What is "diabetes insipidus"

diabetes \di`a*be"tes\, n. [NL., from Gr. ?, fr. ? to pass or cross over. See Diabase.] (Med.) Any of several diseases which is attended with a persistent, excessive discharge of urine; when used without qualification, the term usually refers to diabetes mellitus. The most common form is diabetes mellitus, in which the urine is not only increased in quantity, but contains saccharine matter, and the condition if untreated is generally fatal.

Note: The two major subtypes recognized are

diabetes insipidus and

diabetes mellitus. In diabetes insipidus there is excretion of large amounts of urine of relatively low density, accompanied by extreme thirst, but the urine contains no abnormal constituent. The more serious form diabetes mellitus (from Latin mellitus, sweetened with honey) is a metabolic disease in which the utilization of carbohydrate is reduced and that of lipids and proteins is increased. This form is caused by a deficiency in insulin (which is mostly formed in the pancreas), and may be accompanied by glucosuria, hyperglycemia, elecrolyte loss, ketoacidosis, and sometimes coma. It has severe long-term effects, including damage to the nerves, the retina, and the kidney, and degeneration of blood vessels which may lead to poor circulation, especially in the limbs, subsequent infection, and eventual loss of limbs. Diabetes mellitus itself has recognized variants, being divided into insulin-dependent diabetes mellitus and non-insulin-dependent diabetes mellitus. Non-insulin-dependent diabetes mellitus is also called adult-onset diabetes (abbreviated NIDDM), and is the less severe form of diabetes mellitus, occurring mostly in obese individuals over the age of 35. It may be treated by diet and oral hypoglycemic agents, though occasionally serious degenerative effects may develop. Insulin-dependent diabetes mellitus (abbreviated IDDM), also called type I diabetes, is a severe form of the disease, usually starting when the affected person is young (hence also called juvenile-onset diabetes). In addition to the increased urine (polyuria) common to all forms of diabetes, this form is characterized by low levels of insulin in the blood, ketoacidosis, increased appetite, and increased fluid intake, and may lead to weight loss and eventually the severe degenerative effects mentioned above. Treatment requires administration of insulin and careful regulation of the diet.
--Stedman

Diabetes mellitus [NL., sweet diabetes], that form of diabetes in which the urine contains saccharine matter.

Diabetes insipidus [NL., lit., diabetes], the form of diabetes in which the urine contains no abnormal constituent.

n. A disease characterized by excretion of large amount of severely diluted urine, which cannot be reduced when fluid intake is reduced. It is generally related to a tumor or insult to the pituitary gland, where the hormonal signals the pituitary gives to the kidneys break down, and the kidneys do not conserve water, but express all water as urine. This is a rather rare disease.

n. a rare form of diabetes resulting from a deficiency of vasopressin (the pituitary hormone that regulates the kidneys); characterized by the chronic excretion of large amounts of pale dilute urine which results in dehydration and extreme thirst

Diabetes insipidus (DI) is a condition characterized by excessive thirst and excretion of large amounts of severely dilute urine, with reduction of fluid intake having no effect on the concentration of the urine. There are different types of DI, each with a different set of causes. The most common type in humans is the neurological form, called central DI (CDI), which involves a deficiency of arginine vasopressin (AVP), also known as antidiuretic hormone (ADH). The second common type of DI is nephrogenic diabetes insipidus (NDI), which is due to kidney or nephron dysfunction caused by an insensitivity of the kidneys or nephrons to ADH. DI can also be gestational, or caused by alcohol or some types of drug abuse. DI should not be confused with nocturia.

Although they have a common name, diabetes mellitus and diabetes insipidus are two entirely separate conditions with unrelated mechanisms. Both cause large amounts of urine to be produced ( polyuria). However, diabetes insipidus is either a problem with the production of antidiuretic hormone (central diabetes insipidus) or kidney's response to antidiuretic hormone (nephrogenic diabetes insipidus), whereas diabetes mellitus causes polyuria via a process called osmotic diuresis, due to the high blood sugar leaking into the urine and taking excess water along with it.

The number of new cases of diabetes insipidus each year is 3 in 100,000. Diabetes insipidus usually starts in childhood or early adulthood and affects men more commonly than women. The term "diabetes" is derived from the Greek word meaning siphon.