MedlinePlus Medical Encyclopedia: Diabetes insipidus

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Diabetes insipidus - central

Contents of this page:
Illustrations Alternative names Definition Causes, incidence, and risk factors Symptoms Signs and tests	Treatment Expectations (prognosis) Complications Calling your health care provider Prevention

Illustrations

Endocrine glands

Alternative names Return to top

Central diabetes insipidus

Definition Return to top

Central diabetes insipidus is a rare condition -- marked by extreme thirst and excessive urine output -- caused by a deficiency of the hormone vasopressin that normally would limit the amount of urine made. See also diabetes insipidus - nephrogenic.

Causes, incidence, and risk factors Return to top

Central diabetes insipidus is a rare condition caused by damage to the hypothalamus or pituitary gland in the brain. Damage may be related to surgery, infection, inflammation, tumor, or injury to the head. Sometimes the cause remains unknown. Very rarely, diabetes insipidus can be caused by a genetic defect.

Normally, the hypothalamus in the brain makes vasopressin, a hormone that causes the kidneys to conserve water by making concentrated urine. In diabetes insipidus, there is a lack of vasopressin. Without vasopressin, the kidneys fail to reabsorb excess filtered water. This results in a rapid loss of water from the body in the form of dilute urine.

A person with diabetes insipidus drinks large quantities of water, driven by extreme thirst, to compensate for the water loss.

Symptoms Return to top

Increased urine volume
Excessive thirst
Confusion and changes in consciousness if the patient is unable to drink

Signs and tests Return to top

Urinalysis
Low urine salt concentration
Urine output greater than 3 liters a day
Water restriction test: while the patient is hospitalized -- urine volume and ability of the kidney to concentrate urine is evaluated every hour, plasma sodium concentration is evaluated every 2 hours
MRI of the head, revealing an abnormality in or near the pituitary gland
Blood serum sodium/salt concentration may be high if the condition is untreated

Treatment Return to top

The cause of the underlying condition should be treated.

Vasopressin (desmopressin) will be administered either as a nasal spray, oral tablets, or injections under the skin. This controls the urine output and fluid balance, and prevents dehydration.

In mild cases, increased water intake may be all that is needed. If the thirst mechanism is not working (for example, if a part of the brain called the hypothalamus is damaged), a prescription for a certain amount of water intake may also be needed (usually 2-2.5 L per day) to ensure proper hydration.

Expectations (prognosis) Return to top

The outcome is dictated by the underlying disorder. If treated, diabetes insipidus does not cause severe problems or reduce life expectancy.

Complications Return to top

Dehydration
Electrolyte imbalance
Confusion and changes in mental status may develop if the condition is not treated. All patients with diabetes insipidus should wear a medic alert bracelet or necklace to alert care givers to this condition in an emergency situation

Calling your health care provider Return to top

Call your health care provider if symptoms indicate diabetes insipidus may be present.

Prevention Return to top

Many of the cases may not be preventable. Prompt treatment of infections, tumors and injuries may reduce risk.

Update Date: 8/6/2004

Updated by: Aniket R. Sidhaye, M.D., Division of Endocrinology and Metabolism, Johns Hopkins University School of Medicine, Baltimore, MD. Review provided by VeriMed Healthcare Network.

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