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2 Puzzling Cases of Excessive Peeing in Dogs

Excessive peeing in dogs isn’t a disease in itself, but it’s a possible symptom of ailments such as diabetes, kidney infection and cystitis.

excessive peeing in dogs
Excessive peeing in dogs can be a symptom of several different ailments, including pyelonephritis. Photo: bogitw

Recently, I had a good reminder never to jump to conclusions.

This involved not 1 but 2 cases — both concerned excessive peeing in dogs. When their basic tests came back normal, I nearly went off in the wrong direction. Fortunately, a methodical approach saved the day.

Symptoms of Cystitis

The first case, Dog A, was peeing little and often — as if she had cystitis. But her urine dipstick test was normal: no blood.

Puzzling. The primary differential diagnosis of a urinary infection was unlikely.

So why couldn’t this dog stop peeing?

Excessive Thirst

Bizarrely, later the same week, another dog came trotting in, bright as a button. This dog was fit and well but peeing lakes of urine so large you could sail a boat across them. This dog was thirsty. Very thirsty.

Again, a dipstick test came back as normal with no signs of sugar, protein or blood in the urine. Puzzling.

So if there were no signs of infection, diabetes or renal disease, why was the dog drinking so much?

An Incorrect Assumption

In both cases, I nearly made an assumption: Because there was not even a trace of blood in the urine, a urinary tract infection (UTI) was less likely.

But I was wrong.

Something didn’t feel right. So I double-checked the results with a different test — a more sensitive test that gives a yes/no answer to infection.1 Guess what?

Both tests came back positive for the presence of bacteria.

Happily, both dogs responded well to antibiotics. Dog A stopped squatting repeatedly, and Dog B is drinking normally and no longer pees lakes. Excessive peeing in these dogs is now completely resolved, and a follow-up test confirmed they are both free from infection.

But it was a timely reminder not to jump to conclusions based on 1 test alone. Instead, keep digging.

What’s the most common cause of a canine kidney infection? Bacteria that travel upstream from the bladder into the kidney. Photo: mburleson

A Twist in the Diagnosis

So why the contradictory results?

Well, as it happens, these dogs did have an infection, but not in the bladder. Instead, their infection was higher up the urinary tract in the kidney — hence the lack of blood so often associated with cystitis.

Thank goodness we got to grips with it quickly! Not to have done so could have resulted in a full-blown pyelonephritis or kidney infection.

What’s also interesting is that despite having the same diagnosis, Dog A and Dog B had different presentations, so not all excessive peeing in dogs looks the same.

If your dog shows similar signs, then don’t ignore them, but badger the vet to get to the bottom of things. With this in mind, let’s look at these cases in more detail.

Excessive Peeing in a Dog, Case #1

Dog A was a nervous female. Her people suspected a problem when she started licking her private parts more than usual. Then she became fixated on squatting to pee, stopping every few steps but passing only a few drops of urine at a time.

These are textbook signs of bladder discomfort. This is most often due to inflammation of the bladder wall as a result of infection or physical irritation from bladder stones or urinary crystals.

Whatever the underlying cause, this inflammation is what the term “cystitis” refers to2:

  • Cyst-: a hollow object filled with liquid
  • -itis: inflammation

The inflammation causes the increased need to pee. The sore bladder lining sends out distress signals, just like a full bladder. The dog then mistakes the sensation for having a full bladder and repeatedly squats to relieve themselves.

Just as there’s no smoke without fire, it’s unusual to have inflammation without blood. When the lining is sore, it usually seeps blood into the urine. There doesn’t have to be much present for it to show as a trace on a dipstick. But in Dog A’s case … nothing.

A Test for Infection

Fortunately, an instinct made me dig a little deeper with a further test. This involves a neat in-house lab test that gives a “yes” or “no” answer to the presence of bacteria. This came back positive — bacteria (a.k.a. infection) were present.

The suspicion then became that the bacteria had come from higher up the urinary tract. What’s upstream of the bladder? Why, the kidneys, of course.

We sent the urine away to be cultured. This gives further information about the type of bacteria present and the best antibiotic to kill them.

These results can take several days to come back, so in the meantime, the patient started taking a broad-spectrum antibiotic.

Happily, the culture confirmed the bugs were sensitive to the antibiotic, and the dog made a full recovery.

Excessive peeing in dogs doesn’t always present the same way. For instance, some dogs may squat and try to pee often, with nothing coming out, while others may be constantly thirsty and actually pee a lot. Photo: Couleur

Excessive Peeing in a Dog, Case #2

This second case, Dog B, was also a strange one. Instead of displaying signs of cystitis, this dog was thirsty and peeing loads (what’s technically known as polydipsia polyuria or pd/pu.)

According the dog’s human, the thirst had suddenly shot up after a recent change of diet. Then, despite going back to his regular food, the dog had stayed thirsty and his peeing got beyond a joke. He was otherwise fit and well and didn’t have a fever.

Uppermost in a vet’s mind when presented with a thirsty dog are problems such as:

  • Sugar diabetes (diabetes mellitus)
  • Liver disease
  • Kidney disease
  • Cushing’s disease
  • Fanconi syndrome
  • Psychogenic polydipsia

With nothing showing on the dipstick (no blood, protein or sugar), we ran a blood test.

The results were all normal. Puzzling still.

I ran screening blood tests looking at organ function. These results came back all normal. Weird, very weird.

Scratching my head, I turned my thoughts to specific blood tests for particular conditions. But then I remembered how Case 1 had nearly tripped me up.

We ran the yes/no test for bacteria in the urine … and it came back positive.

Same story: Case 2 was started on broad-spectrum antibiotic while waiting for culture results to come back. Happily, his thirst eased the next day, and by Day 3 he was back to normal. Phew!

Excessive peeing in dogs can be a symptom of a urinary tract infection. Learn more about UTIs from the veterinarian in this video:

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Pyelonephritis: What Is a Kidney Infection?

A closer look at what these cases had in common — besides excessive peeing in 2 dogs — were bacteria in the urine.

The kidneys filter blood to produce urine and get rid of naturally occurring waste products. If there is an infection in the kidneys, then the symptoms aren’t always clear-cut.

More typically, the clues include:

  • Going off food
  • Lacking energy
  • A tender tummy
  • Swollen kidneys
  • Vomiting
  • Fever
  • Thirst
  • Blood in the urine
  • Weight loss
  • In the worst cases, septic shock
  • In mild cases, no signs

What causes a kidney infection?

Actually, the most common cause of a kidney infection is bacteria that travel upstream from the bladder, up the ureter and into the kidney.3

Kidney infections are more common in females than males because of their different anatomy. The short, wide vulva provides a super-highway for bacteria to enter the urinary tract from the outside world.

This is why keeping female dogs hygienically clean around their private parts is so important.

Diagnosing Pyelonephritis

It may be necessary to work out exactly where the source of infection is when dealing with excessive peeing in dogs. This can involve imaging, such as scanning the bladder (to rule out bladder cancer, polyps or stones) and kidney.

Examining a sample of urine sediment under the microscope can also help. This shows up renal casts (or signs of kidney distress) along with bacteria or urinary crystals.

It may also be necessary to rule out the bacteria having come from elsewhere, such as the womb (in female dogs) or prostate (in males).

Screening blood tests are also helpful, to see if kidney damage has occurred or not.

Excessive peeing in senior dogs may be a sign of pyelonephritis, which can cause major damage to the kidneys. Photo: mkortelainen

Treating a Kidney Infection

As with my 2 cases, a long course of antibiotics does the trick. However, if the patient is already sick, then intravenous fluids may be necessary. This helps flush or wash the kidneys through and help wash out the infection.

For the worst cases, up to 6 weeks of antibiotics may be required to completely clear things up.

A Special Word About Senior Pets and Pyelonephritis

Now here’s a thing: Some pets have a low-grade UTI and don’t have symptoms. Why is this worrying?

Because there’s a risk of bacteria traveling upstream to damage the kidneys. Indeed, in older cats, there is a theory that low-grade bacterial infections cause ongoing kidney damage.

Which Animals Are Most at Risk of a Subclinical Infection?

The answer is older pets who produce weak or dilute urine. Less-concentrated urine loses its natural disinfectant properties. Thus, bacteria can flourish in the bladder.

Another risk group is diabetics. All that sugar in the urine provides an inviting environment for bacteria.

If the pet doesn’t show symptoms, such as excessive peeing, then the condition could deteriorate and cause kidney damage. This is the last thing an elderly cat or dog with diabetes or renal disease needs.

So what’s to be done?

Regular urine screening is the answer. Picking up infection on a lab test before the pet shows symptoms could prevent kidney damage.

This is all part of senior pet checks, and it’s one of the reasons your vet needs to see older patients every 3–6 months.


  1. RapidBac™Vet.
  2. Ward, Ernest, DVM. “Cystitis in Dogs.” VCA Hospitals. 2009.
  3. Brown, Scott A., VMD, PhD, DACVIM. “Pyelonephritis in Small Animals.” MSD Manual.
vet-cross60pThis article on the possible medical causes of excessive peeing in dogs was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed Dec. 20, 2018.

If you have questions or concerns, call your vet, who is best equipped to ensure the health and well-being of your pet. This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis or treatment. See additional information.