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Diabetes: Type 1

What is type 1 diabetes?

Type 1 diabetes is a lifelong disorder that happens when your body stops making insulin. When you don’t have insulin, the level of sugar in your blood gets too high.

When you digest food, your body breaks down much of the food into sugar (glucose). Your blood carries the sugar to your cells for energy. Insulin made by the pancreas gland moves the sugar from the bloodstream into the cells.

When your pancreas stops making insulin, sugar cannot get into your cells. Sugar then builds up in the blood. Too much sugar in the blood can cause many problems. These problems can be life-threatening if they are not treated. However, treatment with insulin can control your blood sugar level.

Type 1 diabetes usually starts in childhood or early adulthood. When you have type 1 diabetes, you will need to take insulin for the rest of your life (unless you have a pancreas cell transplant).

Type 1 diabetes is also called type 1 diabetes mellitus or juvenile diabetes. It used to be called insulin-dependent diabetes.

How does it occur?

Type 1 diabetes happens when most or all of the insulin-producing cells in the pancreas have been injured or destroyed. Usually the exact cause is not known. Sometimes the diabetes may happen because of a viral infection or because the pancreas has been injured. Or it may result from an immune system disorder, which is when the body sees part of itself as foreign and attacks it--in this case, attacking the pancreas.

What are the symptoms?

Symptoms may start suddenly or they may develop over days to weeks. Symptoms vary widely from person to person. Common symptoms include:

  • urinating a lot
  • increased thirst
  • blurry vision
  • dry mouth
  • tiredness
  • increased hunger
  • unexpected weight loss
  • fruity-smelling breath.

If the diabetes is not diagnosed and treated, you could develop a life-threatening problem called ketoacidosis and possibly go into a coma and die.

How is it diagnosed?

Your healthcare provider will ask about your medical history and your symptoms and examine you. He or she will test the level of sugar in your blood. Three blood tests may be done to diagnose type 1 diabetes:

  • a fasting plasma glucose test (FPG), also called a fasting blood sugar (FBS)
  • hemoglobin A1C
  • random blood sugar test (RBS)

For the FPG test your blood is tested in the morning before you have eaten anything. If this test shows you have a fasting blood sugar of 126 milligrams per deciliter (mg/dL), or 7.0 millimoles per liter (mmol/L) or higher, you may have diabetes. Two FBG tests may be needed for a diagnosis.

The A1C is a blood test that can be used to check your average blood sugar over the past 2 to 3 months.

You may also have a blood sugar test at a random time. If your random blood sugar test is over 200 mg/dl (11.1 mmol/l), it very likely means you have diabetes.

When type 1 diabetes is suspected, you may have tests to check for antibodies to your insulin or the pancreas cells that make insulin. This may be done when it’s not clear whether you have type 1 or type 2 diabetes.

How is it treated?

Insulin is the main treatment for type 1 diabetes. The goal is to keep your blood sugar level in a normal range—that is, a range similar to the blood sugar levels of people who don’t have diabetes. Good blood sugar control involves using the correct insulin dose, eating a healthy diet, and getting regular exercise according to your healthcare provider’s recommendation. Controlling your blood sugar can prevent other serious problems caused by diabetes.

If your type 1 diabetes comes on suddenly, treatment usually begins in the emergency room. There you will receive insulin by IV (in your vein) until your blood sugar is back to a safe level. Before you go home you will be switched from receiving IV insulin to giving yourself shots of insulin. Your healthcare provider and clinic staff will to teach you about caring for yourself when you have type 1 diabetes. You will learn to manage your diabetes at home, at school, at work, and during sports and other activities.

If your type 1 diabetes comes on over several days or a couple of weeks, you may be diagnosed at your healthcare provider’s office. Your provider will get your blood sugar into a safe range right away and start to teach you how to care for your diabetes at home.

Insulin is the mainstay of your treatment. The other 2 important parts of diabetes management are diet and exercise. You will also need to keep a close watch of your blood sugar and have plan for managing your diabetes when you are ill.

  • Insulin therapy

    Different types of Insulin are available. They vary by how quickly they act to lower the blood sugar level and how long their effects last. Several kinds of insulin may be used to keep your blood sugar in the recommended range 24 hours a day.

    Commonly used types of insulin preparations and their names are:

    • rapid-acting insulin: Humalog, NovoLog, Apidra
    • short-acting insulin: Humulin R, Novolin R (regular)
    • intermediate-acting insulin: Humulin N, Novolin N (NPH)
    • long-acting insulin: Lantus/Levemir

    You and your healthcare provider will work together to find the types and doses of insulin that will keep your sugar levels in the recommended range. You will need to check your blood sugars at home, often 4 or more times a day to start. Based on when your sugar is high or low, your daily activities, and your work or school schedule, you will probably take a combination of insulins, usually a short-acting and a longer acting, to give you better control. Your provider may teach you how to mix different insulins in 1 syringe so it’s only 1 shot. There are also premixed insulin combinations that can be purchased with a prescription.

    Shots of insulin may be given under the skin of the thigh or abdomen 1 or more times a day. You will learn how to measure your insulin dose, clean your skin, and give yourself shots.

    The insulin pump is another way to give the body insulin. The pump is worn at the waist like a pager. A tube connected to the pump is inserted under the skin. As your blood sugar level changes, you can adjust the amount of insulin pumped through the tube. The insulin pump is usually not considered for use when you are first diagnosed with diabetes. It may be a possibility when you and your healthcare provider are confident that you have learned how to check your blood sugar, manage your insulin, and keep your blood sugar normal.

    A medicine called pramlintide (SYMLIN) is now available to help if you are taking mealtime insulin but it is not controlling your blood sugar sufficiently. It is injected just before 1 or more meals. Insulin doses may need to be adjusted because adding SYMLIN can cause very low blood sugar (hypoglycemia) up to 3 hours after a shot.

  • Diet

    The main goal of your diet plan is to maintain a normal blood sugar level. Your healthcare provider will give you guidelines about which foods you should eat and how many calories you should eat each day. The number of calories recommended for your daily diet is based on your weight and whether you need to lose or gain weight. You will also learn how to space your meals so you avoid going too long without food.

    Your provider may refer you to a dietitian for help with diet planning and meal management. A dietitian can help you design a meal and snack plan that fits your lifestyle. Your prescribed diet will include a lot of lean protein, complex carbohydrates (such as whole-grain pasta, breads, and cereals), and foods with high fiber. Your regular diet should not include sugar-rich food such as soft drinks, candy, and desserts.

  • Exercise

    Exercise is very important. A good activity plan can help control your blood sugar level. It also helps keep you healthy and avoid the complications of diabetes. Talk to your healthcare provider about making an activity plan for you.

  • Blood sugar tests

    Because you are using insulin to lower your blood sugar, you must carefully follow your healthcare provider's directions for checking your blood sugar. This will not only help you have good blood sugar control, but it will also help you prevent possibly life-threatening low levels of blood sugar (hypoglycemia).

    You will learn how to check your blood sugar at home. You will use a small machine called a blood glucose meter or glucometer to use to test your blood sugar. You will need some lancets (little blades or needles to prick your finger) and some test strips to put drops of blood on. Your provider will tell you when and how often you need to check your blood sugar. When you are first diagnosed with diabetes you will need to check your blood sugar often. After you have your diabetes under control, your provider will tell you how you can decrease your sugar checks.

    Keep a log of your blood sugar measurements. (Many glucose meters record and display a log of your recent sugar readings.) Your provider will check the log at your appointments to see how well your treatment is working. It is very important to take your blood sugar log or your glucose meter to every appointment. This is the basis for deciding whether your insulin regimen needs to be adjusted.

    A blood test called hemoglobin A1C (or just “A1C”) can show your average blood sugar control over the past 2 or 3 months. Your provider may do this test every 3 months to check your overall control of your blood sugar level. This is the best way to see if you are keeping your diabetes under control. However, it does not replace daily blood sugar measurements. Daily checks of your blood sugar show whether your treatment is working throughout the day.

  • Sick-day plan

    Diabetes is harder to control when you are sick. Blood sugar can get very high and become a medical emergency. Be prepared for illness with a sick-day plan. The plan will include checking your blood sugar more often and knowing how to adjust your insulin dose. Your healthcare provider will work with you to develop the plan.

Doctors are working to find new and more effective ways to treat diabetes. For example, surgical transplants of the whole pancreas or just a few cells from the pancreas are becoming more frequent. Transplants of just the pancreas cells that make insulin are called islet cell transplants. If your body does not reject the whole pancreas or the islet cells, this tissue may make enough insulin every day so you can stop taking insulin.

How long will the effects last?

Type 1 diabetes is a lifelong condition. Its symptoms increase or decrease depending on your response to the insulin, your new diet, and how well you are able to control your blood sugar level.

Taking good care of yourself to avoid complications is especially important with diabetes. Possible diabetic complications include heart disease, stroke, blindness, kidney failure, and nerve damage, especially to your feet and legs. Carefully controlling your blood sugar will prevent or delay these complications. You must also not smoke. Smoking is very harmful to the blood vessels. It speeds up and worsens the complications of diabetes.

Keeping your blood pressure and your cholesterol levels in the recommended ranges also helps prevent diabetes complications

How can I take care of myself?

Guidelines for eating

  • Read food labels. Choose foods with lean protein, complex carbohydrates, and lots of fiber. Choose foods low in saturated fats. Choose whole grain bread products and brown rice. Avoid sugar and foods made with white flour and white rice.
  • Spread your total calories out evenly through the day.
  • Time your meals to match your peak insulin effects and scheduled activities. Try to always have your meals, snacks, and exercise at the same time each day.
  • When you increase your activity, check your blood sugar more often. You may need to eat more or decrease the insulin you are taking. This will help keep you from having low blood sugar.
  • Learn how to make good food choices when you eat out.
  • Ask for diabetic meals when you travel (for example, in hotels and on planes). Order your meals ahead of time.

Guidelines for managing calories

  • Drink water or other calorie-free drinks when you feel an urge to eat between meals.
  • Limit the amount of alcohol you drink. It can cause low blood sugar. Over time it can also make nervous system problems caused by diabetes worse.
  • Buy only the foods in your diet plan.
  • Eat on a regular schedule.
  • Eat slowly and chew food thoroughly.

Guidelines for managing insulin

  • Follow your healthcare provider's instructions for giving yourself insulin.
  • Ask your healthcare provider about the causes and symptoms of low blood sugar and what to do when you have low blood sugar.
  • Know when and how to test your blood.
  • Follow your healthcare provider's instructions for adjusting your insulin dosage according to the results of your blood tests.
  • Carry some form of sugar at all times, so you can treat low blood sugar quickly.
  • Carry a protein snack, such as cheese and crackers or peanuts, to make sure you eat as often as you should.
  • Make sure your family members know what to do if your sugar is too high or too low.

Guidelines for seeing your healthcare provider

  • Follow your healthcare provider's recommendations for follow-up visits. Always take your blood sugar log to your appointments with you.
  • Eyes are affected by diabetes. You should have your eyes checked within 5 years of diagnosis if you are under 30 and right away if you are over 30. You will then need eye checkups at least every year. Women with diabetes who become pregnant should have their eyes checked each trimester because diabetic eye problems can worsen quickly during pregnancy. Excellent blood sugar control can reduce the risk of worsening diabetic eye disease.

Much of the daily care of your diabetes is up to you. Telling your provider early about changes in your health can keep your condition from getting worse. Having a plan for handling problems early may also prevent visits to the emergency room or hospital.

Problems you should watch for are:

  • chest pain or pressure that is new or getting worse
  • new feelings of numbness and tingling
  • speech problems
  • loss of vision
  • trouble thinking clearly
  • vomiting and diarrhea
  • being very thirsty and urinating a lot
  • fast breathing and fruity smelling breath
  • blood sugar below 70 mg/dL and not corrected by several rounds of eating or drinking 15 grams of carbohydrate
  • blood pressure that has a top (systolic) number greater than 180 mmHg or less than 90 mmHg, or a bottom (diastolic) number that is greater than 110 mmHg

These problems may be telling you that it's time to call your provider or 911, depending on how severe they are.

Other guidelines for managing diabetes and its complications

  • Learn how to care for your skin and feet. Check your feet every day. Wear comfortable, well-fitting shoes to help prevent foot injury. Break in new shoes gradually.
  • Exercise regularly according to your healthcare provider's advice. Exercise helps insulin do its job better. It also helps you to keep a normal blood pressure and a healthy heart. Wear well-fitting, supportive, and well-cushioned shoes when you exercise.
  • Ask your provider if you need to check your urine for ketones. Ketones are chemicals that can show that your sugar is too high. Your provider will tell you when and how to check for ketones. It is usually necessary only if you are starting to come down with an illness or if your sugars have been running too high.
  • Ask your provider if you should take a daily low dose of aspirin.
  • Carry a medical ID (such as a card or bracelet) that says you have diabetes, in case of an emergency.

Learn about diabetes and its complications so you can make the correct decisions to control your blood sugar levels. There is a lot to learn. Talk to your healthcare provider about how you can learn all you need to know. You can also check with the local American Diabetes Association chapter, your local hospital, or the health department about diabetes educators and dietitians who can help you or about classes in your area. It's good for your family to also learn about diabetes.

You can get diabetic cookbooks and more information about diabetes from:

The American Diabetes Association
Phone: 800-DIABETES (800-342-2383)
Web site:

How can I help prevent type 1 diabetes or its complications?

Type 1 diabetes cannot be prevented. However, many problems caused by diabetes can be avoided or lessened if you:

  • Follow the guidelines your healthcare provider gives you.
  • Keep a normal blood sugar level.
  • Learn how to inject insulin correctly.
  • Learn how to test your blood sugar.
  • Know when to adjust your medicine.
  • Eat a healthy diet.
  • Exercise regularly according to your provider’s recommendation.
  • Do not smoke. Smoking speeds up the damage to the heart and blood vessels.
  • Have other medical problems treated, especially high blood pressure and high cholesterol.
  • Keep your appointments with your provider.
  • Get your eyes checked as often as your provider recommends.
  • Call your provider right away if you are sick because it may get hard to control your blood sugar.
  • Ask your provider when you should call about high or low blood sugar so you can get help controlling your blood sugar.
  • Make an appointment to see your provider if you have any questions.
Developed by Phyllis G. Cooper, RN, MN, and RelayHealth.
Published by RelayHealth.
Last modified: 2011-08-12
Last reviewed: 2011-05-23
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
© 2011 RelayHealth and/or its affiliates. All rights reserved.
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