Hyperglycaemia means high blood sugar level. This can develop over many hours or days.

It is possible for your blood sugar level to be high without you realising.

Many people do not experience the symptoms of hyperglycaemia until their blood sugar levels are extremely high. Although their blood contains too much sugar, they cannot tell unless they do a finger prick test.


  • Feeling excessively thirsty
  • Frequently passing large volumes of urine
  • Feeling tired
  • Blurred vision
  • Infections (e.g. thrush, cystitis, wound infections)
  • Weight loss

Common Causes

  • Sickness
  • Infection
  • Stress
  • Too much carbohydrate food at once
  • Not enough insulin or diabetes tablets
  • Other tablets or medicines.


For Type 1 diabetes

  1. Contact your doctor or Credentialled Diabetes Educator for advice about increasing your dose of short acting insulin. You may also need extra doses of this insulin (e.g. 2-4 units every 2 hours).
  2. Test your blood glucose levels frequently, as well as your urine for ketones every time you pass urine.
  3. Drink extra water or low calorie fluids to keep up with fluid lost by passing more urine.

Contact your doctor or go to hospital if:

  • Vomiting stops you from drinking and makes eating difficult
  • Blood glucose levels remain high
  • Moderate to large ketones are present in the urine.

In type 1 diabetes, high blood glucose levels can progress to a serious condition called Ketoacidosis.

For Type 2 diabetes

It is normal for blood glucose levels to go up and down throughout the day. An occasional high blood glucose level is not a problem. But if your blood glucose level remains high for a few days or if you are sick, contact your doctor or Credentialed Diabetes Educator.