Type 1 Diabetes Symptoms & Causes

Because our research informs our treatment, our diabetes team is known for our innovative treatments and science-driven approach. Children’s Hospital Boston is home to the world’s most extensive pediatric hospital research enterprise, and we partner with elite health care and biotech organizations around the globe. But as specialists in family-centered care, our physicians never forget that your child is precious, and not just a patient.

In dealing with your child’s diabetes, you probably want to know the basics about what diabetes is, and how type 1 diabetes differs from other forms of the disease.

What is diabetes?

Diabetes (diabetes mellitus) is a lifelong condition that occurs when the body doesn’t make enough insulin, or when the body doesn’t respond properly to the insulin it makes. There are many forms of diabetes mellitus, several of which have undergone name changes as the disease has become better understood.

  • type 1 diabetes: Formerly known as “juvenile” or “insulin-dependent” diabetes,type 1 diabetes is caused by the immune system’s failure to recognize the beta cells as belonging to the body, so it attacks and destroys them. This is why type 1 diabetes is considered an autoimmune disease. Children with type 1 diabetes must take insulin injections every day.
  • type 2 diabetes: Formerly known as “adult onset” or “non-insulin dependent” diabetes, type 2 diabetes typically occurs in people who are overweight, physically inactive and over age 40, although more and more children are developing type 2 diabetes, possibly because of childhood obesity. Some children need insulin; others can control their diabetes with healthful eating and exercise, or oral medicines (hypoglycemic agents).
  • MODY (maturity onset diabetes of youth): a form of diabetes that has been diagnosed before the age of 35 years in at least three generations of family members. Doctors have identified many specific genetic defects (mutations) in such families. Some patients who have MODY need insulin. Others can effectively manage their condition with diet and/or oral medicines.
  • secondary diabetes: This is a form of the disease in which the beta cells are destroyed, not by the body’s immune system, but by cystic fibrosis (“secondary to cystic fibrosis”), pancreatic surgery or another cause.

Note: diabetes insipidus is a very different condition from diabetes mellitus.

Is there more than one form of type 1 diabetes?

There are two forms of type 1 diabetes:

  • immune-mediated diabetes: an autoimmune disorder in which the body’s immune system destroys, or attempts to destroy, the cells in the pancreas that produce insulin. This is the most common form of type 1 diabetes, and it accounts for most cases.
  • idiopathic type 1: refers to rare forms of the disease with no known cause

What is insulin?

Insulin is the hormone that allows glucose to enter the cells of the body to provide fuel in the form of glucose. Without insulin, glucose builds up in the bloodstream, starving the body’s cells. Children with type 1 diabetes must take daily insulin injections and must regularly monitor their blood sugar levels.

  • Insulin is a protein hormone made by the beta cells of an area of the pancreas (an organ that lies behind the stomach).
  • Insulin is needed to help glucose (sugar) enter the cells of the body.
    • When glucose enters the cells, it can be used to produce energy, or it can be stored in the liver and muscles (as glycogen) for later use.
  • If the body doesn’t produce its own insulin, it must be injected so the body can function properly.
    • Insulin can’t be taken by mouth because the digestive system would destroy it.
  • Insulin for injection comes from several sources.
    • Human insulin is the kind most commonly used today to treat diabetes. It’s made in special bacteria (by genetic engineering) so that it’s identical to the insulin the human body produces

How and when should I give insulin to my child?

Your child’s diabetes team will help you decide what types of insulin your child should use, and when you should give it.

  • Your child’s nurse will teach you how to measure and inject the insulin.
  • Your team will also give you tips for:
    • the best time(s) in the day to give insulin—the timing of meals, as well as the pre-meal blood glucose level, may affect the time you should give the injection
    • storing and transporting your child’s insulin


Does having type 1 diabetes put my child at risk for other conditions?

Unfortunately, children who have diabetes are also at risk for other autoimmune conditions such as autoimmune thyroid diseaseceliac disease and, rarely, Addison’s disease.


What’s a healthful diet for kids with type 1 diabetes?

Proper meal-planning is very important if your child has diabetes, since the type and amount of food your child eats affects her blood sugar levels. If she eats too much, her blood sugar may go up too high. If she skips meals, her blood sugar may go too low. Good blood sugar control requires a balance of food, exercise and medication. Healthy meals include foods that contain the right amounts of carbohydrates, protein and fat.

Carbohydrates (“carbs”) are an important source of energy for kids, and they affect the body's blood sugar the most since the body turns carbohydrates into blood sugar. If your child eats too many foods with carbs, her blood sugar can go too high. About half the calories your child eats should come from carbs, and a certain amount of carbohydrates should be included with each meal and snack. Your child’s dietitian can help you decide how much carbohydrate your child needs each day.

Sugar is a carbohydrate. It doesn’t affect your child’s blood sugar any differently from other carbs. Your child can eat sweets and sugars if they’re counted as part of her daily carbohydrate intake. (Sweets don’t have many vitamins or minerals, so your child should eat them only in small amounts.)

Proteins and fats don’t affect the body’s blood sugar level as much as carbs do. But the amount of protein and fat in your child’s diet may need to be counted, since it’s important for her to eat them in appropriate amounts. Too much fat can increase your child’s risk for heart disease and may make it difficult for her to maintain a healthy weight. Your child’s dietitian can help you decide how much protein and fat your child needs.

How can I monitor my child’s diabetes day-to-day?

Checking your child’s blood glucose (sugar) levels every day will tell you if she’s maintaining a good balance of insulin, food and exercise.

  • Your child’s diabetes doctor or nurse educator will recommend the best goal or target range for your child’s blood glucose levels. If these levels are in the target range most of the time, this means that her diabetes is well controlled.
  • It’s important to measure your child’s blood glucose levels at certain times during the day. Your diabetes team will give you specific recommendations on when and how often you should check her levels.
  • You’ll use a blood glucose meter to measure the amount of glucose in a drop of your child’s blood, in order to check if her blood glucose levels are within her goal range. Your diabetes team member will recommend a meter for your child and teach you how to use it. These are small and simple to use—and involve just a tiny pinprick.

What about emergencies?

We’ll teach you how to cope with emergency situations in which you may need to administer extra insulin (“booster shot”) or check your child’s urine for ketones (toxins released by the body’s breakdown of fat caused by a lack of sugar to the cells of the body. We’ll help you recognize signs that your child may need emergency attention.

What about exercise for kids with type 1 diabetes?

Exercise is always important for growing children, regardless of diabetes. When exercise is combined with the right amounts of food and insulin, it will help keep your child healthy, and her blood glucose levels will remain in balance.

In general, exercise tends to lower blood glucose levels.

  • When your child exercises, her muscles use glucose at an increased rate to provide energy.
  • Exercise increases the body’s sensitivity to insulin.
    • The insulin has a greater effect on lowering blood glucose levels when a child is exercising, and even for some time after the exercise is over.

To avoid low blood glucose when exercising:

  • Plan vigorous activities for roughly the same times each day.

  • Plan activities to follow meals and snacks.

  • Check your child’s blood glucose level before and after exercise.

  • Add an extra snack before exercise.

  • Plan activities and snacks according to when insulin starts to work, when its peak effect is reach and how long it works to lower blood glucose levels.

Your diabetes team will help you figure out how insulin works in your child; what types of snacks are most helpful before exercise; how to check your child’s glucose; and any other questions you may have—we’re here to help.

What are the dangers of not treating type 1 diabetes?

Uncontrolled type 1 diabetes can be dangerous. It can lead to serious, even life-threatening, problems such as:

  • kidney damage (nephropathy)
  • diabetic retinopathy
  • poor circulation (especially of the feet)

What are some complications associated with diabetes?

People who have diabetes are also at risk for other autoimmune conditions such as autoimmune thyroid disease, celiac disease and, rarely, Addison’s disease.                                                     

Although type 1 diabetes can cause many different problems, there are several key complications that if uncontrolled, can cause emergencies.

  • hypoglycemia (low blood sugar, “insulin reaction”):
    • occurs when blood sugar drops too low—so the body doesn’t have the source of energy it needs to function properly
    • can result from:
      • too high an insulin dose
      • a missed meal or snack
      • more physical activity than usual
      • sickness with vomiting and/or diarrhea
    • if unchecked, can result in a low blood glucose medical emergency with loss of consciousness or seizure
      • treated by injecting the hormone glucagon
    • common signs and symptoms include shakiness, sweating, weakness, blurry vision, rapid heartbeat
    • If your child has signs or symptoms of hypoglycemia, measure her blood glucose level (if possible) and give her a fast-acting carbohydrate, such as fruit juice, hard candy or raisins.
  • hyperglycemia (high blood sugar):
    • occurs when blood sugar is too high
    • can be a sign that diabetes is not well controlled
    • caused by build-up of glucose in the bloodstream; possible causes:
      • not enough insulin—glucose can’t enter the body’s cells
      • too much food, wrong kinds of food
      • less physical activity than recommended
      • sickness
    • symptoms can resemble those of diabetes—excessive urination, bedwetting, weight loss, thirst, yeast infections, nausea and vomiting
    • If your child has signs or symptoms of hyperglycemia
      • measure her blood glucose level

      • check her urine for ketones

      • check with your diabetes team to see if you should administer a “booster shot” of extra insulin

    • If your child has signs or symptoms of hyperglycemia, PLUS a rapid heartbeat and deep, rapid breathing, call your doctor immediately, since she may be in the medical emergency called diabetic ketoacidosis.
  • diabetic ketoacidosis (diabetic coma):
    • loss of consciousness due to untreated or under-treated diabetes
      • lack of sugar to the cells of the body cause the body to break down fats, releasing toxins (ketones) into the bloodstream faster than the kidneys can get rid of them
    • Diabetic ketoacidosis is a serious condition that requires immediate medical attention; children become very sick; call your doctor if your child has ketones in her blood.


Insulin, food and exercise: How do we find the right balance?

Many factors can affect your child’s blood sugar level, including:

  • exercise
  • some foods
  • some medications (non-diabetic)
  • illness, fever

The key to maintaining your child’s blood sugar in a normal range is to balance your child’s insulin dosage, type and amount of food intake and level of exercise. Your diabetes team will help you determine a healthful regimen for your child that balances these key elements.

How do we cope with traveling and vacationing?

Traveling with a child who has diabetes requires some advance planning—but it is doable, and your child’s condition doesn’t have to slow up the family’s plans. Joseph Wolfsdorf, MD, associate chief of Children’s Division of Endocrinology, has written a helpful article called Traveling with Diabetes. Wolfsdorf’s article offers tips for packing, airline travel, spending time outdoors, dining out, transporting insulin, wearing an ID bracelet, packing an emergency kit and lots more.

Your diabetes team will give you a great deal of helpful information about helping your child manage other kinds of stays outside your home when you’re not around—such as sleepovers, school, day care and summer camp (including diabetes camp programs). Here, too, some planning and communication smooth the way.

Will my child be OK?

With proper attention to maintaining the balance among your child’s insulin, food and exercise, she should not only be OK—she should be able to maintain good general health. But untreated diabetes can be dangerous, and can lead to damage to nerves, blood vessels, heart, eyes, kidneys and circulation.