There are different kinds of Diabetes. Diabetes insipisud causes the patient to have increased urine output and therefore have intense thirst. The cause of this is the control of Antidiuretic hormone (ADH) in the blood. What ADH does is it influences the amount of fluid that the kidneys need to reabsorb and the amount that passes through and is excreted as urine. Diabetes insipidus occurs when the amount of ADH produced is below normal or the kidneys don't respond to ADH. The patient's blood will have high concentration.
Although the cause of Diabetes Insipidus is unknown some believe it may be hereditary. But central DI can be caused by:
-cancers that have spread to the pituitary gland
-excessive use of alcohol