Diabetes insipidus (die-uh-BEE-teze in-SIP-uh-dus) is an uncommon disorder that causes an imbalance of fluids in the body. This imbalance leads you to produce large amounts of urine. It also makes you very thirsty even if you have something to drink.

While the terms "diabetes insipidus" and "diabetes mellitus" sound similar, they're not related. Diabetes mellitus — which involves high blood sugar levels and can occur as type 1 or type 2 — is common and often referred to simply as diabetes.

There's no cure for diabetes insipidus. But treatments can relieve your thirst and decrease your urine output and prevent dehydration.

Signs and symptoms of diabetes insipidus include:

• Being extremely thirsty
• Producing large amounts of pale urine
• Frequently needing to get up to urinate during the night
• Preferring cold drinks

If your condition is serious and you drink a lot of fluids, you can produce as much as 20 quarts (about 19 liters) of urine a day. A healthy adult typically urinates an average of 1 to 2 quarts (about 1 to 2 liters) a day.

An infant or young child with diabetes insipidus may have the following signs and symptoms:

• Heavy, wet diapers
• Bed-wetting
• Trouble sleeping
• Fever
• Vomiting
• Constipation
• Delayed growth
• Weight loss

When to see a doctor

See your doctor immediately if you notice excessive urination and extreme thirst.

Diabetes insipidus occurs when your body can't properly balance the body's fluid levels.

Your kidneys filter the fluid portion of your blood to remove waste products. The majority of the fluid is returned to the bloodstream while the waste and a smaller amount of fluid make up urine. Urine is excreted from your body after being temporarily stored in your bladder.

A hormone called anti-diuretic hormone (ADH), or vasopressin, is needed for the fluid that's filtered by the kidneys to go back into the bloodstream. ADH is made in a part of the brain called the hypothalamus and stored in the pituitary gland, a small gland found in the base of the brain. Conditions that cause a deficiency of ADH or block the effect of ADH result in production of excess urine.

If you have diabetes insipidus, your body can't properly balance fluid levels. The cause depends on the type of diabetes insipidus you have. Types include:

• Central diabetes insipidus. Damage to the pituitary gland or hypothalamus from surgery, a tumor, head injury or illness can cause central diabetes insipidus by affecting the usual production, storage and release of ADH. An inherited genetic disease also can cause this condition.

• Nephrogenic diabetes insipidus. Nephrogenic diabetes insipidus occurs when there's a defect in the structures in your kidneys that makes your kidneys unable to properly respond to ADH.

  The defect may be due to an inherited (genetic) disorder or a chronic kidney disorder. Certain drugs, such as lithium or antiviral medications such as foscarnet (Foscavir), also can cause nephrogenic diabetes insipidus.

• Gestational diabetes insipidus. Gestational diabetes insipidus is rare. It occurs only during pregnancy when an enzyme made by the placenta destroys ADH in the mother.

• Primary polydipsia. Also known as dipsogenic diabetes insipidus, this condition can cause production of large amounts of diluted urine from drinking excessive amounts of fluids.

  Primary polydipsia can be caused by damage to the thirst-regulating mechanism in the hypothalamus. The condition has also been linked to mental illness, such as schizophrenia.

Sometimes, there's no obvious cause of diabetes insipidus. However, in some people, the disorder may be the result of an autoimmune reaction that causes the immune system to damage the cells that make vasopressin.

Nephrogenic diabetes insipidus that's present at or shortly after birth usually has an inherited (genetic) cause that permanently changes the kidneys' ability to concentrate urine. Nephrogenic diabetes insipidus usually affects males, though women can pass the gene on to their children.

Dehydration

Diabetes insipidus may lead to dehydration. Dehydration can cause:

• Dry mouth
• Changes in skin elasticity
• Thirst
• Fatigue

Electrolyte imbalance

Diabetes insipidus can cause an imbalance in minerals in your blood, such as sodium and potassium (electrolytes), that maintain the fluid balance in your body. Symptoms of an electrolyte imbalance may include:

• Weakness
• Nausea
• Vomiting
• Loss of appetite
• Muscle cramps
• Confusion

Tests used to diagnose diabetes insipidus include:

• Water deprivation test. While being monitored by a doctor and health care team, you'll be asked to stop drinking fluids for several hours. To prevent dehydration while fluids are restricted, ADH allows your kidneys to decrease the amount of fluid lost in the urine.

  While fluids are being withheld, your doctor will measure changes in your body weight, urine output, and the concentration of your urine and blood. Your doctor may also measure blood levels of ADH or give you synthetic ADH during this test. This will determine if your body is producing enough ADH and if your kidneys can respond as expected to ADH.

• Magnetic resonance imaging (MRI). An MRI can look for abnormalities in or near the pituitary gland. This test is noninvasive. It uses a powerful magnetic field and radio waves to construct detailed pictures of brain tissues.
• Genetic screening. If others in your family have had problems with excess urination, your doctor may suggest genetic screening.

Treatment options depend on the type of diabetes insipidus you have.

• Central diabetes insipidus. If you have mild diabetes insipidus, you may need only to increase your water intake. If the condition is caused by an abnormality in the pituitary gland or hypothalamus (such as a tumor), your doctor will first treat the abnormality.

  Typically, this form is treated with a synthetic hormone called desmopressin (DDAVP, Nocdurna). This medication replaces the missing anti-diuretic hormone (ADH) and decreases urination. You can take desmopressin in a tablet, as a nasal spray or by injection.

  Most people still make some ADH, though the amount can vary day to day. So, the amount of desmopressin you need also may vary. Taking more desmopressin than you need can cause water retention and potentially serious low-sodium levels in the blood.

  Other medications might also be prescribed, such as chlorpropamide. This can make ADH more available in the body.

• Nephrogenic diabetes insipidus. Since the kidneys don't properly respond to ADH in this form of diabetes insipidus, desmopressin won't help. Instead, your doctor may prescribe a low-salt diet to reduce the amount of urine your kidneys make. You'll also need to drink enough water to avoid dehydration.

  Treatment with the drug hydrochlorothiazide (Microzide) may improve your symptoms. Although hydrochlorothiazide is a type of drug that usually increases urine output (diuretic), it can reduce urine output for some people with nephrogenic diabetes insipidus.

  If your symptoms are due to medications you're taking, stopping these medicines may help. However, don't stop taking any medication without first talking to your doctor.

• Gestational diabetes insipidus. Treatment for most people with gestational diabetes insipidus is with the synthetic hormone desmopressin.
• Primary polydipsia. There is no specific treatment for this form of diabetes insipidus, other than decreasing fluid intake. If the condition is related to a mental illness, treating the mental illness may relieve the diabetes insipidus symptoms.

If you have diabetes insipidus:

• Prevent dehydration. As long as you take your medication and have access to water when the medication's effects wear off, you'll prevent serious problems. Plan ahead by carrying water with you wherever you go and keep a supply of medication in your travel bag, at work or at school.
• Wear a medical alert bracelet or carry a medical alert card in your wallet. If you have a medical emergency, a health care professional will recognize immediately your need for special treatment.

You're likely to first see your primary care doctor. However, in some cases when you call to set up an appointment you may be referred to a specialist called an endocrinologist.

Here's some information to help you get ready for your appointment.

What you can do

• Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance. Your doctor may ask you to stop drinking water the night before but do so only if your doctor asks you to.
• Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment. Be prepared to answer specific questions about how often you urinate and how much water you drink each day.
• Write down key personal information, including any major stresses or recent life changes.
• Make a list of your key medical information, including recent surgical procedures, the names of all medications you're taking and doses, and any other conditions for which you've recently been treated. Your doctor will also want to know about any recent injuries to your head.
• Take a family member or friend along, if possible. Sometimes it can be difficult to remember all the information provided to you during an appointment. Someone who accompanies you may remember something that you missed or forgot.
• Write down questions to ask your doctor.

For diabetes insipidus, some basic questions to ask your doctor include:

• What's the most likely cause of my symptoms?
• What kinds of tests do I need?
• Is my condition likely temporary or will I always have it?
• What treatments are available, and which do you recommend for me?
• How will you monitor whether my treatment is working?
• Will I need to make any changes to my diet or lifestyle?
• Will I still need to drink a lot of water if I'm taking medications?
• I have other health conditions. How can I best manage these conditions together?
• Are there any dietary restrictions I need to follow?
• Are there brochures or other printed material I can take home or websites you recommend?

What to expect from your doctor

Your doctor is likely to ask you several questions, including:

• When did you begin experiencing symptoms?
• How much more are you urinating than usual?
• How much water do you drink each day?
• Do you get up at night to urinate and drink water?
• Are you pregnant?
• Are you being treated, or have you recently been treated for other medical conditions?
• Have you had any recent head injuries, or have you had neurosurgery?
• Has anyone in your family been diagnosed with diabetes insipidus?
• Does anything seem to improve your symptoms?
• What, if anything, appears to worsen your symptoms?

What you can do in the meantime

While you're waiting for your appointment, drink until your thirst is relieved, as often as necessary. Avoid activities that might cause dehydration, such as physical exertion or spending time in the heat.