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Type 1 diabetes

Definition

Type 1 diabetes is a lifelong (chronic) disease in which there are high levels of sugar (glucose) in the blood.

See also:

Alternative Names

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

Causes

Type 1 diabetes can occur at any age. However, 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. The pancreas is found 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, beta 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.

The exact cause of type 1 diabetes is unknown. Most likely it is an autoimmune disorder. An infection or some other trigger causes the body to mistakenly attack the cells in the pancreas that make insulin. This kind of disorder can be passed down through families.

Symptoms

These symptoms may be the first signs of type 1 diabetes, or may occur when the blood sugar is high:

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

For other people, these warning symptoms may be the first signs of type 1 diabetes, or they 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, inability to keep down fluids
  • Stomach pain

Low blood sugar (hypoglycemia) can develop quickly in people with diabetes who are taking insulin. Symptoms usually appear when the blood sugar level falls below 70 mg/dL. 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 two times
  • Random (nonfasting) blood glucose level -- you may have diabetes if it is higher than 200 mg/dL, and you have 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
  • Hemoglobin A1c test
    • Normal: Less than 5.7%
    • Pre-diabetes: Between 5.7% and 6.4%
    • Diabetes: 6.5% or higher

Ketone testing is also sometimes used. The ketone test is done using a urine sample or blood sample. Ketone testing may be done:

  • 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 or exams will help you and your doctor monitor your diabetes and prevent problems caused by diabetes:

  • Check the skin and bones on your feet and legs.
  • Check to see if your feet are getting numb.
  • Have your blood pressure checked at least every year (blood pressure goal should be 130/80 mm/Hg or lower).
  • Have your hemoglobin A1c test (HbA1c) done 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 70-100 mg/dL).
  • Get yearly tests to make sure your kidneys are working well (microalbuminuria and serum creatinine).
  • Visit your eye doctor at least once a year, or more often if you have signs of diabetic eye disease.
  • 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

Because type 1 diabetes can start quickly and the symptoms can be severe, people who have just been diagnosed may need to stay in the hospital.

If you have just been diagnosed with type 1 diabetes, you should probably have a check-up each week until you have good control over your blood sugar. Your health care provider will review the results of your home blood sugar monitoring and urine testing. Your provider will also look at your diary of meals, snacks, and insulin injections.

As the disease gets more stable, you will have fewer follow-up visits. Visiting your health care provider is very important so you can monitor any long-term problems from diabetes.

You are the most important person in managing your diabetes. You should know the basic steps to diabetes management:

  • How to recognize and treat low blood sugar (hypoglycemia)
  • How to recognize and treat high blood sugar (hyperglycemia)
  • Diabetes meal planning
  • How to give insulin
  • How to check blood glucose and urine ketones
  • How to adjust insulin and food when you exercise
  • How to handle sick days
  • Where to buy diabetes supplies and how to store them

INSULIN

Insulin lowers blood sugar by allowing it to leave the bloodstream and enter cells. Everyone with type 1 diabetes must take insulin every day.

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

Insulin types differ in how fast they start to work and how long they last. The health care provider will choose the best type of insulin for you and will tell you at what time of day to use it. More than one type of insulin may be mixed together in an injection to get the best blood glucose control. You may need insulin shots from one to four times a day.

Your health care provider or diabetes nurse educator will teach you how to give insulin injections. At first, a child's injections may be given by a parent or other adult. By age 14, most children can give their own injections.

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

  • When they exercise
  • When they are sick
  • When they will be eating more or less food and calories
  • When they are traveling

DIET AND EXERCISE

People with type 1 diabetes should eat at about the same times each day and try to eat the same kinds of foods. This helps to prevent blood sugar from becoming too high or low. See also:

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 extra calories and fat to reach a healthy weight.

Ask your health care provider before starting any exercise program. People with type 1 diabetes must take special steps before, during, and after intense physical activity or exercise. See also: Diabetes and exercise

MANAGING YOUR BLOOD SUGAR

Checking your blood sugar levels at home and writing down the results will tell you how well you are managing your diabetes. Talk to your doctor and diabetes educator about how often to check.

A device called a glucometer can read blood sugar levels. 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 in 30 - 45 seconds.

Keep a record of your blood sugar for yourself and your doctor or nurse. This will help if you have problems managing your diabetes. You and your doctor should set a target goal for your blood sugar levels at different times during the day. You should also plan what to do when your blood sugar is too low or high.

For more information, see: Managing your blood sugar

Low blood sugar is called hypoglycemia. Blood sugar levels below 70 mg/dL are too low and can harm you.

FOOT CARE

Diabetes damages the blood vessels and nerves. This can make you less able to feel pressure on the foot. You may not notice a foot injury until you get a severe infection.

Diabetes can also damage blood vessels. Small sores or breaks in the skin may become deeper skin sores (ulcers). The affected limb may need to be amputated if these skin ulcers do not heal or become larger or deeper.

To prevent problems with your feet:

  • Stop smoking if you smoke.
  • Improve control of your blood sugar.
  • Get a foot exam by your health care provider at least twice a year and learn whether you have nerve damage.
  • Check and care for your feet EVERY DAY, especially if you already have known nerve or blood vessel damage or current foot problems.
  • Make sure you are wearing the right kind of shoes.

PREVENTING COMPLICATIONS

Your doctor may prescribe medications or other treatments to reduce your chances of developing eye disease, kidney disease, and other conditions that are more common in people with diabetes.

See also:

Support Groups

For more information and resources, see diabetes support group.

Outlook (Prognosis)

Diabetes is a lifelong disease and 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 problems with the eyes, kidneys, nervous system, and heart in type 1 diabetes. However, problems may occur even in people with good diabetes control.

Possible Complications

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 normal signs of a heart attack.

After many years, diabetes can lead to other serious problems:

  • You could have eye problems, including trouble seeing (especially at night) and sensitivity to light. You could become blind.
  • Your feet and skin could develop sores and infections. If you have these sores for too long, your foot or leg may need to be removed. Infection can also cause pain and itching.
  • Diabetes may make it harder to control your blood pressure and cholesterol. This can lead to heart attack, stroke, and other problems. It can become harder for blood to flow to the legs and feet.
  • Nerves in the body can become damaged, causing pain, tingling, and loss of feeling.
  • Because of nerve damage, you could have problems digesting the food you eat. You could feel weakness or have trouble going to the bathroom. Nerve damage can also make it harder for men to have an erection.
  • High blood sugar and other problems can lead to kidney damage. The kidneys might not work as wellas they used to. They may even stop working.

See also: Diabetic ketoacidosis

When to Contact a Medical Professional

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 symptoms of diabetic ketoacidosis.

Also call your doctor if you have:

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

You can treat early signs of hypoglycemia at home by eating sugar or candy, or by 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

There is no way to prevent type 1 diabetes. There is no screening test for type 1 diabetes in people who have no symptoms.

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

References

Alemzadeh R, Ali O. Diabetes Mellitus. In: Kliegman RM, ed. Kliegman: Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders; 2011:chap 583.

American Diabetes Association. Standards of medical care in diabetes -- 2011. Diabetes Care. 2011. 34 Suppl 1:S11-S61.

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

Pignone M, Alberts MJ, Colwell JA, Cushman M, Inzucchi SE, Mukherjee D, et al. Aspirin for primary prevention of cardiovascular events in people with diabetes: a position statement of the American Diabetes Association, and an expert consensus document of the American College of Cardiology Foundation. Circulation. 2010. 121:2694-2701.


Review Date: 6/28/2011
Reviewed By: Ari S. Eckman, MD, Division of Endocrinology, Diabetes and Metabolism, Trinitas Regional Medical Center, Elizabeth, NJ. Review provided by VeriMed Healthcare Network. 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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