Cranial diabetes insipidus is a rare condition that results in persistent thirst and frequent urination. It occurs due to problems with arginine vasopressin (AVP), a hormone that plays a role in kidney function.

Cranial diabetes insipidus is also known as central diabetes insipidus or AVP deficiency (AVP-D).

It is a rare condition that results in persistent thirst and frequent urination. Cranial diabetes insipidus develops due to problems with the hypothalamus or pituitary gland and the production or action of the hormone vasopressin.

Also known as antidiuretic hormone, vasopressin communicates with the kidneys. When a person does not produce enough, or vasopressin does not function correctly, the kidneys may excrete too much water through urination.

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AVP-D is a rare endocrine condition, meaning it occurs due to a problem with hormones. Although rare, it is the most common form of diabetes insipidus, affecting roughly 1 in 25,000 people.

Formerly known as cranial or central diabetes insipidus, health experts agreed to change the name to AVP-D. This is to help prevent potential confusion between diabetes insipidus and diabetes mellitus.

AVP-D occurs due to problems with the production or action of the hormone AVP, also known as antidiuretic hormone. AVP plays a key role in maintaining the body’s fluid balance by communicating with the kidneys.

Usually, an adult may pass around 1 to 2 liters (L) of urine per day. However, with AVP-D, a person will typically pass more than 3 to 3.5 L of urine per day. In severe cases, some people may produce more than 15 L daily.

AVP-D occurs due to problems with the hormone vasopressin. It develops when the body either produces too little AVP, or it does not function correctly.

Vasopressin is responsible for regulating bodily fluids. One way it does this is by communicating with the kidneys to control the amount of urine the body produces. However, if it does not produce enough functioning vasopressin, the body releases excess fluid in urine.

Many cases of AVP-D are idiopathic, meaning they have no known cause. However, the condition often relates to damage to the hypothalamus or pituitary gland. The hypothalamus refers to the part of the brain that produces vasopressin, and the pituitary gland is an endocrine gland at the base of the brain that secretes the hormone into the bloodstream.

Health experts may categorize possible causes of AVP-D as either primary or secondary. Some evidence suggests that primary AVP-D occurs due to genetic variations that impair the production or secretion of vasopressin. Secondary causes refer to conditions and injuries that affect vasopressin production. These can include brain lesions resulting from head injuries, cancers, or brain surgery.

In addition to cranial diabetes insipidus, other types of the condition include:

  • Nephrogenic diabetes insipidus: This type is also known as arginine vasopressin resistance (AVP-R). Although the body produces enough vasopressin, the condition develops as the kidneys do not respond correctly to the hormone. This results in the body excreting too much fluid in the urine.
  • Dipsogenic diabetes insipidus: This type occurs due to a problem with the hypothalamus. Often due to trauma such as brain surgery or a major head injury, a person experiences constant thirst and drinks more fluids, resulting in the need for frequent urination.
  • Gestational diabetes insipidus: As the name implies, this is a temporary condition that can develop during pregnancy. It occurs when a pregnant person produces too much of an enzyme that breaks down vasopressin.

The main symptoms of AVP-D are excessive thirst, known as polydipsia, and frequent urination, known as polyuria, even at night, which is known as nocturia. Thirst cravings can also be strong enough to wake people up at night.

People living with AVP-D are at risk of experiencing dehydration due to excessive production of dilute urine. This loss of fluids may also increase the risk of hypernatremia. This describes excessive levels of sodium in the blood.

Other symptoms may include:

  • weakness
  • lethargy
  • fatigue
  • muscle aches and pain

The diagnostic process for diabetes insipidus will initially involve a physical exam and reviewing personal and family history. Symptoms such as excessive thirst and urination can indicate diabetes insipidus.

If a doctor suspects the condition, they will request specialized tests. These tests can help distinguish diabetes insipidus from other conditions and help determine the subtype.

These tests may include:

  • Blood and urine tests: A doctor can analyze these samples to determine the concentration of salts and sugars. For example, if blood sugar levels are within range and blood sodium levels are high, this could suggest AVP-D.
  • Water deprivation tests: This test involves an individual avoiding drinking fluids for several hours. A doctor will then measure the amount of urine a person passes and track changes in their blood and urine.
  • Stimulation tests: This test describes when a person receives a solution through an intravenous (IV) line that stimulates vasopressin production. Doctors will then measure levels of copeptin in the blood. This is a substance that increases with increasing levels of vasopressin.
  • Imaging scans: A doctor may also request imaging tests, such as CT or MRI scans, to see if they can identify any damage to the hypothalamus or pituitary gland.

Treatment options for AVP-D will vary depending on the severity of the condition. For example, with mild AVP-D, a person may just need to drink water when necessary.

In more severe cases, a person may require desmopressin. This refers to a synthetic form of vasopressin that is available as a nasal spray, tablet or other oral forms, and through an IV. As a synthetic version of vasopressin, the drug acts on vasopressin receptors to help the body regulate the fluid in urine.

In other cases, a person may require treatment for an underlying condition causing AVP-D. For example, if AVP-D develops due to a tumor, a person may undergo surgery or receive radiation or immunotherapy to treat the tumor.

Cranial diabetes insipidus, also known as arginine vasopressin deficiency, refers to a condition that causes excessive thirst and urination. It is the most common subtype of diabetes insipidus. It typically occurs due to a deficiency in functioning vasopressin. This is a hormone that helps regulate the amount of fluid in urine.

In many cases, the exact cause is unknown. In other cases, it may occur due to problems or damage to the hypothalamus or pituitary gland. Treatment will typically involve a synthetic version of vasopressin or management of an underlying cause.