Complications of Diabetes and Related Health Problems

Reviewed by: HU Medical Review Board | Last reviewed: September 2024 | Last updated: September 2024

Type 2 diabetes is what is known as a chronic health condition or disease. This means it will affect you for the rest of your life. However, there are steps you can take to control type 2 diabetes and live a healthy life. Understanding the complications of diabetes and related health problems can also help you be aware of any changes to your health.

Low blood sugar

Low blood sugar, hypoglycemia, is a short-term, usually sudden, complication that affects many people with type 2 diabetes. Hypoglycemia is defined as a blood sugar level of 70 mg/dL or lower in patients with diabetes.1

Early symptoms of low blood sugar include:1

  • Shakiness or feeling jittery
  • Sweating
  • Dizziness
  • Feeling hungry
  • Fast heartbeat
  • Headache
  • Feeling confused, irritable, anxious, nervous, or moody

Late symptoms of low blood sugar include:1

  • Slurred speech
  • Muscle weakness
  • Convulsions and seizures
  • Blurred vision
  • Death, though this is rare

Low blood sugar can result from exercise, especially in people with type 2 diabetes who are being treated with insulin or other drugs that increase the risk of low blood sugar.1

If you have diabetes, it is important to recognize the signs and symptoms of low blood sugar and to take steps to correct it. If low blood sugar cannot be corrected, hypoglycemia may become severe. Severe hypoglycemia (blood glucose below 54 mg/dL) is a medical emergency and may be life-threatening. It may require treatment with a rescue medicine like glucagon. If hypoglycemia becomes severe enough that glucagon is used, seek medical attention immediately.2

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High blood sugar

High blood sugar (hyperglycemia) is a hallmark of diabetes. Either the body does not make enough insulin (type 1 diabetes) or the body does not respond properly to insulin (type 2 diabetes). Insulin is needed so glucose (sugar) can move from the bloodstream into the tissues and cells of the body, where it is used for energy or stored for later use.3

Blood vessel damage

If not treated, persistent high blood sugar can have serious health complications. Too much sugar in the blood can cause buildup of plaque in blood vessels and disrupt the body’s ability to relax and contract blood vessels. This can lead to large blood vessel complications, like heart disease and stroke.3,4

Small blood vessel damage may also occur. Diseases that may be caused by small blood vessel damage from high blood sugar include kidney disease, nerve problems, and eye or vision problems.3

Diabetic ketoacidosis

When the body does not have enough insulin, glucose (sugar) cannot enter the cells for energy and remains in the bloodstream. As a result, the body begins to break down fat for fuel. When fat is broken down, chemicals called ketones build up in the blood.3,5

Ketones make the blood acidic, throwing off the normal chemical balance in the body. This condition is called diabetic ketoacidosis (DKA). It may happen if a person skips a dose of insulin or if their body needs more insulin, in cases like infection or stress.3,5

Because DKA is caused by a lack of insulin, it is more common in type 1 diabetes. However, it can sometimes happen to those with type 2 diabetes. DKA is life-threatening and may be lethal if left untreated.3

Hyperglycemic hyperosmolar syndrome

Hyperglycemic hyperosmolar syndrome (HHS) is a life-threatening complication of type 2 diabetes that causes extremely high blood sugar and dehydration.3,5,6

The term “hyperosmolar” is when the blood has too much sugar and salt. This causes the body to release water, electrolytes, and sugar by urination. Excess urination and water loss lead to severe dehydration. Once dehydrated, your kidneys are no longer able to release glucose (sugar). As a result, your blood sugar may get very high, sometimes as much as 10 times the normal level.3,5,6

Other complications

Diabetes may cause other health complications and health issues, including:7-14

  • Leg and foot problems. Diabetes can affect blood flow to the legs and feet, which may cause nerve problems and increase the risk of infection. Diabetes also increases the risk of amputation.
  • Skin problems. Diabetes can affect the skin in various ways. Color changes, thickening of the skin, blisters, open sores, dry or cracked skin, and skin tags may all occur with diabetes.
  • Mouth and teeth complications. Nearly 1 in 4 people with diabetes will end up with gum disease (periodontal disease), a chronic inflammatory disease that can destroy the gums. Gum disease leads to tooth loss and bone destruction of the jaw. Dry mouth may also occur in those with diabetes.
  • Infection. Diabetes can impair the function of your immune system, leaving you more likely to get infections. Higher levels of glucose in certain areas, like urine, can lead to the growth of bacteria and other disease-causing pathogens. Decreased circulation also means the body is less able to send immune cells to fight off infections.
  • Problems with sexual functioning. Diabetes damages the nerves and vessels in the body, which can lead to sexual problems. Erectile dysfunction (ED) is trouble achieving and maintaining an erection. One study found that more than half of men with type 2 diabetes experienced ED.
  • Mental health problems. Studies have shown that people with diabetes are 2 to 3 times more likely to have depression than people without diabetes.