Diabetes - Type 2

Diabetes mellitus is a metabolic disorder characterized by hyperglycemia and other signs, as distinct from a single disease or condition. The World Health Organization recognizes three main forms of diabetes: type 1, type 2, and gestational diabetes, which have similar signs, symptoms, and consequences, but different causes and population distributions. Type 1 is usually due to autoimmune destruction of the pancreatic beta cells which produce insulin. Type 2 is characterized by tissue-wide insulin resistance and varies widely; it sometimes progresses to loss of beta cell function. Gestational diabetes is similar to type 2 diabetes, in that it involves insulin resistance; the hormones of pregnancy cause insulin resistance in those women genetically predisposed to developing this condition.

Types 1 and 2 are incurable chronic conditions, but have been treatable since insulin became medically available in 1921, and are nowadays usually managed with a combination of dietary treatment, tablets and frequently insulin. Gestational diabetes typically resolves with delivery.

Type 2 diabetes mellitus—previously known as adult-onset diabetes, maturity-onset diabetes, or non-insulin-dependent diabetes mellitus (NIDDM)—is due to a combination of defective insulin secretion and insulin resistance or reduced insulin sensitivity, which almost certainly involves the insulin receptor in cell membranes. In the early stage the predominant abnormality is reduced insulin sensitivity, characterized by elevated levels of insulin in the blood. At this stage hyperglycemia can be reversed by a variety of measures and medications that improve insulin sensitivity or reduce glucose production by the liver, but as the disease progresses the impairment of insulin secretion worsens, and therapeutic replacement of insulin often becomes necessary. There are numerous theories as to the exact cause and mechanism for this resistance, but central obesity (fat concentrated around the waist in relation to abdominal organs, not it seems, subcutaneous fat) is known to predispose for insulin resistance, possibly due to its secretion of adipokines that impair glucose tolerance. Abdominal fat is especially active hormonally. Obesity is found in approximately 90% of developed world patients diagnosed with type 2 diabetes. Other factors include aging and family history, although in the last decade it has increasingly begun to affect children and adolescents, likely in connection with the greatly increased childhood obesity seen in recent decades in some places.

Type 2 diabetes may go unnoticed for years in a patient before diagnosis, as visible symptoms are typically mild or non-existent, without ketoacidotic episodes, and can be sporadic as well. However, severe long-term complications can result from unnoticed type 2 diabetes, including renal failure, vascular disease, vision damage, etc.

Type 2 diabetes is usually first treated by attempts to change physical activity, diet, and weight loss. These can restore insulin sensitivity, even when the weight loss is modest, for example, around 10 to 15 lb, most especially when it is in abdominal fat deposits. Some Type 2 diabetics can achieve satisfactory glucose control, sometimes for years, as a result. However, the underlying tendency to insulin resistance is not lost, and so attention to diet, exercise, and weight must continue. The usual next step, if necessary, is treatment with oral antidiabetic drugs. As insulin production is initially unimpaired in Type 2s, oral medication can still be used to improve insulin production, to regulate inappropriate release of glucose by the liver, and attenuate insulin resistance to some extent, and to substantially attenuate insulin resistance. If these fail, insulin therapy will be necessary to maintain normal or near normal glucose levels. A disciplined regimen of blood glucose checks is recommended in most cases, most particularly and necessarily when taking medications.

...More at Wikipedia

Related Links:

• US National Library of Medicine
• Mayo Clinic

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