What is Diabetes insipidus?

There are two forms of diabetes in dogs: diabetes insipidus ("weak or watery diabetes") and diabetes mellitus ("sugar diabetes").

Diabetes insipidus (DI) is rare in dogs and is only definitively diagnosed after extensive blood and urine tests.

My dog is drinking and urinating a lot. Is diabetes insipidus the likely cause?

"There are many causes of increased thirst (polydipsia) and increased urine production (polyuria), including diabetes, liver problems and kidney disease."

There are many causes of increased thirst (polydipsia) and increased urine production (polyuria), including diabetes, liver problems and kidney disease, to name a few. It is essential that several diagnostic tests be performed to determine the cause of your pet's problem.

What causes diabetes insipidus?

Part of the job of the kidneys is to continually filter the blood that passes through them and to maintain the balance of the body's water by excreting or reabsorbing fluid as required.

Efficient re-absorption requires an adequate level of a hormone known as antidiuretic hormone (ADH) or vasopressin which is produced by the posterior lobe of the pituitary gland in the brain. If this hormone is not produced in sufficient quantities or if the kidney fails to respond to it, diabetes insipidus can occur.

What diagnostic tests are required for the diagnosis of diabetes insipidus?

There are three basic causes for DI: a defect in ADH (antidiuretic hormone, a hormone that is normally produced in the pituitary gland and that controls water balance in the body); a defect in the kidney's response to ADH; or excessive water intake (called psychogenic polydipsia or compulsive water drinking). The diagnosis of diabetes insipidus can be challenging and may require extensive and complicated tests. Fortunately it is a rare disease in dogs.

A series of tests will be necessary to diagnose DI, and may include any or all of the following:

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 excessive intake of fluid, a defect in ADH, or a defect in the kidney's response to ADH.

3.    Desmopressin stimulation test

4.    Pituitary hormone levels

5.    MRI (Magnetic Resonance Imaging)

Can the condition be cured?

"This condition cannot be cured. However, like sugar diabetes, watery diabetes or diabetes incipidus can be successfully controlled."

This condition cannot be cured. However, like sugar diabetes, watery diabetes or diabetes incipidus can be successfully controlled. Diabetes insipidus is treated by administering antidiuretic hormone either by injection or in the form of nasal drops.