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Hyperglycaemia (high blood sugar)

A high blood sugar (glucose) level, called “hyperglycaemia”, is common if you have diabetes. Find out who it affects and how to treat it.

Managing diabetes is all about keeping your blood sugar level in a good range, but that’s not always possible, so you’ll probably have hyperglycaemia at some point.

Hyperglycaemia can affect:

  • people with type 1 diabetes or type 2 diabetes
  • women with diabetes during their pregnancy (gestational diabetes)
  • anyone who is seriously ill, for instance someone who has just had a stroke or has a severe infection

Hyperglycaemia and hypoglycaemia are different

They may look and sound nearly the same but hyperglycaemia is the opposite of hypoglycaemia.

Notice the spelling: hyperglycaemia has an “er” at the start and means high or ‘excess’ sugar and the other has an “o”, so is often called a “hypo”, which describes low blood sugar level.

Treating hyperglycaemia

Most people will have mild hyperglycaemia that either happens only a few times or is easy to treat. It may even go away on its own without any treatment.  

But hyperglycaemia can also be dangerous if blood sugar levels are very high or stay high for a long time. So make sure you know how to treat hyperglycaemia, because it can lead to serious health problems if not treated. 

Dangers of high blood sugar

Regularly having high blood sugar levels for long periods of time (over months or years) can lead to damage to parts of the body such as the eyes, nerves, kidneys and blood vessels.

Very high blood sugar levels can also cause life-threatening complications, such as diabetic ketoacidosis (DKA) and hyperosmolar hyperglycaemic state (HHS).

What is diabetic ketoacidosis (DKA)?

DKA is caused when the body starts to break down fat to get the energy it needs, which causes it to produce substances called “ketones”. If you have too many ketones in your body, you can become very ill. 

DKA can lead to a diabetic coma and death. DKA mostly happens to people with type 1 diabetes. If you have ketones seek medical advice on how to treat DKA.

What is hyperosmolar hyperglycaemic state (HHS)?

(HHS) is severe dehydration caused by the body trying to get rid of excess sugar. It mostly affects people with type 2 diabetes. It can develop over a course of weeks through a combination of illness (e.g.infection) and dehydration. Treatment for HHS usually requires hospital admission.

Symptoms of hyperglycaemia

Symptoms of hyperglycaemia in people with diabetes usually develop slowly over a few days or weeks. In some cases, there may be no symptoms until the blood sugar level is very high.

Symptoms of hyperglycaemia include:

  • increased thirst and a dry mouth
  • needing to pee frequently
  • tiredness
  • blurred vision
  • unintentional weight loss
  • recurrent infections, such as thrush, bladder infections (cystitis) and skin infections
  • tummy pain
  • feeling or being sick
  • breath that smells fruity

Speak to your GP or diabetes care team if you get this often as you will need to change your treatment or lifestyle to keep your blood sugar levels within a healthy range

Symptoms of hyperglycaemia can also be due to undiagnosed diabetes, so see your GP if this applies to you. 

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