Diabetes insipidus (DI) is a rare disease that causes frequent urination. The large volume of urine is dilute, mostly water. To make up for lost water, a person with DI may feel the need to drink large amounts and is likely to urinate frequently, even at night, which can disrupt sleep and, on occasion, cause bedwetting.
Because of the excretion of abnormally large volumes of dilute urine, people with DI may quickly become dehydrated if they do not drink enough water. Children with DI may be irritable or listless and may have fever, vomiting, or diarrhea. Milder forms of DI can be managed by drinking enough water, usually between 2 and 2.5 liters a day. DI severe enough to endanger a person’s health is rare.
Diabetes insipidus should not be confused with diabetes mellitus (DM), which results from insulin deficiency or resistance leading to high blood glucose, also called blood sugar. DI and DM are unrelated, although they can have similar signs and symptoms, like excessive thirst and excessive urination.
DM is far more common than DI and receives more news coverage. DM has two main forms, type 1 diabetes and type 2 diabetes. DI is a different form of illness altogether.
How fluid in the body normally regulated?
The body has a complex system for balancing the volume and composition of body fluids. The kidneys remove extra body fluids from the bloodstream. These fluids are stored in the bladder as urine.
If the fluid regulation system is working properly, the kidneys make less urine to conserve fluid when water intake is decreased or water is lost, for example, through sweating or diarrhea. The kidneys also make less urine at night when the body’s metabolic processes are slower.
What are the types of diabetes insipidus?
- Central DI
- Nephrogenic DI
- Dipsogenic DI
- Gestational DI
The most common form of serious DI, central DI, results from damage to the pituitary gland, which disrupts the normal storage and release of ADH. 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.
ephrogenic DI 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 DI is never discovered.
Desmopressin will not work for this form of DI. Again, with this combination of drugs, one should drink fluids only when thirsty and not at other times.
This defect results in an abnormal increase in thirst and fluid intake that suppresses ADH secretion and increases urine output. 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 DI.
Gestational DI occurs only during 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.