Hyperglycaemia in diabetes
Hyperglycaemia means too much sugar in the bloodstream. For someone with known diabetes it is a sign that their diabetes is not well controlled. Hyperglycaemia will happen to most people with diabetes at some point, but it shouldn’t happen every day.
| Regulating your blood sugar levels |
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Under normal circumstances the body secretes insulin to regulate the blood sugar (also known as glucose) level and keep it within a healthy range (about 4 to 8 mmol/L). This is how it works: you eat food; the carbohydrates are broken down into sugars (glucose) and passed into the bloodstream. The raised level of sugars in the blood triggers the insulin-secreting cells of the pancreas to release insulin into the bloodstream. Insulin improves the uptake of glucose from the blood across cell membranes and into the cells of the body, thus taking it out of the circulation. The result is a lowered blood glucose level which then switches off the release of insulin. |
How does hyperglycaemia come about?
In people with diabetes, the cells in the pancreas that produce insulin are either destroyed so that they can’t produce insulin (type 1 diabetes), or the insulin that the cells do produce doesn’t work properly (type 2 diabetes).
Both of these scenarios result in insulin not doing its job of helping glucose to move from the bloodstream into the cells of the body and the muscles where it is used as fuel. So the glucose builds up in the blood and you will have a high blood glucose level.
To combat this, people with diabetes either have to inject insulin several times a day or they take oral medicines. These either stimulate the pancreas to produce insulin, or make cells more sensitive to insulin to help reduce the blood glucose level. Exercising and eating a healthy diet also help to keep blood sugar levels under control.
Common causes of hyperglycaemia
Missed doses — people with diabetes must take care not to miss doses of insulin or take too little or they run the risk of becoming hyperglycaemic. The same applies to missing oral diabetes tablets. Incorrect insulin injection technique (such as not gently swirling insulin vials, as instructed, to mix and re-suspend the particles before injecting) can also lead to hyperglycaemia.
Overeating — especially eating too many simple carbohydrates — can make blood sugar levels rise.
Lack of exercise — regular exercise helps insulin to work better.
Mental or emotional stress — Being under stress can cause the release of glucose into the bloodstream and stress hormones can bring about resistance to the action of insulin, both actions contributing to high blood sugar.
Physical stress — being ill, suffering major physical trauma or undergoing major surgery, or having an infection, causes the body to produce more of certain hormones which stimulate the liver to make extra glucose. Any severe stress to the body, for example a heart attack or kidney disease, can raise blood sugar levels.
How will hyperglycaemia affect me?
If you have a high blood sugar level, and insulin isn’t doing its job of moving the glucose out of the bloodstream into the cells, your body will resort to other methods to try and remove the glucose. You will notice that you are passing larger quantities of urine than is normal and doing it more often than usual. You will become thirsty due to the large amounts of fluid you are losing through urination.
You will also feel tired, because you are passing a lot of the glucose in your urine and it is not reaching your cells and muscles where it is needed as fuel.
So, the symptoms of high blood sugar are:
- excessive thirst;
- passing large volumes of urine, frequently;
- tiredness or weakness;
- weight loss; and
- blurred vision.
The weight loss happens because excessive calories are lost in the urine — this can also make you feel hungry. The blurred vision is a result of the lens of your eye changing shape.
When is hyperglycaemia serious?
People with type 1 diabetes have little or no insulin. In these people hyperglycaemia may happen quickly and progress to diabetic ketoacidosis. Diabetic ketoacidosis is a dangerous condition in which the body starts to break down fats for fuel because it has no insulin to allow it to use glucose.
Toxic chemicals called ketones are produced as a byproduct and they make the blood acidic. Without treatment, coma and death can result.
The symptoms of diabetic ketoacidosis are:
- excessive thirst;
- excessive urination;
- nausea and/or vomiting;
- weakness and fatigue;
- abdominal pain;
- rapid, deep breathing;
- breath smelling like nail polish remover or apple cider;
- confusion; and
- coma, eventually, if not treated.
Hyperglycaemia may develop more slowly in people with type 2 diabetes but can still progress to dehydration, confusion, and coma — known as ‘hyperosmolar hyperglycaemia’.
What to do about hyperglycaemia
Most people with diabetes usually have to test their own blood sugar levels regularly — this is called self-monitoring of blood glucose. They do this by testing a drop of blood obtained by pricking their finger. If hyperglycaemia is detected it is usually controlled with insulin injections or oral diabetic medications. The exact choice of medication and the doses and timing vary from person to person and may change over time — for example, a person may need more insulin if they have an infection.
During an illness of any kind, it’s essential that people with diabetes monitor their blood glucose levels closely. Even if you are eating less than usual, or are sick with nausea and vomiting, your blood sugar levels may still be high. You should continue to take your insulin or tablets — contact your doctor or diabetes team early so that you can get help managing the situation.
If your blood glucose levels don’t respond to medication, you should contact your doctor or diabetes nurse educator for advice. Obviously, if blood glucose levels continue to rise or you are very unwell or your blood glucose levels are very high you should seek medical attention immediately.
Your doctor should be able to advise you on what blood glucose levels constitute an emergency, and on what to do.
Last Reviewed: 14 September 2009
- 1. Therapeutic Guidelines (eTG). Factors that alter diabetes therapy. In: Endocrinology guidelines [updated 2009, Jun; accessed 2009, Oct 9]. Available from: http://www.tg.org.au
2. Therapeutic Guidelines (eTG). Hyperosmolar hyperglycaemia. In: Endocrinology guidelines [updated 2009, Jun; accessed 2009, Oct 9]. Available from: http://www.tg.org.au
