Conditions & Treatments

Type 1 Diabetes

Type 1 diabetes may also be known by a variety of other names, including the following: insulin-dependent diabetes mellitus (IDDM), juvenile diabetes, brittle diabetes, and sugar diabetes.

Type 1 Diabetes

What is type 1 diabetes?

Type 1 diabetes may also be known by a variety of other names, including the following:

  • Insulin-dependent diabetes mellitus (IDDM)

  • Juvenile diabetes

  • Brittle diabetes

  • Sugar diabetes

There are two forms of type 1 diabetes:

  • Idiopathic type 1 diabetes. This refers to rare forms of the disease with no known cause.

  • 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.

Immune-mediated diabetes is the most common form of type 1 diabetes, and the one generally referred to as type 1 diabetes. The information on this page refers to this form of type 1 diabetes.

Type 1 diabetes accounts for 5 to 10 percent of all diagnosed cases of diabetes in the U.S. Type 1 diabetes usually develops in children or young adults, but can start at any age.

What causes type 1 diabetes?

The cause of type 1 diabetes is unknown, but it is believed that genetic and environmental factors (possibly viruses) may be involved. The body's immune system attacks and destroys the insulin producing cells in the pancreas. Insulin allows glucose to enter the cells of the body to provide energy.

When glucose cannot enter the cells, it builds up in the blood, depriving the cells of nutrition. People with type 1 diabetes must take daily insulin injections and regularly monitor their blood sugar levels.

What are the symptoms of type 1 diabetes?

Type 1 diabetes often appears suddenly. The following are the most common symptoms of type 1 diabetes. However, each individual may experience symptoms differently. Symptoms may include:

  • High levels of sugar in the blood when tested

  • High levels of sugar in the urine when tested

  • Unusual thirst

  • Frequent urination

  • Extreme hunger 

  • Unexplained weight loss

  • Blurred vision

  • Nausea, vomiting, and abdominal pain

  • Extreme weakness and fatigue

  • Irritability and mood changes

  • Fruity breath and rapid breathing

In children, symptoms may be similar to those of having the flu.

The symptoms of type 1 diabetes may resemble other conditions or medical problems. Always consult your doctor for a diagnosis.

What can be expected with type 1 diabetes?

Type 1 diabetes may cause the following:

  • Hypoglycemia (low blood sugar, sometimes called an insulin reaction, occurs when blood sugar drops below 70 mg/dl)

  • Hyperglycemia (high blood sugar, occurs when blood sugar is too high, and can be a sign that diabetes is not well-controlled)

  • Ketoacidosis (a form of severe dehydration due to untreated or undertreated diabetes, which can result in loss of consciousness or brain damage)

Long-term complications that may result from uncontrolled type 1 diabetes include:

  • Heart disease

  • Kidney disease

  • Eye problems

  • Neuropathy (nerve problems)

  • Foot problems

Treatment for type 1 diabetes

Specific treatment for type 1 diabetes will be determined by your doctor based on:

  • Your age, overall health, and medical history

  • Extent of the disease

  • Your tolerance for specific medications, procedures, or therapies

  • Expectations for the course of the disease

  • Your opinion or preference

People with type 1 diabetes must have daily injections of insulin to keep their blood sugar level within normal ranges. Other parts of the treatment protocol may include:

  • Appropriate diet (to manage blood sugar levels)

  • Exercise (to lower and help the body use blood sugar)

  • Careful self-monitoring of blood sugar levels several times a day, as directed by your doctor

  • Careful self-monitoring of ketone levels in the urine several times a day, as directed by your doctor

  • Regular monitoring of the hemoglobin A1c (HbA1c) levels. This test shows the average amount of sugar in the blood over the last three months. The result will indicate if the blood sugar level is under control; HbA1c under 7 percent is optimal, though a person's HbA1c level may vary by age. The frequency of HbA1c testing will be determined by your doctor. It is recommended that testing occur at least twice a year if the blood sugar levels have been in the target range and stable, and more frequently if the blood sugar level is unstable.

Advances in diabetes research have led to improved methods of managing diabetes and treating its complications. However, scientists continue to explore the causes of diabetes and ways to prevent and treat the disorder. Other methods of administering insulin through inhalers and pills are currently being studied. Scientists are investigating gene involvement in type 1 and type 2 diabetes, and some genetic markers for type 1 diabetes have been identified. Pancreas and islet cell transplants remain experimental.

Treatment Programs


Massachusetts General Hospital understands that a variety of factors influence patients' health care decisions. That's just one reason why we're dedicated to ensuring patients understand their diagnosis and treatment options. Because a single option might not serve all patients, we offer a wide range of coordinated treatments and related services across the hospital. Patients should consult with their primary care doctor or other qualified health care provider for medical advice and diagnosis information.

Select a treatment program for more information:



Digestive Healthcare Center

  • Weight Center
    The Massachusetts General Hospital Weight Center is a fully integrated center within the Digestive Healthcare Center that supports the spectrum of needs for people of all ages seeking help with obesity and weight loss.
Imaging

  • Pediatric Imaging
    The Pediatric Imaging Program at Massachusetts General Hospital Imaging specializes in ensuring the safety and comfort of child patients while providing the latest technology and the expertise of specialized pediatric radiologists.
MassGeneral Hospital for Children

  • Psychology Assessment Center
    The pediatric neuropsychology specialists at Massachusetts General Hospital’s Psychology Assessment Center provide neuropsychological assessments to aid in the diagnosis and treatment of neurological, medical, genetic and developmental disorders.
  • Pediatric Endocrine Program and Diabetes Center
    The Pediatric Endocrinology Program and Diabetes Center at MassGeneral Hospital for Children is an international referral center for the management of pediatric diabetes and endocrine disorders in children and adolescents.
Transplant Center

  • Transplant Psychiatry Program
    The Transplant Psychiatry Program in the Massachusetts General Hospital Transplant Center is an important part of the comprehensive and life-long care provided to transplant patients and donors.
  • Transplant Infectious Disease Program
    The Transplant Infectious Disease Program, part of the Massachusetts General Hospital Transplant Center, is a part of the life-long care provided to organ, bone marrow and stem cell transplant recipients and others with increased risk for infections.
Diabetes Unit

  • Diabetes Eye Screening Programs
    Learn more about Diabetes Eye Screening Programs at Chelsea HealthCare Center Revere HealthCare Center.
  • Diabetes Self-Management Education and Support Program
    The Diabetes Self Management Education and Support (DSME/S) Program is an outpatient program designed for adults, children, and seniors with Type 1 or Type 2 Diabetes.
  • Diabetes Clinical Center
    The Mass General Diabetes Clinical Center is one of the oldest outpatient centers in the country dedicated to the comprehensive treatment of persons with diabetes, pre-diabetes, and associated disorders.
General and Gastrointestinal Surgery

  • Bariatric and Metabolic Surgery Program
    The Bariatric and Metabolic Surgery Program at Massachusetts General Hospital offers a full spectrum of safe and effective surgical procedures for obesity, weight disorders and metabolic disease.

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