| Subject | Contents |
| Definition | A condition marked by extreme thirst and excessive urine output caused by a deficiency of a hormone ( vasopressin ) that normally would limit the amount of urine made. See also diabetes insipidus - nephrogenic .
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| Alternative Names | Central diabetes insipidus
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| Causes, incidence, and risk factors | 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 | Increased urine volumeExcessive thirst Confusion and changes in consciousness if the patient is unable to drink |
| Signs and tests | 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 two 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 | 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 presciption for a certain amount of water intake may also be needed (usually 2-2.5 L per day) to ensure proper hydration. |
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| Expectations (prognosis) | The outcome is dictated by the underlying disorder. If treated, diabetes insipidus does not cause severe problems or reduce life expectancy. |
| Complications | DehydrationElectrolyte imbalance Confusion and changes in mental status can 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 | Call your health care provider if symptoms indicate diabetes insipidus may be present. |
| Prevention | Many of the cases may not be preventable. Prompt treatment of infections, tumors and injuries may reduce risk. |
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