What Causes High Blood Sugar Levels In Non-Diabetics?


High blood sugar or glucose, also called hyperglycemia , occurs when there is too much sugar in the blood. High blood sugar is a major symptom of diabetes, but it can also occur in people without type 1 or type 2 diabetes, either from stress or trauma, or gradually as a result of certain chronic conditions.

It is important to keep high blood sugar levels under control, even if you do not have diabetes, because high blood glucose levels can slow your healing ability, increase the risk of infections, and cause permanent damage to your nerves, blood vessels and organs like your eyes and kidneys … Damage to blood vessels due to high blood sugar also increases the risk of heart attack and stroke.

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Non-diabetic hyperglycemia and prediabetes

You are considered to have glucose intolerance or prediabetes if your fasting glucose is 100-125 mg / dL and hyperglycemia if your fasting blood glucose is greater than 125 mg / dL or more than 180 mg / dL one to two hours after lunch.

The body obtains glucose primarily through the consumption of carbohydrates, but also through the breakdown of glycogen into glucose, a process called glycogenolysis, or the conversion of non-carbohydrate sources to glucose called gluconeogenesis, which occurs primarily in the liver.

While the brain, kidneys, and red blood cells use 50% to 80% of glucose for energy, the rest of the glucose is used for energy. It is stored as glycogen in the liver and muscles and can be used later for energy or converted into adipose tissue.

In healthy people, blood glucose is regulated by the hormone insulin to remain at a constant level of 80 to 100 mg / dL. Insulin keeps blood sugar levels stable by increasing glucose absorption and storage and decreasing inflammatory proteins that raise blood sugar levels when there is excess glucose in the blood.

Certain conditions can raise blood glucose levels, interfering with insulin's ability to remove glucose from the bloodstream. When this happens, you develop hyperglycemia, which increases your risk for prediabetes, diabetes, and related complications.

Common causes

Cushing's syndrome

Cushing's syndrome occurs as a result of excessive secretion of adrenocorticotropic hormone, a hormone produced in the front of the pituitary gland that causes excess cortisol to be produced and released from the adrenal glands. Pituitary adenomas or pituitary tumors are responsible for Cushing's syndrome in more than 70% of cases, while long-term use of corticosteroids can also significantly increase the risk.

People with Cushing's syndrome are at increased risk of developing glucose intolerance and hyperglycemia as a result of increased levels of cortisol throughout the body. Cortisol is a hormone that counteracts the effects of insulin by blocking the absorption of glucose from the bloodstream, increasing insulin resistance and keeping blood sugar levels high. Elevated cortisol levels also partially reduce insulin release, from which it is produced in the pancreas .

About 10-30% of people with Cushing syndrome will develop impaired glucose tolerance, and 40-45% will develop diabetes.

Corticosteroid medications are often prescribed to reduce inflammation throughout the body, but they can lead to Cushing's syndrome and hyperglycemia because they activate certain enzymes that increase the conversion of non-carbohydrate molecules to glucose (gluconeogenesis). Corticosteroids also alter pancreatic cell function by suppressing cell signaling pathways involved in the release of insulin from the pancreas.

Pancreas diseases.

Pancreatic diseases such as pancreatitis , pancreatic cancer, and cystic fibrosis can cause hyperglycemia because the pancreatic cells are damaged in these conditions. Insulin is produced and released by cells in the pancreas. When the pancreas is inflamed and damaged, the cells of the pancreas can no longer produce enough insulin to remove glucose from the blood and control blood sugar levels.

Polycystic ovary syndrome

Polycystic ovary syndrome (PCOS), characterized by irregular menstrual periods, is a common endocrine disorder in women of reproductive age. Women with PCOS have hormonal imbalances, such as elevated levels of testosterone, insulin, and inflammatory proteins called cytokines , which are secreted from adipose tissue.

Despite elevated insulin levels, women with PCOS are insulin resistant because their insulin hormones cannot properly absorb glucose or use it for energy. Insulin receptors in women with PCOS cannot effectively bind to insulin. Because insulin carries glucose, excess glucose remains in the bloodstream and causes hyperglycemia.


Physical stress on the body, including trauma, burns, and other trauma, can lead to elevated blood sugar levels, altering the way glucose is metabolized. Stress-induced hyperglycemia occurs when physical stressors in the body stimulate an overactive sympathetic nervous system, the body's fight or flight response, releasing cytokines and hormones that counteract the action of insulin to remove excess glucose from the bloodstream. .

These cytokines and hormones such as adrenaline increase glucose production by breaking down glycogen stores to glucose (glycogenolysis) and converting non-carbohydrate sources to glucose (gluconeogenesis).

Elevated levels of the stress hormone cortisol, which is also released, blocks the action of insulin to transport glucose from the bloodstream to cells, further contributing to high blood sugar levels.

Surgery and stress

Changes in glucose metabolism caused by physical stress on the body also occur after surgery. Surgery is a controlled form of stress in the body that results in a similar increase in cytokines and hormones that stimulate glucose production in the liver and block the action of insulin to remove excess glucose from the blood.

Post-operatively, up to 30% of patients may develop stress-induced hyperglycemia, and blood glucose levels remain elevated long after they return home from the hospital. High blood sugar after surgery can significantly affect your overall health and increase your risk for diabetes and other serious diseases.


Stress-induced hyperglycemia can also be the result of physical stress caused by an infection such as pneumonia or urinary tract infections . Elevated levels of the stress hormone cortisol, produced during infections, block insulin's ability to remove excess glucose from the bloodstream, keeping the body in a high blood sugar state.

High blood glucose is also a consequence of infections, which is a normal response to meeting the needs of organs such as the brain, kidneys, and red blood cells, which depend on glucose for energy to support the immune system. to respond to fight infection.

Side effects of medications

Certain medications, such as catecholamine vasopressors, such as dopamine and norepinephrine, immunosuppressants such as tacrolimus and cyclosporine, and corticosteroids, can increase blood glucose levels by activating enzymes that increase blood glucose levels and interfere with the release and activity of insulin to absorb glucose from the blood. .

Hospitalized intravenous patients may also be at increased risk of developing hyperglycemia because the fluid contains a sugar solution that helps restore electrolyte balance. In patients who are ill or recovering from surgery or injury, the concentration of this fluid must be carefully controlled to avoid new surges in blood sugar.


High blood sugar is associated with obesity, as excess fat cells disrupt the balance of glucose and insulin. Excess fat cells called adipocytes secrete inflammatory proteins such as interleukins and tumor necrosis factor, which increase the body's resistance to insulin by activating processes that interfere with the body's ability to produce and release insulin when the blood sugar levels rise. is tall.

Excess fat cells also reduce the ability to remove glucose from the blood for use as energy or storage as glycogen in skeletal muscle. In obesity, elevated levels of lipids or fatty acid molecules activate pathways that disrupt insulin signaling in the muscles.


A family history of diabetes can increase the risk of developing hyperglycemia. While diabetes can be prevented through diet and lifestyle factors, impaired insulin sensitivity can be inherited and can make you more prone to developing high blood sugar levels.

Pregnant women can also develop gestational diabetes, often between 24 and 28 weeks gestation, due to hormonal changes that affect the body's glucose metabolism. The effects of pregnancy hormones can affect insulin's ability to remove excess glucose from the blood, leaving blood sugar levels high.

Lifestyle risk factors


Diet plays an important role in increasing blood sugar levels. Excessive consumption of foods that contain sugar and carbohydrates raises blood sugar levels after a meal, as the food breaks down into glucose molecules that enter the bloodstream.

In a healthy person, the presence of more glucose molecules in the blood signals the pancreas to release insulin, which helps absorb glucose from the blood and transports it to the muscles and liver for use for energy and storage. When the blood sugar level drops, the pancreas signals to release more insulin stop and the blood sugar should return to a stable baseline level.

When blood sugar levels rise steadily due to repeated and excessive consumption of sugar and carbohydrates, the excess glucose in the bloodstream stimulates the pancreas to secrete too much insulin. Over time, the body stops responding to insulin due to chronic blood sugar levels, leading to insulin resistance and keeping blood sugar levels high.

Eating a healthy, balanced diet with protein, fat, and high-fiber foods while limiting sugar and refined and processed carbohydrates can help control blood sugar levels.

Excessive alcohol consumption can also affect blood sugar levels, which interferes with the liver's ability to regulate glucose production and release and has a negative impact on your body's response to insulin.

Lack of physical activity

Lack of physical activity can raise blood sugar levels, as skeletal muscle is the main part of the body that uses glucose for energy or stores additional glucose as glycogen for later use. With low levels of physical activity, the muscles become inactive and cannot effectively remove glucose from the blood.

Regular exercise can help lower blood sugar levels by increasing the muscle's need to remove glucose from the blood for energy.

Get the word of drug information

High blood sugar can be due to a variety of causes, not just diabetes. You do not have to live with diabetes to develop hyperglycemia. High blood sugar levels can increase your risk of developing diabetes and related complications later on.

Many factors can contribute to high blood sugar levels, and some of them, such as diet and exercise, can help control blood glucose levels. Sometimes high blood sugar in people without diabetes can be associated with prediabetes, which can lead to the development of diabetes. If you often have high blood sugar levels, it is important to see your doctor and keep them under control.

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