Diabetes
mellitus, often referred to simply as diabetes (Ancient
Greek: "to pass through"), is a syndrome of disordered
metabolism, usually due to a combination of hereditary and environmental
causes, resulting in abnormally high blood sugar levels (hyperglycemia).
Blood glucose levels are controlled by a complex interaction
of multiple chemicals and hormones in the body, including the
hormone insulin made in the beta cells of the pancreas. Diabetes
mellitus refers to the group of diseases that lead to high blood
glucose levels due to defects in either insulin secretion or
insulin action in the body.
Diabetes
develops due to a diminished production of insulin (in type
1) or resistance to its effects (in type 2 and gestational).
Both lead to hyperglycemia, which largely causes the acute signs
of diabetes: excessive urine production, resulting compensatory
thirst and increased fluid intake, blurred vision, unexplained
weight loss, lethargy, and changes in energy metabolism.
All
forms of diabetes have been treatable since insulin became medically
available in 1921, but there is no cure. The injections by a
syringe, insulin pump, or insulin pen deliver insulin, which
is a basic treatment of type 1 diabetes. Type 2 is managed with
a combination of dietary treatment, exercise, medications and
insulin supplementation.
Diabetes
and its treatments can cause many complications. Acute complications
(hypoglycemia, ketoacidosis, or nonketotic hyperosmolar coma)
may occur if the disease is not adequately controlled. Serious
long-term complications include cardiovascular disease (doubled
risk), chronic renal failure, retinal damage (which can lead
to blindness), nerve damage (of several kinds), and microvascular
damage, which may cause erectile dysfunction and poor wound
healing. Poor healing of wounds, particularly of the feet, can
lead to gangrene, and possibly to amputation.
Adequate
treatment of diabetes, as well as increased emphasis on blood
pressure control and lifestyle factors (such as not smoking
and maintaining a healthy body weight), may improve the risk
profile of most of the chronic complications. In the developed
world, diabetes is the most significant cause of adult blindness
in the non-elderly and the leading cause of non-traumatic amputation
in adults, and diabetic nephropathy is the main illness requiring
renal dialysis in the United States.