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Diabetes Complications

If you have diabetes, you may be at risk of developing diabetes-related complications.

Complications of diabetes on this page:

Short-Term Complications of Diabetes

The most common short-term complications of diabetes are:

  • Hypoglycemia — blood glucose that's too low.
  • Hyperglycemia — blood glucose that's too high.


Low blood glucose is called hypoglycemia. Hypoglycemia occurs when the blood glucose level goes below 70 mg/dL.

Several things can cause this condition, including:

  • Too much insulin
  • Too much medication
  • Not enough food in your system
  • Too much exercise

Symptoms of hypoglycemia include:

  • Confusion
  • Increased hunger
  • Nervousness
  • Seizures
  • Shaking
  • Sweating
  • Weakness
  • Coma, in the worst of cases


The opposite of hypoglycemia is hyperglycemia. Hyperglycemia happens when your blood glucose goes above normal.

Symptoms of hyperglycemia include:

  • Blurred vision or extreme tiredness
  • Frequent urination or dehydration
  • Increased thirst or hunger
  • Nausea or vomiting
  • Rapid or deep breathing
  • Sweet or fruity smell on your breath
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High Blood Glucose with Ketones

DKA is the short name for diabetic ketoacidosis.

Usually only affecting people with type 1 diabetes, DKA occurs when the body does not have enough insulin to change sugar into energy. When there's not enough insulin, glucose stays in the blood and cannot be used for fuel.

Since the body still needs fuel for energy, it must then ;burn body fat instead.

When the body burns fat, it forms waste products called ketones, which build up in the blood and come out in the urine.

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High Blood Glucose without Ketones

HHNS is a condition of high blood glucose that usually occurs only in people with type 2 diabetes. HHNS is short for hyperglycemic hyperosmolar non-ketotic syndrome.

In some ways, HHNS is like DKA in people with type 1 diabetes. The difference is that people with type 2 diabetes rarely get ketones in their blood.

For people who have type 2 diabetes, their pancreas still makes some insulin. Even a small amount of insulin can change glucose into energy.

The body uses the sugar first before it has to use fat for fuel, so it rarely produces ketones.

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Long-Term Complications of Diabetes

Heart Problems

Heart disease is a very common problem linked to diabetes, especially for people with type 2 diabetes.

High blood glucose and cholesterol levels can cause the blood vessels to narrow and clog.

Clogged blood vessels make it difficult for blood to reach all parts of the body. This can result in high blood pressure and increase your risk of heart attack or stroke.

To reduce your risk of heart disease:

  • Eliminate high amounts of fat and cholesterol from your diet.
  • Maintain good control of your blood glucose and blood pressure.
  • Do not smoke.
  • Work with a dietician, diabetes educator, or health care provider to develop a weight loss and physical activity plan.

Eye Problems

One of the most serious eye complications caused by diabetes is called diabetic retinopathy. Diabetic retinopathy occurs when diabetes damages the retina, the light sensitive tissue in the back of the eye.

Several factors influence the likelihood of developing retinopathy, including:

  • High blood glucose
  • High blood pressure
  • Genetics
  • How long you have had diabetes

If you have had diabetes for many years, you may be at a higher risk of developing diabetic retinopathy.

Sometimes the retina can be damaged before any symptoms are noticed. Early detection is the key to preventing blindness caused by diabetic retinopathy.

Signs of diabetic retinopathy include:

  • Blurry vision
  • A dark empty spot that locks your vision
  • Difficulty adjusting from bright to dim light
  • Floaters and flashes
  • Poor night vision
  • Sudden loss of vision

To reduce your risk of developing diabetic retinopathy:

  • Maintain good control of your blood glucose and blood pressure.
  • Visit your eye doctor at least once a year for a dilated eye exam.

Nerve Damage

High blood glucose can cause nerve damage, a condition known as neuropathy.

Neuropathy can affect your:

  • Bladder
  • Heart
  • Intestines
  • Stomach
  • Sexual organs

Neuropathy also can cause you to lose all feeling in your feet, and you can hurt your feet without knowing it. Foot sores can become serious very fast and are hard to heal.

Signs of neuropathy include:

  • Difficulty controlling bladder or bowel movements
  • Pain or tingling in your feet or hands
  • Problems digesting food
  • Problems with sexual function

To reduce your neuropathy risk:

  • Ask your doctor to check your feet.
  • Check your feet routinely at home and report any problems to your doctor immediately.
  • Maintain good control of your blood glucose.

Kidney Problems

High blood glucose can damage the blood vessels in the kidneys and can cause kidney problems, called nephropathy.

The blood vessels in the kidneys act as a filter to dispose of waste products in the body.

For people with diabetes who have high blood glucose, the kidneys have to work harder to dispose of waste. Over time, this extra work can damage your kidneys

If this happens, you may need to take medication or have medical treatments, such as kidney dialysis or a kidney transplant.

When diagnosed early, there are several treatments that can prevent kidney disease from getting worse.

To reduce your risk of kidney disease:

  • Maintain good control of your blood glucose and blood pressure.
  • See your doctor regularly.

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How to Avoid Complications of Diabetes

The best ways to avoid diabetes complications are to:

  • Take an active role in managing your disease.
  • Maintain good blood glucose levels.
  • Visit your health care professional regularly.

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