Type 1 Diabetes

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Silvio Inzucchi, MD
Mark E. Molitch, MD

Additional Resources
Mayo Clinic
American Diabetes Association

What is type 1 diabetes?

Type 1 diabetes, sometimes called insulin-dependent diabetes and juvenile diabetes, can develop at any age but most often occurs in children, teens, and young adults. In type 1 diabetes, a person’s pancreas produces little or no insulin, so insulin treatment is needed for a lifetime.

The causes of type 1 diabetes are not fully known. In most cases, the body’s immune system attacks and destroys the part of the pancreas that produces insulin. Because type 1 is an autoimmune disease, people with other autoimmune, conditions, such as Hashimoto disease or primary adrenal insufficiency (Addison disease), are more likely to develop type 1 diabetes. 10–15% of people with type 1 diabetes have a family history of this disease.

What are the symptoms of type 1 diabetes?

Type 1 diabetes prevents the body's cells from functioning properly and leads to increased blood sugar levels. This can cause a variety of problems for the body, including increasing the risk for heart attack or stroke, creating kidney problems, contributing to vision issues, causing reproductive or erectile problems and preventing sores from healing.

Patients with type 1 diabetes are typically diagnosed based on their symptoms. The signs of juvenile diabetes include:

  • Increased thirst
  • Increased urination
  • Constant feelings of hunger
  • Weight loss
  • Blurred vision
  • Constantly feeling tired
  • A fruity smell on the breath

If you or your child are experiencing these symptoms you need to see a doctor right away. Waiting to get a diagnosis of juvenile diabetes or ignoring these juvenile diabetes signs can allow blood sugar to accumulate to dangerous, potentially fatal levels.

How is type 1 diabetes diagnosed and treated?

Your doctor will use blood tests to diagnose diabetes. A blood glucose level above 125 mg/dL after fasting overnight or above 200 mg/dL after eating may indicate diabetes. Your doctor may also take a medical history and order further blood tests to rule out type 2 diabetes.

People with type 1 diabetes must have daily injections of insulin to keep a normal level of glucose in the blood. Blood glucose is kept under the best control with three or more injections per day, or when insulin is delivered throughout the day with an insulin pump. A healthy diet, exercise, and regular monitoring of blood glucose levels are also important to manage diabetes.

How do you monitor blood sugar levels?

To monitor your blood glucose, you first stick your finger or forearm with a special lancet (a needle) to get a drop of blood, which you put on a chemically-treated paper strip. Then you insert the strip into a small computerized machine (blood glucose meter) that reads the blood glucose from the strip. Your blood glucose level shows up as a number on a screen. You can use these blood glucose readings to adjust the doses of insulin that you take every day.

Your doctor or diabetes educator will discuss the various types of available strips and meters and prescribe one for you. They will also talk with you about how often to check your glucose.

A newer technology called continuous glucose monitoring measures glucose levels every few minutes throughout the day and night. It uses a device called a sensor that is inserted under the skin. The sensor then transmits information about glucose levels to a small monitor (about the size of a cellphone). People on insulin pumps are most likely to use this system.

When should you see your doctor?

If you or your child have symptoms or a family history of diabetes, ask your doctor if testing is needed. Having diabetes requires daily care. All general physicians (family doctors, internists, primary care physicians) can diagnose and treat diabetes. Some people see an endocrinologist, a specialist in diabetes and other hormone-related conditions, for treatment.

Questions to ask your doctor

  • What can I (or my child) do to keep blood glucose level on target?
  • What should I (or my child) eat?
  • Which medicines do I (or my child) need?
  • What type of exercise is best for me (or my child)?
  • How often should I (or my child) check blood glucose levels?
  • Should I (or my child) see a diabetes educator?
  • Should I (or my child) see an endocrinologist?