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Type 1 diabetes

Definition

Type 1 diabetes is a chronic (lifelong) disease that occurs when the pancreas does not produce enough insulin to properly control blood sugar levels.

See also:

Alternative Names

Insulin-dependent diabetes; Juvenile onset diabetes; Diabetes - type 1

Causes

There are several forms of diabetes. Type 1 diabetes used to be called juvenile or insulin-dependent diabetes. Type 1 diabetes can occur at any age, but it is most often diagnosed in children, adolescents, or young adults.

Insulin is a hormone produced by special cells, called beta cells, in the pancreas, an organ located in the area behind your stomach. Insulin is needed to move blood sugar (glucose) into cells, where it is stored and later used for energy. In type 1 diabetes, these cells produce little or no insulin.

Without enough insulin, glucose builds up in the bloodstream instead of going into the cells. The body is unable to use this glucose for energy. This leads to the symptoms of type 1 diabetes.

Within 5 - 10 years, the insulin-producing beta cells of the pancreas are completely destroyed and the body can no longer produce insulin.

The exact cause is unknown, but most likely there is a viral or environmental trigger in genetically susceptible people that causes an immune reaction. The body's white blood cells mistakenly attack the insulin-producing pancreatic beta cells.

Symptoms

Some people will have no symptoms before they are diagnosed with diabetes.

Others may notice these symptoms as the first signs of type 1 diabetes, or when the blood sugar is high:

  • Feeling tired or fatigued
  • Feeling hungry
  • Being very thirsty
  • Urinating more often
  • Losing weight without trying
  • Having blurry eyesight
  • Losing the feeling or feeling tingling in your feet

For others, warning symptoms that they are becoming very sick may be the first signs of type 1 diabetes, or may happen when the blood sugar is very high (see: diabetic ketoacidosis):

  • Deep, rapid breathing
  • Dry skin and mouth
  • Flushed face
  • Fruity breath odor
  • Nausea or vomiting, unable to keep down fluids
  • Stomach pain

Low blood sugar (hypoglycemia) can develop quickly in people with diabetes who are taking insulin. Symptoms typically appear when the blood sugar level falls below 70. Watch for:

  • Headache
  • Hunger
  • Nervousness
  • Rapid heartbeat (palpitations)
  • Shaking
  • Sweating
  • Weakness

Exams and Tests

Diabetes is diagnosed with the following blood tests:

  • Fasting blood glucose level -- diabetes is diagnosed if it is higher than 126 mg/dL on two occasions
  • Random (nonfasting) blood glucose level -- diabetes is suspected if it is higher than 200 mg/dL, and the patient has symptoms such as increased thirst, urination, and fatigue (this must be confirmed with a fasting test)
  • Oral glucose tolerance test -- diabetes is diagnosed if the glucose level is higher than 200 mg/dL after 2 hours.

Ketone testing is also used in type 1 diabetes. Ketones are produced by the breakdown of fat and muscle. They are harmful at high levels. The ketone test is done using a urine sample. Ketone testing is usually done at the following times:

  • When the blood sugar is higher than 240 mg/dL
  • During an illness such as pneumonia, heart attack, or stroke
  • When nausea or vomiting occur
  • During pregnancy

The following tests will help you and your doctor monitor your diabetes and prevent complications of diabetes:

  • Check the skin and bones on your feet and legs.
  • Check the sensation in your feet.
  • Have your blood pressure checked at least every year (blood pressure goal should be 130/80 mm/Hg or lower).
  • Have your glycosulated hemoglobin (HbA1c) checked every 6 months if your diabetes is well controlled; otherwise, every 3 months.
  • Have your cholesterol and triglyceride levels checked yearly (aim for LDL cholesterol levels below 100 mg/dL).
  • Get yearly tests to make sure your kidneys are working well (microalbuminuria and serum creatinine).
  • Visit your ophthalmologist at least once a year, or more often if you have signs of diabetic retinopathy.
  • See the dentist every 6 months for a thorough dental cleaning and exam. Make sure your dentist and hygienist know that you have diabetes.

Treatment

This version of the Encyclopedia has no treatment information. Please discuss any and all treatment options for your condition with your healthcare professional.

Support Groups

For additional information and resources, see diabetes support group.

Outlook (Prognosis)

Diabetes is a lifelong disease for which there is not yet a cure. However, the outcome for people with diabetes varies. Studies show that tight control of blood glucose can prevent or delay complications to the eyes, kidneys, nervous system, and heart in type 1 diabetes. However, complications may occur even in those with good diabetes control.

Possible Complications

After many years, diabetes can lead to serious problems with your eyes, kidneys, nerves, heart, blood vessels, and other areas in your body.

If you have diabetes, your risk of a heart attack is the same as someone who has already had a heart attack. Both women and men with diabetes are at risk. You may not even have the typical signs of a heart attack.

In general, complications include:

Other complications include:

  • Erection problems
  • Infections of the skin, female genital tract, and urinary tract

When to Contact a Medical Professional

If you are newly diagnosed with type 1 diabetes, you should probably have medical follow-up weekly until you have good control of blood glucose. Your health care provider will review the results of home glucose monitoring and urine testing. The provider will also look at your diary of meals, snacks, and insulin injections.

As the disease becomes more stable, follow-up visits will be less often. Visiting your health care provider is very important for monitoring possible long-term complications from diabetes.

Call 911 if you have:

  • Chest pain or pressure, shortness of breath, or other signs of angina
  • Loss of consciousness
  • Seizures

Call your health care provider or go to the emergency room if you have these symptoms of ketoacidosis:

  • Deep and rapid breathing
  • Extreme thirst and drinking and frequent urination
  • Severe nausea and vomiting, and inability to drink liquids or eat
  • Sweet-smelling breath
  • Shortness of breath
  • Confusion
  • Severe abdominal pain
  • High glucose or ketone levels in your urine
  • Very high blood sugar

Also call your doctor if you have:

  • Symptoms that your blood sugar is going too high (being very thirsty, having blurry vision, having dry skin, feeling weak or tired, needing to urinate a lot)
  • Blood sugar levels that are running higher than the goals you and your doctor have set
  • Symptoms that your blood sugar is getting too low (weakness or fatigue, trembling, sweating, feeling irritable, unclear thinking, fast heartbeat, double or blurry vision, uneasy feeling)
  • You are having blood sugar readings below 70 mg/dL
  • Numbness, tingling, pain in your feet or legs
  • Sores or infections on your feet
  • Problems with your eyesight

You can treat early signs of hypoglycemia at home by eating sugar or candy or taking glucose tablets. If your signs of hypoglycemia continue or your blood glucose levels stay below 60 mg/dL, go to the emergency room.

Prevention

Currently, there is no way to prevent type 1 diabetes. There is no effective screening test for type 1 diabetes in people with no symptoms.

To prevent complications of diabetes, visit your health care provider or diabetes educator at least four times a year. Talk about any problems you are having.

Stay up-to-date with all of your vaccinations and get a flu shot every year in the fall.

References

Alemzadeh R, Wyatt DT. Diabetes Mellitus. In: Kliegman RM, ed. Kliegman: Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders; 2007:chap 590.

American Diabetes Association. Standards of medical care in diabetes -- 2009. Diabetes Care. 2009;32:S13-S61.

Alemzadeh R, Wyatt DT. Diabetes mellitus. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 590.


Review Date: 5/20/2009
Reviewed By: Deborah Wexler, MD, Assistant Professor of Medicine, Harvard Medical School, Endocrinologist, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
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