a broadly applied term used to denote a complex group of syndromes that have in common a disturbance in the oxidation and utilization of glucose, which is secondary to a malfunction of the beta cells of the pancreas, whose function is the production and release of insulin. Because insulin is involved in the metabolism of carbohydrates, proteins and fats, diabetes is not limited to a disturbance of glucose homeostasis alone.

nephrogenic diabetes insipidus a rare form caused by failure of the renal tubules to reabsorb water; there is excessive production of antidiuretic hormone but the tubules fail to respond to it. Characteristics include polyuria, extreme thirst, growth retardation, and developmental delay. The condition does not respond to exogenous vasopressin. It may be inherited as an X-linked trait or be acquired as a result of drug therapy or systemic disease.
Patients need to ensure that their blood glucose levels are kept as normal as possible so that delicate tissues in the body (especially blood vessels in the eyes, kidneys and peripheral nerves) are not damaged by high glucose levels over a long period of time. To achieve this, patients need to measure their glucose regularly and learn how to adjust their insulin doses in order to optimise their glucose levels (diabetes control). Good diabetes control helps to minimise the risk of long-term diabetes complications, as well as short-term symptoms (such as thirst).
Diabetes mellitus is a diagnostic term for a group of disorders characterized by abnormal glucose homeostasis resulting in elevated blood sugar. It is among the most common of chronic disorders, affecting up to 5–10% of the adult population of the Western world. The prevalence of diabetes is increasing dramatically; it has been estimated that the worldwide prevalence will increase by more than 50% between the years 2000 and 2030 (Wild et al., 2004). It is clearly established that diabetes mellitus is not a single disease, but a genetically heterogeneous group of disorders that share glucose intolerance in common. The concept of genetic heterogeneity (i.e. that different genetic and/or environmental etiologic factors can result in similar phenotypes) has significantly altered the genetic analysis of this common disorder.
The diabetic patient should learn to recognize symptoms of low blood sugar (such as confusion, sweats, and palpitations) and high blood sugar (such as, polyuria and polydipsia). When either condition results in hospitalization, vital signs, weight, fluid intake, urine output, and caloric intake are accurately documented. Serum glucose and urine ketone levels are evaluated. Chronic management of DM is also based on periodic measurement of glycosylated hemoglobin levels (HbA1c). Elevated levels of HbA1c suggest poor long-term glucose control. The effects of diabetes on other body systems (such as cerebrovascular, coronary artery, and peripheral vascular) should be regularly assessed. Patients should be evaluated regularly for retinal disease and visual impairment and peripheral and autonomic nervous system abnormalities, e.g., loss of sensation in the feet. The patient is observed for signs and symptoms of diabetic neuropathy, e.g., numbness or pain in the hands and feet, decreased vibratory sense, footdrop, and neurogenic bladder. The urine is checked for microalbumin or overt protein losses, an early indication of nephropathy. The combination of peripheral neuropathy and peripheral arterial disease results in changes in the skin and microvasculature that lead to ulcer formation on the feet and lower legs with poor healing. Approx. 45,000 lower-extremity diabetic amputations are performed in the U.S. each year. Many amputees have a second amputation within five years. Most of these amputations are preventable with regular foot care and examinations. Diabetic patients and their providers should look for changes in sensation to touch and vibration, the integrity of pulses, capillary refill, and the skin. All injuries, cuts, and blisters should be treated promptly. The patient should avoid constricting hose, slippers, shoes, and bed linens or walking barefoot. The patient with ulcerated or insensitive feet is referred to a podiatrist for continuing foot care and is warned that decreased sensation can mask injuries.
 Type 1 diabetes mellitus is a chronic metabolic syndrome defined by an inability to produce insulin, a hormone which lowers blood sugar. This leads to inappropriate hyperglycaemia (increased blood sugar levels) and deranged metabolism of carbohydrates, fats and proteins. Insulin is normally produced in the pancreas, a glandular organ involved in the production of digestive enzymes and hormones such as insulin and glucagon. These functions are carried out in the exocrine and endocrine (Islets of Langerhans) pancreas respectively.

Jump up ^ Boussageon, R; Bejan-Angoulvant, T; Saadatian-Elahi, M; Lafont, S; Bergeonneau, C; Kassaï, B; Erpeldinger, S; Wright, JM; Gueyffier, F; Cornu, C (2011-07-26). "Effect of intensive glucose lowering treatment on all cause mortality, cardiovascular death, and microvascular events in type 2 diabetes: meta-analysis of randomised controlled trials". The BMJ. 343: d4169. doi:10.1136/bmj.d4169. PMC 3144314. PMID 21791495.
Having diabetes requires life-long treatment and follow-up by health professionals. Diabetes can be linked to damage of the eyes, kidneys and feet. It is also associated with increased risk of strokes, heart attacks and poor blood circulation to the legs. Medical care aims to minimise these risks by controlling diabetes, blood pressure and cholesterol and screening for possible complications caused by the diabetes. 
central diabetes insipidus a metabolic disorder due to injury of the neurohypophyseal system, which results in a deficient quantity of antidiuretic hormone (ADH or vasopressin) being released or produced, resulting in failure of tubular reabsorption of water in the kidney. As a consequence, there is the passage of a large amount of urine having a low specific gravity, and great thirst; it is often attended by voracious appetite, loss of strength, and emaciation. Diabetes insipidus may be acquired through infection, neoplasm, trauma, or radiation injuries to the posterior lobe of the pituitary gland or it may be inherited or idiopathic.
A type 2 diabetes diet or a type 2 diabetic diet is important for blood sugar (glucose) control in people with diabetes to prevent complications of diabetes. There are a variety of type 2 diabetes diet eating plans such as the Mediterranean diet, Paleo diet, ADA Diabetes Diet, and vegetarian diets.Learn about low and high glycemic index foods, what foods to eat, and what foods to avoid if you have type 2 diabetes.

Home blood glucose monitoring kits are available so patients with diabetes can monitor their own levels. A small needle or lancet is used to prick the finger and a drop of blood is collected and analyzed by a monitoring device. Some patients may test their blood glucose levels several times during a day and use this information to adjust their doses of insulin.

When you have type 2 diabetes, your cells don't get enough glucose, which may cause you to lose weight. Also, if you are urinating more frequently because of uncontrolled diabetes, you may lose more calories and water, resulting in weight loss, says Daniel Einhorn, MD, medical director of the Scripps Whittier Diabetes Institute and clinical professor of medicine at the University of California in San Diego.