Central diabetes insipidus, also called neurogenic diabetes insipidus, is a type of

diabetes insipidus Diabetes insipidus (DI), recently renamed to Arginine Vasopressin Deficiency (AVP-D) and Arginine Vasopressin Resistance (AVP-R), is a condition characterized by large amounts of dilute urine and increased thirst. The amount of urine produced ...

due to a lack of

vasopressin Human vasopressin, also called antidiuretic hormone (ADH), arginine vasopressin (AVP) or argipressin, is a hormone synthesized from the AVP gene as a peptide prohormone in neurons in the hypothalamus, and is converted to AVP. It then trave ...

(ADH) production in the brain. Vasopressin acts to increase the volume of blood (intravascularly), and decrease the volume of

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellul ...

produced. Therefore, a lack of it causes increased urine production and

volume depletion Hypovolemia, also known as volume depletion or volume contraction, is a state of abnormally low extracellular fluid in the body. This may be due to either a loss of both salt and water or a decrease in blood volume. Hypovolemia refers to the loss ...

. It is also known as neurohypophyseal diabetes insipidus, referring to the

posterior pituitary The posterior pituitary (or neurohypophysis) is the posterior lobe of the pituitary gland which is part of the endocrine system. The posterior pituitary is not glandular as is the anterior pituitary. Instead, it is largely a collection of axonal ...

(neurohypophysis), which is supplied by the

hypothalamus The hypothalamus () is a part of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamus ...

in the brain. This condition has only

polyuria Polyuria () is excessive or an abnormally large production or passage of urine (greater than 2.5 L or 3 L over 24 hours in adults). Increased production and passage of urine may also be termed diuresis. Polyuria often appears in conjunction wi ...

in common with

diabetes Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...

. Although not mutually exclusive, with most typical cases, the name diabetes insipidus is a misleading misnomer. A better name might be "hypothalamic-neurohypophyseal ADH deficiency".

Signs and symptoms

Increased thirst, polyuria and dehydration with metabolic encephalopathy.

Causes

Unknown

In at least 25% of cases (the most commonly occurring classification), neurogenic diabetes insipidus is of unknown cause, meaning that the lack of vasopressin production arose from an unknown cause. http://www.medical-library.org/journals4a/diabetes_insipidus.htm It is also due to damage of the hypothalamus, pituitary stalk, posterior pituitary, and can arise from head trauma.

Acquired

The lack of vasopressin production usually results from some sort of damage to the

pituitary gland In vertebrate anatomy, the pituitary gland, or hypophysis, is an endocrine gland, about the size of a chickpea and weighing, on average, in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain. The h ...

. It may be due to damage to the brain caused by: * Benign suprasellar tumors (20% of cases) * Infections (encephalitis, tuberculosis, etc.) * Trauma (17% of cases) or neurosurgery (9% of cases) * Non-infectious granuloma (

sarcoidosis Sarcoidosis (also known as ''Besnier-Boeck-Schaumann disease'') is a disease involving abnormal collections of inflammatory cells that form lumps known as granulomata. The disease usually begins in the lungs, skin, or lymph nodes. Less commonly af ...

, Langerhans cell histiocytosis etc.) * Leukaemia * Autoimmune - associated with thyroiditis * Other rare causes which include

hemochromatosis Iron overload or hemochromatosis (also spelled ''haemochromatosis'' in British English) indicates increased total accumulation of iron in the body from any cause and resulting organ damage. The most important causes are hereditary haemochromatosi ...

and

histiocytosis In medicine, histiocytosis is an excessive number of histiocytes (tissue macrophages), and the term is also often used to refer to a group of rare diseases which share this sign as a characteristic. Occasionally and confusingly, the term "histioc ...

. Vasopressin is released by the

, but unlike most other pituitary hormones, vasopressin is produced in the

. Neurogenic diabetes insipidus can be a failure of production at the hypothalamus, or a failure of release at the pituitary.

Genetic

The most rare form of central DI is familial neurogenic diabetes insipidus. This form of DI is due to an inherited mutation of the

arginine vasopressin-neurophysin II Neurophysin II is a carrier protein with a size of 19,687.3 Da and is made up of a dimer of two virtually identical chains of amino acids. Neurophysin II is a cleavage product (formed by splitting of a compound molecule into a simpler one) of the ...

(AVP-NPII) gene, inherited in an autosomal dominant manner. At one point, only 45 families worldwide were known to possess this genetic trait. http://diabetesinsipidus.org/4di_familial.htm It is now more widely recognized, although the precise number of people affected with this form of DI is unknown at the present time. There is also an X-linked familial form.Wolfram Syndrome (also called DIDMOAD) is characterised by DI, diabetes mellitus,

sensorineural deafness Sensorineural hearing loss (SNHL) is a type of hearing loss in which the root cause lies in the inner ear or sensory organ (cochlea and associated structures) or the vestibulocochlear nerve (cranial nerve VIII). SNHL accounts for about 90% of rep ...

, and optic atrophy.

Diagnosis

In many respects, the diagnosis of central diabetes insipidus begins as a diagnosis of exclusion. Specifically, other more common causes of polyuria and polydipsia are ruled out. Common rule outs include: diabetes mellitus, chronic kidney disease, hypokalemia, hypercalcemia, and psychogenic polydipsia. Once these conditions have been ruled out a water deprivation test is employed to confirm the diagnosis of CDI.

Treatment

The disorder is treated with vasopressin analogs such as

desmopressin Desmopressin, sold under the trade name DDAVP among others, is a medication used to treat diabetes insipidus, bedwetting, hemophilia A, von Willebrand disease, and high blood urea levels. In hemophilia A and von Willebrand disease, it should on ...

. Nonetheless, many times desmopressin alone is not enough to bring under control all the symptoms, and another intervention must be implemented.

References

External links

{{Hypothalamic disease Hypothalamus disorders Pituitary disorders