What is the difference between diabetes insipidus and diabetes mellitus
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. Diabetes insipidus and diabetes mellitus are unrelated, although they can have similar signs and symptoms, like excessive thirst and excessive urination.
Diabetes mellitus is far more common than diabetes insipidus and receives more news coverage. Diabetes mellitus has two main forms, type 1 diabetes and type 2 diabetes. Diabetes insipidus is a different form of illness altogether.
How is 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.
The hypothalamus makes antidiuretic hormone (ADH), which directs the kidneys to make less urine.
To keep the volume and composition of body fluids balanced, the rate of fluid intake is governed by thirst, and the rate of excretion is governed by the production of antidiuretic hormone (ADH), also called vasopressin. This hormone is made in the hypothalamus, a small gland located in the brain. ADH is stored in the nearby pituitary gland and released into the bloodstream when necessary. When ADH reaches the kidneys, it directs them to concentrate the urine by reabsorbing some of the filtered water to the bloodstream and therefore make less urine. Diabetes insipidus occurs when this precise system for regulating the kidneys' handling of fluids is disrupted.
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.
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.
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.
Gestational Diabetes Insipidus
Gestational diabetes insipidus 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.