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

12 thoughts on “Psychogenic Polydipsia In Dogs

  1. Brian

    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.

    Reply
  2. colebear

    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.

    Reply
  3. Brett

    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

    Reply
  4. Mary Sproat

    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.

    Reply
    1. Dr. James W. Randolph Post author

      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.

      Reply
  5. Caroline

    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!

    Reply
    1. Dr. James W. Randolph Post author

      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.

      Reply
  6. Mindy & Bob

    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

    Reply
    1. Dr. James W. Randolph Post author

      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!

      Reply

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