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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 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

  • Having a poor 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

Symptoms of high blood sugar

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

  • Thirst, dry mouth

  • Frequent need to pee

  • Feeling tired or drowsy

  • Upset stomach (nausea) and vomiting

  • Belly (abdominal) pain

  • Itchy, dry skin

  • Blurry vision

  • Fast breathing and breath that smells fruity 

  • Weakness

  • Dizziness

  • 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 blood sugars stay 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. Also test your blood sugar as directed. If the plan isn't working for you, discuss it with your healthcare provider.

Other things to do

  • 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 can’t help yourself.

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

 When to call your healthcare provider

Call your healthcare provider right away if you have any of the following:

  • 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: Jessica Gotwals BSN MPH
Online Medical Reviewer: Rita Sather RN
Online Medical Reviewer: Robert Hurd MD
Date Last Reviewed: 12/1/2021
© 2000-2022 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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