What is hyperglycemia?

Hyperglycemia, or high blood glucose, occurs when there is too much sugar in the blood. When you have hyperglycemia for long periods of time, you can have damage to nerves, blood vessels, and other body organs.

What are the causes of hyperglycemia?

  • Skipping or forgetting your insulin or oral glucose-lowering medication
  • Eating the wrong foods
  • Eating too much food
  • Infection
  • Illness
  • Increased stress
  • Decreased activity

What are the symptoms of hyperglycemia?

It is important to know the early signs of hyperglycemia. If hyperglycemia is left untreated, it may develop into an emergency condition called ketoacidosis.

Signs and symptoms of hyperglycemia include:

  • Increased thirst
  • Blurred vision
  • Frequent urination
  • Increased hunger
  • Numbness or tingling in the feet

Additional early symptoms include:

  • Fatigue (feeling weak, tired)
  • Sugar in the urine
  • Weight loss
  • Blood glucose of more than 180 mg/dl
  • Vaginal and skin infections
  • Slow-healing cuts and sores

Last reviewed by a Cleveland Clinic medical professional on 03/03/2017.


  • American Diabetes Association. Hyperglycemia Accessed 3/3/2017.
  • Inzucchi SE, Bergenstal RM, Buse JB, et al. Management of hyperglycemia in type 2 diabetes: a patient-centered approach: position statement of the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD). Diabetes Care. 2012;35(6):1364-79.

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