What Is the Difference Between Hyperglycemia and Hypoglycemia?

What Is Hyperglycemia?

In relation to diabetes, hyperglycemia refers to chronically high blood glucose levels. Most medical professionals define hyperglycemia by using the blood glucose goals that you and your physician have established and combining those goals with the blood glucose target ranges set by the American Diabetes Association. It’s important to understand that you’ll probably experience high blood glucose levels occasionally, despite your best efforts at control. As with any chronic disease, talk with your physician and diabetes care team if the pattern of your blood glucose readings is consistently higher or lower than your blood glucose goals.

Complications from Hyperglycemia

Persistent hyperglycemia can cause a wide range of chronic complications that affect almost every system in your body. When large blood vessels are affected, it can lead to:

  • Stroke (cerebral vascular disease)
  • Heart attack or Congestive Heart Failure (coronary heart disease)
  • Circulation disorders and possible amputation (peripheral vascular disease)

When smaller blood vessels are affected, it can lead to:

  • Kidney disease (nephropathy)
  • Nerve damage (neuropathy)
  • Diabetic eye disease (retinopathy)

Joseph Monks: Writer, Producer, and Film Director

Joseph Monks sitting in a director's chair.

Joseph Monks, who has diabetic retinopathy, creates and produces films for his production company Sight Unseen Pictures. He is also the first blind filmmaker to direct a feature film.

Says Joe, “I’m not uncomfortable with the term ‘blind.’ Of course, I’m not thrilled about it, but it’s accurate. The lights went out for me in early 2002 as a result of diabetic retinopathy—the death of my retinas. It is what it is, so when it happened, I decided that I wouldn’t let it end my career. As you can imagine, I’m glad I didn’t want to be a pilot!”

Learn more about the wide range of artistic and cultural activities you can continue to pursue with low vision and blindness:

  • Audio described theater, film, and television
  • Museums and art tours, including touch galleries and touch tours
  • Painting and crafting, including ways to set up and adapt your work area

Severe Complications from Hyperglycemia

Very high blood glucose levels can also lead to the acute, life-threatening conditions, diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic syndrome (HHS), which require immediate medical attention.

Diabetic Ketoacidosis (DKA) occurs most frequently in persons with type 1 diabetes. DKA results from dehydration during relative insulin deficiency, associated with high blood glucose levels and organic acids called ketones. Physical signs and symptoms of DKA include:

  • Hyperglycemia (250 mg/dL or greater)
  • Dry, parched mouth
  • Extreme thirst
  • Frequent urination
  • General weakness
  • Fruity breath
  • Nausea and vomiting
  • Abdominal pain
  • Deep, rapid breathing

Hyperosmolar Hyperglycemic Syndrome (or HHS) occurs most frequently in older adults with type 2 diabetes, especially residents of long-term care facilities. It occurs in people whose diabetes is not controlled properly and is usually brought on by an illness or infection. Physical signs and symptoms of HHS include:

  • Severe hyperglycemia (greater than 600 mg/dL)
  • Dry, parched mouth
  • Extreme thirst (which may gradually disappear)
  • Warm, dry skin that does not sweat
  • High fever (greater than 101 degrees F)
  • Sleepiness or confusion
  • Hallucinations
  • Weakness on one side of the body

Contact your physician if you note any of the above symptoms. Your physician will decide if this is a mild case that can be treated at home or a moderate to severe case that requires hospitalization.

Reducing the Risk Factors for Complications

You can reduce your risk factors for complications related to hyperglycemia by doing the following:

  • Maintaining your blood glucose levels within a normal range
  • Keeping your blood pressure under control
  • Controlling your blood fats (cholesterol and triglycerides)
  • Avoiding/stopping smoking
  • Increasing your physical activity
  • Avoiding excess alcohol consumption
  • Developing healthy eating habits and losing weight if necessary

What Is Hypoglycemia?

Hypoglycemia refers to dangerously low blood glucose levels that drop below 70 mg/dL. Significant hypoglycemia is considered below 54 mg/dL. It is an acute complication of diabetes and occurs in individuals who use insulin or specific kinds of oral diabetes medication. If you use oral diabetes medications, ask your physician or diabetes educator whether hypoglycemia should be a concern.

Symptoms of Hypoglycemia

Symptoms of hypoglycemia include the following:

  • Sweating
  • Rapid pulse
  • Shakiness, dizziness, weakness
  • Decreased coordination
  • Difficulty concentrating
  • Blurred vision
  • Headache
  • Trouble performing routine tasks
  • Note: Symptoms can vary from person to person and episode to episode.

Treating Hypoglycemia

To treat hypoglycemia, you must immediately:

  • Check your blood glucose level to determine the amount of carbohydrates needed to raise your blood glucose to a safe level.
  • Use the 15/15 Rule: Consume 15 grams of carbohydrates (4 ounces of regular juice or soda, 1 tablespoon honey, 2 tablespoons raisins, 7 Life Savers®, 9 Sweet Tarts®, or 3-4 glucose tablets) and retest your blood glucose in 15 minutes. If it is still below 70 mg/dL, you should consume an additional 15 grams of carbohydrates. Following the 15/15 Rule can help avoid over-treatment and resulting hyperglycemia.
  • If you are not planning to have a meal within one to two hours after treating a hypoglycemic reaction, eat a snack containing 15-30 grams of carbohydrates to prevent another episode of hypoglycemia.

Complications from Hypoglycemia

If hypoglycemia is not treated immediately, it can result in:

  • Severe confusion and disorientation
  • Unconsciousness
  • Seizures
  • Coma
  • Death

Ways to Manage Hypoglycemia

Other tips for managing hypoglycemia include:

  • Keep glucose-containing products close by at all times.
  • Clearly label sugar-free products in a format of your choosing to distinguish them from regular products.
  • Make sure you can test your own blood glucose, measure insulin accurately, and determine recommended food portions to help prevent and properly treat low blood glucose.
  • Be sure to wear diabetes identification at all times.

By Debra A. Sokol-McKay,MS, CDE, OTR/L, SCLV,

Updated November 2022 by Kim Ladd, RN, BS, CPHQ, CDCES

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