Fluid deprivation test no change in the water loss despite fluid deprivation, desmopressin may be administered to distinguish between the two types of diabetes insipidus which are central & nephrogenic diabetes insipidus. The time of deprivation may vary from 4 to 18 hours. The serum osmolality and urine osmolality are both measured in the test. The conditions can be distinguished in the following way: Fluid deprivation test A fluid or water deprivation test is a medical test which can be used to determine whether the patient has diabetes insipidus as opposed to other causes of polydipsia (a condition of excessive thirst that causes
Primary polydipsia Primary polydipsia Primary polydipsia is a form of polydipsia characterised by excessive fluid intake in the absence of physiological stimuli to drink. This includes psychogenic polydipsia (PPD – not to be confused with postpartum depression), which is caused by psychiatric disorders, often schizophrenia, and often accompanied by the sensation of dry mouth. Some forms of primary polydipsia are explicitly non-psychogenic. Primary polydipsia is a diagnosis of exclusion. In diagnosis, primary polydipsia is usually categorised as: The terms primary polydipsia and psychogenic polydipsia are sometimes incorrectly used interchangeably – to be considered psychogenic, the patient needs to have some other psychiatric