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Type 1 diabetes

  • Alternative Names

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


    Some people will have no symptoms before they are diagnosed with diabetes.

    Others may notice these symptoms as the first signs of type 1 diabetes, or when the blood sugar is high:

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

    For others, warning symptoms that they are becoming very sick may be the first signs of type 1 diabetes, or 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, unable to keep down fluids
    • Stomach pain

    Low blood sugar (hypoglycemia) can develop quickly in people with diabetes who are taking insulin. Symptoms typically appear when the blood sugar level falls below 70 mg/dL. Watch for:

    • Headache
    • Hunger
    • Nervousness
    • Rapid heartbeat (palpitations)
    • Shaking
    • Sweating
    • Weakness

    Signs 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 on two occasions
    • Random (nonfasting) blood glucose level -- diabetes is suspected if it is higher than 200 mg/dL, and the patient has 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 -- this test has been used in the past to help patients monitor how well they are controlling their blood glucose levels. In 2010, the American Diabetes Association recommended that the test be used as another option for diagnosing diabetes and identifying pre-diabetes. Levels indicate:
      • Normal: Less than 5.7%
      • Pre-diabetes: Between 5.7% and 6.4%
      • Diabetes: 6.5% or higher

    Ketone testing is also used in type 1 diabetes. Ketones are produced by the breakdown of fat and muscle. They are harmful at high levels. The ketone test is done using a urine sample. Ketone testing is usually done at the following times:

    • 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 will help you and your doctor monitor your diabetes and prevent complications of diabetes:

    • Check the skin and bones on your feet and legs.
    • Check the sensation in your feet.
    • Have your blood pressure checked at least every year (blood pressure goal should be 130/80 mm/Hg or lower).
    • Have your glycosulated hemoglobin (HbA1c) checked 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 ophthalmologist at least once a year, or more often if you have signs of diabetic retinopathy.
    • See the dentist every 6 months for a thorough dental cleaning and exam. Make sure your dentist and hygienist know that you have diabetes.