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Diabetes: Preventing High Blood Sugar Emergencies


High blood sugar occurs when the sugar (glucose) level in your blood rises above your target range. It can happen if:

  • You miss a dose of your type 2 diabetes medicine or a required dose of insulin.
  • You eat more than expected.
  • You exercise less than you are used to doing.
  • You take medicines that raise your blood sugar as a side effect. Examples include some anti-inflammatory medicines (corticosteroids) and some decongestants.
  • You are stressed or ill.
  • You are pregnant.

If you take insulin, you may have some mornings when your blood sugar level is very high, even if it was low when you went to bed. Talk with your doctor if this happens. You may need to check your blood sugar during the night to find out why your levels are high in the morning.

How do you prevent high blood sugar emergencies?

High blood sugar usually happens slowly over hours or days. Use this information to help prevent an emergency.

  • Know the symptoms of high blood sugar.
    • Symptoms of high blood sugar include feeling very thirsty, feeling very tired, and urinating more than usual.
    • Post a list of the symptoms in a place where you can see it often, such as on your refrigerator door. Add any symptoms you have noticed that may not be on the list.
  • Check your blood sugar often.
    • This is especially important when you are sick or not following your normal routine. Testing your blood sugar at home will help you know when it is high, even if you don't notice symptoms.
    • Keep a record of high blood sugar levels. Write down your symptoms and how you treated them. Take the record with you when you see your doctor.
    • Call your doctor if you often have high blood sugar or your blood sugar is often above your target range. Your medicine may need to be adjusted or changed.
  • Have a plan for dealing with high blood sugar.
    • Your doctor will give you blood sugar goals and recommend ways to treat high blood sugar. Follow these instructions when your blood sugar is high.
    • Make sure other people (at work and at home) know the symptoms of high blood sugar. Teach them what to do in case of an emergency.
  • Treat infections early.

    Infections that aren't treated can raise your risk for a high blood sugar emergency.

  • Take your medicines as prescribed.

    Don't skip or change diabetes medicine or insulin doses without first talking with your doctor.

  • Drink plenty of fluids.
    • Water and sugar-free drinks are best. Avoid soda pop, fruit juice, and other drinks that have a lot of sugar. Avoid caffeinated drinks and alcohol.
    • If your blood sugar levels are above your target range, drink extra liquids. This helps replace the fluids lost through your urine.
  • Wear medical identification at all times.

    Wearing a medical alert bracelet or necklace is very important in case you are too sick to speak for yourself.


Current as of: March 1, 2023

Author: Healthwise Staff
Medical Review:
E. Gregory Thompson MD - Internal Medicine
Kathleen Romito MD - Family Medicine
Adam Husney MD - Family Medicine
Rhonda O'Brien MS, RD, CDE - Certified Diabetes Educator