Diabetes insipidus is a condition in which the body loses too much fluid through urination, causing a significant risk of dangerous dehydration and a range of other conditions.

Diabetes insipidus, which health experts also call water diabetes, is a rare condition that affects roughly 1 in every 25,000 people in the United States.

It develops when the kidneys are unable to prevent the excretion of water, resulting in constant thirst and frequent urination. Usually, a person will produce about 2 quarts (qt) of urine per day. People with diabetes insipidus may produce up to 20 qt of urine daily.

While the condition shares a name with diabetes mellitus and may present with similar symptoms, they are unrelated. Diabetes mellitus affects blood sugar, which may cause a person to urinate more often to remove the extra glucose. By contrast, diabetes insipidus affects the kidneys’ ability to properly concentrate urine.

Diabetes insipidus usually does not cause serious problems. Typically, people can manage the condition by drinking enough water to stay hydrated. However, this can be more difficult for those who may have trouble addressing their thirst, such as infants or older adults. In these individuals, diabetes insipidus can result in severe complications, such as confusion, seizures, brain damage, or death.

The condition takes two main forms: central diabetes insipidus and nephrogenic diabetes insipidus. In the former, the pituitary gland fails to secrete the antidiuretic hormone vasopressin, which regulates bodily fluids. In the latter, vasopressin secretion is not affected, but the kidneys do not respond to the hormone correctly.

Diabetes insipidus is not a common condition, and therefore, diagnosis can be challenging and involves ruling out other possible explanations for symptoms.

In this article, we discuss diabetes insipidus in detail, including its symptoms, possible causes, and diagnosis.

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The two main symptoms of diabetes insipidus are the frequent urge to pass high volumes of diluted urine and excessive thirst. These symptoms are also known as polyuria and polydipsia, respectively, and they are two of the three polys of diabetes.

Other symptoms of diabetes insipidus can include:

  • waking up frequently to urinate
  • experiencing bed wetting
  • passing colorless urine
  • having dry skin
  • having constipation
  • experiencing muscle weakness

As a result of these symptoms, people may also experience dehydration and disrupted sleep. Without sufficient treatment, diabetes insipidus can also lead to permanent kidney damage.

Additionally, infants with diabetes insipidus may have the following symptoms:

  • irritability
  • poor feeding
  • stalled growth
  • high fever

Typically, diabetes insipidus occurs due to problems with vasopressin. This hormone is responsible for helping the kidneys balance the amount of fluid and electrolytes in the body.

While many cases of diabetes insipidus have no known cause, certain factors may contribute, such as:

  • a tumor in or near the pituitary gland
  • damage to the hypothalamus or pituitary gland during surgery
  • insufficient vasopressin production by the hypothalamus
  • failure of the pituitary gland to release vasopressin into the bloodstream
  • a brain injury or inflammation
  • genetic conditions
  • certain medications
  • kidney disease

Specific causes may vary among the four types of diabetes insipidus, which we describe in the sections below.

Central diabetes insipidus

Central diabetes insipidus develops due to a reduction or absence of vasopressin. The condition can be present from birth, which health experts also call primary central diabetes insipidus. A person may acquire secondary central diabetes insipidus later in life.

The cause of primary central diabetes insipidus often remains unknown. Some causes result from an abnormality in the gene responsible for vasopressin secretion.

The secondary type may occur due to conditions and injuries that affect vasopressin production. These can include brain lesions resulting from head injuries, cancers, or brain surgery.

Other systemic, or body-wide, conditions and infections can also trigger central diabetes insipidus.

Nephrogenic diabetes insipidus

An individual can inherit or acquire nephrogenic diabetes insipidus. This type affects the response of the kidneys to vasopressin, which can affect water balance to varying degrees.

Nephrogenic diabetes insipidus can have numerous causes, including:

  • kidney cysts that have developed due to a number of conditions, such as:
    • autosomal dominant polycystic kidney disease
    • nephronophthisis
    • medullary cystic disease complex
    • medullary sponge kidney
  • the release of an outlet tube obstruction from a kidney
  • kidney infection
  • high blood calcium levels
  • some cancer types
  • certain medications, especially lithium, but also:
    • demeclocycline
    • amphotericin B
    • dexamethasone
    • dopamine
    • ifosfamide
    • ofloxacin
    • orlistat
  • rarer conditions, including:
  • chronic hypokalemic nephropathy, a kidney disease that develops due to low blood potassium levels

Gestational diabetes insipidus

In rare cases, pregnancy can cause a disturbance of vasopressin, especially during the third trimester. This occurs due to the placenta releasing an enzyme that degrades vasopressin.

Pregnancy also causes a lower thirst threshold, making a person drink more fluids, while other, typical physiological changes during pregnancy can also affect the kidneys’ response to vasopressin.

Gestational diabetes insipidus is treatable during gestation and typically resolves a couple of weeks after childbirth. The condition affects only a few individuals in every 100,000 pregnant people.

Dipsogenic diabetes insipidus

This type results from an issue with the hypothalamus, which affects an individual’s sense of thirst, causing them to drink and urinate more often.

Causes can include:

  • damage to the hypothalamus from:
    • surgery
    • infection
    • inflammation
    • a tumor
    • a head injury
  • mental health conditions
  • some medications

The main goal of treatment for all types of diabetes insipidus is to relieve thirst and decrease urine production.

Typically, treatment for most types of diabetes insipidus in both adults and children will involve the administration of desmopressin (DDAVP). This medicine is a synthetic version of vasopressin and is available in many different forms, such as tablet, injection, and nasal spray.

DDAVP replaces the vasopressin the body is not producing. However, it is important to use the correct dose of DDAVP and only use it when necessary. This is because too much may cause the body to retain too much fluid and develop hyponatremia.

As the nephrogenic type occurs due to the kidneys not responding to vasopressin, DDAVP is not a suitable treatment. Instead, a doctor will attempt to treat the underlying cause, which may include switching medications or prescribing a class of diuretics known as thiazides to help reduce the amount of urine the kidneys produce.

Additionally, a doctor may recommend:

  • taking anti-inflammatory medicines, such as nonsteroidal anti-inflammatory drugs
  • taking other types of diuretics
  • lowering one’s intake of salt and protein in their diet to help the kidneys make less urine

Due to its prevalence and sharing symptoms with other conditions, diabetes insipidus can be difficult to diagnose.

Typically, a doctor will perform a physical examination, view medical history, and ask questions about symptoms. They may also request tests and procedures such as:

  • Urinalysis: This test can help determine whether urine is too diluted. Additionally, it can measure glucose levels in the urine to help distinguish between diabetes mellitus and insipidus.
  • Blood tests: These tests measure the levels of electrolytes and other substances in the blood. They may also help determine the type of diabetes insipidus.
  • Water deprivation test: This involves a person refraining from drinking any fluids for several hours to induce dehydration. A doctor will then measure the amount of urine they pass, their weight, and any changes in blood and urine. They may also administer vasopressin or other medicines during the test. This may help identify the cause of diabetes insipidus as well.
  • Imaging: A doctor may suggest imaging tests, such as MRI scans, to identify any damage to the hypothalamus or pituitary gland.
  • Stimulation tests: A healthcare professional will administer a solution that stimulates the body to produce vasopressin. They will then measure blood for copeptin, a substance that increases with vasopressin. Results can help determine whether a person has diabetes insipidus or a different condition known as primary polydipsia, which can also cause people to drink large quantities of fluids.

In addition to helping determine whether an individual has diabetes insipidus or another condition, these diagnostic tests can also indicate the type and causes of the condition. This in turn can help guide appropriate treatment options and management strategies.

Differential diagnosis for diabetes insipidus can include diabetes mellitus, or side effects from current courses of medication, such as diuretics, which may affect water balance.

Diabetes insipidus and diabetes mellitus are not related. While the names and some symptoms may be similar, the two conditions have very different causes and treatment options.

The words “mellitus” and “insipidus” come from the early days of diagnosing the condition. Doctors would taste the urine to gauge sugar content. If the urine tasted sweet, it meant sugar was present, and diabetes mellitus was a likely diagnosis.

However, if the urine was bland or neutral, due to being too diluted, it would indicate diabetes insipidus. The term “insipidus” derives from the word “insipid,” meaning “weak” or “tasteless.”

In diabetes mellitus, elevated blood sugar prompts the production of large volumes of urine to help remove the excess sugar from the body. In diabetes insipidus, it is the water balance system that is not functioning effectively.

Diabetes mellitus is far more common than diabetes insipidus. However, diabetes insipidus progresses far more rapidly. Of the two conditions, diabetes mellitus can result in more complications and is typically more difficult to manage.

Diabetes insipidus is often difficult, if not impossible, to prevent, as it results from either genetic issues or other conditions.

However, it is possible to manage symptoms effectively. It is often a lifelong condition, but with ongoing treatment, the outlook can be positive.

Diabetes insipidus is a rare condition that affects how the kidneys maintain fluid balance in the body. It causes excessive urine production, which results in frequent urination and persistent thirst.

There are many types and causes, but it typically occurs due to problems with vasopressin, which is a hormone that regulates bodily fluids.

Diagnosing diabetes insipidus can be difficult and may involve ruling out other conditions with similar symptoms, such as diabetes mellitus.

Individuals can usually manage the condition by drinking sufficient amounts of water and taking medications to stay hydrated.