Hyperglycemia (High Blood Glucose): Causes, Symptoms, DKA and Prevention

Blood glucose (blood sugar) is the main sugar in the blood and the body's main source of energy. It comes from food: the body breaks most food down into glucose and releases it into the blood. Rising glucose signals the pancreas to release insulin, a hormone that helps glucose into the cells to be used for energy.

In diabetes, the body does not make enough insulin, cannot use it well, or both — so too much glucose stays in the blood instead of reaching the cells. Hyperglycemia means high blood glucose, and it mostly affects people with diabetes.

Causes

Managing diabetes means balancing a diabetes meal plan, regular physical activity and, for some, diabetes medicines. Hyperglycemia can follow if you:

• eat too much, or the wrong foods;
• do not take your medicines correctly;
• do not get physical activity;
• are stressed or ill.

Less often, people without diabetes get hyperglycemia, from conditions that affect insulin or blood glucose — problems with the pancreas or adrenal glands, certain medicines, and severe illnesses.

Symptoms

• feeling thirsty;
• feeling tired or weak;
• headaches;
• urinating often;
• blurred vision.

If you have diabetes and often have high glucose or these symptoms, talk with your health care team — your meal plan, activity plan or medicines may need to change. If you do not have diabetes and have these symptoms, see a provider to find the cause.

Complications and DKA

Untreated, hyperglycemia can cause other problems; in diabetes, long-term hyperglycemia can lead to serious complications. Very high glucose can cause diabetes-related ketoacidosis (DKA): without enough insulin to get glucose into the cells, the liver breaks down fat for fuel, producing acids called ketones. Made too fast, ketones can build up to dangerous, life-threatening levels.

Symptoms of DKA: trouble breathing; nausea or vomiting; belly pain; confusion; feeling very tired or sleepy.

If you have a home ketone test, check your ketones every 4 to 6 hours when your glucose is very high or you have these symptoms. If ketones are moderate or high — or you have no test — contact your provider at once or get emergency help.

Diagnosis and treatment

People with diabetes usually check their glucose daily, with a blood glucose meter or a continuous glucose monitor (CGM); providers also have blood tests for high glucose. Frequent highs may mean changes to the meal plan, activity or medicines. Severe hyperglycemia with symptoms of DKA needs hospital treatment, often with intravenous (IV) fluids and insulin.

Prevention

Managing diabetes helps prevent hyperglycemia:

• follow your diabetes meal plan;
• get regular physical activity;
• take any diabetes medicines correctly;
• check your blood glucose regularly;
• have regular check-ups with your health care team.

Sources

• MedlinePlus, U.S. National Library of Medicine, "Hyperglycemia." https://medlineplus.gov/hyperglycemia.html
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