diabetes insipidus


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Related to diabetes insipidus: nephrogenic diabetes insipidus, diabetes mellitus, SIADH

Diabetes Insipidus

 

Definition

Diabetes insipidus (DI) is a disorder that causes the patient to produce tremendous quantities of urine. The massively increased urine output is usually accompanied by intense thirst.

Description

The balance of fluid within the body is maintained through a number of mechanisms. One important chemical involved in fluid balance is called antidiuretic hormone (ADH). ADH is produced by the pituitary, a small gland located at the base of the brain. In a healthy person and under normal conditions, ADH is continuously released. ADH influences the amount of fluid that the kidneys reabsorb into the circulatory system and the amount of fluid that the kidneys pass out of the body in the form of urine.
Production of ADH is regulated by the osmolality of the circulating blood. Osmolality refers to the concentration of dissolved chemicals (such as sodium, potassium, and chloride; together called solute) circulating in the fluid base of the blood (plasma). When there is very little fluid compared to the concentration of solute, the pituitary will increase ADH production. This tells the kidneys to retain more water and to decrease the amount of urine produced. As fluid is retained, the concentration of solute will normalize. At other times, when the fluid content of the blood is high in comparison to the concentration of solute, ADH production will decrease. The kidneys are then free to pass an increased amount of fluid out of the body in the urine. Again, this will allow the plasma osmolality to return to normal.
Diabetes insipidus occurs when either the amount of ADH produced by the pituitary is below normal (central DI), or the kidneys' ability to respond to ADH is defective (nephrogenic DI). In either case, a person with DI will pass extraordinarily large quantities of urine, sometimes reaching 10 or more liters each day. At the same time, the patient's blood will be very highly concentrated, with low fluid volume and high concentrations of solute.
DI occurs on average when a person is about 24 years old, and occurs more frequently in males than in females.

Causes and symptoms

DI may run in families. The cause of this type of DI is unknown. Other times, central DI can be caused by:
  • an injury to the head
  • brain surgery
  • cancers that have spread to the pituitary gland (most commonly occurring with breast cancer)
  • sarcoidosis (or other related disorders), causing destruction of the pituitary gland
  • any condition or illness that causes decreased oxygen delivery to the brain
  • the use of certain medications that decrease ADH production (like the antiseizure drug phenytoin)
  • the excessive use of alcohol
Central DI may also occur in women who are pregnant or have just given birth, and in patients with AIDS who have suffered certain types of brain infections. Nephrogenic DI sometimes occurs in patients who are taking the medication lithium, patients who have high levels of blood calcium, and patients who are pregnant.
DI is easily confused with an entirely unrelated disorder, psychogenic polydipsia. Polydipsia refers to drinking large amounts of water. Psychogenic polydipsia is a psychiatric problem that makes a person drink huge quantities of water uncontrollably.
Symptoms of DI include extreme thirst and the production of tremendous quantities of urine. Patients with DI typically drink huge amounts of water, and usually report a specific craving for cold water. When the amount of water passed in the urine exceeds the patient's ability to drink ample replacement water, the patient may begin to suffer from symptoms of dehydration. These symptoms include weakness, fatigue, fever, low blood pressure, increased heart rate, dizziness, and confusion. If left untreated, the patient could lapse into unconsciousness and die.

Diagnosis

Diagnosis should be suspected in any patient with sudden increased thirst and urination. Laboratory examination of urine will reveal very dilute urine, made up mostly of water with no solute. Examination of the blood will reveal very concentrated blood, high in solute and low in fluid volume.
A water deprivation test may be performed. This test requires a patient to stop all fluid intake. The patient is weighed just before the test begins, and urine is collected and examined hourly. The test is stopped when:
  • the patient has lost more than 5% of his or her original body weight
  • the patient has reached certain limits of low blood pressure and increased heart rate
  • the urine is no longer changing significantly from one sample to the next in terms of solute concentration.
The next step of the test involves injecting a synthetic form of ADH, with one last urine sample examined 60 minutes later. Comparing plasma and urine osmolality allows the doctor to diagnose either central DI, nephrogenic DI, partial DI, or psychogenic polydipsia.

Treatment

A number of medications can be given to decrease the quantity of fluid passed out into the urine. These include rasoprassin (Pitressin) injected and desmopressin acetate (DDAVP) inhaled through the nose. Other medications that may be given include some antidiuretic drugs (chlorpropamide, clofibrate, carbamazepine). Patients with nephrogenic DI, however, will also require special diets that restrict the amount of solute taken in. These patients are also treated with a type of medication called a thiazide diuretic.

Prognosis

Uncomplicated diabetes insipidus is controllable with adequate intake of water and most patients can lead normal lives.

Key terms

Concentration — Refers to the amount of solute present in a solution, compared to the total amount of solvent.
Dilute — A solution that has comparatively more fluid in it, relative to the quantity of solute.
Osmolality — A measure of the solute-to-solvent concentration of a solution.
Solute — Solid substances that are dissolved in liquid in order to make a solution.

Resources

Periodicals

Singer, Irwin, et al. "The Management of Diabetes Insipidus in Adults." Archives of Internal Medicine 157, no. 12 (June 23, 1997): 1293+.

di·a·be·tes in·sip·i·dus

chronic excretion of very large amounts of pale urine of low specific gravity, causing dehydration and extreme thirst; ordinarily results from inadequate output of pituitary antidiuretic hormone; the urine abnormalities may be mimicked as a result of excessive fluid intake, as in psychogenic polydipsia. Two types exist: central and nephrogenic. Autosomal dominant [MIM*125700, *125800, *192340], X-linked [MIM*304800 and *304900], and even autosomal recessive forms [MIM*222000] have been described.
See also: nephrogenic diabetes insipidus.

diabetes insipidus

(ĭn-sĭp′ĭ-dəs)
n.
A chronic disorder marked by excessive urination and usually intense thirst and dehydration, caused either by insufficient production or release of the pituitary hormone vasopressin or by inability of the kidneys to respond effectively to vasopressin.

diabetes insipidus

[insip′idəs]
a metabolic disorder caused by injury of the neurohypophyseal system. It is characterized by copious excretion of urine and excessive thirst, caused by deficient production or secretion of the antidiuretic hormone (ADH) or inability of the kidney tubules to respond to ADH. Rarely the symptoms are self-induced by an excessive water intake. The condition may be acquired, familial, idiopathic, neurogenic, nephrogenic, or psychogenic.
observations The onset may be dramatic and sudden, and urinary output may exceed 10 L in 24 hours. Diagnosis is established by a water deprivation test in which urine volume increases and urine osmolality decreases. A person with diabetes insipidus who is unconscious as result of trauma or surgery continues to produce massive quantities of urine. If fluids are not administered in adequate amounts, the patient becomes severely dehydrated and hypernatremic.
interventions In mild cases, no treatment is necessary. Vasopressin in an intramuscular injection or nasal spray is effective. Thiazide diuretics, by inducing a state of salt depletion, sometimes decrease the diuresis of water by as much as 50%.
nursing considerations Infants, small children, and the elderly are particularly vulnerable to serious circulatory disturbances when dehydrated. Therefore exceedingly careful monitoring is essential when the condition is suspected, especially after head surgery or trauma.

diabetes insipidus

Endocrinology A condition characterized by defective water homeostasis due to a defect in ADH secretion, resulting in inadequate reabsorption of water by the kidney tubules and excretion of a large volume of dilute urine Types Central–due to a defect in the neurohypophysis (posterior pituitary) and/or hypothalamus; peripheral/nephrogenic–defect in the renal tubule

di·a·be·tes in·sip·i·dus

(DI) (dī-ă-bē'tēz in-sip'i-dŭs)
Chronic excretion of very large amounts of pale urine of low specific gravity, causing dehydration and extreme thirst; ordinarily results from inadequate output of pituitary antidiuretic hormone.
See also: nephrogenic diabetes insipidus

diabetes insipidus

A rare disease caused by inadequate production of the antidiuretic hormone (vasopressin) of the PITUITARY. Excessive quantities of dilute urine are produced and there is great thirst. Diabetes insipidus can also occur if the kidneys are abnormally insensitive to the anti-diuretic hormone. The condition should not be confused with ordinary DIABETES MELLITUS.

diabetes insipidus

; DI disease due to insufficient production of antidiuretic hormone (ADH, vasopressin) at the posterior pituitary; characterized by voiding large volumes of very dilute urine, with resultant nocturia and dehydration; patients are treated by replacement hormone (vasopressin or desmopressin)

di·a·be·tes in·sip·i·dus

(DI) (dī-ă-bē'tēz in-sip'i-dŭs)
Chronic excretion of very large amounts of pale urine of low specific gravity, causing dehydration and extreme thirst.

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 may be acquired through infection, neoplasm or trauma to the posterior lobe of the pituitary gland or it may be inherited or idiopathic. Called also central diabetes insipidus.

dipsogenic diabetes insipidus
see psychogenic diabetes insipidus (below).
nephrogenic diabetes insipidus
a rare form of diabetes insipidus, resulting from failure of the renal tubules to reabsorb water; there is excessive production of antidiuretic hormone but the tubules fail to respond to it.
psychogenic diabetes insipidus
a primary polydipsia resulting from a disorder of thirst control, or as a behavioral problem. The polyuria is secondary to the excessive water intake. Called also dipsogenic diabetes insipidus.
References in periodicals archive ?
Although diabetes insipidus can lead to dehydration if its treatment is not appropriately monitored, it can also lead to patient harm or death from over-hydration, as illustrated in this article.
Sonuc olarak, poliuri ve hipernatremi gelisen CDDA erken dogmus yenidoganlarda merkezi diabetes insipidus ihtimali dusunulmeli, bu durumun arka hipofizdeki kanamaya ikincil ve gecici olabilecegi, tedavide intranazal desmopresin asetatin etkili oldugu akilda tutulmalidir.
Hypothalamic obesity complicated by adipsic central diabetes insipidus following surgical resection of a craniopharyngioma.
For example, elevated urinary AQP2 levels, as detected by EIA procedures, (48) are associated with such conditions as diabetes insipidus, CHF, and liver cirrhosis.
If you would like more information on diabetes insipidus, you can call the Pituitary Foundation on 01454 201612.
Merkezi diabetes insipidus bobrek medullasina ulasan antidiuretik hormon (ADH) miktarinin yetersizligi nedeniyle olusurken, nefrojenik diabetes insipidus ise ADH yapim ve salgilanmasinda herhangi bir bozukluk olmaksizin ADH ve benzerlerine bobregin yanit yetersizligi nedeniyle olusmaktadir (2,3).
Major haemodynamic changes definitely do occur after donor brain death, mainly owing to the diabetes insipidus caused by the brain oedema and elevated intracranial pressure.
Polyendocrinopathy was the most common morbidity, with hypothyroidism (96%), adrenocorticotropic hormone deficiency (84%), and diabetes insipidus (53%) occurring most frequently.
3) Diabetes insipidus is rarely a feature because the posterior lobe is usually not part of the adenoma.
In contrast to AVP, it is stable ex vivo (1) and reflects the AVP system, as shown in diabetes insipidus or the syndrome of inappropriate antidiuretic hormone secretion (2).
There was no evidence of hyperprolactinemia, diabetes insipidus, visual defects or any residual sellar tumor on MRI (Figure 2).
Involvement of the skull can also cause exophthalmos and diabetes insipidus.

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