What are the types of diabetes insipidus?
Central Diabetes Insipidus
The most common form of serious diabetes insipidus, central diabetes insipidus, results from damage to the pituitary gland, which disrupts the normal storage and release of ADH. Damage to the pituitary gland can be caused by different diseases as well as by
head injuries, neurosurgery, or
genetic disorders. To treat the ADH deficiency that results from any kind of damage to the hypothalamus or pituitary, a synthetic hormone called desmopressin can be taken by an injection, a nasal spray, or a pill. While taking desmopressin, a person should drink fluids only when thirsty and not at other times. The drug prevents water excretion, and water can build up now that the kidneys are making less urine and are less responsive to changes in body fluids.
Nephrogenic Diabetes Insipidus
Nephrogenic diabetes insipidus results when the kidneys are unable to respond to ADH. The kidneys' ability to respond to ADH can be impaired by drugs-like lithium, for example-and by chronic disorders including polycystic kidney disease, sickle cell disease, kidney failure, partial blockage of the ureters, and inherited genetic disorders. Sometimes the cause of nephrogenic
diabetes insipidus is never discovered.
Desmopressin will not work for this form of diabetes insipidus. Instead, a person with nephrogenic
diabetes insipidus may be given hydrochlorothiazide (HCTZ) or indomethacin. HCTZ is sometimes combined with another drug called amiloride. The combination of HCTZ and amiloride is sold under the brand name Moduretic. Again, with this combination of drugs, one should drink fluids only when thirsty and not at other times.
Dipsogenic Diabetes insipidus
Dipsogenic diabetes insipidus is caused by a defect in or damage to the thirst mechanism, which is located in the hypothalamus. This defect results in an abnormal increase in thirst and fluid intake that suppresses ADH secretion and increases urine output. Desmopressin or other drugs should not be used to treat dipsogenic
diabetes insipidus because they may decrease urine output but not thirst and fluid intake. This fluid overload can lead to water intoxication, a condition that lowers the concentration of sodium in the blood and can seriously damage the brain. Scientists have not yet found an effective treatment for dipsogenic
Gestational Diabetes Insipidus
Gestational diabetes insipidus occurs only
pregnancy and results when an enzyme made by the placenta destroys ADH in the mother. The placenta is the system of blood vessels and other tissue that develops with the fetus. The placenta allows exchange of nutrients and waste products between mother and fetus.
Most cases of gestational diabetes insipidus can be treated with desmopressin. In rare cases, however, an abnormality in the thirst mechanism causes gestational
diabetes insipidus, and desmopressin should not be used.