Diabetes mellitus refers to a group of diseases that affect how the body uses blood sugar (glucose). Glucose is an important source of energy for the cells that make up the muscles and tissues. It’s also the brain’s main source of fuel.

The main cause of diabetes varies by type. But no matter what type of diabetes you have, it can lead to excess sugar in the blood. Too much sugar in the blood can lead to serious health problems.

Chronic diabetes conditions include type 1 diabetes and type 2 diabetes. Potentially reversible diabetes conditions include prediabetes and gestational diabetes. Prediabetes happens when blood sugar levels are higher than normal. But the blood sugar levels aren’t high enough to be called diabetes. And prediabetes can lead to diabetes unless steps are taken to prevent it. Gestational diabetes happens during pregnancy. But it may go away after the baby is born.

Diabetes symptoms depend on how high your blood sugar is. Some people, especially if they have prediabetes, gestational diabetes or type 2 diabetes, may not have symptoms. In type 1 diabetes, symptoms tend to come on quickly and be more severe.

Some of the symptoms of type 1 diabetes and type 2 diabetes are:

Type 1 diabetes can start at any age. But it often starts during childhood or teen years. Type 2 diabetes, the more common type, can develop at any age. Type 2 diabetes is more common in people older than 40. But type 2 diabetes in children is increasing.

When to see a doctor

To understand diabetes, it’s important to understand how the body normally uses glucose.

How insulin works

Insulin is a hormone that comes from a gland behind and below the stomach (pancreas).

The role of glucose

Glucose — a sugar — is a source of energy for the cells that make up muscles and other tissues.

The exact cause of most types of diabetes is unknown. In all cases, sugar builds up in the bloodstream. This is because the pancreas doesn’t produce enough insulin. Both type 1 and type 2 diabetes may be caused by a combination of genetic or environmental factors. It is unclear what those factors may be.

Risk factors for diabetes depend on the type of diabetes. Family history may play a part in all types. Environmental factors and geography can add to the risk of type 1 diabetes.

Sometimes family members of people with type 1 diabetes are tested for the presence of diabetes immune system cells (autoantibodies). If you have these autoantibodies, you have an increased risk of developing type 1 diabetes. But not everyone who has these autoantibodies develops diabetes.

Race or ethnicity also may raise your risk of developing type 2 diabetes. Although it’s unclear why, certain people — including Black, Hispanic, American Indian and Asian American people — are at higher risk.

Prediabetes, type 2 diabetes and gestational diabetes are more common in people who are overweight or obese.

Long-term complications of diabetes develop gradually. The longer you have diabetes — and the less controlled your blood sugar — the higher the risk of complications. Eventually, diabetes complications may be disabling or even life-threatening. In fact, prediabetes can lead to type 2 diabetes. Possible complications include:

Complications of gestational diabetes

Most women who have gestational diabetes deliver healthy babies. However, untreated or uncontrolled blood sugar levels can cause problems for you and your baby.

Complications in your baby can be caused by gestational diabetes, including:

Complications in the mother also can be caused by gestational diabetes, including:

Type 1 diabetes can’t be prevented. But the healthy lifestyle choices that help treat prediabetes, type 2 diabetes and gestational diabetes can also help prevent them:

Sometimes drugs are an option. Oral diabetes drugs such as metformin (Glumetza, Fortamet, others) may lower the risk of type 2 diabetes. But healthy lifestyle choices are important. If you have prediabetes, have your blood sugar checked at least once a year to make sure you haven’t developed type 2 diabetes.

Type 1 diabetes symptoms often start suddenly and are often the reason for checking blood sugar levels. Because symptoms of other types of diabetes and prediabetes come on more gradually or may not be easy to see, the American Diabetes Association (ADA) has developed screening guidelines. The ADA recommends that the following people be screened for diabetes:

Tests for type 1 and type 2 diabetes and prediabetes

If your provider thinks you may have type 1 diabetes, they may test your urine to look for the presence of ketones. Ketones are a byproduct produced when muscle and fat are used for energy. Your provider will also probably run a test to see if you have the destructive immune system cells associated with type 1 diabetes called autoantibodies.

Your provider will likely see if you’re at high risk for gestational diabetes early in your pregnancy. If you’re at high risk, your provider may test for diabetes at your first prenatal visit. If you’re at average risk, you’ll probably be screened sometime during your second trimester.

Depending on what type of diabetes you have, blood sugar monitoring, insulin and oral drugs may be part of your treatment. Eating a healthy diet, staying at a healthy weight and getting regular physical activity also are important parts of managing diabetes.

Treatments for all types of diabetes

An important part of managing diabetes — as well as your overall health — is keeping a healthy weight through a healthy diet and exercise plan:

Treatments for type 1 and type 2 diabetes

Treatment for type 1 diabetes involves insulin injections or the use of an insulin pump, frequent blood sugar checks, and carbohydrate counting. For some people with type 1 diabetes, pancreas transplant or islet cell transplant may be an option.

Treatment of type 2 diabetes mostly involves lifestyle changes, monitoring of your blood sugar, along with oral diabetes drugs, insulin or both.

Monitoring your blood sugar

Depending on your treatment plan, you may check and record your blood sugar as many as four times a day or more often if you’re taking insulin. Careful blood sugar testing is the only way to make sure that your blood sugar level remains within your target range. People with type 2 diabetes who aren’t taking insulin generally check their blood sugar much less often.

People who receive insulin therapy also may choose to monitor their blood sugar levels with a continuous glucose monitor. Although this technology hasn’t yet completely replaced the glucose meter, it can lower the number of fingersticks necessary to check blood sugar and provide important information about trends in blood sugar levels.

Even with careful management, blood sugar levels can sometimes change unpredictably. With help from your diabetes treatment team, you’ll learn how your blood sugar level changes in response to food, physical activity, medications, illness, alcohol and stress. For women, you’ll learn how your blood sugar level changes in response to changes in hormone levels.

Besides daily blood sugar monitoring, your provider will likely recommend regular A1C testing to measure your average blood sugar level for the past 2 to 3 months.

Compared with repeated daily blood sugar tests, A1C testing shows better how well your diabetes treatment plan is working overall. A higher A1C level may signal the need for a change in your oral drugs, insulin regimen or meal plan.

Your target A1C goal may vary depending on your age and various other factors, such as other medical conditions you may have or your ability to feel when your blood sugar is low. However, for most people with diabetes, the American Diabetes Association recommends an A1C of below 7%. Ask your provider what your A1C target is.

Insulin

People with type 1 diabetes must use insulin to manage blood sugar to survive. Many people with type 2 diabetes or gestational diabetes also need insulin therapy.

Many types of insulin are available, including short-acting (regular insulin), rapid-acting insulin, long-acting insulin and intermediate options. Depending on your needs, your provider may prescribe a mixture of insulin types to use during the day and night.

Insulin can’t be taken orally to lower blood sugar because stomach enzymes interfere with insulin’s action. Insulin is often injected using a fine needle and syringe or an insulin pen — a device that looks like a large ink pen.

An insulin pump also may be an option. The pump is a device about the size of a small cellphone worn on the outside of your body. A tube connects the reservoir of insulin to a tube (catheter) that’s inserted under the skin of your abdomen.

A continuous glucose monitor, on the left, is a device that measures blood sugar every few minutes using a sensor inserted under the skin. An insulin pump, attached to the pocket, is a device that’s worn outside of the body with a tube that connects the reservoir of insulin to a catheter inserted under the skin of the abdomen. Insulin pumps are programmed to deliver specific amounts of insulin continuously and with food.

A tubeless pump that works wirelessly is also now available. You program an insulin pump to dispense specific amounts of insulin. It can be adjusted to give out more or less insulin depending on meals, activity level and blood sugar level.

A closed loop system is a device implanted in the body that links a continuous glucose monitor to an insulin pump. The monitor checks blood sugar levels regularly. The device automatically delivers the right amount of insulin when the monitor shows that it’s needed.

The Food and Drug Administration has approved several hybrid closed loop systems for type 1 diabetes. They are called “hybrid” because these systems require some input from the user. For example, you may have to tell the device how many carbohydrates are eaten, or confirm blood sugar levels from time to time.

A closed loop system that doesn’t need any user input isn’t available yet. But more of these systems currently are in clinical trials.

Oral or other drugs

Sometimes your provider may prescribe other oral or injected drugs as well. Some diabetes drugs help your pancreas to release more insulin. Others prevent the production and release of glucose from your liver, which means you need less insulin to move sugar into your cells.

Still others block the action of stomach or intestinal enzymes that break down carbohydrates, slowing their absorption, or make your tissues more sensitive to insulin. Metformin (Glumetza, Fortamet, others) is generally the first drug prescribed for type 2 diabetes.

Another class of medication called SGLT2 inhibitors may be used. They work by preventing the kidneys from reabsorbing filtered sugar into the blood. Instead, the sugar is eliminated in the urine.

Transplantation

In some people who have type 1 diabetes, a pancreas transplant may be an option. Islet transplants are being studied as well. With a successful pancreas transplant, you would no longer need insulin therapy.

But transplants aren’t always successful. And these procedures pose serious risks. You need a lifetime of immune-suppressing drugs to prevent organ rejection. These drugs can have serious side effects. Because of this, transplants are usually reserved for people whose diabetes can’t be controlled or those who also need a kidney transplant.

Bariatric surgery

Some people with type 2 diabetes who are obese and have a body mass index higher than 35 may be helped by some types of bariatric surgery. People who’ve had gastric bypass have seen major improvements in their blood sugar levels. But this procedure’s long-term risks and benefits for type 2 diabetes aren’t yet known.

Treatment for gestational diabetes

Controlling your blood sugar level is essential to keeping your baby healthy. It can also keep you from having complications during delivery. In addition to having a healthy diet and exercising regularly, your treatment plan for gestational diabetes may include monitoring your blood sugar. In some cases, you may also use insulin or oral drugs.

Your provider will monitor your blood sugar level during labor. If your blood sugar rises, your baby may release high levels of insulin. This can lead to low blood sugar right after birth.

Treatment for prediabetes

Treatment for prediabetes usually involves healthy lifestyle choices. These habits can help bring your blood sugar level back to normal. Or it could keep it from rising toward the levels seen in type 2 diabetes. Keeping a healthy weight through exercise and healthy eating can help. Exercising at least 150 minutes a week and losing about 7% of your body weight may prevent or delay type 2 diabetes.

Drugs — such as metformin, statins and high blood pressure medications — may be an option for some people with prediabetes and other conditions such as heart disease.

Signs of trouble in any type of diabetes

Many factors can affect your blood sugar. Problems may sometimes come up that need care right away.

High blood sugar

High blood sugar (hyperglycemia in diabetes) can occur for many reasons, including eating too much, being sick or not taking enough glucose-lowering medication. Check your blood sugar level as directed by your provider. And watch for symptoms of high blood sugar, including:

If you have hyperglycemia, you’ll need to adjust your meal plan, drugs or both.

Increased ketones in your urine

Diabetic ketoacidosis is a serious complication of diabetes. If your cells are starved for energy, your body may begin to break down fat. This makes toxic acids known as ketones, which can build up in the blood. Watch for the following symptoms:

You can check your urine for excess ketones with a ketones test kit that you can get without a prescription. If you have excess ketones in your urine, talk with your provider right away or seek emergency care. This condition is more common in people with type 1 diabetes.

Hyperglycemic hyperosmolar nonketotic syndrome

Hyperosmolar syndrome is caused by very high blood sugar that turns blood thick and syrupy.

Symptoms of this life-threatening condition include:

This condition is seen in people with type 2 diabetes. It often happens after an illness. Call your provider or seek medical care right away if you have symptoms of this condition.

Low blood sugar (hypoglycemia)

If your blood sugar level drops below your target range, it’s known as low blood sugar (diabetic hypoglycemia). If you’re taking drugs that lower your blood sugar, including insulin, your blood sugar level can drop for many reasons. These include skipping a meal and getting more physical activity than normal. Low blood sugar also occurs if you take too much insulin or too much of a glucose-lowering medication that causes the pancreas to hold insulin.

Check your blood sugar level regularly and watch for symptoms of low blood sugar, including:

Low blood sugar is best treated with carbohydrates that your body can absorb quickly, such as fruit juice or glucose tablets.

Diabetes is a serious disease. Following your diabetes treatment plan takes total commitment. Careful management of diabetes can lower your risk of serious or life-threatening complications.

Lifestyle recommendations for type 1 and type 2 diabetes

Also, if you have type 1 or type 2 diabetes:

Many substances have been shown to improve the body’s ability to process insulin in some studies. Other studies fail to find any benefit for blood sugar control or in lowering A1C levels. Because of the conflicting findings, there aren’t any alternative therapies that are currently recommended to help everyone to manage blood sugar.

If you decide to try any type of alternative therapy, don’t stop taking the drugs that your provider has prescribed. Be sure to discuss the use of any of these therapies with your provider. Make sure that they won’t cause bad reactions or interact with your current therapy.

Also, no treatments — alternative or conventional — can cure diabetes. If you’re using insulin therapy for diabetes, never stop using insulin unless directed to do so by your provider.

Living with diabetes can be difficult and frustrating. Sometimes, even when you’ve done everything right, your blood sugar levels may rise. But stick with your diabetes management plan and you’ll likely see a positive difference in your A1C when you visit your provider.

Good diabetes management can take a great deal of time and feel overwhelming. Some people find that it helps to talk to someone. Your provider can probably recommend a mental health professional for you to speak with. Or you may want to try a support group.

Sharing your frustrations and triumphs with people who understand what you’re going through can be very helpful. And you may find that others have great tips to share about diabetes management.

Your provider may know of a local support group. You can also call the American Diabetes Association at 800-DIABETES (800-342-2383) or the Juvenile Diabetes Research Foundation at 800-533-CURE (800-533-2873).

You’re likely to start by seeing your health care provider if you’re having diabetes symptoms. If your child is having diabetes symptoms, you might see your child’s health care provider. If blood sugar levels are very high, you’ll likely be sent to the emergency room.

If blood sugar levels aren’t high enough to put you or your child immediately at risk, you may be referred to a provider trained in diagnosing and treating diabetes (endocrinologist). Soon after diagnosis, you’ll also likely meet with a diabetes educator and a registered dietitian to get more information on managing your diabetes.

Here’s some information to help you get ready for your appointment and to know what to expect.

What you can do

Preparing a list of questions can help you make the most of your time with your provider. For diabetes, some questions to ask include:

What to expect from your doctor

Your provider is likely to ask you many questions, such as:

© 1998-2024 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved.

We Make Health Possible

As East Central Indiana’s population grows, we’re putting health care where people need it most. Besides Hancock Regional Hospital, ranked as one of the nation’s safest by the Lown Hospital Index, our network includes more than 30 other locations near your home or work.

Learn More about Hancock