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High Blood Sugar (Hyperglycemia) in Diabetes

What is high blood sugar?

High blood sugar means that the level of sugar in your child’s blood is higher than recommended. High blood sugar can be serious if it's not treated. If your child’s blood sugar runs too high over time (months or years), it can cause problems with the heart, eyes, kidneys, nerves, and blood vessels. A very high blood sugar can cause life-threatening problems.

The medical term for high blood sugar is hyperglycemia.

What is the cause?

Your child’s body breaks down some of the foods your child eats into sugar. The blood carries the sugar to the cells of the body. Your child needs the sugar in the cells for energy, but too much sugar in the blood is not good for your child’s health. Insulin is a hormone made by the pancreas, which is an organ in the upper belly. The body uses insulin to help move sugar from the blood into the cells. When your child’s body does not have enough insulin or has trouble using its own insulin, sugar cannot get into the cells and builds up in your child’s blood. Blood sugar that stays high is the main problem of diabetes.

Sometimes your child may have high blood sugar even though he is taking diabetes medicine. This can happen for many reasons but it always means that your child’s diabetes is not in good control. Some reasons why blood sugar might go too high are:

  • Not taking diabetes medicine when he should, or not taking the right amount
  • Taking medicines, such as steroids, for other medical problems
  • Taking in too many calories, eating too many carbohydrates, such as foods made mainly with sugar or white flour, or having too many high-sugar drinks
  • Not getting enough physical activity (exercise lowers blood sugar)
  • Being under stress
  • Being sick, including colds, flu, an infected tooth, or a urinary tract infection, especially if your child has a fever
  • Having problems with the insulin your child taking--for example, he may need a different type of insulin or the insulin may not be working because it has not been stored properly
  • Having a problem with an insulin pump, if your child is using one--for example, the pump is turned off or the catheter has come out

What are the symptoms?

Usually high blood sugar causes no symptoms, especially if it is brief. However, if your child’s blood sugar gets very high and stays that high for a day or longer, he may have symptoms. Symptoms may include:

  • Blurry vision
  • Dry mouth
  • Increased thirst
  • Urinating a lot
  • Feeling tired

Very high blood sugar (600 mg/dL or higher) can cause coma and even death.

How is it diagnosed?

The level of sugar in your child’s blood can be measured with blood tests at home or at your healthcare provider’s office.

When your child has diabetes, commonly recommended blood sugar levels are:

 Age         Morning OR 2 hours before or after a meal
Birth to 6 years    100 to 180 mg/dL     
6 to 12 years      90 to 180 mg/dL    
13 to 18 years     90 to 130 mg/dL    

For children under age 19 with diabetes, the A1C goal is 7.5

A1C results may also be given as the eAG, or estimated average glucose. Blood sugar is also called blood glucose. You can use your child’s A1C results and the chart below to know what your child’s average blood glucose has been.

 A1C   Estimated Average Glucose (eAG)
 7     154 mg/dL 
 8     183 mg/dL 
 9     212 mg/dL 
 10     240 mg/dL 
 11     269 mg/dL 
 12     298 mg/dL 

How is it treated?

Very high blood sugar can be a medical emergency. Ask your healthcare provider what a very high blood sugar would be for your child. Your child may need to stay at the hospital to get his blood sugar back to normal, to treat the cause of the high blood sugar, and to treat any problems caused by the high blood sugar, such as dehydration.

High blood sugar caused by medicines your child is taking usually goes away when he stops taking the medicine. Never stop giving your child medicine without talking to your child’s healthcare provider. The provider may be able to change the type or amount of medicine your child takes. Depending on the medicine, it may take days to weeks for blood sugar to go back to the proper levels.

How can I take care of my child?

Follow your healthcare provider's directions carefully to keep your child’s blood sugar normal. This usually means your child needs to:

  • Eat a healthy diet as recommended by your child’s healthcare provider. Ask for a referral to a dietitian if you are not sure what your child should be eating.
  • Exercise according to his provider's recommendation.
  • Take medicine exactly as directed, if any has been prescribed.
  • Check blood sugar as often as instructed and take blood sugar records to every checkup. This helps your provider adjust your child’s medicines.
  • Carry a medical ID (such as a card or bracelet) that says your child has diabetes.

Ask your healthcare provider:

  • When to call about a high blood sugar level
  • How to take care of your child if he is sick (Because blood sugar is likely to be higher if your child is ill, ask your healthcare provider for a “sick day plan.”)
  • What symptoms or problems you should watch for and what to do if your child has them

Make sure you know when your child should come back for a checkup. Keep all appointments for provider visits or tests.

Developed by RelayHealth.
Pediatric Advisor 2015.3 published by RelayHealth.
Last modified: 2015-01-09
Last reviewed: 2015-01-08
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright ©1986-2015 McKesson Corporation and/or one of its subsidiaries. All rights reserved.
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