When your cat experiences an inability to retain appropriate amounts of water, they may be suffering from water diabetes, or diabetes insipidus. Water diabetes is rare disorder and distinct from sugar metabolizing related diabetes, also known as diabetes mellitus. Water diabetes can lead to potentially deadly conditions such as dehydration or even death, if not treated. If you suspect water diabetes in your cat, you should consider seeking immediate veterinary care.

Symptoms of diabetes insipidus can start off as subtle changes, but quickly escalate as your cat’s inability to retain water increases.

There are two distinct types of water diabetes in felines with distinct causes and origins. Both relate to ADH, or antidiuretic hormone, which is produced in the pituitary gland (brain) and used by the kidneys to stimulate blood vessels that cause the kidneys to contract and retain urine and water. 

The cause of water diabetes, or diabetes insipidus, in cats relates to some malfunction in either the creation or utilization of the hormone ADH. The reason for the ADH malfunction is different depending on which of the two types of diabetes insipidus your cat is suffering from.

Causes of central diabetes insipidus include:

Causes of Nephrogenic Diabetes Insipidus include:

In order to diagnose and treat water diabetes, your vet will begin by performing a thorough physical exam of your cat. It is important to supply your vet with approximate time frames for when the increased water consumption and elimination began, as well as any history of trauma or injury to your pet. The vet will attempt to rule out other potential conditions such as renal failure, liver disease, pyometra in female cats, and cancer. If a veterinarian suspects a tumor in the brain or pituitary gland, they may order images via x-ray or MRI, in order to accurately diagnose the underlying cause.

Your vet may also perform a water deprivation test in order to determine whether your cat is appropriately producing and/or using ADH. In this test, water is withheld from your cat while it is safely monitored at your veterinarian’s office. Levels of hydration in your cat are measured to see if the feline is responding adequately to the production of ADH that should accompany water deprivation. Additionally, your vet may order blood work during this test which may include tests that will show whether appropriate levels of ADH are being produced and will allow your vet to differentiate between the two types of water diabetes.

Treatment of water diabetes will depend on the underlying causes and on what version of the condition your cat is suffering from.

Treatment for central diabetes insipidus typically takes the form of medication that mimics the effect of the ADH that is normally produced by the pituitary gland. The most common of these medications is called desmopressin. Your veterinarian may also prescribe additional medications or treatments to address the underlying cause for your cat’s failure to produce ADH. For example, in the case of injury, your veterinarian may prescribe anti-inflammatory drugs. Additional treatment options may be available if water diabetes is due to a tumor.

Treatment for nephrogenic diabetes insipidus will vary from that of the central version of the condition. The most common course of treatment will be diuretics that help concentrate the urine. In some cases, your veterinarian may also prescribe chlorpropamide, which can help enhance the kidney’s ability to utilize ADH.

If treatment through medications would irritate already stressed kidneys or have other severe secondary effects, your veterinarian may advise you to manage the condition through increased water intake for your cat. This may be done through altering your cat’s diet to a specially prescribed, high moisture food or through regular water supplementation at your veterinarian’s office. This route can be tricky, however, since you must ensure your cat is getting an adequate amount of fluids.

Although water diabetes in cats is a permanent and lifelong condition in most cases, it is one that can be managed easily. With daily medication and proper monitoring of water intake, most symptoms of water diabetes will subside nearly immediately after beginning treatment. Unless the underlying cause of the condition is an acute injury that heals, this will mean a lifelong commitment to your cat to provide medicine and support. However, if proper treatment is provided by you and your veterinarian, your cat’s prognosis is good for a long and happy life.