In this Article

What is Hyperglycemia?

Hyperglycemia, or high blood glucose, can be a dangerous problem for individuals with diabetes. Although hyperglycemia is sometimes defined as a blood glucose reading above 180, everyone is different — and people have symptoms of hyperglycemia at different levels.

In the short term, hyperglycemia can cause serious side effects, and may even become life threatening. For example, one sign of dangerously high blood glucose is ketones in your urine. Ketones are acids your body makes when it burns fat instead of glucose for energy. They can build up to toxic levels in your body. This condition is called ketoacidosis.

Over the long term, high blood glucose can increase your chance of diabetes complications. Without glucose, your brain can’t function. So when ketoacidosis is severe, you can go into a coma, or even die. That’s why you need to be alert to the symptoms of hyperglycemia and act right away to correct it.

When to See a Doctor

Call for advice or an appointment if:

  • You can’t control your hyperglycemia, in spite of taking action to correct it.
  • You have two or three readings in a row with results of 240 mg/dL or higher.
  • You have more than two unexplained episodes of hyperglycemia in a week.
  • You have repeated high glucose readings during a particular time of day.
  • You have moderate to large amounts of ketones in your urine.

Get emergency care if you can’t reach your healthcare provider, or if you have large amounts of ketones in your urine.


Most often, high blood glucose happens when you don’t follow your self-management plan. Sickness or stress can also cause your glucose to rise too high. And sometimes — in spite of your best efforts — your glucose may rise without any apparent reason.

Diagnosis and Tests

Routine blood sugar monitoring with your blood glucose meter or device will help you maintain your blood sugar levels and alert you and your provider if you are at risk for developing hyperglycemia.

If needed to confirm hyperglycemia, your provider may also order an A1C test, which provides measurement of your blood sugar for the past few months.


The best treatment for hyperglycemia is to return to your self-management plan:

  • Regular exercise
  • Taking your medications
  • Follow your recommended diet
  • Regularly monitor your blood sugar
  • Regulate your insulin

When hyperglycemia becomes serious, you may require treatment at a hospital. There providers rely on a few treatment methods to normalize your blood sugar levels:

  • Fluid and electrolyte replacement
  • Insulin, usually administered through an IV to help deliver needed nutrients to your body faster

Your provider may also adjust to your medications or prescribe additional medications to help manage your condition.


The best way to avoid hyperglycemia is to stay on your self-management plan:

  • Monitor your blood glucose regularly to catch hyperglycemia early on
  • Take your medications as prescribed
  • Follow your meal plan — eating nutritious foods regularly, in the right amount
  • Get regular exercise to burn up glucose and help your whole body work better


Along with checking your blood glucose, watch out for the following symptoms:

  • Extreme thirst
  • Dry, itchy skin
  • Frequent urination
  • Blurry vision
  • Extreme hunger
  • Fatigue

Because hyperglycemia tends to come on gradually, you may not notice these symptoms right away. A high reading on your glucose meter may be your first sign that blood glucose levels are running too high.

Ketoacidosis symptoms

Ketoacidosis may occur when hyperglycemia is severe. People with type 1 diabetes are at the greatest risk of ketoacidosis. That’s because people with type 2 diabetes usually have at least some insulin available to take glucose into the cells. Ketoacidosis symptoms include:

  • Ketones in your urine
  • A fruity odor on your breath
  • Extreme thirst or hunger
  • Nausea/vomiting
  • Extreme drowsiness
  • Stomach pain
  • Body aches