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 the hormone insulin made in the beta cells of the pancreas. The two most common forms of diabetes are due to either a diminished production of insulin (in type 1), or diminished response by the body to insulin (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 types of diabetes have been treatable since insulin became medically available in 1921, but there is no cure for diabetes. Type 1 diabetes can only be treated with injected insulin, with dietary and other lifestyle adjustments commonly being part of the treatment. Type 2 is usually managed with a combination of dietary treatment, tablets and, frequently, insulin supplementation. Insulin can also be delivered continuously by a specialized pump which provides subcutaneous insulin through a temporary catheter.
Diabetes and its treatments can cause many complications. Acute complications (hypoglycemia, ketoacidosis, or coma) may occur if the disease is not adequately controlled. Serious long-term complications include cardiovascular disease, chronic renal failure, retinal damage (which can lead to blindness), nerve damage, and microvascular damage, which may cause poor wound healing. Poor healing of wounds, particularly of the feet, can lead to gangrene, and possibly to amputation. 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.
