Hyperglycaemia occurs when the body can't remove glucose (sugar) from the blood and turn it into energy. It usually only happens in people with diabetes.
Over time there may be further symptoms including weight loss and blurred vision.
Your doctor 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.
Hyperglycaemia is caused by an increase in blood glucose (sugar) levels. In people with diabetes, the body is unable to break glucose down into energy.
There are two types of diabetes, described below.
Insulin is the hormone that helps remove glucose from the blood and converts it to energy.
If you have diabetes, you will be advised about how to manage your blood glucose levels. However, there are some situations that can trigger an increase in blood glucose, including:
Read more information about the causes of hyperglycaemia.
If you have diabetes, your diabetic care team will explain how to monitor and manage your blood glucose levels. If you have type 1 diabetes it is important not to miss or alter your dose of insulin and to maintain your fluid and food intake.
If hyperglycaemia occurs, your blood glucose levels will need to be lowered again. Increasing the dose of insulin is one way of doing this.
It is also important that you test your blood glucose levels regularly. Your doctor will advise you about when and how often your blood should be tested.
If you have uncontrolled type 2 diabetes, or if it is difficult to control, you will be carefully monitored by the healthcare professionals looking after you.
Read more information about how hyperglycaemia is treated.
You should visit your doctor if you or your child experiences the symptoms of hyperglycaemia, even if you haven’t been diagnosed with diabetes.
You should seek medical attention urgently if you start to experience any of the following symptoms as they may be a sign of diabetic ketoacidosis (where the body is unable to break down glucose):
Diabetic ketoacidosis is a serious condition that can be life-threatening and lead to coma (a sleep-like state where someone is unconscious for a long period of time).
If diabetic ketoacidosis is left untreated, there may be other serious complications such as long-term damage to blood vessels, nerves and organs.
Read more information about the complications of hyperglycaemia.
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:
If the symptoms of hyperglycaemia are prolonged, they may cause:
Diabetic ketoacidosis is a complication that can occur if hyperglycaemia is left untreated. The symptoms include:
You should seek urgent medical attention if you experience any of these symptoms, as they will need to be treated in hospital.
Read more information about the complications of hyperglycaemia.
Hyperglycaemia is caused by an increase in blood glucose (sugar) levels. This usually occurs in people with diabetes.
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.
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.
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.
If you have diabetes, your doctor will 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:
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 doctor may arrange for your weight and blood glucose levels to be monitored in case you start to develop hyperglycaemia.
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 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.
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, 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:
You should visit your doctor if you experience the symptoms of hyperglycaemia because you may have undiagnosed diabetes. Your doctor 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.
You should seek medical attention urgently if you start to experience any of the following symptoms:
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 (or tablets). Your doctor will be able to provide you with information and advice about how you can do this.
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. Your doctor will advise you when, and how often, you should test your glucose levels. If you have uncontrolled type 2 diabetes, or if it is difficult to control, you will be carefully monitored by the healthcare professionals who are looking after you.
If left untreated, hyperglycaemia can lead to complications such as diabetic ketoacidosis or long-term damage to blood vessels, nerves and organs.
Diabetic ketoacidosis 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:
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 death.
If you have diabetic ketoacidosis, you will need to receive urgent hospital treatment. In hospital, you may be given:
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:
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.