Diabetes Mellitus

Diabetes (dı¯-ā -bē ́tez) mellitus (me-lı¯ ́tū s; sweetened with honey) is a metabolic condition marked by inadequate uptake of glucose from the blood. The name “diabetes mellitus” is derived from the phrase “sweet urine” because some of the excess glucose is expelled into the urine, resulting in glycosuria (glucose in the urine). Chronically elevated blood glucose levels damage blood vessels, especially the smaller arterioles.
Because of its damaging effects on the vascular system, diabetes is the leading cause of retinal blindness, kidney failure, and nontraumatic leg amputations in the United States. Diabetes is also associated with increased incidence of heart disease and stroke. Three categories of diabetes mellitus are type 1 diabetes, type 2 diabetes, and gestational diabetes.


Type 1 diabetes, also referred to as insulin-dependent diabetes mellitus (IDDM), is characterized by absent or diminished production and release of insulin by the pancreatic islet cells. This type tends to occur in children and younger individuals, and is not directly associated with obesity. Type 1 diabetes develops in a person who harbors a genetic predisposition, although some kind of triggering event is required to start the process. Often, the trigger is a viral infection; then the process continues as an autoimmune condition in which the beta cells of the pancreatic islets are the primary focus of destruction. When the beta cells are destroyed, no insulin is produced, so blood glucose cannot be taken up and utilized by the body tissues. Treatment of type 1 diabetes requires daily injections of insulin. Newer monitoring instruments allow rapid monitoring of blood glucose, allowing better management of food and insulin. Insulin pumps provide the ability to program insulin delivery as well as manual dosage, greatly improving the treatment and lifestyle of people with IDDM.


Type 2 diabetes, also known as insulin-independent diabetes mellitus
(IIDM), results from either decreased insulin release by the pancreatic beta cells or decreased insulin effectiveness at peripheral tissues. This type of diabetes was previously referred to as adult-onset diabetes because it tended to occur in people over the age of 30. However, type 2 diabetes is now rampant in adolescents and young adults. Obesity plays a major role in the development of type 2 diabetes, and more young people today are considered overweight than ever before. Weight reduction supports the prevention of type 2 diabetes and appears to decrease the symptoms of type 2 diabetes that are already presenting. Most type 2 diabetes patients can be successfully treated with a combination of diet, exercise, and medications that enhance insulin release or increase its sensitivity at the tissue level. In more severe cases, a person with type 2 diabetes must take insulin injections.









Gestational diabetes is seen in some pregnant women, typically in the latter half of the pregnancy. If untreated, gestational diabetes can pose a risk to the fetus as well as increase delivery complications. Most at risk for developing this condition are women who are overweight, African American, Native American, or Hispanic, or those who have a family history of diabetes. While gestational diabetes usually resolves after giving birth, a woman who presents with the condition has a 20–50% chance of developing type 2 diabetes within 10 years.


Until recently, there was no cure for diabetes, but in the past few years pancreas transplants have helped individuals with severe cases of diabetes. Pancreas transplants have several drawbacks, however:
They require major surgery, there is a long donor waiting list, and many complications can arise due to the surgery, either from potential rejection of the transplanted organ or the toxic effects of the necessary immunosuppressant antirejection drugs. Recently, a less invasive surgery, called an islet cell transplant, has been developed.
In this procedure, the islet cells are removed from a donor pancreas and purified. Then the cells are injected into a vein that enters the liver. Once in the liver, the islet cells embolize (form big clots) and start producing insulin almost immediately. Islet cell transplants are still very new and have many complications. The process of extracting and purifying the islet cells is complicated and can have a high failure rate; bleeding or major blood clots may occur in the vein where the islet cells are transplanted; and the immunosuppressant drugs that must be taken have serious side effects. Furthermore, recent studies have shown that the efficacy of islet cell transplants is only temporary. Most patients need to resume insulin shots within 2 years of transplantation. Thus, islet cell transplant surgery is reserved for patients who have severe forms of diabetes.

source : Human anatomy