Diagnosis of diabetes insipidus

There are three basic causes for diabetes insipidus (DI): a defect in antidiuretic hormone (ADH); a defect in the kidney’s response to ADH; or psychogenic polydipsia.

The diagnosis of DI can be challenging. Tests include:

1. blood and urine tests – complete panels to rule out diabetes mellitus, kidney and liver disease
2. a water deprivation test and/or a modified water deprivation test to determine if the symptoms are caused by psychogenic polydipsia, a defect in ADH, or a defect in the kidney’s response to ADH (the animal must be properly hydrated, hospitalised, and screened for kidney disease prior to doing a water deprivation test)
3. a desmopressin stimulation test
4. pituitary hormone levels
5. MRI (Magnetic Resonance Imaging)