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Type 1 diabetes

Contents of this page:


Endocrine glands
Endocrine glands
Insulin pump
Insulin pump
Glucose test
Glucose test
Insulin pump
Insulin pump
Type I diabetes
Type I diabetes
Monitor blood glucose - series
Monitor blood glucose - series

Alternative Names    Return to top

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

Definition    Return to top

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:

Causes    Return to top

Diabetes is a lifelong disease for which there is not yet a cure. There are several forms of diabetes. Type 1 diabetes is often called juvenile or insulin-dependent diabetes. In this type of diabetes, cells of the pancreas produce little or no insulin, the hormone that allows sugar (glucose) to enter body cells.

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 despite high levels in the bloodstream. This leads to increased hunger.

In addition, the high levels of glucose in the blood causes increased urination. This leads to excessive thirst. Within 5 - 10 years, the insulin-producing beta cells of the pancreas are completely destroyed and the body can not longer produce insulin.

Type 1 diabetes can occur at any age. Many patients, however, are diagnosed after age 20.

The exact cause is unknown. Genetics, viruses, and autoimmune problems may play a role.

Symptoms    Return to top

Possible symptoms include:

Exams and Tests    Return to top

Diabetes is diagnosed with the following blood tests:

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:

People with diabetes should have their A1c (HbA1c) levels checked every 3 - 6 months. The HbA1c is a measure of average blood glucose during the past 2 - 3 months. It can help determine how well treatment is working.

Treatment    Return to top

The immediate goals of treatment are to treat diabetic ketoacidosis and high blood glucose levels. Because type 1 diabetes can come on suddenly and the symptoms can be severe, newly diagnosed people may need to stay in the hospital.

The long-term goals of treatment are to:

These goals are accomplished through:


Insulin lowers blood sugar by allowing it to leave the bloodstream and enter cells. Everyone needs insulin. People with type 1 diabetes can't make their own insulin. They must take insulin every day.

Insulin is usually injected under the skin. In some cases, a pump delivers the insulin continuously. Insulin does not come in pill form.

Insulin preparations differ in how fast they start to work and how long they last. The health care professional will review your blood glucose levels to determine the appropriate type of insulin you should use. More than one type of insulin may be mixed together in an injection to achieve the best blood glucose control.

The injections are needed, in general, from one to four times a day. People are taught how to give insulin injections by their health care provider or a diabetes nurse educator. At first, a child's injections may be given by a parent or other adult. By age 14, most children can be expected (but should not be required) to give their own injections.

People with diabetes need to know how to adjust the amount of insulin they are taking in the following situations:


Meal planning for type 1 diabetes should be consistent, to allow food and insulin to work together to regulate blood glucose levels. If meals and insulin are out of balance, blood glucose levels can go up and down. (See: Diabetes diet)

The American Diabetes Association and the American Dietetic Association have information for planning healthy, balanced meals. It can help to talk with a registered dietitian or nutrition counselor.


Regular exercise helps control the amount of sugar in the blood. It also helps burn excess calories and fat to achieve a healthy weight.

Ask your health care provider before starting any exercise program. Those with Type 1 diabetes must take special precautions before, during, and after intense physical activity or exercise.


Blood glucose monitoring is done by checking the glucose content of a small drop of blood. The testing is done on a regular basis and will let you know how well diet, medication, and exercise are working together to control diabetes.

The results can be used to adjust meals, activity, or medications to keep blood sugar levels within an appropriate range. Tests are usually done before meals and at bedtime. More frequent testing may be needed when you are sick or under stress.

Testing will provide valuable information so the health care provider can suggest improvements to your care and treatment. Testing will identify high and low blood sugar levels before serious problems develop.

A device called a glucometer can provide an exact blood sugar reading. There are different types of devices. Usually, you prick your finger with a small needle called a lancet to get a tiny drop of blood. You place the blood on a test strip and put the strip into the device. You should have results within 30 - 45 seconds.

Keeping accurate records of your test results will help you and your health care provider plan how to best control your diabetes.


Diabetes causes damage to the blood vessels and nerves. This can reduce your ability to feel injury to or pressure on the foot. You may not notice a foot injury until severe infection develops.

Diabetes also affects the body's immune system, decreasing the ability to fight infection. Small infections can rapidly progress to death of the skin and other tissues. Amputation may be needed.

To prevent injury to the feet, get into a routine of checking and caring for your feet daily. See: Diabetes foot care.


Low blood sugar is known as hypoglycemia. It can occur from too much insulin, too much exercise, or too little food. Hypoglycemia can develop quickly in people with diabetes. Symptoms typically appear when the blood sugar level falls below 70. Watch for:

If these symptoms occur and you have a blood sugar test kit available, do a blood sugar check. If the level is low, eat something with sugar: fruit juice, several teaspoons of sugar, a cup of skim milk, or regular soda. If you don't have a test kit handy, eat sugar anyway - it can't hurt. Symptoms should go away within 15 minutes. If the symptoms don't go away, eat more sugar and test the sugar level again.

AFTER the symptoms go away, you can eat more substantial food. Eat simple sugar first to get the situation under control. Even if you or your child is hungry, do not eat "real" food until the sugar level comes up. Real food won't produce enough sugar and takes too long to digest.

If you are a parent, relative, or friend of someone experiencing these symptoms, monitor the person closely. If symptoms become worse (confusion, seizures, or unconsciousness) give the person a shot of glucagon. If you don't have glucagon, call 911 immediately.

You should have some glucagon stored for emergencies. Make sure everyone in your home, as well as babysitters and caregivers, knows how to use it. Also check the expiration date.

Don't panic. Glucagon works very fast -- usually within 15 minutes. Lay the person on the side to prevent choking. If the person is not better in 15 minutes, call 911.


When there is not enough insulin to move glucose into cells, glucose can build up in the blood. The body then looks for other forms of energy and uses fat as a fuel source. As fats are broken down, acids called ketones build up in the blood and urine. In high levels, ketones are poisonous. This condition is known as ketoacidosis.

You can check for ketones using a simple urine test available at pharmacies. This test should be done every 4 - 6 hours anytime a person with diabetes has a blood sugar level above 240. Also do the test if the person:

The warning signs that ketoacidosis is getting serious might include:

If these symptoms occur, call the doctor or go to the emergency room right away. If left untreated, this condition will lead to coma and even death.


You are the most important person in managing your diabetes. Diabetes education involves learning how to live with your diabetes. It helps prevent complications.

You should know the basic steps to diabetes management:

Support Groups    Return to top

For additional information and resources, see diabetes support group.

Outlook (Prognosis)    Return to top

The outcome for people with diabetes varies. Studies show that tight control of blood glucose can prevent or delay complications to the eyes, kidneys, and nervous system. However, complications may occur even in those with good diabetes control.

Possible Complications    Return to top

Emergency complications include:

Long-term complications include:

When to Contact a Medical Professional    Return to top

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

Go to the emergency room or call 911 if you have symptoms of severe hypoglycemia or insulin reaction:

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 if your blood glucose levels stay below 60 mg/dL, go to the emergency room.

Prevention    Return to top

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.

Regularly have the following tests:

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

References    Return to top

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 -- 2008. Diabetes Care. 2008;31:S12-S54.

Eisenbarth GS, Polonsky KS, Buse JB. Type 1 Diabetes Mellitus. In: Kornenberg HM, Melmed S, Polonsky KS, Larsen PR. Kronenberg: Williams Textbook of Endocrinology. 11th ed. Philadelphia, Pa: Saunders Elsevier;2008:chap 31.

Update Date: 6/17/2008

Updated by: Elizabeth H. Holt, MD, PhD, Assistant Professor of Medicine, Section of Endocrinology and Metabolism, Yale University. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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