High Blood Glucose

High Blood Sugar Symptoms and Treatment

High blood glucose is called “hyperglycemia”.

Causes of High Blood Glucose:

  • Eating too much food (relative to the amount of insulin taken)
  • Less activity than usual
  • Not enough insulin (the usual dose of insulin is too low)
  • Missing a dose of insulin
  • Illness
  • Stress – both negative (worry or fear) and positive (excitement)

Signs and Symptoms of High Blood Glucose

Symptoms of high blood glucose are usually seen when the blood glucose is greater than 14.0 mmol/L for several hours.

Signs and symptoms of high blood glucose are:

  • Increased urination (peeing)
  • Dry mouth
  • Increased thirst
  • Lack of energy, drowsiness
  • Blurred vision
  • Difficulty concentrating

As parents we tend to worry about the lows and do all we can to avoid them. However, it is important to remember that chronic high blood glucose has its associated problems, too. Since high blood glucose makes it difficult to concentrate, school performance may suffer as a result of high blood glucose (even in the short term). Similarly, lack of energy may affect your child’s functioning in and enjoyment of sports and leisure activities. Not to mention that fact that chronic highs increase your child’s risk of future complications. For this reason, it is important to strive for good overall blood glucose control, which includes as few swings as possible (both lows AND highs).

Treatment of High Blood Glucose “With” Ketones

If the blood glucose is higher than 14.0 mmol/L for a long period of time, the body may burn fat for energy. Ketones may develop as a result of the metabolism of fat, which, if untreated, could lead to a life-threatening condition called diabetic ketoacidosis (DKA).

Treatment of High Blood Glucose “Without” Ketones

If your child’s blood glucose is above the target range, a correction dose of insulin should be given.

The amount of this correction dose depends on:

  • How high the blood glucose is
  • How sensitive your child’s body is to insulin, which is indicated by their Insulin Sensitivity Factor (ISF)

Your child’s doctor or diabetes nurse educator should provide you with a method for correcting highs, so that you know how much insulin to give to correct high blood glucose: a “sliding scale”, a correction number, a correction formula, or an Insulin Sensitivity Factor (ISF). These are all paths to the same goal: lowering above-target blood glucose.

More on calculating corrections for high blood glucose:

Remember the Following Guidelines for Managing Highs:

  • Whenever your child’s blood glucose is greater than 14.0 mmol/L, check for ketones.
  • If the blood glucose is high due to illness, follow the 10 Safety Rules for Illness Management or, if you are uncertain about what to do, call your doctor or diabetes nurse educator.
  • If your child is on a Conventional insulin program, it is NOT helpful to give more (intermediate-acting) N/NPH at bedtime for high blood glucose. Your child’s doctor will give you guidelines on how much extra rapid-acting insulin to give, using your “correction formula” or “sliding scale”. To make sure the correction is working, check the blood glucose two to three hours later.

High blood glucose without ketones is not harmful in the short term. If there is a pattern of high blood glucose, contact your child’s health care team for possible insulin dose adjustments.

More on insulin dose adjustment:

Insulin Adjustment in the Managing Blood Glucose section


The above information was reviewed for content accuracy by clinical staff of the Alberta Children’s Hospital Diabetes Clinic.