first aid considerations.
Hypoglycaemia can cause confusion, irritability and irrational behaviour.
This means someone experiencing a hypo may appear intoxicated or unusually aggressive even though they are having a medical emergency.
If a person with known diabetes suddenly behaves unusually, consider low blood glucose among the possible causes.
If they are conscious and able to swallow safely, help them follow their usual hypo treatment. If responsiveness deteriorates, call 999.
NHS 111 can provide urgent advice where the situation is not immediately life-threatening.
For example, someone with diabetes may need urgent advice if:
Call 999 instead if the person is unconscious, having a seizure, seriously confused, struggling to stay awake, having breathing difficulties or showing signs of a life-threatening diabetic emergency.
Our When to Call 999 vs 111 vs GP guide explains the difference between these services.
If someone with a suspected diabetic emergency becomes unresponsive:
See our CPR Explained guide for further information.
Common mistakes include:
A standard first aid kit does not usually contain diabetes medication, insulin or glucagon.
People who need these items normally carry or store their own prescribed supplies according to their individual care plan.
A general first aid kit can still support overall emergency preparedness by providing basic first aid supplies for unrelated injuries and by forming part of a wider emergency response system.
You can view our range of first aid kits for workplace, home, travel and other environments.
| Situation | What to do |
|---|---|
| Suspected hypo and fully conscious | Give fast-acting glucose according to their usual plan and monitor their response. |
| Symptoms improve | Follow with longer-acting carbohydrate where appropriate and stay with them until recovered. |
| No quick improvement | Reassess, seek urgent medical help and call 999 if their condition is worsening. |
| Unconscious or unable to swallow | Give nothing by mouth. Call 999, check breathing and use the recovery position or CPR as appropriate. |
| Prescribed glucagon available | Use it only if you know how and follow the person's plan and product instructions. |
| Possible DKA | Call 999 or go to A&E for serious symptoms such as vomiting, abdominal pain, deep breathing, fruity breath, drowsiness or confusion. |
| Unsure what is happening | Monitor the person closely and seek urgent NHS advice; call 999 if they become seriously unwell. |
The NHS provides detailed guidance on low blood sugar, high blood sugar and diabetic ketoacidosis. St John Ambulance also provides clinically reviewed first aid advice on diabetic emergencies.
You can read the NHS guidance on hypoglycaemia, NHS guidance on hyperglycaemia and NHS guidance on diabetic ketoacidosis.
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