Diabetes

What is Diabetes?

Diabetes is a life-long disease marked by high levels of sugar in the blood.

Alternative names

Diabetes can be caused by too little insulin (a hormone produced by the pancreas to control blood sugar), resistance to insulin, or both.

To understand diabetes, it is important to first understand the normal process of food metabolism. Several things happen when food is digested:

• A sugar called glucose enters the bloodstream. Glucose is a source of fuel for the body.
• An organ called the pancreas makes insulin. The role of insulin is to move glucose from the bloodstream into muscle, fat, and liver cells, where it can be used as fuel.

People with diabetes have high blood sugar. This is because their pancreas does not make enough insulin or their muscle, fat, and liver cells do not respond to insulin normally, or both.

There are three major types of diabetes:

• Type 1 diabetes is usually diagnosed in childhood. The body makes little or no insulin, and daily injections of insulin are needed to sustain life.
• Type 2 diabetes is far more common than type 1 and makes up most of all cases of diabetes. It usually occurs in adulthood. The pancreas does not make enough insulin to keep blood glucose levels normal, often because the body does not respond well to the insulin. Many people with type 2 diabetes do not know they have it, although it is a serious condition. Type 2 diabetes is becoming more common due to the growing number of older Americans, increasing obesity, and failure to exercise.
• Gestational diabetes is high blood glucose that develops at any time during pregnancy in a woman who does not have diabetes.

Diabetes affects more than 20 million Americans. About 54 million Americans have prediabetes. There are many risk factors for diabetes, including:

• A parent, brother, or sister with diabetes
• Obesity
• Age greater than 45 years
• Some ethnic groups (particularly African Americans, Native Americans, Asians, Pacific Islanders, and Hispanic Americans)
• Gestational diabetes or delivering a baby weighing more than 9 pounds
• High blood pressure
• High blood levels of triglycerides (a type of fat molecule)
• High blood cholesterol level
• Not getting enough exercise

The American Diabetes Association recommends that all adults over age 45 be screened for diabetes at least every 3 years. A person at high risk should be screened more often.

Causes

Diabetes can be caused by too little insulin (a hormone produced by the pancreas to control blood sugar), resistance to insulin, or both.

To understand diabetes, it is important to first understand the normal process of food metabolism. Several things happen when food is digested:

• A sugar called glucose enters the bloodstream. Glucose is a source of fuel for the body.
• An organ called the pancreas makes insulin. The role of insulin is to move glucose from the bloodstream into muscle, fat, and liver cells, where it can be used as fuel.

People with diabetes have high blood sugar. This is because their pancreas does not make enough insulin or their muscle, fat, and liver cells do not respond to insulin normally, or both.

There are three major types of diabetes:

• is usually diagnosed in childhood. The body makes little or no insulin, and daily injections of insulin are needed to sustain life.
• Type-2-Diabetes is far more common than type 1 and makes up most of all cases of diabetes. It usually occurs in adulthood. The pancreas does not make enough insulin to keep blood glucose levels normal, often because the body does not respond well to the insulin. Many people with type 2 diabetes do not know they have it, although it is a serious condition. Type 2 diabetes is becoming more common due to the growing number of older Americans, increasing obesity, and failure to exercise.
• Gestational-Diabetes is high blood glucose that develops at any time during pregnancy in a woman who does not have diabetes.

Diabetes affects more than 20 million Americans. About 54 million Americans have prediabetes. There are many risk factors for diabetes, including:

• A parent, brother, or sister with diabetes
• Obesity
• Age greater than 45 years
• Some ethnic groups (particularly African Americans, Native Americans, Asians, Pacific Islanders, and Hispanic Americans)
• Gestational diabetes or delivering a baby weighing more than 9 pounds
• High blood pressure
• High blood levels of triglycerides (a type of fat molecule)
• High blood cholesterol level
• Not getting enough exercise

The American Diabetes Association recommends that all adults over age 45 be screened for diabetes at least every 3 years. A person at high risk should be screened more often.

Symptoms & Signs

High blood levels of glucose can cause several problems, including frequent urination, excessive thirst, hunger, fatigue, weight loss, and blurry vision. However, because type 2 diabetes develops slowly, some people with high blood sugar experience no symptoms at all.

Symptoms of type 1 diabetes:

• Increased thirst
• Increased urination
• Weight loss in spite of increased appetite
• Fatigue
• Nausea
• Vomiting

Patients with type 1 diabetes usually develop symptoms over a short period of time, and the condition is often diagnosed in an emergency setting.

Symptoms of type 2 diabetes:

• Increased thirst
• Increased urination
• Increased appetite
• Fatigue
• Blurred vision
• Slow-healing infections
• Impotence in men

Exams and Tests

A urine analysis may be used to look for glucose and ketones from the breakdown of fat. However, a urine test alone does not diagnose diabetes. The following blood glucose tests are used to diagnose diabetes:

• Fasting blood glucose level -- diabetes is diagnosed if higher than 126 mg/dL on two occasions. Levels between 100 and 126 mg/dl are referred to as impaired fasting glucose or pre-diabetes. These levels are considered to be risk factors for type 2 diabetes and its complications.
• Random (non-fasting) blood glucose level -- diabetes is suspected if higher than 200 mg/dL and accompanied by the classic symptoms of increased thirst, urination, and fatigue. (This test must be confirmed with a fasting blood glucose test.)
• Oral glucose tolerance test -- diabetes is diagnosed if glucose level is higher than 200 mg/dL after 2 hours (This test is used more for type 2 diabetes.)

You should also ask your doctor how often to you need your hemoglobin A1c (HbA1c) level checked. The HbA1c is a measure of average blood glucose during the previous 2 to 3 months. It is a very helpful way to determine how well treatment is working.

Ketone testing is another test that is used in type 1 diabetes. Ketones are produced by the breakdown of fat and muscle, and they are harmful at high levels. The ketone test is done using a urine sample. High levels of blood ketones may result in a serious condition called ketoacidosis. Ketone testing is usually done at the following times:

• When the blood sugar is higher than 240 mg/dL
• During acute illness (for example, pneumonia, heart attack, or stroke)
• When nausea or vomiting occur
• During pregnancy

Treatments

There is no cure for diabetes. Treatment involves medicines, diet, and exercise to control blood sugar and prevent symptoms and complications.

LEARN THESE SKILLS

Basic diabetes management skills will help prevent the need for emergency care. These skills include:

• How to recognize and treat low blood sugar (hypoglycemia) and high blood sugar (hyperglycemia)
• What to eat and when
• How to take insulin or oral medication
• How to test and record blood glucose
• How to test urine for ketones (type 1 diabetes only)
• How to adjust insulin or food intake when changing exercise and eating habits
• How to handle sick days
• Where to buy diabetes supplies and how to store them

After you learn the basics of diabetes care, learn how the disease can cause long-term health problems and the best ways to prevent these problems. People with diabetes need to review and update their knowledge, because new research and improved ways to treat diabetes are constantly being developed.

SELF-TESTING

If you have diabetes, your doctor may tell you to regularly check your blood sugar levels at home. There are a number of devices available, and they use only a drop of blood. Self-monitoring tells you how well diet, medication, and exercise are working together to control your diabetes and can help your doctor prevent complications.

The American Diabetes Association recommends that premeal blood sugar levels fall in the range of 80 to 120 mg/dL and bedtime blood levels fall in the range of 100 to 140 mg/dL. Your doctor may adjust this depending on your circumstances.

WHAT TO EAT

You should work closely with your health care provider to learn how much fat, protein, and carbohydrates you need in your diet. A registered dietician can be very helpful in planning dietary needs.

People with type 1 diabetes should eat at about the same times each day and try to be consistent with the types of food they choose. This helps to prevent blood sugars from becoming extremely high or low.

Persons with type 2 diabetes should follow a well-balanced and low-fat diet.

HOW TO TAKE MEDICATION

Medications to treat diabetes include insulin and glucose-lowering pills called oral hypoglycemic drugs.

Persons with type 1 diabetes cannot make their own insulin, so daily insulin injections are needed. Insulin does not come in pill form. Injections that are generally needed one to four times per day. Some people use an insulin pump, which is worn at all times and delivers a steady flow of insulin throughout the day. Other people may use a new type of inhaled insulin.

Insulin preparations differ in how quickly they start to work and how long they remain active. Sometimes different types of insulin are mixed together in a single injection. The types of insulin to use, the doses needed, and the number of daily injections are chosen by a health care professional trained to provide diabetes care.

People who need insulin are taught to give themselves injections by their health care providers or diabetes educators.

Unlike type 1 diabetes, type 2 diabetes may respond to treatment with exercise, diet, and medicines taken by mouth. There are several types of medicines used to lower blood glucose in type 2 diabetes. They fall into one of three groups:

1. Medications called oral sulfonylureas that increase insulin production by the pancreas.
2. Medications called thiazolidinediones that help increase the cell's sensitivity (responsiveness) to insulin.
3. Medications that delay absorption of glucose from the gut. These include acarbose and miglitol.

There are some injectable medicines used to lower blood sugar. They include exenatide and pramlintide.

Most persons with type 2 diabetes will need more than one medication for good blood sugar control within 3 years of starting their first medication. Different groups of medications may be combined or used with insulin.

Some people with type 2 diabetes find they no longer need medication if they lose weight and increase activity, because when their ideal weight is reached, their own insulin and a careful diet can control their blood glucose levels.

It is unknown if hypoglycemic medicines taken by mouth are safe for use in pregnancy. Women who have type 2 diabetes and take these medications may be switched to insulin during pregnancy and while breastfeeding.

Gestational diabetes is treated with insulin and changes in diet.

EXERCISE

Regular exercise is especially important for people with diabetes. It helps with blood sugar control, weight loss, and high blood pressure. People with diabetes who exercise are less likely to experience a heart attack or stroke than diabetics who do not exercise regularly. You should be evaluated by your physician before starting an exercise program.

Here are some exercise considerations:

• Choose an enjoyable physical activity that is appropriate for your current fitness level.
• Exercise every day, and at the same time of day, if possible.
• Monitor blood glucose levels before and after exercise.
• Carry food that contains a fast-acting carbohydrate in case you become hypoglycemic during or after exercise.
• Carry a diabetes identification card and a mobile phone or change for a payphone in case of emergency.
• Drink extra fluids that do not contain sugar before, during, and after exercise.

Changes in exercise intensity or duration may need changes in diet or medication dose to keep blood sugar levels from going too high or low.

FOOT CARE

People with diabetes are prone to foot problems because of the likelihood of damage to blood vessels and nerves and a decreased ability to fight infection. Problems with blood flow and damage to nerves may cause an injury to the foot to go unnoticed until infection develops. Death of skin and other tissue can occur.

If left untreated, the affected foot may need to be amputated. Diabetes is the most common condition leading to amputations.

To prevent injury to the feet, people with diabetes should adopt a daily routine of checking and caring for the feet as follows:

• Check your feet every day, and report sores or changes and signs of infection.
• Wash your feet every day with lukewarm water and mild soap, and dry them thoroughly.
• Soften dry skin with lotion or petroleum jelly.
• Protect feet with comfortable, well-fitting shoes.
• Exercise daily to promote good circulation.
• See a podiatrist for foot problems or to have corns or calluses removed.
• Remove shoes and socks during a visit to your health care provider and remind him or her to examine your feet.
• Stop smoking, which hinders blood flow to the feet.

Where to get support

For additional information, see diabetes resources.

Prognosis

With good blood glucose and blood pressure control, many of the complications of diabetes can be prevented.

Studies have shown that strict control of blood sugar and blood pressure levels in persons with diabetes helps reduce the risk of kidney disease, eye disease, nervous system disease, heart attack, and stroke.

Possible Complications

Emergency complications include diabetic hyperglycemic hyperosmolar coma.

Long-term complications include:

• Diabetic retinopathy
• Diabetic nephropathy
• Diabetic neuropathy
• Peripheral vascular disease
• Hyperlipidemia, hypertension, atherosclerosis, and coronary artery disease

When to contact a medical professional

Go to the emergency room or call the local emergency number (such as 911) if symptoms of ketoacidosis occur:

• Increased thirst and urination
• Nausea
• Deep and rapid breathing
• Abdominal pain
• Sweet-smelling breath
• Loss of consciousness

Go to the emergency room or call the local emergency number if symptoms of extremely low blood sugar (hypoglycemic coma or severe insulin reaction) occur:

• Weakness
• Drowsiness
• Headache
• Confusion
• Dizziness
• Double vision
• Lack of coordination
• Convulsions or unconsciousness

Prevention

Maintaining an ideal body weight and an active lifestyle may prevent the onset of type 2 diabetes. Currently there is no way to prevent type 1 diabetes.

References

Standards of medical care in diabetes--2007. Diabetes Care. Jan 2007;30 Suppl 1:S4-S41.

Larsen PR, Kronberg HM, Schlomo M, et al. Williams Textbook of Endocrinology. 10th ed. St. Louis, Mo: WB Saunders; 2003:1427-1468, 1485-1504.

Armstrong C. ADA Releases Standards of Medical Care for Patients with Diabetes. Am Fam Physician. Sept 2006; 74(5); 871-874.

Caballero E. Prediabetes. J Clin Endocrinol Metab. Jan 2007; 92(1); 15A-16A.

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Review Date: 6/17/2008

Reviewed By: Elizabeth H. Holt, MD, PhD, Assistant Professor of Medicine, Section of Endocrinology and Metabolism, Yale University. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.