Diabetes insipidus (DI) is an uncommon condition that occurs when the kidneys are unable to conserve water as they perform their function of filtering blood. The amount of water conserved is controlled by antidiuretic hormone (ADH), also called vasopressin.
Causative factors for diabetes insipidus
Diabetes insipidus can be caused by two problems with ADH.
One is too little ADH is produced, that condition is called central diabetes insipidus.
The other is there’s enough ADH produced, but the kidneys can’t respond to it. That condition is known as nephrogenic diabetes insipidus.
Cranial surgery, especially hypophysectomy; head injury, especially basal skull fractures); the polyuria is often transient in such cases
Craniopharyngioma, hypothalamic tumors, pineal tumors, metastases
Symptoms of diabetes insipidus:
Excessive urine production (polyuria)
In some people, these symptoms can become extreme, causing dehydration.
How to diagnose diabetes insipidus?
Diagnosing diabetes insipidus requires serial measurements of blood and urine. The person goes without water during this time and gets progressively thirstier. The concentrations of sodium in the blood and urine are determined over time. An ADH substitute might then be administered to see if the person’s kidneys respond to it by concentrating the urine. The laboratory values and response to ADH can make the diagnosis.