Diabetes is a disease that causes an abnormally high level of sugar, or glucose, to build up in the blood. In type 2 diabetes -- previously called non-insulin dependent or adult-onset diabetes - this rise occurs even though the body is producing insulin, which body cells normally use to convert blood glucose into energy.
The glucose level in a person with untreated type 2 diabetes may be high for a period of years without causing any symptoms -- until severe complications occur. If early symptoms do occur, they usually consist of increased thirst and appetite, frequent urination, weight loss, and blurry vision.
Type 2 diabetes accounts for about 98% of all cases of diabetes. It's usually diagnosed in adults over age 30 but can develop in younger people as well. People with a family history of type 2 diabetes have a greater risk of developing it. In addition, type 2 diabetes very commonly occurs in overweight people.
Insulin is produced by specialized cells (beta cells) in the pancreas, located in the abdomen just behind the stomach. Once the beta cells have made the insulin, the pancreas releases the insulin into the bloodstream, which carries it to all the cells in the body.
Insulin is required for the entry of glucose into body cells. Once released into the bloodstream, insulin attaches to the cells, triggering a process that allows the glucose to enter them and be converted to energy.
Although the pancreas does produce insulin in people with type 2 diabetes, the cells of the body "resist" the insulin's effects. As a result, the glucose circulating in the bloodstream cannot enter the cells and be used for energy.
People with diabetes, whether type 1 or type 2, have an increased risk of severe complications if the disease goes undiagnosed and untreated -- or if it is poorly managed. High blood glucose levels make it easier for blockages to form in the blood vessels that supply the heart, brain, and legs as well as the rest of the body. High blood glucose can also damage nerves, causing numbness and tingling -- especially in the legs and feet.
Diabetes-related damage to a person's circulatory and nervous systems increases the risk of heart attacks, strokes, blindness, kidney failure, and foot and leg amputations. These complications may be present at the time of diagnosis of type 2 diabetes. The good news is that early diagnosis and aggressive treatment of diabetes can help keep these complications from developing.
The first steps in the treatment of type 2 diabetes are weight loss, if needed, and an appropriate diet. Weight loss can reduce the need for medication as well as the risk of developing complications. Planning a diet that will provide healthy amounts of carbohydrates, protein, fats, and cholesterol and help control body weight often requires close attention from a doctor and possibly a nutritionist. A doctor can also suggest an appropriate exercise regimen.
If medications are needed, there are several different types of drugs for type 2 diabetes that can be taken by mouth. In addition, insulin may be required in some individuals. Some patients will require more than one medication to achieve and maintain good diabetes control.
Drugs in the oldest class of type 2 diabetes medications, called sulfonylureas, increase the amount of insulin produced by the pancreas, thus helping to compensate for the body's resistance to insulin. Patients taking sulfonylureas should not miss meals or take excessive doses: This can cause blood glucose to drop to unsafe levels that, if prolonged, can lead to mental confusion and even coma.
A drug from another class of medications, metformin, works three ways: It lowers the amount of glucose produced in the liver, decreases the absorption of glucose in the intestines, and improves the body's resistance to insulin. The side effects of this medication are mainly gastrointestinal, such as diarrhea, nausea, and vomiting.
Acarbose slows the absorption of glucose in the intestines and therefore helps prevent the high glucose levels that occur after eating in people with diabetes. The most common side effects of acarbose are also gastrointestinal: abdominal pain, diarrhea, and gas.
The newest class of medications has a long formal name - thiazolidinediones -- but is called "glitazones" for short, because the names of all the available drugs in this class end with "-glitazone." These drugs work by lowering the entire body's resistance to insulin and may be taken with metformin and/or a sulfonylurea. A patient taking these medications must have regular blood tests to monitor for potential liver problems.
Insulin injections may be required in two circumstances for treatment of type 2 diabetes. First, a newly diagnosed patient with extremely high blood glucose levels may be started on insulin therapy, with a possible switch to pill therapy once the blood glucose has stabilized. Second, if pill therapy doesn't work to control a patient's blood glucose, insulin can be used instead -- or insulin and pills may be used together.
Effective control of diabetes depends on patients' regularly checking (monitoring) their blood glucose levels at home. This usually involves pricking a finger with a small needle, putting a drop of blood on a test strip, and inserting the strip into a machine (blood glucose monitor) that gives the glucose level within a few minutes. Regular monitoring of blood glucose levels helps patients with diabetes keep a record of how well their blood glucose is controlled.
The doctor will also check the patient's blood and run a lab test known as HbA1C to determine how well the blood glucose has been controlled over the last several months. Checking glucose levels at home along with this blood test helps doctors determine the best dose of insulin.