Psychogenic Polydipsia In Dogs

Psychogenic polydipsia(PP) is a syndrome resulting in a patient drinking inappropriately large amounts of fluid. In the case of dogs and cats their fluid intake is usually limited to water.

Muffie drinks too much water because of psychogenic polydipsia.

Poly is a Latin prefix meaning “many.” Dipsia is a Latin verb meaning “to drink.” Therefore, the polydipsic patient drinks often, or in large quantities, resulting in a 24-hour intake being higher than normal.

Of course, if intake is excessive, output, in the form of urine, will also be excessive, resulting in polyuria. Together they form a condition called polydipsia/polyuria, or pu/pd.

There is a very, very long list of medical abnormalities that can result in polydipsia. Diabetes mellitus,
Diabetes insipidus, Cushing’s Disease, renal failure, hyperthyroidism, liver disease, pyometra and many more.

Today, however, we are going to discuss a cause of pu/pd that is all in the patient’s head. As the name indicates, psychogenic polydipsia results from a thought process in a dog or cat’s psyche, or mind. Something stimulates the patient to want to drink and continue drinking instead of stopping when his thirst is satisfied. Such patients may be “excitable,” “wound too tightly,” or have a nervous personality.

In order for kidneys to work properly (in any species), the renal medulla (medulla is a Latin term meaning “middle”), which contains many structures, must have a solute gradient. To grossly oversimplify the solute gradient, think of a water bath with chemicals in a jar. The chemicals are least concentrated in the top of the jar, with concentration increasing toward the bottom. In order for the structures in the middle of the kidneys to work properly, they must be bathed in this mixture that is appropriately graduated.

In the patient with psychogenic polydipsia, the huge volume of water imbibed causes a constant effort to remove excess fluid from the body so that the bloodstream will stay in proper balance. As the kidneys work overtime to excrete the overabundance as urine, some of the solute in the solute gradient gets removed, too. As the exuberant drinking continues, eventually almost all of the solute is gone and the kidneys cease to have the ability to concentrate urine. This endpoint is called solute washout.

Fortunately, the kidneys know how to fix solute washout all on their own. However, there is an important step that we must perform: limit water intake. In a one-pet household, this is easy. Your pet’s doctor tells you a healthy amount of water for your pet to drink, and you ration it out through the day. Obviously, you can’t put out the entire day’s allowance of water first thing in the morning, or your dog will drink all of it at once, then be dehydrated for the remainder of the day. Allow a third in the morning, a third at lunchtime and the final third when you come home from work. If no one is home during the day you can provide two aliquots, but that’s not as good for your pet.

Alternatively, you might rig a timed pump for his water bowl, dispensing an hourly quantity of water.

Recovery from solute washout is not immediate, but the pet with psychogenic polydipsia will usually improve within a few weeks.

Options are limited if you have more than one pet. If you supply enough water for both, the PP dog will drink it all, leaving the other pet to dehydrate. If you put out an unlimited amount of water, the PP dog will be back to drinking excessively the first day.

Some clients manage. Muffie, pictured above, lives with three other dogs. She drinks, she urinates, and she maintains her housetraining despite the incredible volume of water intake and output. She thrives in spite of the potential for electrolyte imbalance, a tribute to our bodies’ amazing ability to tolerate abuse. Even laboratory testing shows no abnormalities, other than a very, very low specific gravity.

Click to read more about dog diabetes

See you tomorrow, Dr. Randolph.

MMPP

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Dr. Randolph
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30 Comments

  1. Just adopted a 9 yr old WFT with 3x Essie drinking. All tests plus an ultrasound have been performed, finding nothing The internist thinks its Psychogenetic Polydipsia. I just found out last night that the dog has had it for 3 years. Isn’t this dangerous for the kidneys?

    • Not at all, unless it gets bad enough to cause solute washout. Did you inquire of the internist about a water deprivation test? Is she your only pet? If so, the internist can give you a daily water allowance to control the problem. Thanks for reading, Dr. Randolph.

  2. My question is actually about psychogenic polydipsia in cats. I couldn’t find anywhere online that was similar to this page so I am hoping you can help or point me in the right direction. I fell in love with a 1 year old cat at an adoption event (he hopped right in my arms and licked my nose–well my face mask anyway). He has been diagnosed with psychogenic polydipsia after the rescue ruled out any medical cause (all blood work and other tests were normal) for his excessive drinking. He will drink until he is sick. They did say that it showed up after his sister was adopted. Have you seen any pets stop this behavior? I have other pets in the home and I was hoping if there was some way I could work with him, he might eventually improve and I could monitor water accessibility until them. I would be willing to work with a vet behaviorist and am very open to medication as a tool along with behavior support. However, my other pets do need access to water and so I am not sure he would be a good fit in my house if there was no hope of him ever getting better but I want to check as many places as I can to see if there is any way to make it work. Thanks!

  3. Dr. Randolph,

    My husband and I are pulling our hair out with our 10 year old rescue boxer who is increasingly obsessive over water consumption. We have been to the vet several times and ruled out all other causes and zero’d in on the psychogenic polydipsia as a diagnosis. We have 2 other dogs in the house and have to limit water because she will drain everything. We have to LOCK bathroom doors so she doesn’t open them and open toilet lids. She is not able to hold her urine during the day and has completely ruined our brand new house flooring as a result. When she drinks, it’s always in excess and has gotten to the point where she will drink, vomit, repeat.

    We tried her on prozac to take the edge off. I also combined it with some training: leave a full bowl down, let her drink some, then back her away til she goes and lays down. Repeat every 10 min. We did this for weeks with no progress. I feel like we are out of options and are just existing with this problem. I’m desperate for a solution that we, and the other 2 dogs can live with. I feel so bad for them to have a structured water schedule because their sister has a mental issue. Any advice would be greatly appreciated.

    • Tough, tough, tough problem. I feel for you. Please ask your veterinarian to refer you to a board-certified veterinary behaviorist. If he doesn’t know of any, click on that link and look for someone nearby. If there is no one close to your location, some behaviorists will work with and through your local doctor, advising him, who, in turn, can advise you. (It has to do with doctor-client-patient relationship and state of licensure). Together, they should be able to work out a solution. Please write back and let us know how your new program goes, and bless you for hanging in there.

  4. Where can I find out how common this disorder (psychogenic pupd) is? Where can I get a pump that will time water output? Thank you

    • I found this pump on Amazon for less than $7. It’s possible that it would put out TOO much water, so you might have to scale down to an aquarium pump. Just Google “water pump” and go from there. While I was on Amazon, I found this timer, which appears to be the exact same timer our feeder has, and it’s only $12.
      As for how common this condition is, psychogenic polydipsia isn’t a reportable condition, so I don’t imagine anyone has statistics on its incidence. Good luck on your build and please keep us posted on your progress! Thanks for reading MyPetsDoctor.com.

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