Hyperglycemia (High Blood Sugar)

Hyperglycemia is a hallmark sign of diabetes.

Hyperglycemia is the medical term for high blood sugar and is defined as an abnormally high blood glucose (blood sugar) level. According to the hyperglycemia definition, this condition typically results from the body’s inability to produce enough insulin or to use insulin effectively.

Blood sugar is measured in a sample of blood taken from a vein or a small finger stick sample of blood. It can be measured in a laboratory either alone or with other blood tests, or it can be measured using a handheld glucometer, a small device that allows frequent monitoring of blood glucose levels without the need for a doctor's office or laboratory.

Hyperglycemia or high blood sugar is a hallmark sign of diabetes (both type 1 diabetes and type 2 diabetes) and prediabetes. Normal ranges for blood glucose measurements can vary slightly among different laboratories, but in general, a fasting (early a.m. before breakfast) glucose level is considered normal if it is between 70-100 mg/dL. Glucose levels may rise slightly above this range following a meal. Random blood glucose measurements are usually lower than 125 mg/dL.

Several medical conditions can cause hyperglycemia, but the most common by far is diabetes mellitus. Diabetes mellitus is what causes high glucose levels in the majority of the population. Diabetes affects over 8% of the total U.S. population. In diabetes, blood glucose levels rise either because there is an insufficient amount of insulin in the body or because the body cannot use insulin well. Normally, the pancreas releases insulin after a meal so that the cells of the body can utilize glucose for fuel. This keeps blood glucose levels in the normal range.

Type 1 diabetes is responsible for about 5% of all cases of diabetes and results from damage to the insulin-secreting cells of the pancreas. Type 2 diabetes is far more common and is related to the body's inability to effectively use insulin. In addition to type 1 and type 2, gestational diabetes is a form of diabetes that develops in pregnant women. Studies show that between 2% to 10% of all pregnant women get gestational diabetes.

Sometimes, high blood sugar is not the result of diabetes. Other medical conditions that can cause hyperglycemia include:

• Pancreatitis (inflammation of the pancreas)
• Pancreatic cancer
• Hyperthyroidism (overactive thyroid gland)
• Cushing's syndrome (elevated blood cortisol level)
• Unusual tumors that secrete hormones, including glucagonoma, pheochromocytoma, or growth hormone-secreting tumors
• Severe stresses on the body, such as heart attack, stroke, trauma, or severe illnesses, can temporarily lead to hyperglycemia
• Taking certain medications, including prednisone, estrogens, beta-blockers, glucagon, oral contraceptives, phenothiazines, and others, can elevate blood glucose levels

While symptoms can vary from person to person, these five common signs often indicate high blood sugar (hyperglycemia):

1. Increased thirst
2. Frequent urination
3. Fatigue or weakness
4. Blurred vision
5. Unexplained weight loss or increased hunger

If you have high glucose levels, symptoms may vary from person to person and can range from mild to severe. The main symptoms of hyperglycemia are increased thirst and frequent need to urinate.

Other symptoms of hyperglycemia that can occur with high blood sugar are:

• Headaches
• Tiredness
• Blurred vision
• Hunger
• The trouble with thinking or concentrating
• Frequent urination

Other symptoms and signs of high blood sugar include:

• Sunburns. Pain from a sunburn causes pain, which increases blood sugar.
• Coffee. Some people with diabetes have an extra sensitivity to caffeine.
• Gum disease. Gum disease is a complication of diabetes and can make blood sugars rise.
• Losing sleep. Going a night or two without sleeping can cause the body to use insulin less efficiently.
• Nose spray. Some nasal sprays have chemicals that trigger the liver to make more blood sugar.

Severely elevated blood sugar levels can result in a medical emergency ("diabetic coma"). This can occur in both people with type 1 and those with type 2 diabetes. People with type 1 diabetes may develop diabetic ketoacidosis (DKA), and those with type 2 diabetes can develop hyperglycemic hyperosmolar nonketotic syndrome (HHNS, also referred to as hyperglycemia hyperosmolar state). These so-called hyperglycemia crises are serious conditions that can be life-threatening if not treated immediately. With blood sugar levels so high, symptoms can become very serious and may even lead to death. Hyperglycemic crises cause about 2,400 deaths each year in the U.S.

Over time, hyperglycemia can lead to damage to organs and tissues. Long-term hyperglycemia can impair the immune response, leading to poor healing of cuts and wounds. It can also cause nerve damage, vision problems, and damage to the blood vessels and kidneys (see below).

To identify hyperglycemia, levels of blood sugar are measured using several blood tests. These tests help determine whether your glucose levels are within the normal range or elevated.

Different kinds of blood tests can diagnose hyperglycemia, such as:

• Random blood glucose: This test reflects the blood sugar level at a given point in time. Normal values are generally between 70 and 125 mg/dL, as discussed earlier. More than 125 mg/dL may indicate high glucose count.
• Fasting blood glucose: This is a measurement of blood sugar level taken in the early morning before eating or drinking anything since the night before. Normal fasting blood glucose levels are less than 100 mg/dL. Levels above 100 mg/dL up to 125 mg/dL suggest prediabetes, while levels of 126 mg/dL or above are diagnostic of diabetes.
• Oral glucose tolerance test: This is a test that measures blood glucose levels at given time points after a dose of sugar is consumed. This test is most commonly used to diagnose gestational diabetes.
• Glycohemoglobin A1c: This is a measurement of glucose that is bound to red blood cells and provides an indication of blood sugar levels over the past 2 to 3 months.

Knowing how to tell if your blood sugar is high can help you catch early signs of hyperglycemia and get treatment before complications develop.

Mild or transient hyperglycemia may not need medical treatment, depending upon the cause. People with mildly elevated glucose or prediabetes can often lower their glucose levels by incorporating diet and lifestyle changes. These approaches focus on how to lower blood sugar gradually and how to reduce blood sugar levels immediately during sudden spikes. Discuss any dietary or lifestyle changes with your healthcare team to ensure or use reliable resources such as the American Diabetes Association.

When hyperglycemia levels are consistently high, medical care becomes necessary. Hyperglycemia treatment may include insulin therapy, oral medications, or more structured meal planning and exercise routines.

Insulin is the treatment of choice for people with type 1 diabetes and life-threatening increases in glucose levels. People with type 2 diabetes may be managed with a combination of different oral and injectable medications. Some people with type 2 diabetes also take insulin.

What happens if blood sugar is too high? Persistent severe hyperglycemia can lead to complications such as diabetic ketoacidosis (DKA) in type 1 diabetes or hyperglycemic hyperosmolar state (HHS) in type 2 diabetes, both of which are life-threatening.

What to do when blood sugar is high:

• Check your blood glucose level using a glucometer.
• Drink water to help flush excess glucose from the bloodstream.
• Engage in light physical activity (if safe and approved by your doctor).
• Follow your prescribed medication or insulin regimen.
• Seek immediate medical attention if you have symptoms of DKA or HHS, such as nausea, vomiting, confusion, or difficulty breathing.

High blood sugar due to medical conditions other than diabetes is generally treated by addressing the underlying condition responsible for elevated glucose. In some cases, insulin may be needed to stabilize glucose levels during this treatment.

Long-term complications of prolonged hyperglycemia or high blood sugar can be severe. These occur in people with diabetes and are worse when the condition is poorly controlled. The long-term complications of diabetes tend to develop slowly over time.

Some of the complications of hyperglycemia in poorly controlled diabetes are:

• Heart and blood vessel disease can increase the risk of heart attack, stroke, and peripheral artery disease
• Poor kidney function eventually leads to kidney failure
• Nerve damage can lead to burning, tingling, pain, and changes in sensation
• Eye diseases, including damage to the retina, glaucoma, and cataracts
• Gum disease

What level of blood sugar is dangerous?

In general, blood glucose levels consistently above 180 mg/dL after meals or above 240 mg/dL at any time are considered dangerous and may require urgent medical attention, especially if accompanied by symptoms such as nausea, vomiting, confusion, rapid breathing, or signs of ketones in the urine.

• What causes sudden hyperglycemia? Sudden hyperglycemia can be caused by factors such as missed insulin or diabetes medication doses, eating a large amount of carbohydrates, physical or emotional stress, infections, illness, certain medications (like steroids), dehydration, or hormonal changes that temporarily raise blood sugar.
• What to do when your blood sugar is too high? If your blood sugar is extremely high, you can try out the following measures:
  • Check your blood glucose level using a glucometer.
  • Follow your prescribed medication or insulin regimen.
  • Engage in light physical activity (if safe and approved by your doctor).
  • Drink water to help flush excess glucose from the bloodstream.
  • Seek immediate medical attention if you have symptoms of DKA or HHS, such as nausea, vomiting, confusion, or difficulty breathing.
• When is hyperglycemia an emergency? Hyperglycemia becomes an emergency when blood sugar levels are extremely high — typically above 250-300 mg/dL — and are accompanied by symptoms such as nausea, vomiting, abdominal pain, rapid breathing, confusion, fruity-smelling breath, or extreme fatigue, as these may indicate DKA. If you have sugar levels above 600 mg/dL without symptoms of ketoacidosis, it could indicate HHS. Both DKA and HHS are emergencies that require immediate medical attention.
• How do I bring my blood sugar down immediately? The best ways to bring sugar down immediately may include:
  • Taking your prescribed insulin doses
  • Drinking a large quantity of water to remove excess glucose
  • Doing light exercises that are recommended by your doctor
  • In case of side effects like nausea, vomiting, and confusion, it is better to consult your physician.
• What happens when your blood sugar is too high? Persistent severe hyperglycemia can lead to severe complications like diabetic ketoacidosis (DKA) in type 1 diabetes or hyperglycemic hyperosmolar state (HHS) in type 2 diabetes, both of which are life-threatening.
• What are the symptoms of high blood sugar? The common symptoms of high blood sugar may include:
  • Increased thirst
  • Blurred vision
  • Frequent urination
  • Fatigue or weakness
  • Unexplained weight loss or increased hunger
  • Nausea or vomiting
• What to do if sugar is too high? If your blood sugar is too high, check your glucose level, take any prescribed insulin or diabetes medication as directed, drink water to stay hydrated, engage in light physical activity if it’s safe, and avoid high-carb foods. Seek urgent medical care if you have symptoms such as nausea, vomiting, confusion, or rapid breathing.
• How can I lower my blood sugar quickly? You can lower your blood sugar quickly by taking your prescribed insulin or diabetes medication, drinking water to flush out excess glucose, and engaging in light exercise recommended by your doctor. However, if you experience nausea, vomiting, or confusion, seek immediate medical care instead of managing it by yourself.