Health Topic

Hyperglycemia

Hyperglycemia means high blood sugar or glucose. Hyperglycemia happens when your body doesn't make enough insulin or can't use it the right way.

Reviewed Reviewed by a registered pharmacistGeneral information

Also called: High blood glucose · High blood sugar

Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.

About Hyperglycemia

Blood glucose, or blood sugar, is the main sugar found in your blood. It is your body's primary source of energy. It comes from the food you eat. Your body breaks down most of that food into glucose and releases it into your bloodstream. When your blood glucose goes up, it signals your pancreas to release insulin. Insulin is a hormone that helps the glucose get into your cells to be used for energy.

For people with diabetes, your body doesn't make enough insulin, can't use it as well as it should, or both. Too much glucose stays in your blood and doesn't reach your cells.

Hyperglycemia means high blood glucose. It most often affects people who have diabetes. When you have diabetes, your body doesn't make enough insulin or can't use it the right way. Too much glucose stays in your blood and doesn't reach your cells.

A key part of managing diabetes is controlling your blood glucose levels. To do this, you need to follow a diabetes meal plan and get regular physical activity. You might also need to take diabetes medicines. You have to balance all of these to keep your blood glucose at the right levels. But if you eat too much food or the wrong foods, don't take your medicines correctly, or don't get physical activity, you can get hyperglycemia. It can also happen if you are stressed or sick.

Less commonly, people who don't have diabetes can also get hyperglycemia. It can be caused by conditions that can affect insulin or glucose levels in your blood. They include problems with your pancreas or adrenal glands, certain medicines, and severe illnesses.

The symptoms of hyperglycemia include:

  • Feeling thirsty
  • Feeling tired or weak
  • Headaches
  • Urinating (peeing) often
  • Blurred vision

If you are diabetic and you often have high blood glucose levels or the symptoms of hyperglycemia, talk with your health care team. You may need a change in your diabetes meal plan, physical activity plan, or diabetes medicines.

If you don't have diabetes and you are having these symptoms, see your provider to find out the cause and how to treat it.

If hyperglycemia is not treated, it can cause other problems. In people with diabetes, long-term hyperglycemia can lead to serious health problems (diabetes complications).

If your blood glucose levels get very high, you can develop diabetes-related ketoacidosis (DKA). It happens when your body doesn't have enough insulin to allow blood glucose into your cells for use as energy. Instead, your liver breaks down fat for fuel. This process produces acids called ketones. When too many ketones are produced too fast, they can build up to dangerous levels in your body. This can be life-threatening.

The symptoms of DKA may include:

  • Trouble breathing
  • Nausea or vomiting
  • Pain in your abdomen (belly)
  • Confusion
  • Feeling very tired or sleepy

If you have an an at-home test for ketones, check your ketone level every 4 to 6 hours when your blood glucose is very high or when you are having these symptoms. If the test shows that your ketones are moderate or high, or if you don't have a ketones test, contact your health care provider right away or get emergency medical help.

If you have diabetes, you'll most likely need to check your blood glucose every day and make sure that it's not too high. You can do this with a blood glucose meter or continuous glucose monitoring (CGM) system.

There are also blood tests that providers can use to check if your blood glucose is too high.

If you have diabetes and often have high blood glucose, your health care team may make changes to your diabetes meal plan, physical activity plan, and/or diabetes medicines.

If you have severe hyperglycemia and are having symptoms of DKA, you will need treatment at the hospital. The treatment often includes I.V. (intravenous) fluids and insulin.

If you have diabetes, managing your diabetes can help prevent hyperglycemia. To manage your diabetes, it's important to:

  • Follow your diabetes meal plan
  • Get regular physical activity
  • If you need diabetes medicines, take them correctly
  • Regularly check your blood glucose level
  • Get regular checkups with your health care team

It sits within Endocrine System, Metabolic Problems and Diabetes Mellitus.

The lead U.S. institute for this subject is the National Institute of Diabetes and Digestive and Kidney Diseases.

When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.

Research on Hyperglycemia

1,764 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.

What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.

Research currently under way

Research already completed

Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.

Where to read more

Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.

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Diagnosis and Tests

Related Issues

Clinical Trials

Medical subject headings

Clinicians and researchers index this subject under Hyperglycemia. These are the terms to use when searching medical literature.

This page is built from the MedlinePlus health topic record for Hyperglycemia, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.