Central (Neurogenic) Diabetes Insipidus
What Are the Symptoms of Central Diabetes Insipidus?
People with central diabetes insipidus may appear totally normal upon physical exam. They may have no apparent signs except for the possibility of an enlarged bladder or symptoms of dehydration.
A person with central diabetes insipidus usually experiences the following symptoms:
- Frequent urination -- more than 3 liters of urine a day
- Frequent nighttime awakening to urinate
- Involuntary urination during sleep (bedwetting)
- Pale, colorless urine
- Low measured concentration of urine
- Excessive thirst -- often drinking more than 1 gallon of liquid per day
In severe cases, or if a person can't get enough liquid to drink, central diabetes insipidus can cause:
- Loss of consciousness
Symptoms of central diabetes insipidus in children may be:
- Growth retardation
- Weight loss
How Is Central Diabetes Insipidus Diagnosed?
To determine if you have central DI, doctors will complete a series of tests, including urinalysis and a water restriction test. Urinalysis is used to check for a low concentration of salt in the urine. A water restriction test is generally done during a hospital stay. During a period of water restriction, kidney function and the amount of urine being produced are checked. A blood test checking the plasma sodium concentration is performed every two hours. Vasopressin may be given, after which blood and urine are again checked to see if there's a response.
Doctors may also order a scan of the head called magnetic resonance imaging (MRI). The MRI is used to determine if there are any problems in or around the pituitary gland. Because the antidiuretic hormone, vasopressin, is stored by the pituitary, this gland is often the source of the problem with central diabetes insipidus.
How Is Central Diabetes Insipidus Treated?
Central diabetes insipidus is usually a permanent condition that occurs when the hypothalamus is unable to produce more vasopressin and the store of vasopressin in the pituitary gland has run out. Although central DI cannot be cured, treatment is available for controlling symptoms such as excessive thirst, over consumption of water, and excessive urination. Treatment is also necessary to manage whatever underlying condition may be causing the central DI.
Your doctor may prescribe a medication called desmopressin or DDAVP. This is a modified form of vasopressin. Desmopressin is taken to control urine output, maintain fluid balance, and prevent dehydration. The medication is taken two to three times a day and is usually delivered in the form of a nasal spray, oral tablets, or injections.
In some cases, the treatment for central diabetes insipidus is simple -- drink more water. Many doctors recommend drinking more water to ensure proper hydration in people with mild cases of central diabetes insipidus. If you've lost the feeling of thirst, the doctor may prescribe a certain amount of water to be ingested each day to prevent dehydration and keep you well. Typically, the prescribed amount of water is about 2 to 2.5 liters a day.
If you have central diabetes insipidus, you should always carry medication with you. You also need to avoid situations where water may be unavailable. In addition, be sure to wear some form of "medic alert" jewelry in order to notify health care providers of your central diabetes insipidus in case of an emergency.