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What is a diabetes emergency?

Hypoglycaemia and hyperglycaemia are words that you will hear quite often around the topic of diabetes, but what do they mean? In this blog, we look at how low and high blood sugar levels can affect you and how to treat these.

Hypoglycaemia (low blood sugar)

Hypoglycaemia (hypo), or low blood sugar, is usually identified as a blood sugar reading below 4mmol/L1. Symptoms of hypoglycaemia can vary, but common symptoms include:

  • Fatigue
  • Sweating
  • Feeling dizzy or disorientated
  • Feeling shaky
  • Palpitations and a fast pulse
  • Lips feeling tingly
  • Blurred vision

More symptoms and a video of demonstrating what a hypo can feel like can be found here.

A hypo can occur for a variety of reasons, including:

  • Missing a meal or a snack
  • Exercising more without increasing your carbohydrate intake or decreasing your dose of insulin/other diabetes medication
  • Taking more insulin or other diabetes medications than needed

When you experience a hypo, it is important to treat it immediately by eating or drinking a fast-acting carbohydrate. This can be in the form of fruit juice, sweets, glucose tablets or energy gels. A way to remember what to do is to follow the rule of 15: consume 15 grams of carbs, wait 15 minutes, then check your blood sugar levels again. Repeat this process until your blood sugar comes back up to your target range.

After having a hypo, try to eat 15-20g of a slower-acting carbohydrate, such as a sandwich, piece of fruit or glass of milk. This is to help prevent your blood sugar levels from going too low again2.

It is advised to re-check your blood sugar levels again an hour after your hypo to ensure they haven’t gone too high blood sugar or are persistently low.

While this is a commonly used rule, it is always best to discuss with your healthcare team the best plan for you to follow.

Hyperglycaemia (high blood sugar)

There are so many factors that can cause your blood sugar to rise that it is not uncommon to experience hyperglycaemia (hyper), or high blood sugar levels, if you are a person living with diabetes. Hyperglycaemia is usually characterised by blood sugar levels being above 7mmol/L before a meal and above 8.5 mmol/L two hours after a meal3.

Symptoms of hyperglycaemia include3:

  • Being very thirsty
  • Tiredness
  • Headaches
  • Blurred vision
  • Needing to go to the toilet more than normal

Regularly checking your blood sugar levels can help you identify when your levels go too high. When your blood sugar goes up, there are some ways you can help your body bring it back down:

  • Do some exercise - did you know your leg muscles are some of the biggest muscles in your body? Taking a walk can be an effective way to bring your blood sugar levels down.
  • Remember to take your insulin and other diabetes medication.
  • Try to manage your stress levels.

When does hyperglycaemia become dangerous?

If your blood sugar level is high for a short time, there is no need for emergency treatment. However, if left untreated, high blood sugar levels for a sustained period can lead to a condition called diabetic ketoacidosis (DKA), a serious condition that can lead to a diabetic coma.

If you have diabetes, either your body cannot produce insulin or cannot use it effectively. This means that when the food you eat is broken down to glucose, it cannot enter the cells in your body, and so it builds up in the blood.

Without insulin addressing your rising blood sugar levels, your body breaks down fats to use for energy. When your body breaks down fats, it produces waste products called ketones4. Your body cannot tolerate large amounts of ketones and will try to get rid of them through the urine. Unfortunately, when the body cannot release all the ketones, they build up in your blood, which can lead to DKA.

If your blood sugar level is 15mmol/L or higher, it is recommended that you check your blood or urine for ketones3. If ketones are present, you may need an extra dose of insulin, but it is always best to seek advice from your healthcare team.

How do you know if it is an emergency?

When you are diagnosed with diabetes you learn how your body reacts to different experiences, and you also likely know when things aren’t quite right. But how do you know when it is an emergency? How do you know when it is time to seek help?

Diabetes related emergencies could be defined as any point when symptoms become overwhelming and self-treatment is no longer effective.

The following signs can indicate a serious problem. If you experience any of these signs and are not able to treat them on your own, call for an ambulance right away:

  • Difficulty breathing
  • A high fever
  • A severe headache

If your friends, family and others that you spend time with see any of the following signs, they should call an ambulance immediately:

  • Seizures
  • Loss of consciousness

Be prepared for emergencies – plan ahead

Emergency planning can improve the chances that the signs and symptoms experienced don’t result in a less than favorable outcome.

People living with diabetes can prepare by:

  • Letting friends and loved ones know about your diabetes and informing them of how they can help you identify when your blood sugar level is too high or too low.
  • Wearing a medical ID badge so that people will know what to do in an emergency.
  • Keeping a mobile phone charged so you are able to contact the emergency services.
  • Speaking with your doctor about:
    • Whether you should buy a glucagon kit and how and when to use it, as well as ensuring friends and family know how to use it too.
    • How to handle times of crisis and who to call with questions about diabetes emergencies.


This is general information and does not constitute medical advice and should not be relied upon as such. Please always speak to your healthcare professional about what may constitute a diabetes emergency for you.

The views expressed in the Accu-Chek blog are not necessarily those of Roche Diabetes Care Limited. The content is provided for general information only. It is not intended to amount to advice on which you should rely – you must obtain professional or specialist advice before taking, or refraining from, any action on the basis of the content. Although we make reasonable efforts to ensure that the content is up to date, we make no representations, warranties or guarantees, whether expressed or implied, that the content is accurate, complete or up-to-date.


8 March 2023