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High Blood Sugar (Hyperglycemia)

Too much sugar (glucose) in your blood is called high blood sugar (hyperglycemia). This can lead to 2 dangerous conditions called ketoacidosis and hyperosmolar hyperglycemic state. In severe cases, these can lead to fluid loss (dehydration) and other serious complications like coma.

Talk with your healthcare provider about what blood sugar range is normal for you. Work with your provider to make a plan for treating high blood sugar.

Possible causes of high blood sugar

  • Not having a good treatment plan for diabetes 

  • Being sick

  • Being under stress

  • Taking certain medicines, such as steroids

  • Eating too much food, especially carbohydrates

  • Being less active than normal

  • Not taking enough diabetes medicine

  • Not taking diabetes medicine at the right time

Symptoms of high blood sugar

High blood sugar may not cause symptoms. If you do have symptoms, they may include:

  • Thirst

  • Dry mouth

  • Needing to pee more often

  • Feeling tired or drowsy

  • Upset stomach (nausea) and vomiting

  • Belly (abdominal) pain

  • Itchy, dry skin

  • Blurry vision

  • Fast breathing

  • Breath that smells fruity 

  • Weakness

  • Dizziness

  • Flushed face

  • Wounds or skin infections that don’t heal

  • Unexplained weight loss if high blood sugar lasts for more than a few days 

What to do

If you have symptoms of high blood sugar or think it might be high, check your blood sugar. If your blood sugar is high, do the following unless told otherwise by your provider:

  • Take your diabetes medicines as prescribed. Doses of medicines such as insulin can be increased slightly if your blood sugar stays high. But your provider must approve this. Don't adjust doses by yourself.

  • Check your blood sugar more often, or as directed by your healthcare provider.

  • Drink plenty of sugar-free, caffeine-free liquids such as water. Don’t drink fruit juice.

  • Follow your sick day plan for taking medicine.

  • Check your blood or urine for ketones as directed by your healthcare provider. If you have ketones, don't exercise. This may make your blood sugar higher.

  • Call your provider if your blood sugar and ketones don't go back to your target range.

Woman drinking glass of water.
When you have hyperglycemia, drink plenty of water or other sugar-free, caffeine-free liquids.

Preventing high blood sugar

To help keep your blood sugar from getting too high:

  • Control stress.

  • When you're ill, follow your sick day plan. 

  • Follow your meal plan. Eat only the amount of food on your meal plan.

  • Stick to your exercise plan.

  • Take your insulin or diabetes medicines as directed by your healthcare team.

  • Test your blood sugar as directed.

    If your diabetes plan isn't working for you, talk with your healthcare provider.

What is diabetic ketoacidosis (DKA)?

When you don’t have enough insulin to use the glucose in your blood, your body burns fat for energy. This releases a waste product called ketones. High levels of ketones in your body can lead to diabetic ketoacidosis (DKA). DKA can be life threatening. If you have DKA, you need to be treated in a hospital. Your treatment will likely include:

  • Fluids through IV. This is to replace fluids lost through too much peeing. And it helps dilute the excess sugar in your blood.

  • Electrolytes. These are minerals in your body that help your nerves, muscles, heart, and brain work the way they should. Low insulin can lower your electrolyte levels.

  • Insulin. Insulin helps your body use glucose and reverses the problem that led to DKA.

  • Medicines. You may need medicine for an illness that caused DKA, such as antibiotics for an infection.

Other safety steps

  • Carry a medical ID card or a compact USB drive. Or wear a medical alert bracelet or necklace. It should say that you have diabetes. It should also say what to do in case you pass out or go into a coma.

  • Make sure family, friends, and coworkers know the signs of high blood sugar. Tell them what to do if your blood sugar gets very high and you need help.

  • Talk with your healthcare team about other things you can do to prevent high blood sugar.

 When to get medical care

Get medical care right away if you have any of these:

  • Blood sugar that stays high even after treatment

  • Symptoms of high blood sugar that don't get better

  • Moderate or large amounts of ketones

  • Confusion

  • Shortness of breath or fast breathing

  • Breath that smells fruity

  • Vomiting or unable to eat or drink

Online Medical Reviewer: Chris Southard RN
Online Medical Reviewer: Rajadurai Samnishanth Researcher
Online Medical Reviewer: Rita Sather RN
Date Last Reviewed: 4/1/2024
© 2000-2024 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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