Information for the public
High blood glucose (hyperglycaemia) in type 1 diabetes
High blood glucose (hyperglycaemia) in type 1 diabetes
When your blood glucose levels are too high, this is called hyperglycaemia. High blood glucose levels can cause problems such as making you thirsty or making it hard to concentrate. If your blood glucose levels are too high for a long time, this can cause other problems (such as eye, gum and kidney damage).
Younger children can find out more about hyperglycaemia on the Diabetes UK website.
When you are ill
It can be difficult to keep your blood glucose at your target level when you are ill, so your diabetes team should teach you what to do when this happens. They should give you rules (called 'sick‑day rules') you can follow to help keep your blood glucose at the right level, and tell you when to call them for help. They should remind you about this every year, and more often than that if you need more help.
Younger children can find out more about what to do when you are ill on the Diabetes UK website.
Questions to ask about hyperglycaemia
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Can you tell me when I should measure my blood glucose level more often than usual?
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What should I do if my blood glucose levels are too high?
Checking your blood ketones
If you are ill, or if you are not getting as much insulin as you need, you could get high blood glucose levels. When you have high blood glucose levels, your body sometimes makes chemicals called ketones. If your body makes a lot of ketones, this can be bad for you and you could get a very serious illness called diabetic ketoacidosis (or DKA for short).
Your diabetes team should have given you a meter and blood ketone strips to check your blood ketone levels. To make sure you do not get diabetic ketoacidosis, you should check your blood ketone levels when you are ill or when you have a high blood glucose level. Your diabetes team will show you how to do this. Your diabetes team should tell you not to use out‑of‑date strips. You should always have some strips at home to use if you get ill.
If you do have high blood ketone levels, your diabetes team will tell you how you should treat them and when you should get help.
Blood ketones are measured in mmol/litre (millimoles per litre). Your blood ketone level should be below 0.6 mmol/litre. If the level is above 1.5 mmol/litre, you should speak to your diabetes team straight away.
Younger children can find out more about checking blood ketones on the Diabetes UK website.
Questions to ask about blood ketones
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Could you show me how to measure my blood ketones?
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Can you tell me more about when I should measure my blood ketones?
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What should I do if my blood ketone levels are too high?
Diabetic ketoacidosis
Diabetic ketoacidosis happens if your blood ketone levels get too high. This can happen if you have an illness that gives you high blood ketone levels, or if you forget to inject your insulin. Most people with diabetes never get diabetic ketoacidosis, and you can avoid it by measuring your blood ketone levels and treating them when they get too high.
Finding out if you have diabetic ketoacidosis
If you have high blood glucose levels and any of these problems, you might have diabetic ketoacidosis:
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feeling or being sick (nausea and vomiting)
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pains in your stomach
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feeling out of breath
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feeling dehydrated (your body does not have enough water in it)
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finding it hard to stay awake.
If you have any of these problems, you should check your blood ketone levels straight away. If your blood ketone levels are more than 3 mmol/litre, then you are likely to have diabetic ketoacidosis and you should contact your diabetes team straight away and go to hospital.
If you have any of the problems above but do not have a blood ketone tester or any spare strips, or the strips are out of date, you should contact your diabetes team for advice straight away.
If your diabetes team thinks that you have diabetic ketoacidosis you should be taken to a hospital that looks after children and young people.
Diabetic ketoacidosis is a serious illness and needs to be treated in hospital.
When you get to hospital
When you are in hospital you will be looked after by a team of people (your 'hospital team'). They will do tests to find out if you have diabetic ketoacidosis.
They should tell you about diabetic ketoacidosis and what care and treatments you will need. If you are having trouble staying awake and are being sick, you may have a tube put into your nostril and down into your stomach (a nasogastric tube). This is in case you throw up, to stop the vomit getting into your lungs.
If you are very ill with diabetic ketoacidosis, you should have the special care in the box below.
Special care for children and young people with bad (severe) diabetic ketoacidosis, and children under 2 years old
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You will have a nurse who only cares for you and is with you all the time.
and
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You may be looked after in a special part of the hospital called a high‑dependency unit. Here, you will have more checks than normal.
Parents and carers: all children under 2 with diabetic ketoacidosis should have this special care.
Your care in hospital
You will need fluids (water mixed with salt and other things your body needs) and insulin to get better from diabetic ketoacidosis.
Your hospital team should give you a drip that injects fluids and insulin straight into your veins (intravenous) over 1 or 2 days if you have any of these problems:
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finding it hard to stay awake
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feeling or being sick (nausea and vomiting)
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dehydration (your body does not have enough water in it).
You should be able to start drinking and giving yourself insulin when your diabetic ketoacidosis starts to get better.
If you do not have any of the problems above, you should be able to drink and give yourself insulin.
If you have an insulin pump, your hospital team should turn it off before giving you intravenous insulin. They will turn it back on when your diabetic ketoacidosis starts to get better.
Checking on you while you are in hospital
Your hospital team should check on you often while you are in hospital. They will do lots of tests to make sure you are getting better. These will be blood and urine tests. Your hospital team may need to place a tube in your bladder to help them do tests on your urine (for example, if you cannot go to the toilet on your own).
Your hospital team will do some tests (such as testing your blood glucose levels) every hour.
They will do some tests (such as testing your blood ketone levels) at least every 4 hours, and they should come to see you at least once every 4 hours.
If you are very ill with diabetic ketoacidosis, you should have some tests (such as checking how awake you are) and be seen by your hospital team more often.
Your hospital team should tell you often how you are doing.
Other problems caused by diabetic ketoacidosis
Diabetic ketoacidosis can cause other problems with your body. Your hospital team should check for these problems while you are in hospital. They should treat any problems you get.
One problem sometimes caused by diabetic ketoacidosis is swelling in the brain (also called 'cerebral oedema'). This is a serious problem and needs very quick treatment, so your hospital team will be checking for this often and they will treat it quickly and carefully if it happens.
Making sure you do not get diabetic ketoacidosis again
After you have recovered from diabetic ketoacidosis, it is important to try to stop it happening again. Your hospital team should talk to you about what might have caused it (for example, if it happened because you were ill or had forgotten some insulin injections).
Your diabetes team should teach you and your family and carers how to try to make sure you do not get diabetic ketoacidosis again. They will teach you what to do when you are ill and how to measure your blood ketone levels again. They will also help you remember to inject all your insulin if you have been forgetting.
Younger children can find out more about stopping diabetic ketoacidosis happening on the Diabetes UK website.
Questions to ask about diabetic ketoacidosis
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Could you tell me more about how to tell if I have diabetic ketoacidosis?
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Could you tell me more about the treatment you want me to have for diabetic ketoacidosis? How will it help me?
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How long will the treatment take to start working?
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Can you give me any written information? What websites are helpful?