Symptoms and Signs of High Blood Sugar (Hyperglycemia)

Medical Author:
Medically Reviewed on 9/15/2022

Doctor's Notes on High Blood Sugar (Hyperglycemia)

Hyperglycemia refers to high levels of glucose (blood sugar) in the blood. It is a characteristic sign of type 1 and type 2 diabetes, as well as prediabetes. Diabetes is the most common cause of hyperglycemia. Less common causes can include tumors that secrete hormones, pancreatitis, Cushing's syndrome, and taking certain medications.

Mild hyperglycemia may not result in any symptoms or signs. When present, the most common associated signs and symptoms are increased thirst (known as polydipsia) and the need to urinate frequently. Other possible symptoms that can accompany hyperglycemia are

  • headaches,
  • increased hunger,
  • blurred vision,
  • tiredness, and
  • problems with concentration.

When hyperglycemia is present over the long term, such as in poorly controlled diabetes, it can cause poor wound healing, nerve damage, vision problems, and damage to the blood vessels and kidneys.

What Is the Treatment for Hyperglycemia?

Dangerously high blood sugar levels are treated with intravenous fluid, electrolyte, and insulin administration.

Some people with type 2 diabetes may be able to control their blood sugar through a nutrition and exercise plan and weight loss if appropriate. Insulin is the treatment for type 1 diabetes. Many classes of medications are used to manage type 2 diabetes. These can be taken in both oral and injectable medication forms, and combinations of medications are often prescribed. Some people with type 2 diabetes will benefit from insulin therapy.

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Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.