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High blood sugar

High blood sugar is also called high blood glucose, or hyperglycemia.

High blood sugar almost always happens in people who have diabetes. High blood sugar occurs when:

  • Your body makes too little insulin.
  • Your body does not respond to the signal insulin is sending.

Insulin is a hormone that helps the body move glucose (sugar) from the blood into muscle or fat, where it is stored for later use when energy is needed.

Sometimes high blood sugar occurs due to stress from surgery, infection, trauma, or medicines. After the stress is over, blood sugar returns to normal.

Symptoms of High Blood Sugar

Symptoms of high blood sugar can include:

  • Being very thirsty or having a dry mouth
  • Having blurry vision
  • Having dry skin
  • Feeling weak or tired
  • Needing to urinate a lot, or needing to get up more often than usual at night to urinate

You may have other, more serious symptoms if your blood sugar becomes very high or remains high for a long time.

What to Think About When Your Blood Sugar is High

High blood sugar can harm you. If your blood sugar is high, you need to know how to bring it down. If you have diabetes, here are some questions to ask yourself when your blood sugar is high:

  • Are you eating right?
  • Are you eating too much?
  • Have you been following your diabetes meal plan?
  • Did you have a meal or a snack with a lot of carbohydrates, starches, or simple sugars?

Are you taking your diabetes medicines correctly?

  • Has your doctor changed your medicines?
  • If you take insulin, have you been taking the correct dose? Is the insulin expired? Or has it been stored in a hot or cold place?
  • Are you afraid of having low blood sugar? Is that causing you to eat too much or take too little insulin or other diabetes medicine?
  • Have you injected insulin into a scar or overused area? Have you been rotating sites?

What else has changed?

  • Have you been less active than usual?
  • Do you have a fever, cold, the flu, or another illness?
  • Have you had some stress?
  • Have you been checking your blood sugar regularly?
  • Have you gained weight?
  • Have you started taking any new medicines such as for high blood pressure or other medical problems?

Preventing High Blood Sugar

To prevent high blood sugar, you will need to:

  • Follow your meal plan
  • Stay physically active
  • Take your diabetes medicines as instructed

You and your doctor will:

If your blood sugar is higher than your goals for 3 days and you DO NOT know why, check your urine for ketones. Then call your provider.

Alternative Names

Hyperglycemia - self-care; High blood glucose - self-care; Diabetes - high blood sugar

References

American Diabetes Association. Standards of medical care in diabetes-2016: summary of revisions. Diabetes Care. 2016;39 Suppl 1:S4-S5. PMID: 26696680 www.ncbi.nlm.nih.gov/pubmed/26696680.

Pasquel FJ, Umpierrez GE. Hyperglycemic crises. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 46.

Review Date 8/7/2016

Updated by: Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.