Type 1 Diabetes Mellitus, Diagnosis, Adult

Type 1 diabetes (type 1 diabetes mellitus) is a long-term, or chronic, disease. It occurs when the cells in the pancreas (beta cells) that make a hormone called insulin are destroyed. Normally, insulin allows blood sugar, also called glucose, to enter cells in the body. The cells use glucose for energy. Lack of insulin causes excess glucose to build up in the blood instead of going into cells. As a result, high blood glucose, or hyperglycemia, develops.

There is currently no cure for type 1 diabetes, but it can be managed with insulin therapy and lifestyle changes.

What are the causes?

The exact cause of type 1 diabetes is not known.

What increases the risk?

You may be more likely to develop this condition if you have a family member who has type 1 diabetes. Other factors may also make you more likely to develop type 1 diabetes, such as:

Having a gene for type 1 diabetes that is passed from parent to child (inherited).
Having autoimmune disorders. These are conditions in which the body's disease-fighting system (immunesystem) attacks itself.
Being exposed to certain viruses.
Living in an area with cold weather conditions.

What are the signs or symptoms?

Symptoms may develop slowly over days or weeks, or they may develop suddenly. Symptoms may include:

Increased thirst or hunger.
Increased urination or increased urination during the night.
Sudden or unexplained weight changes.
Tiredness (fatigue) or weakness.
Vision changes, such as blurry vision.

How is this diagnosed?

This condition is diagnosed based on your symptoms, your medical history, a physical exam, and your blood glucose level. Your blood glucose may be checked with one or more of the following blood tests:

A fasting blood glucose (FBG) test. You will not be allowed to eat (you will fast) for 8 hours or longer before a blood sample is taken.
A random blood glucose test. This checks blood glucose at any time of day no matter when you ate.
An A1C (hemoglobin A1C) blood test. This gives information about blood glucose control 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 hemoglobin A1C level is 6.5% or higher.

These blood tests may be repeated to confirm your diagnosis.

How is this treated?

This condition may be managed by a specialist called an endocrinologist. You can help manage your type 1 diabetes by following instructions from your health care provider about:

Taking insulin daily. This helps to keep your blood glucose levels in the healthy range.
Taking medicines to help prevent complications from diabetes. These may include:
- Aspirin.
- Medicine to lower cholesterol.
- Medicine to control blood pressure.
Checking your blood glucose as often as told.
Making diet and lifestyle changes. These may include:
- Following an individualized nutrition plan that is developed by a registered dietitian.
- Getting regular exercise.
- Finding ways to manage stress.

Your health care provider will set individualized treatment goals for you. Your goals will be based on your age, other medical conditions you have, and how you respond to diabetes treatment. In general, the goal of treatment is to maintain the following blood glucose levels:

Before meals (preprandial): 80–130 mg/dL (4.4–7.2 mmol/L).
After meals (postprandial): below 180 mg/dL (10 mmol/L).
Hemoglobin A1C level: less than 7%.

Follow these instructions at home:

Questions to ask your health care provider

Consider asking the following questions:

Do I need to meet with a certified diabetes care and education specialist?
Should I consider joining 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 health care provider.
Keep all follow-up visits as told by your health care provider. This is important.

Where to find more information

American Diabetes Association (ADA): diabetes.org
Association of Diabetes Care and Education Specialists (ADCES): diabeteseducator.org
International Diabetes Federation (IDF): idf.org

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.
You have any of the following problems for more than 6 hours:
- You cannot eat or drink.
- You have nausea and vomiting.
- You have diarrhea.

Get help right away if:

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

These symptoms may represent a serious problem that is an emergency. Do not wait to see if the symptoms will go away. Get medical help right away. Call your local emergency services (911 in the U.S.). Do not drive yourself to the hospital.

Summary

Type 1 diabetes (type 1 diabetes mellitus) is a long-term, or chronic, disease. It occurs when the cells in the pancreas (beta cells) that make a hormone called insulin are destroyed. There is currently no cure for type 1 diabetes.
The exact cause of type 1 diabetes is not known.
This condition is treated by taking insulin and other medicines to help prevent complications from diabetes. Diet and lifestyle changes are also part of treatment.
Your health care provider will set individualized treatment goals for you. Your goals will be based on your age, other medical conditions you have, and how you respond to diabetes treatment.

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.