Type 1 Diabetes Mellitus, Diagnosis, Adult

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Type 1 Diabetes Mellitus, Diagnosis, Adult

Type 1 Diabetes Mellitus, Diagnosis, Adult

Body outline showing some digestive organs with a close-up of the pancreas.

Type 1 diabetes mellitus, or type 1 diabetes, is a long-term (chronic) disease. It happens when the cells in the pancreas that make a hormone called insulin are destroyed.

Normally, insulin lets blood sugar (glucose) enter cells in your body. This gives you energy. If you have type 1 diabetes, glucose cannot get into cells. It builds up in the blood instead. This causes high blood glucose (hyperglycemia).

There is no cure for type 1 diabetes. Treatment can help you manage your condition.

What are the causes?

The exact cause of type 1 diabetes is not known.

What increases the risk?

You may be more likely to have type 1 diabetes if a family member has it as well. You may also be more at risk if:
  • You have a gene for type 1 diabetes that was passed down to you from a parent (inherited).
  • You have an autoimmune disorder. This means that your body's disease-fighting system (immune system) attacks your body.
  • You have been exposed to certain viruses.
  • You live in an area with cold weather.

What are the signs or symptoms?

Symptoms may begin slowly over days or weeks. They may also start all of a sudden. Symptoms may include:
  • Increased thirst or hunger.
  • Needing to pee (urinate) more often or peeing more at night.
  • Sudden weight changes that you cannot explain.
  • Tiredness (fatigue) or weakness.
  • Vision changes. These may include blurry vision.

How is this diagnosed?

A person having a blood sample taken from the arm.

Type 1 diabetes is diagnosed based on your symptoms, your medical history, a physical exam, and your blood glucose level. Your blood glucose may be checked with:
  • A fasting blood glucose (FBG) test. You will not be allowed to eat (you will fast) for 8 hours or more before a blood sample is taken.
  • A random blood glucose test. This test checks your blood glucose at any time of day no matter when you last ate.
  • A hemoglobin A1C (A1C) blood test. This shows what your blood glucose levels have been over the last 2–3 months.

You may be diagnosed with type 1 diabetes if:
  • Your FBG level is 126 mg/dL (7 mmol/L) or higher.
  • Your random blood glucose level is 200 mg/dL (11.1 mmol/L) or higher.
  • Your A1C level is 6.5% or higher.

These blood tests may be done more than once. You may also need other blood tests.

How is this treated?

You may work with an expert called an endocrinologist to find ways to manage your diabetes. You should also follow instructions from your health care provider. You may need to:
  • Take insulin every day. This helps to keep your blood glucose levels in the right range.
  • Take medicines to help prevent problems from diabetes. You may need to take:
    • Aspirin.
    • Medicine to lower your cholesterol.
    • Medicine to control your blood pressure.
  • Check your blood glucose as often as told.
  • Make diet and lifestyle changes. You may be told to:
    • Follow a nutrition plan that has been made just for you by a dietitian.
    • Get regular exercise.
    • Find ways to manage stress.

Your provider will set treatment goals that are right for you. These goals will be based on your age, other conditions you have, and how you respond to treatment. In general, your A1C level should be less than 7% and your blood glucose levels should be:
  • 80–130 mg/dL (4.4–7.2 mmol/L) before meals (preprandial).
  • Below 180 mg/dL (10 mmol/L) after meals (postprandial).

Follow these instructions at home:

Questions to ask your health care provider

You may want to ask your provider:
  • Do I need to meet with a certified diabetes care and education specialist?
  • Should I join a support group for people with diabetes?
  • What equipment will I need to manage my diabetes at home?
  • What diabetes medicines should I take, and when?
  • How often should I check my blood glucose?
  • What number should I call if I have questions?
  • When is my next appointment?

General instructions

  • Take over-the-counter and prescription medicines only as told by your provider.
  • Keep all follow-up visits. You will need regular blood tests to make sure the treatments are working. Your provider may adjust your medicines based on your test results.

Where to find more information

Contact a health care provider if:

  • Your blood glucose level is higher than 240 mg/dL (13.3 mmol/L) for 2 days in a row.
  • You have been sick or have had a fever for 2 days or more, and you are not getting better.
  • For more than 6 hours, you:
    • Cannot eat or drink.
    • Have nausea and vomiting.
    • Have diarrhea.

Get help right away if:

  • Your blood glucose is less than 54 mg/dL (3 mmol/L).
  • You become confused, or you have trouble thinking clearly.
  • You have trouble breathing.

These symptoms may be an emergency. Get help right away. Call 911.
  • Do not wait to see if the symptoms will go away.
  • Do not drive yourself to the hospital.

This information is not intended to replace advice given to you by your health care provider. Make sure you discuss any questions you have with your health care provider.