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.
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.
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See you tomorrow, Dr. Randolph.
Hi Dr. Randolph -I read your article on psychogenic polydipsia – something 2 vets and an endocrinologist confirmed with my dog (adopted 12/2016). I have searched the web for some kind of pump that could be timed to dispense the right amount of water at the right intervals but so far, have been unable to find such a thing. Do you know any place I could get something like this? If not, I will create one, but if I do, do you think there is a market for such a pump? Is there any way I could learn how many dogs & cats suffer from this disorder? If the pump works I may as well put it out there. Thank you. Kay & Mitzvah.
Those are excellent questions, Kay. I don’t know of a timed drinking-water pump, but it would be a great idea. As for marketability, as psychogenic polydipsia isn’t a reportable condition, I don’t imagine anyone has statistics on its incidence. What if you took a low-volume water pump, attached a timer to it, and told it to come on for “x” number of seconds, say, eight times per day? That’s the way the feeder we use works (which is where I got the eight times per day, the maximum number of times its timer allows). Here is a link to one of the pages it’s on (Automatic Pet Feeder). I don’t know where one would purchase the timer separately, but contacting the manufacturer of the feeder (if you can figure out who that is) might work. Good luck! And, if you decide to invent the device, send us one and we’ll test and review it. Best wishes, Dr. Randolph.
6 mo old gsd. She is obsessed with water. Early on I started limiting her to 8 cups a day, which is still maximum for her weight. She consistently tried to get in the bathroom to lick excess water it if tub or all the water in the toilet. She now is big enough to get into the sink so again, excess water. On walks the first thing she will do is seek out any water or even moist ground. We are tired and so frustrated. She cares more about water than food, affection, toys anything.
There are nearly twenty possible causes of excessive thirst/urination in dogs. She needs to see her doctor. Thank you for reading MyPetsDoctor.com. Please let us know what the doctor finds.
I am having the EXACT same problem right now! Did you ever solve this? Literally all the same symptoms. We even caught our dog trying to get in to the toilet to drink water. He is obsessed.
Your veterinarian can work through this with you to arrive at the correct diagnosis. Thanks for reading http://www.MyPetsDoctor.com.
Is there a behavioral training method to discourage overdrinking and the obsessive need for fluid? Rationing in a multi-pet household is inconvenient. Also, my JRT will lick anything with moisture while on bathroom outings (muddy water, the sidewalk, a leaf with drops on it). He is so distracted, he won’t use the bathroom. We’re constantly pulling him away from the moisture after a rain. I’m looking for a training solution!
It shouldn’t be too hard to find a trainer, but first we need to know if we’re dealing with a behavioral problem or a medical problem. Has your dog had a thorough workup, including laboratory tests? Restricting water to a patient whose medical need is driving the thirst could be disastrous. The tests required to differentiate between psychogenic polydipsia (PP) and other conditions are quite straightforward and any veterinarian should be able to handle the process for you. If PP is determined to be the diagnosis, and your pet’s doctor is unable to assist with training, he may be able to refer you to a board-certified veterinary behaviorist. If none is available, check with Bark Busters International. The trainer I’ve worked with locally is fabulous. That is not a guarantee that all Bark Busters trainers will be. Just remember: medical workup first!
Thank you for this very informative article. Can you give any hints as to how to handle a dog with PP in a two dog household?
Gee, Sonya, that’s quite a conundrum. Even if you measure the maximum allowance for the normal-drinking pet, the PU/PD pet is going to drink more than its share. Some of these patients can be helped (at least partially) with treatment for diabetes inspidus, even though she doesn’t have diabetes insipidus. Other than that, I can’t think of any other solution. Sorry!
Hello Dr. Randolph,
My dog, Duke, was injected with Dexamethasone earlier today and now 3 times already he has been urinating everywhere and drinking a little bit more water than usual. Duke’s urinating like this is completely out of character for him. He usually lets me know and I take him out. This time he has not let me know and just does it. Any help or guidance would be greatly appreciated.
Dexamethasone is a corticosteroid. Your pet’s doctor probably used it as an antiinflammatory and/or allergy-blocking medication. Increased thirst and, therefore, increased urination, is a temporary side-effect of corticosteroid use. If it does not subside, be sure to let your veterinarian know.
Thank you so much for this article. My 4 month old Giant Schnauzer was just diagnosed with this this morning. Our veterinarian said he needs 3-5 cups a day. He was drinking well over 10-15 cups a day, leaking urine, peeing everywhere in small amounts, and peeing in his crate even when he was only there 30 minutes. Already tonight he is calm and hasn’t had an accident all day.
Thank you for the success story!
Great article. My 20 month old German Shepherd has been wetting the bed. No UTI so, next is blood work to rule out. Then it’s down to CDI or polygenic polydisis. Romy is very nervous, especially when we leave. Your article potentially helps explain Romy’s condition. I guess we shall see. To rule out central diabetes insipidis would you do the withhold water test? Our veterinarian recommends a trial of ddavp to see if that works. Thanks
Either way is good, Brett, and your local veterinarian knows your pet best, so I would go with his recommendation. Best wishes, Dr. Randolph.
Our veterinarian just diagnosed our wolfhound with psychogenic polydipsia. He was so water-logged he was urinating clear water. He had always been a heavy water drinker, but this was too much. He would leak urine while sleeping. It is hard to deny him water because he looks so pathetic, but as long as I know that it’s all in his head, I can manage. He is 180 pounds.
The calculation for daily water allowance is crucial. Be sure to follow your veterinarian’s calculation and do not give all of the day’s allowance at one time. Psychogenic polydipsia patients will often drink their entire day’s allowance first thing in the morning, then become dehydrated later in the day. The amount of water you listed seems low. Please double-check with your veterinarian.
Is an owner of a PP (psychogenic polydipsia) dog doomed to ration water forever? Are there medications or behaviors to change the PP behavior? Help!
If your veterinarian has determined that your pet has psychogenic polydipsia and NOT Diabetes insipidus, then, no, there are no medications that will help. Restricting water intake is really easy if you have only one pet. Your veterinarian can give you a daily allowance for his water intake, and that’s all he gets unless he does something strenuous and needs more water that day, or is outdoors in the heat. Diabetes insipidus, on the other hand, can be controlled by medication.
Hi Dr. Randolph,
Where’s Muffie? I think perhaps the picture didn’t come through. I’m curious to see the “water drunkard.” We always learn so much from your newsletters, and oftentimes we have a good laugh. You’re a great teacher! Warm Regards,Mindy and Bob
It’s a good thing Mindy and Bob wrote, because I’d called Muffie’s owner the day I was writing the piece and asked him to e-mail me a photo of her. He was out of town, but said he would when he got to his motel for the night. Then, he couldn’t find any digital photos of her, I forgot that I’d mentioned her in the text, and the piece published with no photo! I’m glad to report she’s smiling on the page now!