Hyperglycemia is a condition in which your levels of blood sugar are higher than normal. It’s often a result of diabetes but can also be secondary to other conditions.

Hyperglycemia and diabetes are similar conditions. Hyperglycemia, or high blood sugar with or without diabetes, is the result of too much glucose in your body’s bloodstream. This is due to the body having no insulin or too little insulin for your body’s cells to break down glucose.

Diabetes is a chronic condition affecting the body’s ability to metabolize glucose. People with diabetes can experience periods of both hypoglycemia (too little blood sugar) and hyperglycemia.

However, even people without diabetes can experience hyperglycemia. Hyperglycemia without diabetes is often a temporary state, possibly due to a separate underlying condition. It usually resolves when the condition is treated.

While people with diabetes can experience hyperglycemia, not everyone who has hyperglycemia has diabetes.

Yes, but this depends on the underlying cause of hyperglycemia. In someone without diabetes, temporary hyperglycemia (usually from quickly eating a lot of sugar) does not become diabetes.

However, hyperglycemia is also the main symptom of diabetes. Persistent high blood sugar levels are a sign of both type 1 and type 2 diabetes.

Normal blood sugar fluctuations in response to the food you eat can range from 60–140 mg/dL. People with diabetes will have higher blood sugar levels on a persistent basis.

A normal fasting blood sugar level, which is taken during a period of not eating, is a reading below 99 mg/dL. If this number is between 100–125 mg/dL, you may have prediabetes. A fasting blood sugar level higher than 126 mg/dL indicates diabetes.

Additionally, a random blood sugar reading over 200 mg/dL is consistent with diabetes. This test measures your blood sugar at the time of testing, without fasting.

If your doctor suspects diabetes, they’ll do additional tests in order to confirm a diagnosis.

Symptoms of hyperglycemia and diabetes may not be obvious. Often, either condition is only diagnosed during a routine blood test.

If symptoms of hyperglycemia are present, you may experience:

  • weakness
  • headaches
  • frequent urination
  • blurry vision
  • excessive thirst

Symptoms of type 2 diabetes usually develop over time and may not be obvious. If symptoms are present, they may be signs of more advanced disease. Those symptoms may include all of the above, as well as:

  • numbness in hands and feet
  • extreme fatigue
  • frequent infections
  • sores that take long to heal

Type 1 diabetes can be diagnosed at any age and usually has more severe symptoms. These symptoms have a faster onset and, in addition to hyperglycemia symptoms, may include:

  • nausea
  • vomiting
  • stomach pains

Call your doctor or 911 if you’re experiencing severe symptoms of high blood sugar for days or weeks.

Hyperglycemia may be caused in people without diabetes for many reasons, including:

  • eating a lot of sugar or carbohydrates in a single sitting
  • high stress
  • hormonal changes
  • acute illness
  • infection
  • surgery
  • trauma

In people with diabetes, there are also many reasons for high blood sugar levels. The main cause is that the pancreas either does not make enough insulin or makes no insulin, depending on what type of diabetes you have.

Additionally, high blood sugar levels may be due to:

  • taking too little insulin for food eaten
  • skipping a dose of your diabetes medication
  • taking an incorrect dose of insulin or diabetes medication
  • an insulin pump malfunction
  • a continuous glucose monitor (CGM) malfunction
  • taking expired insulin
  • rationing insulin
  • hormonal changes
  • stress
  • too little sleep
  • lack of exercise
  • dehydration
  • taking certain medications (like steroids)
  • illness or infection
  • eating too much
  • drinking caffeine
  • dawn phenomenon
  • insulin resistance changing due to weight gain or pregnancy

Diabetes itself has many causes. Type 1 diabetes is an autoimmune disease where the body’s immune system has randomly attacked the insulin-producing beta cells of the pancreas resulting in disease.

Type 2 diabetes is a genetic and environmental condition of insulin resistance where the body gradually does not have enough insulin to maintain proper blood sugar levels due to many factors.

Managing diabetic hyperglycemia

If you have diabetic hyperglycemia, it is important to address it quickly. There are ways to bring your blood sugar down fast, including:

  • taking insulin
  • drinking water and staying hydrated
  • exercising
  • taking medications appropriately
  • never using expired insulin
  • never rationing your insulin
  • aiming for between 7–9 hours of sleep per night
  • checking your blood sugars regularly
  • going to your doctor regularly for checkups
  • being aggressive in treating high blood sugar to help prevent diabetic ketoacidosis
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There are both short- and long-term complications of high blood sugar and diabetes.

Short-term complications

In the short term, high blood sugar can make you thirsty and may make you dehydrated due to frequent urination. You may experience blurry vision.

You’ll feel achy and lethargic. If you experience slower-healing wounds, you might be more susceptible to infection.

Additionally, high blood sugar puts you at a higher risk of developing diabetic ketoacidosis (DKA), which can be fatal.

Long-term complications

Additionally, over a longer period, sustained high blood sugar (over 200–250 mg/dL) can cause long-term diabetes complications.

These diabetes complications include:

  • retinopathy
  • loss of vision
  • neuropathy
  • lower-limb amputations
  • kidney damage and kidney disease
  • heart disease
  • stroke
  • premature death

Yes, hyperglycemia, even if you have diabetes, can be treated and possibly cured. Diet, physical activity, insulin or other medications (if you take them), and watching what you eat can treat hyperglycemia.

Diabetes, however, cannot be cured. While there is no cure for diabetes, you can take steps to help minimize and reduce the amount of time you spend in hyperglycemia to prevent short- and long-term diabetes complications.

Hyperglycemia and diabetes are two common conditions that have many similarities. Hyperglycemia is high blood sugar resulting from too little insulin in the bloodstream. If it’s unrelated to diabetes, hyperglycemia is usually temporary.

Diabetes is a chronic condition where the body either makes too little (type 2 diabetes) or no (type 1 diabetes) insulin, resulting in hyperglycemia and warranting daily treatment with diet, exercise, and medications.

People, both with and without diabetes, can experience hyperglycemia. Treating hyperglycemia may require movement, hydration, and medications.

If you have diabetes, it is best to limit the amount of time you spend in hyperglycemia, as it can cause both short- and long-term diabetes complications.