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Patient Information PublicationsClinical CenterNational Institutes of Health

Diabetes Insipidus This information will give you and yourfamily basic facts about diabetesinsipidus. The glossary at the enddefines certain terms used throughout.If you have questions about the diagno -sis and treatment of this disorder, feelfree to talk with your physician andnurse. They will be glad to help you.

What is diabetes insipidus? Diabetes insipidus is a rare disorder ofwater metabolism. This means that thebalance between how much water orfluid you drink is not balanced with thefluid you urinate. Diabetes insipidus iscaused by a lack of, or nonresponse to,the antidiuretic hormone vasopressin.

This hormone controls water balance byconcentrating urine. Patients with dia-betes insipidus urinate too much, sothey need to drink a lot to replace thefluid they lose.

Vasopressin is made by the cells of thehypothalamus (located in the brain) andis stored and secreted by another partof the brain called the posterior pituitarygland. The antidiuretic hormone is then

released into the bloodstream where itcauses tubules within the kidney toreabsorb water. Water that cannot bereabsorbed is passed out of the body inthe form of urine. Decreased secretion

of vasopressin causes less water to bereabsorbed and more urine to beformed. When vasopressin is present atnormal levels, more water is reab -sorbed and less urine is formed.

You should not confuse diabetesinsipidus with the metabolic disease,

diabetes mellitus. Diabetes mellitus is adifferent disease caused by a lack of, oran impaired response to, the hormoneinsulin. This hormone is made by thepancreas and helps in carbohydratemetabolism.

Without insulin, a person cannot makeuse of the carbohydrates he or shetakes in, such as sugar. The hormoneinsulin affects sugar so that it can enter

the body's cells and be used for energy.When insulin is insufficient or not pres-ent, an abnormally high amount ofsugar will be in the blood and urine.The chart at the end of this bookletexplains in greater detail the differencebetween diabetes insipidus and dia-betes mellitus.

There are two types of diabetesinsipidus. While the symptoms of thesetwo disorders are similar, the causesare different. The next sectionsdescribe central diabetes insipidus andnephrogenic diabetes insipidus.

Patient Information Publications 1 Diabetes Insipidus

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Central diabetes insipidusIf you have been diagnosed with centraldiabetes insipidus, there are somethings you should know about how thedisorder is caused and what you andyour doctor can do about it.

What causes it?In central diabetes insipidus, the antidi-uretic hormone vasopressin is eithermissing or present at a low level. Thislow level or lack of vasopressin is due to

a malfunction in the part of your brain,the posterior pituitary gland, whichreleases the hormone into your blood-stream. Injury to the head, tumors, neu-rosurgical operations, infections, orbleeding can affect your brain's ability torelease the right amount of vasopressin.

What are the symptoms?! excessive urination (polyuria) which

is followed by

! excessive thirst (polydipsia)

Patients with central diabetes insipidusare often extremely tired because theycannot get enough sleep uninterruptedby the need to urinate. Their urine isvery clear and odorless. These symp-toms can appear at any time. Becausethey lose so much water from urination,they also feel very thirsty. If this disorderis untreated, they could become serious-ly dehydrated, and their bodies will nothave enough water to function properly.

Nephrogenic diabetesinsipidusNephrogenic diabetes insipidus is muchless common than central diabetesinsipidus. If you have been diagnosedwith nephrogenic diabetes insipidus,your doctor or nurse will discuss the dis-order and its treatment with you. Theywill be happy to answer your questions.

What causes it?Nephrogenic diabetes insipidus may be

caused by kidney diseases that makethe kidneys unable to respond to vaso-pressin. While there is enough vaso-pressin in the body (unlike in central dia-betes insipidus), the kidneys cannotrespond to the hormone's signal to reab-sorb water. The disease may beacquired or inherited by male children.

What are the symptoms?The symptoms of nephrogenic diabetesinsipidus are similar to central diabetesinsipidus; that is, excessive urination(polyuria) followed by excessive thirst(polydipsia).

How is it treated?The first step in treating this disease iscorrect diagnosis. In addition to the med-ications available, balancing your wateror fluid intake with your urine output isalso part of treatment. If this disorder isuntreated, you could become seriouslydehydrated, and your body will not haveenough water to function.


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What tests can find out if Ihave central diabetesinsipidus or nephrogenicdiabetes insipidus?The two most common tests used todiagnose diabetes insipidus are the fol-lowing:

! water deprivation test/vasopressintest

! hypertonic saline infusion test.

Other tests which may be used are theurine specific gravity test and the serumor urine osmolality test. These testsmeasure the concentration of solid parti-cles in your urine. Patients with diabetesinsipidus have urine with fewer solidsthan that of people without the disease.

With the water deprivation test, you willbe asked not to drink any fluids. Yourdoctor will tell you how long you mustabstain from drinking. Then, laboratorytests will be done to show any changein the amount and concentration of par-ticles in your urine.

The vasopressin test is done if thewater deprivation test does not result insufficiently concentrated urine.Vasopressin is given by the doctor ornurse by injection to test your body'sreaction to the hormone.

During the hypertonic saline infusion

test, you will receive a mixture of saltand water by intravenous infusion. Yourdoctor or nurse will then draw bloodfrom you which will be tested forosmolality and vasopressin content.

The serum or urine osmolality test isdone to find out the concentration ofparticles in your blood or urine.

The urine specific gravity test is also away to find out the concentration ofsolid particles in urine. Patients with dia -betes insipidus have fewer particles inurine, so their specific gravity measure-ments will be below normal.

What is the therapy forcentral diabetes insipidus?If you are treated for central diabetes

insipidus, you will sniff a drug calledDDAVP (Desmopressin), a derivative ofvasopressin. You will be shown the rightway to use this drug by your physician,nurse, or pharmacist.

What is the therapy fornephrogenic diabetesinsipidus?If you have nephrogenic diabetesinsipidus, water pills (thiazide diuretics)may be prescribed by your doctor. Youmay be confused as to why you need totake diuretics for this disorder. Thiazidediuretics have been shown to stimulatethe production of a hormone that helpsyour body retain salt. This addedamount of salt keeps you from losingtoo much water.

What should I do whileI am being treated fordiabetes insipdus?It is important for you to rememberthese things while you are treated fordiabetes insipidus:


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It is very important that you balanceyour water intake with your urinary out-put. However, it is also very importantthat you do not drink too much water. Ifyou drink too much water, this couldcause very serious side effects. This isthe reason why it is so important for youand your physician to discuss a specificplan to meet your individual needs.

Call your doctor or nurse when younotice that you cannot balance your uri-nary output with your water intake. Asign of this imbalance is that you will uri-nate a large amount of clear, odorlessfluid. After urination, you will be verythirsty and feel the need to drink a largeamount of water.

Call your doctor or nurse if you haveside effects from the medications thatwere ordered for you. When you are atthe Clinical Center, your physician,nurse, or pharmacist will discuss withyou how the drugs work, how and whento take them, and their side effects. Youmay also want to refer to any writteninformation they give you.

And of course, always feel free to askyour doctor or nurse any questions youhave about your diagnosis and treat -ment.

True/False statements

1 .Q:

A:

Excessive urination is polydipsia.

False .

Excessive urination is calledpolyuria.

Patient Information Publications

2 . Q: Patients who have diabetesinsipidus are seldom very thirsty.

A: False . Patients are usually verythirsty. The medical termfor this thirst is polydipsia.

3. Q: Call your doctor or nurse if youcannot balance your fluid intakeand fluid output.

A: True . This is necessary so that

too much water is not lostbefore medical action canbe taken.

4. Q: Patients with diabetes insipidusbecome dehydrated if their fluidintake and fluid output are notbalanced.

A: True .

5. Q:

The lack of or deficiency of theantidiuretic hormone vasopressincauses central diabetesinsipidus.

A: True .

6. Q: Infections, tumors, neurosurgicaloperations, bleeding, and headinjuries may cause central dia-betes insipidus.

A: True .

7. Q: Nephrogenic diabetes insipidus isacquired or may be inherited bymale children.

A: True .

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8. Q: In diabetes mellitus, the hormonevasopressin (made in the pancreas)

is deficient, or the body's cells areunresponsive to it.

A: False .Remember, diabetes mellitusis not the same as diabetesinsipidus. The hormone lacking indiabetes mellitus is insulin.

9. Q: Patients do not need to call theirdoctor or nurse if they can't balance

their fluid intake and fluid output.A: False.

Patients should call their doc-tor or nurse so that they do notbecome dehydrated.

Glossary

Antidiuretic Any agent that reduces the output of urine.

Central diabetes insipidus A metabolic disease caused by the lack ofthe antidiuretic hormone vasopressin, or apoor response to it. Symptoms of this dis-ease are excessive urination of largeamounts of colorless urine followed byexcessive thirst. It is not related to diabetesmellitus.

Dehydration

A condition that results from the body losingtoo much water.

Diabetes A general term relating to disorders charac-terized by excessive urine excretion

(polyuria) as in diabetes mellitus anddiabetes insipidus. When used alone, the

term refers to diabetes mellitus.Diabetes insipidus: central andnephrogenicDisorders of water balance.

Diabetes mellitus A chronic disease caused by a lack of thehormone insulin or a poor response to it.

Diuretics (thiazide)Substances that increase the amount of

urine excreted.Hypertonic saline test

A test that involves water loading and salineinfusion. After this, blood is drawn for meas-uring osmolality and vasopressin content.

Hypothalamus A part of the brain located below the cere-brum. Here, nerve cells form vasopressinthat concentrates urine.

Insulin A hormone formed in the pancreas andsecreted in the blood for proper fat, protein,and carbohydrate metabolism.

KidneysTwo abdominal organs located in the lowerback. The kidneys filter the blood andexcrete the end products of body metabo-lism in the form of urine. The kidneys regu-late all the water in the body by selectively

excreting or reabsorbing water, resulting indiluted or concentrated urine.

Nephrogenic diabetes insipidus A rare disorder of water metabolism


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and is stored and secreted

Comparison of Diabetes Insipidus and Diabetes Mellitus

Central diabetes Nephrogenic diabetes Diabetes mellitusinsipidus insipidus

How common Uncommon Uncommon Commonis the disease?

What causes The mechanism for The kidneys are unable Enough of the hormonethe disease? secreting vasopressin to respond to the diuretic insulin is not secreted,

malfunctions. hormone vasopressin. or the bodys cells do notIt is acquired or may be respond to it. Heredity,inherited by male children. o b e s i t y, pregnancy, and

drugs can also leadto diabetes mellitus.

What do these Vasopressin is a Vasopression causes Insulin is made in thehormones do hormone that controls tubules within the kidney pancreas, where itand why are water metabolism. It is to reabsorb water. Water controls carbohydratethey important? made in the hypothalamus that is not absorbed metabolism. It controls

(a part of the brain) is released as urine. sugar (glucose) levels

in the body.by the posterior pituitarygland (also in the brain)

What are the signs Sudden or gradual urina- Same as central diabetes Excessive urinationsymptoms tion of large amounts of insipidus: polyuria (polyuria), excessiveof the disease? clear, colorless fluid, followed by polydipsia. thirst (polydipsia), and

followed by excessive excessive appetitethirst (polydipsia). (polyphagia). May beDehydration can occur sudden or gradual withif fluid balance is no symptoms. Tired-not maintained. ness, weight gain or

loss, skin infectionsthat do not heal.

What diagnostic Water deprivation test/ Water deprivation test/ Fasting blood sugartests detect the vasopressin test. vasopressin test. 2-hour post-prandial testdisease? blood sugar test

Hypertonic saline Hypertonic saline Glucose tolerance testinfusion test. infusion test. Hemoglobin A1C blood test

What treatments Balance fluid intake Balance urine output Correct sugar/insulincombat the and urine output. with fluid intake. intake.disease?

Replace antidiuretic Diuretics. Prevent progressionhormone, vasopressin, of disease.find, if possible, under-lying cause of disease. Diet.

Oral or injectablemedication.


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This information is prepared specifically forp a t i e n t s part icipating in clinical research atthe Clinical Center at the National Institutesof Health and is not necessarily applicableto individuals who are patients elsewhere. Ifyou have questions about the informationpresented here, talk to a member of yourhealthcare team.

2006Where applicable, brand names of commer-cial products are provided only as illustra-tive examples of acceptable products, anddo not imply endorsement by NIH; nor doesthe fact that a particular brand name prod-uct is not identified imply that such productis unsatisfactory.

National Institutes of HealthNIH Clinical CenterBethesda, MD 20892

Questions about the Clinical [email protected]

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