When blood glucose levels (also called blood sugar levels) are too high, it's called hyperglycemia.

Glucose is a sugar that comes from foods, and is formed and stored inside the body. It's the main source of energy for the body's cells and is carried to each through the bloodstream. But even though we need glucose for energy, too much glucose in the blood can be unhealthy.

Hyperglycemia is the hallmark of diabetes — it happens when the body either can't make insulin (type 1 diabetes) or can't respond to insulin properly (type 2 diabetes). The body needs insulin so glucose in the blood can enter the cells to be used for energy. In people who have developed diabetes, glucose accumulates in the blood, resulting in hyperglycemia.

Hyperglycemia can cause serious health problems if left untreated. Too much sugar in the bloodstream for long periods of time can cause damage to the vessels that supply blood to vital organs, which can increase the risk of heart disease and stroke, kidney disease, vision problems, and nerve problems in people with diabetes.

These problems don't usually show up in kids or teens with diabetes who have had the disease for only a few years. However, they can occur in adulthood in some people, particularly if they haven't managed or controlled their diabetes properly.

Blood sugar levels are considered high when they're above someone's target range. The diabetes health care team will let you know what your child's target blood sugar levels are, which will vary based on factors like your child's age.

Causes of High Blood Sugar Levels

A major goal in controlling diabetes is to keep blood sugar levels as close to the desired range as possible. It's a three-way balancing act of:

1. diabetes medications (such as insulin)
2. food
3. activity level

All of these need to be balanced to keep blood sugar levels under control. If any one is off, blood sugar levels can be, too.

In general, problems controlling blood sugar levels are due to one or more of the following:

• not getting enough insulin or other diabetes medication
• not following the meal plan (like eating too much on a special occasion without adjusting medicines)
• not getting enough exercise
• illness or stress
• use of certain medications that can raise blood sugar, like steroids used to treat inflammation

Signs and Symptoms of High Blood Sugar Levels

The symptoms of hyperglycemia are similar to those experienced when someone is diagnosed with diabetes, such as:

• Frequent urination: The kidneys respond to high levels of glucose in the bloodstream by flushing out the extra glucose in urine. A child with diabetes who has hyperglycemia may need to urinate more frequently and in larger volumes.
• Extreme thirst: Kids with hyperglycemia who lose a lot of fluid from urinating often will become very thirsty and may drink a lot in an attempt to prevent dehydration.
• Weight loss despite increased appetite: Without enough insulin to help the body use glucose, the body breaks down muscle and stored fat in an attempt to provide fuel to hungry cells.
• Fatigue: Because the body can't use glucose for energy properly, kids with hyperglycemia may be unusually tired.

Checking for High Blood Sugar Levels

As part of the diabetes management plan, you'll need to check your child's blood sugar levels daily with a blood glucose meter. Doing so will help you identify when your child has high blood sugar levels, which do not always cause symptoms. Someone who isn't testing regularly might have blood sugar levels high enough to damage the body without even realizing it.

The HbA1c test, which doctors usually order periodically, also can show if someone has been having significant hyperglycemia over time, even though the person may not have had obvious symptoms.

If you find that your child has consistently high blood sugar levels, the diabetes health care team may suggest adjusting the diabetes medications or meal plan to bring your child's blood sugar levels back into a healthy range.

In other cases, an equipment issue, like an insulin pump malfunction or expired insulin, may be the problem. Make sure you contact the diabetes team if your child's blood sugar levels are consistently above the target range.

Treating High Blood Sugar Levels

Treating high blood sugar levels involves correcting the underlying cause. The diabetes health care team will give you specific advice on how to keep your child's blood sugar levels in a healthy range, but here are some suggestions for managing some causes of hyperglycemia:

A single high blood sugar reading usually isn't cause for alarm — it happens to everyone with diabetes from time to time. However, consistently high blood sugar levels need to be addressed.

What Is Diabetic Ketoacidosis (DKA)?

Insulin allows glucose to get into the body's cells. Without enough insulin, the body can't use glucose for energy and starts to use fat for fuel. This can occur, for example, when someone skips doses of insulin, or when the need for insulin suddenly increases (as in during stress or illness) and the doses are not adjusted.

When the body uses fat for energy, chemicals called ketones are released into the blood. Some of the ketones, like extra glucose, are passed out of the body through the urine.

But high levels of ketones in the blood can be a problem because they cause the blood to become acidic. Too much acid in the blood throws off the body's chemical balance and causes the symptoms mentioned below.

DKA is a very serious — but completely preventable — condition that can lead to coma or death if it's not treated promptly. It occurs more often in people with type 1 diabetes but can sometimes happen to those with type 2 diabetes.

Signs and Symptoms of DKA

The symptoms of DKA usually don't develop all at once — they usually come on slowly over several hours. The signs and symptoms of DKA include:

• fatigue
• excessive thirst/urination
• dry mouth and dehydration

These symptoms are caused by the sustained hyperglycemia (usually lasting several hours) that typically occurs before someone develops DKA.

If the person remains untreated, these symptoms can occur:

• abdominal pain
• nausea and/or vomiting
• fruity (acetone) breath odor
• rapid, deep breathing
• confusion
• unconsciousness ("diabetic coma")

Checking for DKA

How do you know if your child has DKA? The signs and symptoms of DKA can mimic or be triggered by other illnesses, like the flu, so it's very important to check your child's blood sugar levels and urine ketones during illness — especially if there are high blood sugar readings — or if your child has symptoms of DKA.

Because high levels of ketones in the blood will cause ketones to appear in the urine, ketones can be checked at home by testing a sample of your child's urine. If the urine test for ketones is negative, it generally means that symptoms are not due to DKA. However, because the urine test for ketones is very sensitive, and because ketones can even appear in the urine of an ill child without DKA, you should contact the health care team for advice according to the instructions you have been given regarding a positive test for ketones.

Tests done by a lab or hospital can confirm whether a child has DKA, if necessary. Some newer blood glucose meters also offer the option of testing blood for ketones. Ask the diabetes health care team if such a meter is a good idea for your child.

Treating DKA

DKA requires immediate medical treatment with intravenous (IV) insulin and fluids and close monitoring in a hospital. Contact the diabetes health care team immediately or seek emergency care if your child is sick and you don't know what to do or if you think your child is having symptoms of DKA.

All adult family members and your child's caregivers and school staff should know about the risk of DKA in a child with diabetes, and they should know when to call 911.

In addition, all kids and teens with diabetes should wear some sort of medical identification (like a bracelet or necklace) and/or carry medical identification (ID) information at all times. Besides identifying your child as having diabetes, these IDs can provide emergency contact information.

Avoiding Hyperglycemia and Preventing DKA

The best way to prevent DKA is to treat high blood sugar levels appropriately, which means following the diabetes management plan prescribed by the diabetes health care team.

Make sure that your child:

• takes insulin and diabetes medications as prescribed
• follows the meal plan and/or makes appropriate adjustments to diabetes medications when changes to the meal plan are made
• monitors his or her blood sugar levels regularly and ketone levels when indicated
• follows the instructions and advice of the diabetes health care team and diabetes management plan, which should include instructions for sick days

By regularly monitoring blood sugar levels, you will know when your child's blood sugar is high. If that happens, contact the diabetes health care team for more information and to learn how to help bring your child's diabetes back under control and avoid complications like DKA.

Reviewed by: Steven Dowshen, MD
Date reviewed: October 2010