Hyperglycaemia

What is hyperglycaemia?

Hyperglycaemia occurs when your blood sugar rises above the normal level, usually above 11 mmol/l.

Hyperglycaemia can happen after you've eaten a big meal or if you are ill. Having the occasional brief rise in blood sugar is not usually serious.

There are two very good reasons why you should avoid having hyperglycaemia:

  • If you develop extremely high blood sugar, this can become a medical emergency if it’s not recognized and treated appropriately
  • Prolonged periods of even moderately high blood sugar can lead to serious diabetic complications in the future.

High blood sugar

How do you know you have high blood sugar? Here are the common signs:

  • You feel thirsty
  • You need to urinate more often
  • You may also feel hungrier than usual
  • You'll often feel more tired and sleepy than usual
  • You may have blurred vision and/or cramps in your legs. You may have noticed that the signs of hyperglycaemia are like the early signs of diabetes. In fact, you may have had some of these signs when you first found out you had diabetes.


    • You can have moderately high blood sugar and not experience any of these symptoms. Even so, it can still damage your blood vessels and cause long-term complications.

    If your blood sugar is often high

    Test your blood sugar. If your blood sugar is frequently too high, you may need to discuss a change of treatment with your doctor.

    It’s extremely important for your long-term health to keep your blood sugar levels within the normal range.

    Your blood sugar rises if:

    • You forget to take your treatment
    • You eat too much at mealtimes (especially carbohydrates)
    • You are ill and have a fever
    • You exercise less than usual
    • You are under physical or emotional stress
    • Your period is due.

    To avoid high blood sugar

    There are things you can do to avoid getting high blood sugar - following a daily routine helps. Try to stick to a regular schedule with your medication, meals and exercise.

    When you are ill

    The stress of illness tends to increase blood sugar. It’s really important to be aware of hyperglycaemia and to test your blood sugar when you are ill.

    Continue to take your medication throughout your illness. You may need to make adjustments to your treatment.

    It’s worth discussing with your doctor the best way for you to manage your diabetes whenever you’re unwell.

    Will you need insulin when you're ill?

    If you normally control your diabetes very well with diet and/or tablets, you may find when you’re ill that your usual treatment does not work so well.

    Sometimes, when this happens, insulin injections are needed. This does not happen to everyone, but it is a possibility that your doctor will discuss with you if it becomes necessary.

    If you do need insulin when you’re ill, you will be able to return to your normal treatment as soon as you’re well again.

    Sick days and how to survive them

    • Drink at least 3 litres of sugar-free liquid every 24 hours. Drink more if you are still thirsty.
    • If you can't eat regular meals, have nourishing fluids. Most people can take soft drinks or soups even when they feel too sick to eat solid food.
    • If you can’t even take fluids, you should see your doctor.

    Hyperglycaemia: A summary

    It is caused by high blood sugar, usually above 11 mmol/l
    Signs of hyperglycaemia are like those of untreated diabetes
    There are different reasons why hyperglycaemia may happen
    Trying to stick to a regular daily routine can help keep blood sugar stable
    Avoiding hyperglycaemia when you’re ill is very important.

     

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      INS/692/0107

    Last updated: May 2007