Hyperglycaemia

Page last reviewed: 13/07/2011

Hyperglycaemia occurs when there is a higher than normal level of glucose (sugar) in the blood. This causes:

  • increased thirst
  • the need to urinate frequently
  • tiredness

Glucose is produced when food is digested. Hyperglycaemia occurs when the body is unable to remove the glucose from the blood and turn it into energy. This usually only happens in people with diabetes. There are two types of diabetes:

  • type 1 diabetes (insulin-dependent)
  • type 2 diabetes (non-insulin dependent)

Type 1 diabetes

In type 1 diabetes, the body produces little or no insulin. Insulin is a hormone that takes glucose out of the blood and moves it into the cells, where it is broken down to produce energy.

People with type 1 diabetes require lifelong treatment to replace the insulin that their body does not produce. They will also need to check their blood glucose level regularly to prevent any complications from developing.

For more information, see the Health A-Z topic on Type 1 diabetes.

Type 2 diabetes

In type 2 diabetes, either the body does not make enough insulin, or it cannot use the insulin properly. This is called insulin resistance. This type of diabetes is often linked to obesity or being overweight. It is sometimes referred to as maturity onset diabetes because it occurs mostly in people who are over 40 years of age.

For more information, see the Health A-Z topic on Type 2 diabetes.

Outlook

Hyperglycaemia usually occurs in people who have diabetes. For example, it can occur in people with type 1 diabetes if they miss a dose of insulin. If this happens, appropriate steps need to be taken to lower blood glucose levels, such as increasing the dose of insulin. Diet and exercise can also be used to adjust blood glucose levels. 

Left untreated, hyperglycaemia can develop into diabetic ketoacidosis. This is a serious condition that can lead to coma (a sleep-like state where someone is unconscious for a long period of time), or even death. Diabetic ketoacidosis will need to be treated in hospital.

Glossary
Glucose
Glucose (or dextrose) is a type of sugar that is used by the body to produce energy.
Blood
Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.
Insulin
Insulin is a hormone released by the pancreas. It helps the body to control blood sugar levels.
Onset
The onset is the beginning or early stages of a condition or disease.
Obesity
Obesity is when a person has an abnormally high amount of body fat.

Page last reviewed: 13/07/2011

The symptoms of hyperglycaemia are the same as those of untreated diabetes. Diabetes is a chronic (long-term) condition that is caused by having too much glucose (sugar) in the blood.

If you have untreated diabetes, the symptoms will develop very gradually, usually over a period of weeks or months. However, if you have hyperglycaemia, the symptoms will be more severe and come on very suddenly.

The symptoms of hyperglycaemia include:

  • being thirsty
  • having a dry mouth
  • needing to urinate frequently
  • tiredness
  • recurrent infections, such as thrush (a yeast infection)  

If the symptoms of hyperglycaemia are prolonged, they may cause:

  • weight loss: as your body removes excess glucose through your urine, causing you to lose calories
  • blurred vision

Diabetic ketoacidosis

Diabetic ketoacidosis is a complication that can occur if hyperglycaemia is left untreated. The symptoms include:

  • nausea or vomiting (feeling or being sick)
  • stomach pain
  • a fruity smell on your breath, which may smell like pear drops or nail varnish
  • drowsiness or confusion
  • hyperventilation (rapid breathing)
  • dehydration (when the normal water content of your body is reduced, which can cause a headache, dry skin and a weak, rapid heartbeat)
  • unconsciousness

You should seek urgent medical attention if you experience any of these symptoms, as they will need to be treated in hospital.

 

Page last reviewed: 13/07/2011

Hyperglycaemia is caused by an increase in blood glucose (sugar) levels.

Blood glucose levels

The food that you eat is digested and broken down into other substances, including a simple sugar called glucose. Glucose then enters your bloodstream.

The amount of glucose in your blood is controlled by a hormone called insulin, which is produced by your pancreas (a narrow organ that lies behind the stomach). Insulin takes glucose out of your blood and moves it into your cells, where it is broken down to produce energy.

If you have diabetes

In people with diabetes, the body is unable to break glucose down into energy. This is because there is either not enough insulin to move the glucose, or because the insulin that is there does not work properly. The glucose remains in the blood, causing a high blood glucose level.

Hyperglycaemia

The high blood glucose level means that glucose enters the urine. The glucose takes extra water and electrolytes (minerals and salts in the blood) with it into the urine.

This causes the symptoms of hyperglycaemia, such as increased thirst and the need to urinate frequently. Eventually, this leads to dehydration (when the normal water content of the body is reduced).

Triggers of hyperglycaemia

If you have diabetes, your GP should give you advice about how to manage your blood glucose levels. However, there are some events that can trigger an increase in blood glucose, including:

  • emotional stress
  • a change of medication
  • a wrong (or missed dose) of insulin
  • changing your diet, or eating too much
  • not exercising regularly
  • an illness, such as a cold
  • oral or intravenous steroid therapy

Olanzapine and risperidone

Olanzapine and risperidone are medications that are sometimes used to treat mental health conditions, such as schizophrenia (a condition that can cause hallucinations and delusions).

Sometimes, hyperglycaemia and diabetes can occur as a side effect of taking these medicines. If you are taking either of these, your GP may arrange for your weight and blood glucose levels to be monitored in case you start to develop hyperglycaemia.

Causes in children

Children with hyperglycaemia may have undiagnosed diabetes. This will usually be type 1 diabetes, but it could be type 2 diabetes if the child is obese.

Gestational diabetes

Gestational diabetes is when a woman develops diabetes during pregnancy. This may occur if your body is unable to produce enough extra insulin to meet the demands of pregnancy. This leads to an increased level of glucose in the blood.

Page last reviewed: 13/07/2011

If you have been diagnosed with diabetes (a long-term condition caused by too much glucose in the blood), you may recognise the symptoms of hyperglycaemia.

In this case, you should follow the advice of your diabetic care team (a team of specialists who help monitor and treat diabetes).

However, visit your GP if you are unsure about your symptoms, or you have not previously been diagnosed with diabetes. 

Blood test

Your GP will usually be able to diagnose hyperglycaemia based on a description of your symptoms. They may confirm the diagnosis by testing the level of glucose (sugar) in your blood. 

This is done by taking a sample of blood from a vein in your arm. Your GP may ask you to fast (not eat) for eight hours before the sample of blood is taken.

Page last reviewed: 13/07/2011

How you treat hyperglycaemia will depend on what type of diabetes you have, and how you have been advised to manage your blood glucose levels.

If you have diabetes

If you have type 1 diabetes, you should have a diabetic care team (a team of specialists who help monitor and treat your condition). They should explain what to do if you develop hyperglycaemia.

You may be advised to:

  • Increase your dose of insulin (a hormone that removes glucose from your blood so that your cells can break it down into energy).
  • Change your diet. For example, you may be advised to avoid foods that cause your glucose levels to rise, such as cakes or sugary drinks.
  • Take more exercise, as this can reduce your blood glucose level.
  • Monitor your glucose level. You may be given a home testing kit to check the level of glucose in your blood.

If you have type 2 diabetes your GP or diabetes care team will explain what to do if you develop hyperglycaemia.  You may be advised to

-       Change your diet (as before)

-       Exercise (as before)

-       Monitor your blood glucose (as before)

-       Change your medication

If you do not have diabetes

You should visit your GP if you experience the symptoms of hyperglycaemia because you may have undiagnosed diabetes. Your GP will test your blood glucose levels and discuss the results with you. If you have diabetes, you will be given advice about how to manage the condition.

When to seek medical attention

You should seek medical attention urgently if you start to experience any of the following symptoms:

  • nausea or vomiting (feeling or being sick)
  • stomach pain
  • a fruity smell on your breath, which may smell like pear drops or nail varnish
  • drowsiness or confusion
  • hyperventilation (rapid breathing)
  • dehydration (when the normal water content of your body is reduced, which can cause a headache, dry skin and a weak, rapid heartbeat)
  • unconsciousness

If you have these symptoms, you may have diabetic ketoacidosis, which will need hospital treatment.

Page last reviewed: 13/07/2011

Diabetic ketoacidosis

If left untreated, hyperglycaemia can lead to diabetic ketoacidosis. This is when a lack of insulin means that cells cannot take glucose from the blood to use as energy. Instead, the cells start to break down fats to use as energy.

This causes ketosis (the build up of ketones in the blood) and acidosis (increased blood acidity). Ketones are chemicals that are produced by the body.

The symptoms of ketoacidosis include:

  • nausea or vomiting (feeling or being sick)
  • stomach pain
  • a fruity smell on your breath, which may smell like pear drops or nail varnish
  • drowsiness or confusion
  • hyperventilation (rapid breathing)
  • dehydration (when the normal water content of your body is reduced, which can cause a headache, dry skin and a weak, rapid heartbeat)
  • unconsciousness

If you experience any of these symptoms, seek urgent medical attention. If left untreated, ketoacidosis can lead to coma (a sleep-like state when someone is unconscious for a long period of time), and even death.

Treating diabetic ketoacidosis

If you have diabetic ketoacidosis, you will need to receive urgent hospital treatment. In hospital, you may be given:

  • fluids, to replace the water you have lost
  • electrolytes (minerals and salts that should be in the blood, such as potassium), to replace those you have lost
  • insulin (a hormone that removes glucose from your blood) to lower your blood glucose level

Long-term complications

In the long term, hyperglycaemia can increase the likelihood of complications developing as a result of diabetes. This is because high levels of glucose in the blood can damage blood vessels, nerves and organs. If your blood glucose level is not well controlled, you may be more at risk of developing:

  • damage to your kidneys
  • damage to your eyes
  • damage to the nerves of your feet
  • heart disease (when the heart's blood supply is blocked)
  • erection problems (in men)

Page last reviewed: 13/07/2011

If you have type 1 diabetes, in order to prevent hyperglycaemia from occurring, you will need to control your blood glucose levels by maintaining the right combination of diet and insulin injections.

It is important not to miss or alter your dose of insulin and to maintain your fluid and food intake. It is also important that you test your blood glucose levels regularly. if you have uncontrolled type 2 diabetes ask your GP or diabetes specialist for help with your diabetes care

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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