Diabetes Insipidus – Definition and Types

Diabetes Insipidus (DI) is different from Diabetes Mellitus. However, symptoms of both diseases include increased urination and thirst. Diabetes Insipidus is a very rare form of diabetes resulting from a deficiency of vasopressin (the pituitary hormone that regulates the kidneys). This form of diabetes is characterized by the chronic excretion of large amounts of pale dilute urine which results in dehydration and extreme thirst. Disorders of the hypothalamus are one cause of Diabetes Insipidus.

In simple language, Diabetes Insipidus is a condition in which there is an abnormal increase in urine output, fluid intake and often thirst. Sometimes, Diabetes Insipidus is also called as "Water Diabetes” to distinguish it from Diabetes Mellitus, which can also be referred as "Sugar Diabetes”.

Types of Diabetes Insipidus

Basically, there are four main types of Water Diabetes:

Neurogenic DI: This is the most common type of Diabetes Insipidus, which is caused by a lack of vasopressin, a hormone that normally acts upon the kidney to reduce urine output by increasing the concentration of the urine.  This type of Water Diabetes is commonly called “Pituitary Diabetes Insipidus”.

Nephrogenic DI: Caused due to the inability of the kidney to respond normally to antidiuretic hormone (ADH). ADH, which is also known as vasopressin, is a hormone that normally acts upon the kidney to reduce urine output by increasing the concentration of the urine.

Dipsogenic DI: Occurs due to a defect 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 DI: Occurs only during pregnancy. A lack of vasopressin can also develop during pregnancy if the pituitary is slightly damaged and/or the placenta destroys the hormone too rapidly.  This second type of vasopressin deficiency is called Gestational DI.

Pituitary is the master gland of the endocrine system; located at the base of the brain.