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Here’s a head scratcher for you.
You take your pup out for walks, and she uses the potty pretty well outdoors. You would in fact say that she appears to be well potty-trained.
And yet, when she gets up off her bed from sleeping or napping there’s a small wet spot where she was laying. Or perhaps you even see little drips of pee on the floor when she’s walking around the house.
What almost seems worse, is that she doesn’t even seem to be aware that it’s happening.
So what’s going on?
If your dog is leaking urine, you may have a medical condition called urinary incontinence on your hands. In this article, we’re going to go over how to recognize urinary incontinence in dogs, some different causes for this syndrome, how we as veterinarians diagnose these conditions, and lastly, how we approach treatment for them.
How Do I Know If It’s Incontinence?
There can be many urinary issues that affect dogs. We’ll just be focusing on incontinence here, but for a good overview of some other conditions like urinary tract infections, bladder stones, kidney disease, and others, make sure to also check out Why is My Dog Peeing in the House? 8 Urinary Issues in Pets and What to Do.
Urinary incontinence is typically characterized by two main signs that separate it from other conditions.
The first is that dogs are typically dribbling or leaking urine. The second is that they generally appear unaware that accidents are occurring.
Compare this to a dog with a urinary tract infection, a common first concern among pup parents when they see their dog leaking urine, where there is a sense of urgency, repeated requests to be let outside, and frequent attempts to squat or strain to pee.
The two main presentations for incontinence, as suggested in the intro, are a dog that either appears to leak urine when she’s asleep, leaving a wet spot on her bed (or yours), and/or a dog that is just dripping little bits of pee as she walks around, seemingly unaware.
What Causes Urine Leaking?
Weak Muscles: Urinary Sphincter Mechanism Incompetence
Urinary Sphincter Mechanism Incompetence (USMI) is by far the most common cause of incontinence in dogs that we see.
Also called “spay incontinence”, this condition can affect anywhere from as low as 5% up to 25-30% of spayed female dogs. According to Merck Animal Health, the average age of onset is about 3 years after spaying and about ⅓ of dogs affected are larger breeds, over 45lb.
Why does this happen? There is a muscular sphincter, kind of like a valve if you will, that keeps the urethra shut, allowing the bladder to fill with urine. When the bladder fills to a certain point, your pup’s brain gets a signal that it’s time to pee. With conscious input from your pup when she finds a good place to potty, the sphincter relaxes during urination.
With USMI, that muscular sphincter loses its muscle tone, becoming weaker and allowing urine to leak. This is thought to be related to decreased levels of circulation estrogen.
USMI can occur in older dogs too, even males, but it’s hard to determine if this is also related to decreased hormone circulation or more related to a generalized weakening of the sphincter muscle with age.
Fortunately, in about 90% of cases, a pet with urinary incontinence will respond to medical therapy, according to the University of Illinois College of Veterinary Medicine. We’ll discuss more specifically how USMI is treated a little later on.
But you might ask “Well, if spaying causes this, then why should I spay my dog?”
The truthful answer is that it’s more complicated than that because spaying may not be the only contributing factor to USMI.
According to a 2018 article in the Journal of the American Animal Hospital Association, multiple studies on this topic have shown very variable associations with time of spaying and development of USMI. The article also pointed to other identified variables that may contribute, like anatomic position of the bladder and breed inheritance.
There are other preventive health benefits to spaying and not just related to population control. The conditions of breast cancer and pyometra are very real and life-threatening conditions that exclusively affect unspayed female dogs.
A pyometra is a condition that occurs in middle aged to older dogs. Under repeated hormone influence from multiple heat cycles, the normally sterile uterus becomes thicker with more engorged tissue, making it less resistant to bacteria that can cross the cervix from the vaginal area.
Within 1-2 months of a heat cycle, we can see a uterine infection develop. In many cases, the cervix clamps shut, allowing the uterus to essentially fill with pus. If this goes untreated, every dog with a pyometra will get extremely ill and die.
A rule of thumb is that approximately ¼ of unspayed dogs will develop a pyometra before the age of 10, with risk increasing with age.
And then there’s mammary cancer. Otherwise thought of as breast tumors, mammary cancer can develop in dogs just like in people. However, unlike in humans, where there are a couple different types with not all needing surgery, dogs only get two general types: aggressively malignant, or benign.
The chance of a breast tumor in a dog being malignant is about 50%. According to the American College of Veterinary Surgeons (ACVS), the risk of a dog developing breast cancer is over 25% if she’s not spayed until after 2 years of age, with risk increasing with age as well.
The risk percentages for these conditions, as you’ve probably seen, are not dissimilar from the percentage of dogs that develop urinary incontinence after spaying which ranges from 5%-25%. The difference though, is that while most incontinent dogs respond successfully to medical therapy, pyometras and breast tumors require aggressive surgery that can be risky. It is far safer to spay a young, healthy dog, than to perform a longer, complicated surgery on an older, medically unstable pet. In many cases of breast cancer, chemotherapy is additionally required for the best outcome.
There is risk assessment involved with everything we do for ourselves and for our pets. But the risk of not spaying a female dog always seems to outweigh any benefits of keeping her intact, from both a cost and health perspective.
But our hormones are important for development too. That’s why there is no medical reason to spay a dog prior to 6 months of age. And in some larger breeds, I will counsel folks to wait until after a first heat cycle, but before the second (which often does not occur for several more months). Fortunately, the risk of breast cancer remains below 10%, and the risk of pyometra is still eliminated.
But I Was Born This Way: Congenital Anatomic Abnormalities
The next common medical cause of incontinence is just about exclusively seen in really young dogs. That’s because they were actually born with an anatomic abnormality (a birth defect essentially) that contributes to leakage of urine.
The first and most well-known is called an ectopic ureter. In order to understand what an ectopic ureter is, it’s important to understand a little simple anatomy.
Our urinary system starts with our kidneys, which actually produce urine by filtering out things our body doesn’t need. Urine then automatically travels from the kidney through a narrow tube called a ureter, where it empties into the urinary bladder. The bladder acts as a storage area, allowing urine to be held until it becomes full, at which point a signal is sent to the brain that we have to pee.
In a dog with an ectopic ureter, the ureter does not attach to the bladder in the normal location. Instead, it tunnels either through or around the bladder, emptying into the urethra, beyond where the muscular urinary sphincter is. This prevents urine from being held or sorted by the bladder, leading to continuous leaking. Either just one, or both ureters on each side can be affected.
The classic presentation for this condition is a young puppy that seems to respond to potty training techniques, but is continuously having accidents, especially when lying down or sleeping.
While male dogs can be affected, female dogs are about 20 times more likely to develop the condition compared to males, according to the ACVS.
Besides ectopic ureters, there are some other birth defects of the urinary tract in dogs, including the bladder and urethra. In a patent urachus, a part of the umbilical cord that allows a fetus’ urine waste to be evacuated doesn’t close prior to birth like it’s supposed to. This actually allows leakage of urine from the belly button, which is the only visible remnant of the umbilical cord.
We can also see some dogs have urethras that are either too short or too narrow, called urethral hypoplasia.
And lastly, abnormal development or positioning of the vulva and vagina can lead to urine collection and pooling, leading to the appearance of incontinence.
Other Causes of Pee Leaking
Besides USMI and birth defects, there are a couple of other causes of urine leakage in dogs.
The first is some kind of nerve damage, such as from spinal trauma. Definitive diagnosis of any spinal cord disorder typically requires MRI imaging, but it’s also common for folks to know if something like this has occurred to their pup. Dogs with spinal trauma or nerve damage typically show more signs than just urinary incontinence. In most cases, hindlimb function is fairly poor.
In a newly acquired rescue where little history is known, but some kind of previous trauma is suspected, x-rays may help to highlight evidence of a previous spinal fracture.
Another cause of incontinence that we sometimes see is called urine retention with secondary overflow leakage.
In this case, we have a dog who for some reason that needs to be determined, is terrified to pee and so holds it to the point that the bladder is so full, urine actually leaks out past the muscular sphincter.
There is usually a behavioral cause involved with urine retention. Classically, we’ll have a dog who is otherwise healthy, but when taken outside, will refuse to urinate or not to seem to have to go. When brought back inside the home to a location perceived as more comfortable or secure, the pup may then urinate.
This can be more common in newly acquired rescues with poor previous socialization or adjustment to different outdoor environments. It can be helpful to get your vet, as well as a certified trainer or veterinary behaviorist, involved to help determine the source of your pup’s anxiety.
An overactive bladder or primary bladder hypercontractility, while a common cause in people appears to be rare in dogs. In fact, the most common causes of bladder hypercontractility in a dog will be things irritating the bladder itself, like urinary tract infections or bladder stones.
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How We Figure Out What’s Wrong: Diagnosing Incontinence
Fortunately, in most cases, we can narrow down urinary issues to incontinence pretty quickly, often with some good historical information.
As mentioned, dogs with incontinence characteristically leak urine without realizing it, especially when sleeping. When you bring your pup into your vet with urinary concerns, your vet will ask pointed questions about the nature of the urinary issues, when you’re seeing accidents happen, and how the behavior looks.
I also typically ask a lot of questions for young puppies about how potty training and crate training are going. Puppies have to drink and pee frequently when they’re active and sometimes new pet parents will confuse this behavior with incontinence when we really just need to work on our potty schedule and training.
We always typically rule out other common medical problems like urinary tract infections, by checking a urine sample first. In many cases, we’ll use an ultrasound to guide collection of a sterile urine sample. This also allows a look at the bladder to rule out bladder stones, polyps, and other bladder masses.
Some birth defects of the bladder can be identified with ultrasound, but not often with your regular vet. A specialist in ultrasound, like a veterinary radiologist, can sometimes diagnose ectopic ureters, a patent urachus, and other disorders of the upper urinary tract, as well as visualizing abnormalities in urine flow.
If an abnormality like an ectopic ureter is suspected, contrast study x-rays may be considered, where a special dye is used to highlight the urinary tract, allowing the abnormal path of one or both ureters to be seen.
The lower urinary tract (including the urethra and bladder) can also be directly visualized using an endoscope, which is kind of like a long tube with a camera on the end. Some general veterinary practices have scopes, but endoscopy is more commonly performed with an internal medicine specialist.
Lastly, advanced imaging like a CT scan or MRI may be considered. These methods allow for pictures of little tiny slices of the body to be taken, which makes it easier to highlight and identify the start and end of an anatomic abnormality.
While ultrasound and x-rays can typically be done with pets awake or lightly sedated, scoping and advanced imaging requires general anesthesia.
How to Fix the Leak: Treating Incontinence
Treating incontinence depends greatly on the cause. Is the problem behavioral or medical? And if medical, is it something structural that needs surgery? Or can we treat with medication? Once we figure this out, here is a breakdown of general treatment approaches.
There are two primary medication types that we use to address incontinence in dogs. These medications are most successful in treating USMI, but may also be employed to assist in other cases like ectopic ureters.
Phenylpropanolamine (PPA), is a drug that works by increasing the muscle tone of the urethral sphincter muscle, helping to keep it closed and prevent leaking. It often works pretty well as a first line treatment for incontinence, since it may address incontinence even if low levels of estrogen are not part of the problem.
It does come with some precautions. By its nature of increasing muscular tone, it also increases heart rate and blood pressure, so it has to be used precautiously in dogs with certain concurrent disease conditions, especially heart and kidney disease. It’s common to require at least annual bloodwork and blood pressure checks.
The second type of drug we have is a synthetic estrogen. Synthetic estrogens really only work in cases of USMI where low levels of circulating estrogen are responsible. The two most common synthetic estrogens include diethylstilbestrol (DES), and estriol.
Estriol is becoming more popular because it is short acting, has fewer precautions, and is FDA approved for use in dogs. DES, while effective too, is considered an off-label treatment, and must be ordered through a compounding pharmacy.
Some dogs respond well to just one medication or the other. Uncommonly, we will have some dogs on both at the same time.
In rare cases of USMI that don’t respond to typical medical therapy, other hormone therapies may be considered, but typically through an internal medicine specialist.
USMI is more of a functional problem and as such doesn’t really have a structural fix. But our birth defects affecting the urinary tract are anatomic and structural, and so surgery can be done to correct, or at least improve, these conditions.
A patent urachus, where there is a residual part of the umbilical cord that is connecting the bladder to the body wall of the belly, can be typically cured surgically by removing the abnormal persisting tube and closing its openings in the bladder wall and umbilicus (belly button).
Ectopic ureters are a little tougher though. According to the ACVS, there are a few different surgical options for this condition depending on the positioning of the abnormal ureters. The general goal is to try to relocate the opening of the ureter from its abnormal exit in the urethra, to a more normal position in the bladder wall.
But unfortunately, it appears that in about 25-70% of cases, dogs with ectopic ureters will continue to show signs of incontinence, even with additional medical therapy. The bright side is that male dogs, while far less affected, do have a much higher success rate of up to 80% after surgery.
In cases where positioning of the vagina or vulva is leading to urine collecting or pooling and the subsequent appearance of incontinence, a procedure called a vulvoplasty may be helpful to allow for better evacuation.
But What if These Treatments Don’t Work?
While most cases of urinary incontinence can be treated successfully, it is true that some don’t respond to treatment. This can especially be the case with ectopic ureters, which is frustrating and heartbreaking because these patients are typically so young when diagnosed.
Even if you have an older pup that just seems to have a leaking problem, possibly due to decreased muscle tone with age, and medical therapy isn’t as effective as we’d like, the first thing that helps is knowing what to expect, and setting certain expectations.
Some pet parents are willing to clean up daily after their pets with urine leakage, and they don’t mind doing it. But for others, the idea of the maintenance involved with an incontinent dog is daunting.
Diapers are actually a reasonable way of at least keeping the environment clean and dry in cases where all other therapies have been tried and have failed or only improved things to a point. Diapers are made specifically for dogs and can typically be found at a local pet store.
But while helpful, diapers can be a curse too. As those of us with human children know all too well, babies and toddlers with diapers must be changed several times a day. And the case is just as true for dogs.
If a diaper is not regularly changed, urine and feces will irritate the skin, leading to urine scald, dermatitis, and secondary bacterial infections in very sensitive areas. To avoid this, diapers need to be changed a few times a day, with wipes used to clean the urogenital area between changes to remove any debris or residue.
If caring for an incontinent pup is something you have a really hard time coping with, don’t be ashamed of that. It can be really mentally and emotionally taxing. In old dogs, this may even prompt an end-of-life discussion with your vet.
For young dogs, especially puppies, there are folks out there who have the understanding and stamina to foster and care for these pups long-term. Make sure to reach out to your local shelter or rescue. Your veterinarian may also have resources to help you relocate a pup to a home better equipped to meet a dog’s special needs.
Being as “Pee-cise” as Possible
Urinary issues in pets can be frustrating to be sure and can place a real strain on that special bond we share with our furry friends.
But successful treatment of any urinary issue requires getting as accurate and precise a diagnosis of the underlying cause as possible. So if you notice any new or progressing changes in your pooch’s pee routine, don’t jump to conclusions or make assumptions. Make sure to have her checked out at your vet, so the true cause can be narrowed down.