Hello, my name is Andy Kent. I'm a medicine specialist working in the Midlands. I have particular interests in urinary tract disease, so it's fantastic to be able to speak to you today to talk about something that is a very common presentation to all of us.
You know, we all see on a very regular basis, dogs and occasionally cats with urinary incontinence. And so I think it's one of those topics that's very important for us to have a good grasp of. And I suppose to start by saying that we should keep an open mind with urinary incontinence, that not all of them are SMI, urethral sphincter mechanism incompetence.
Many of them can be, and we will, of course, talk about that as we progress through this presentation, but it's worth remembering that there are other possibilities as well. So let's dive right in and have a chat about how we're going to approach and manage dogs with urinary incontinence. So this just gives you a, a kind of broad outline, I suppose, of, of what we're gonna try and cover.
So we're gonna talk about localization, we're gonna talk a bit about the kind of pathophysiology of, of incontinence. We're gonna talk about diagnostics, some of that, I guess, focused on incontinence, some of that a broader kind of diagnostic tips around urinary tract disease, and then of course we're gonna talk about some specific routes of therapy when it comes to managing patients with urinary incontinence. So I think when we start talking about urinary incontinence, it's really important that we start by thinking about what is normal, what is the normal control of urination, because that really helps us then when we start to think about localising and understanding the areas that this may go wrong.
So I may be teaching many of you to, to suck eggs and apologies if that's the case, but it's worth us just having a little refresher and having this at the forefront of our mind. So we know that in the resting state, in pretty much all of the patients that we deal with, they're going to be largely the same from this point of view. In our resting state, we should have a nice relaxed bladder, we should have a nice constricted and high urethral tone.
What that means is that as the bladder fills, as that urine is coming down from the ureters, from the kidneys, the bladder slowly increases in size and we have enough tone within our urethra to retain that within the urinary bladder. In dogs and cats, we rely very much on the, the general tone of the urethra, rather than what happens in people where we have a more specific, I guess, kind of area of of functional closure of the urethra. In cats and dogs, it's largely about the general tone of the urethra when we think about that.
And so we're mostly under that sympathetic control at that time. When our bladder gets full enough, essentially we're going to see a reversal of that process. So what we're expecting to see is a relaxation of our urethra and then constriction of that detrusor muscle to eject then the, the urine from the body.
And when we see dogs or cats with urinary incontinence, in general, it's something that goes wrong with that system. And we probably think about those things as, you know, neurological versus functional versus anatomical or, you know, whatever way you want to kind of break those things down. We'll look at some, some specific examples of that.
Now, as I said before, the thing that's really important to remember is that in our patients, a lot of the retention of urine within the bladder is because of general tone of the urethra, rather than thinking about specific areas of that within the kind of urethral sphincter, you know, and people there's a more focal zone from that point of view. We're talking about more, more generalised tone of the urethra. So when we think about urinary incontinence, we tend to classify it in this way.
So we see anatomical abnormalities. We will talk about some of those in, in due course. The most common anatomical abnormalities being issues of urethral termination, so things like ectopic ureters, sometimes other developmental disorders of the bladder, so things like vestibular vaginal septal remnants, additional, tissues or membranes within the, the opening of the, the urinary tract.
In cats, often things like urethral dysplasia as a, as a kind of common anatomical abnormality. Number 2, thinking about failure of that urinary bladder to be able to sufficiently accommodate that urine. So our detrusor, you know, dysfunction times when the, the detrusor muscle doesn't necessarily relax appropriately to accommodate the urine or is overreactive in, in how it behaves when there's urine filling up the bladder.
Failure of sufficient functional urethral closure, so this is where our urethral sphincter mechanism incompetence, our USMI comes in. By far the most common cause of urinary incontinence that we see. So not able to generate enough tone along the length of the urethra to retain that urine within the bladder.
And then some of our paradoxical incontinence or overflow incontinence, thinking about neurological disease, for example. So this is largely how we're gonna kind of think about incontinence as we progress through this. So like many of the cases that are going to present to us, and urinary tract disease is no exception to that, we're going to start off by taking a careful history, thinking about the way that our patients might present and broadly, when we talk about urinary tract disease, we might think about trying to classify them into kind of upper and lower urinary tract disease.
But thinking more specifically about urinary incontinence, there's a lot that we can gather from our history taking that is going to help us in narrowing this down. Starting with, it's really important to work out whether what is being described is actually incontinence, because owners will sometimes confuse that with you know, house soiling, inappropriate episodes of urination. If they're finding patches of urine by the back door in the morning, that is less likely to be true incontinence than, you know, we wake up in the morning every day and we find that the bed is wet.
So it's important that we try and get those details to understand whether this is truly urinary incontinence. If necessary, you know, use technology in your favour with these things. Think about using cameras to observe, you know, dogs when they're at home, particularly when they, they may be left, because I think there can be a big overlap with behavioural causes of, of inappropriate urination, for example.
Classical history of, of USMI, you know, is dogs that that tend to leak urine when they're relaxed, when they're asleep. So, urine on, on the bed in the morning would be the, the number one of those. Sometimes they will be more severe and they may drip urine when they're walking around the house.
Certainly, we see that, not uncommon. And our anatomical causes of incontinence. That is different from, for example, dogs with overexcitable bladders, you know, puppies who tend to leak urine when they're very excited.
You know, that's the truth of dysfunction. It's not urethral dysfunction. So think about those things, those things separately.
And occasionally we see, you know, unusual forms of incontinence, such as when we get pooling of urine within the vagina after voiding. And those might be, for example, dogs who will go out and urinate normally in the garden, but when they come back into the house, they will drip urine for a while afterwards. You know, we can give those dogs any medication, that's not going to make any difference to that form of, of incontinence.
So it's important that we try and understand that the true nature of the incontinence to help us narrow down where those issues may be. And of course, because neurological disease, for example, might be on our list of possibilities, making sure that we're also having conversations around whether there are other things going on. You know, these are patients who are also ataxxic, then, you know, that may point us in a particular direction.
Signalment, very important as well. We know that there are huge breed overrepresentations in some of the forms of incontinence. So, for example, ectopic ureters, you know, for a long time, golden retrievers were the poster children of those.
Now we see a lot of French bulldogs with ectopic ureters, but, you know, strong breed predispositions. Urinary tract disease, male versus female, you know, most of the dogs that we see with urinary incontinence will be female. That long urethra allows male dogs to be relatively more resistant from developing urinary incontinence.
Female dogs overrepresented in general in urinary tract disease with other forms as well, of course, infections, etc. And of course age may be important. You know, our classical USMI is middle aged to older dogs, potentially more common when you're neutered, for example.
You know, our anatomical causes, we consider them very strongly in these patients who are presenting below 6 months of age. So again, there's a lot of really useful clues that we can start to gather if we think about the signalment of the patient that is presented to us. Now, of course, we're going to do a a regular clinical examination in these patients as well, that's really important.
But specifically when it comes to urinary tract disease and urinary incontinence, what are we going to start to think about? Well, for me, I'm trying with this localization idea to evaluate the different parts of the, the urinary tract that are relevant, so bladder, urethra. So when we palpate the, the abdomen, when we palpate the bladder in these dogs, is it large, is it small, flabby, firm, is there pain in the bladder?
Can we express it? Sometimes quite tricky to do in dogs, but occasionally we're able to, to express it. Do we want to have a look at something like residual volume of urine post voiding?
From a urethra point of view, you know, probably observation of urination is quite a useful thing with that. Again, whether we can express urine. And then one of my number one tips with urinary tract disease in general is that rectal examination is your friend, not just in male dogs.
There is more that we can evaluate with a rectal examination than just the prostate. It is absolutely vital to do this in female dogs as well. We can really nicely evaluate the urethra.
I will see, you know, a number of dogs every year where I diagnose urethral tumours in the consultation based on a rectal examination. Obviously we do other bits and pieces after that, but these are often patients who have been elusive from a diagnostic point of view before that. So please remember rectal examination to feel specifically for urethral abnormalities in male and female patients.
Neurological examination, you know, really important to do. It's important to remember that dogs who develop neurological causes of incontinence will almost always, I hesitate to say will always. But it's very, very, very uncommon for neurological disease to cause incontinence absent other neurological signs.
So we essentially exclude that possibility on the basis of a basis of a normal neurological examination. So have a look at anal tone, you know, have a look and do a decent neurological examination so that we can make sure that they're normal in other ways, and that largely allows us to exclude neurological causes of of urinary incontinence. And then think about some of the other, the kind of general bits, so things like the confirmation of external genitalia.
Again, that's probably more important when it comes to things like infection risk, but these things can can sometimes go hand in hand. So I'm trying to ask myself when I'm examining these patients, you know, is the bladder. Where I think it should be, is the urethra doing what I think it should be, you know, is everything else kind of normal?
And again, our classical USMI patients should have, you know, small to medium sized bladders. They shouldn't have any obvious, you know, sign of, of concern from. A urethral point of view, they can generally urinate normally, generate a normal stream of urine.
So if you're seeing a dog with suspected USMI and you palpate the abdomen, they've got a huge bladder that you can't express. That is absolutely not what we expect with USMI, and we should consider some of those other possibilities. Now we tend to take a, a view on what diagnostic tests might be useful based on where we're localising things within the urinary tract.
We're not talking so much today about the, the upper urinary tract, you know, we're not talking so much about kidneys, maybe ureters a little bit. But, you know, we tend to, to think about these things in different ways. Ultimately, when it comes to the lower urinary tract, we're likely to be thinking about some form of urine analysis.
We're likely to be thinking about some form of abdominal imaging, and then potentially cystoscopy. We're going to talk quite a lot about the, the, the use and abuse of cystoscopy in these situations. Maybe we talk about other imaging modalities such as radiography and advanced imaging.
So it is good practise to be doing urine analysis on incontinent patients. It's very uncommon that things like urinary tract infection cause incontinence. I'm not a believer that infection causes incontinence.
I, I think that can be a bit of a myth. But certainly dogs who have incontinence commonly get infections, and if you have infections that can make your incontinence worse. But I don't believe infection will cause incontinence in a patient who's not already predisposed to that.
It may just be that they have very low grade incontinence before. So just some kind of broad top tips, when we're thinking about urine, looking at concentration of urine, again. You know, being PUPD does not cause incontinence, but it puts more pressure on the system.
And so, again, we have patients who sometimes will present with urinary incontinence and PUPD. If we can manage that PUPD, we may take the pressure off the system and that urinary incontinence may become less significant. So we want to look at what the USGs are doing.
We want to see if they can concentrate their urine in a normal way. We almost never, or we should almost never look at single USG measurements other than perhaps if we're just looking at whether azotemia is, is going to be renal or or or pre-renal, for example. Really what we need to see in these patients is what happens to your USG over a period of time.
How concentrated can your urine become, how dilute can your urine become. So we try and get multiple urine samples through the day to, to evaluate that in more detail. We're likely to do cultures, we ought to do sediment exams, we're gonna analyse our urine in in other ways.
If we are interested in things like looking for crystals, again, just a reminder that those need to be done on fresh samples, it's not that helpful for us to to evaluate for crystals in samples that we send away to the lab, because many of the crystals that we see in that setting forms simply because of the age of the sample. Now again, from a blood work point of view, by the way, apologies if you can hear purring in the background. I've got a new kitten this week who seems to be sitting pretty much on my right shoulder, purring very loudly.
So if you hear purring or squeaking, you know where it's coming from. It's the kitten who's joining in on the webinar. So yeah, apologies for that.
Anyway, let's get back to, thinking about blood work. Again, these are not things that. To give you a diagnosis, but it's really important that we think about some of these things.
So we would routinely tend to look at creatinine electrolytes in, in our patients with urinary incontinence, because, again, probably like we were saying before, if you have something like kidney disease and you're becoming PUPD that may put more pressure on the system and may be a reason that urinary incontinence becomes more Obvious when it's not been as obvious before. Same with something like hypercalcemia. So we should evaluate for those things.
Equally, if we're talking about dogs with, congenital forms of, of incontinence, for example, like ectopic ureters, we know that ectopic ureters can sometimes be found in dogs who will also have things like renal dysplasia. So it's good practise for us to, to be able to evaluate those things together. Again, this isn't gonna give us a diagnosis, but it's gonna allow us to, to look for comorbidities and and things that we should just bear in mind as we progress through our workup.
Now, in most patients with urinary tract disease, lower urinary tract disease, we're probably going to start with abdominal ultrasound. It's now, you know, likely the most readily available tool when it comes to evaluating the urinary tract. That allows us to look at kidneys, potentially ureters, bladder, prostate, local lymph nodes.
But remember, there is a chunk of the urinary tract that ultrasound is. Not good at the pelvic component of your urinary tract cannot be evaluated with ultrasound. So be cautious in excluding things.
Again, the classical example of this is dogs with urethral tumours, where they can have significant tumour burden within their pelvis and they have a completely normal ultrasound. So be careful in the way that we kind of, you know, discuss that, I guess, with our clients. Now, when it comes to incontinence, many of our patients have a pretty unexciting ultrasound.
One thing that we will sometimes try and do is evaluate location of urethral vesicular junctions using ultrasound, i seeing whether we can see those jets of urine entering the bladder in an appropriate location. Ultrasound can sometimes show that. I have to say it's not something that I'm overly keen on because I think it can be quite a protracted process.
We sometimes give things like diuretics to try and improve our chance of being able to say that, but the sensitivity and specificity of seeing abnormalities with ultrasound is not that great. So if you're particularly keen on that, I'm not gonna discourage you from doing so, but I do strongly discourage our radiologists from spending time doing that because I think I have better ways of being able to evaluate the, the urethro vesicular junctions than with ultrasound, but it is, it is certainly possible. So as we've touched on, ultrasound, absolutely beautiful for evaluating the upper urinary tract, so these are both obstructed kidneys, so a cat on the right, a dog on the left with urethral obstructions.
And lovely for being able to look at the bladder, so these are both dogs with with chronic inflammatory disease of their bladder, likely infectious. So we see lovely thickening of that bladder wall. But as I said before, you know, most of the dogs that we see with incontinence, their bladders will.
Look pretty normal and it doesn't necessarily, you know, differentiate. It's of course important to exclude, you know, obstructive disease, again, coming back to things like overflow incontinence, we will see that in dogs with, bladder neck tumours, for example. So radiography, radiography does allow us to give ourselves a broader overview of the urinary tract.
Again, we probably do less radiographic studies of the urinary tract than we once did because we have, you know, better quality ultrasound and other techniques for evaluating other areas of the urinary tract. But it can still have its place, particularly in situations where you may not have access to something like cystoscopy. So radiography, plain radiographs, very useful for excluding things like stone disease, you know, obstructive disease, potentially looking for things like metastatic disease.
And then historically, we've used a lot of contrast radiographs in dogs with urinary incontinence because it is useful for us to evaluate that section of the urinary tract that we can't see on ultrasound if we don't have access to cystoscopy, which is probably our preferred way to to do so. So looking for obstructive urethral disease in in particular. And we can of course use contrast radiographs to evaluate the location of our ureters.
So looking at IVU. Now doing those radiographically. For me, it's a thoroughly frustrating endeavour.
You know, you end up taking lots of images at different time points, animal in different locations. We've had to do enemas beforehand. Even with that, in some patients they can be really difficult to evaluate whether the insertion of your ureters is appropriate.
So we do them from time to time, but they are falling out of favour. So a couple of nice examples. There's a, you know, classical dog with stone disease.
Again, nothing shows that better than radiography. Here's a retrograde study, so this is a retrograde vaginal urethrogram in a dog with an intramural ectopic ureter. So this is demonstrated this really nicely.
If you never do these kind of studies, we've got a Foley catheter just inside the vestibule and the vestibule is otherwise clamped off, and we're squirting contrast up and into the lower urinary tract, so we get really nice filling of the vagina. We get filling of the urethra and let's bring up a little laser pointer here. Hopefully you see this OK.
You can see this fine line that sits in the middle of the urethra here. So this is our ureter coming down. It doesn't insert in where it should do around here.
It sticks onto the bladder and then it's tunnelling within the wall. So this is a classical intramural ectopic ureter. You can see this is a very old example.
The reason for that, they almost never look like this. So you, you know, you struggle to have really nice examples that that look like this. So when contrast radiographs work, they can work really well, but unfortunately, in many cases, they can be very, very frustrating.
Again, another nice example of of where contrast radiographs can be useful, you know, this is a dog where, again, it's going to be a retrograde contrast study. You can see a filling defect in the central part of the urethra there. That could be a mass lesion, it could be a stricture or a stenosis, but in a, in a dog with an obstructive disease process, that may be the kind of thing where, where contrast radiographs can be useful.
And here an example of a of a dog with an IVU. This is a, you know, really fascinating case. This is a dog that had an IVU for episodes of urine incontinence.
It had a uretro vaginal fistula, probably as a complication of a spay ligation. Now this, to be honest, is the kind of thing. You would not see in any way other than using a contrast study of this nature, but this is a very, very unusual form of incontinence.
So, you know, this is where if we have very atypical cases and we're really not getting to the bottom of them, we may want to revisit that as an idea. How can we overcome some of those frustrations associated with contrast studies? Well, CT is a fantastic tool for that.
As I mentioned before, some of the challenges with classical IVUs, radiographic IVUs, is the many different ways that we end up having to move our patient, the potential, you know, pelvis overlying the areas that we're interested in and that frustration around being able to actually interpret them. CT negates some of those challenges. So we can do CT IVU if we get the timing right, we can get nice filling of our ureters, so we can trace them down, see where they're they're emptying into the lower urinary tract and sometimes then make a diagnosis.
The challenge can be that CT is quite dependent on the quality of your equipment, how big or full the urinary bladder might be, getting that timing spot on so that you're trying to get good filling of the ureter without having a load of contrast within your urinary tract. So it can be a tool that can be useful, particularly for evaluating the the opening of those ureters and looking for ectopic ureters. It is the modality of choice, probably in male dogs for evaluating those things, because the alternatives in male dogs are not quite as good.
However, I would caution that CTIVU in ectopic female dogs is a total waste of money because we have other modalities, typically cheaper modalities that are more sensitive and more specific, give us more information about what we're seeing and what we may then need to do about it than than with CT. So I would urge people not to routinely see. Incontinent female dogs, because it, it's generally a waste of money.
In male dogs, and the reason for this is because the definition of cystoscopy in male dogs using flexible scopes is not quite as good as in female dogs, where we use rigid scopes. CT can certainly still have its place, potentially alongside cystoscopy, for example. Female dogs, less so.
But CTIVU significantly superior to radiographic IVU when it comes to sensitivity and specificity for things like ectopic ureters. Now, the availability of cystoscopy has kind of exploded over the last few years. Part of that has been one of the benefits of, of things like laparoscopic equipment being more available in many practises because there's a lot of, of shared equipment that we can use in those situations.
And for me, cystoscopy has revolutionised our ability to evaluate the the lower urinary tract and so it is a routine part of investigation in patients that present to us with urinary incontinence. It allows us again to assess that section of the urinary tract that we can't see with ultrasound, so the pelvic component of the, the urinary tract. It allows us very accurately to determine the location of the urethro vesicular junctions.
It allows us to evaluate vestibule vagina prep use as appropriate. Sometimes we can even scope into ureters and up into the renal pelvis so we can evaluate the upper urinary tract with this as well. It has by far the best sensitivity and specificity for evaluating for things like ectopic ureters in in our patients, so really, really useful.
Brief overview of what you might need if you're thinking of getting into cystoscopy. So this is, in the first instance aimed at females. So some kind of camera system, again, if you have laparoscopy in your hospital, you're likely to already have something of that nature.
So, you know, a camera head and a light source. As we would use for any other form of rigid endoscopy, and then a rigid scope, and you can see that the scope that I mostly use. This is an integrated, rigid scope that comes from storks, who are, you know, one of the big manufacturers of rigid endoscopy equipment.
And that kind of scope is what we are going to use in 80% of the female dogs that we would scope. It can be a bit short in very large female dogs, so we also have larger scopes to use in that situation. In male dogs, we have to use flexible scopes.
These are generally scopes that have been, or are sold as urethroscopes in people. So they're very, very small. They're about 3 millimetres in size, these scopes.
Now tradition. Traditionally, we used to use reusable scopes like you can see on the, the left, that's again another stort scope called the Flex XC. Those are expensive, they're very fragile.
I mean they're lovely scopes, but they're very, very fragile. So they do get broken from time to time. This kind of space within endoscopy has been totally revolutionised now by the availability of disposable endoscopes.
So the scope there you can see on the right is Stortz's disposable ureterscope that is an alternative to the Flex XC. These are relatively cost effective in comparison to a reusable scope, particularly with the kind of caseloads that we tend to see. We don't have to worry.
So much about breaking them, and they're absolutely fantastic. The image quality of them is, is brilliant. So male cystoscopy just gets better and better.
And that's where actually our ability to evaluate for things like ectopic ureters with, cystoscopy is getting better and better than it used to be. Therefore, our reliance on things like CT is, is getting less and less. So I would encourage you to look into those disposable options if it's something that you're interested in.
And we've kind of already, already touched on this, so, so females would tend to get a rigid scope, about 2.7 millimetres in in diameter, and males we use the, the flexible scopes. So I'll show you what cystoscopy looks like.
Here's an example, this is just a a standard cystoscopy in a female patient, so the dog's gonna be on their back. Uthra therefore at the top of the image, vagina at the bottom of the image. We use a 30 degree scope in in female cystoscopy, so the, the end of the scope is at a 30 degree angle.
That gives us a slightly wider field of view than we would get with a zero degree scope. So we're gonna have a look at the urethra first, so we pass the scope down the urethra into the bladder. And we're using constant irrigation of fluid as we do that.
We have a pressurised bag of fluid attached to the one of the ingress ports of the scope. We're using that fluid then to to distend the tissues away from the end of the scope. So we now get into the bladder, we empty the bladder of urine so we can get a better view, and we replace that with saline.
We're now looking in the bladder neck for where our ureters are, so if we sit in the the bladder neck, they should be looking there on the floor, so there's our left urethro vesicular junction on our right in the image, but the dog's left. And then opposite the other side of it, there's the other urethral vesicular junction. So within 30 seconds, we've been able to definitively identify that this is a patient who does not have ectopic ureters has completely normal urethral openings.
That is much more definitive than any other modality that we might use to be able to evaluate this. We may then have a look around the rest of the bladder if we're worried about anything, see if we can collect samples, biopsies, etc. If that may be indicated.
Otherwise we're gonna come out whilst looking at our urethra and if appropriate, then we may have a look into the vagina. So in terms of answering that question about UVJs, you know, the most effective way for us to be able to do that. Other pieces of equipment that might be useful depending on what we find, so lasers, there's various different lasers that can be useful within the urinary tract.
We predominantly use diode lasers, which is a way for us to cut tissue within the urinary tract and we'll talk about the uses of that later on. And potentially fluoroscopy. So some of the studies that we talk about, contrast studies, for example, or guiding some of those, the, the interventions that we'll mention, they can be guided using fluoroscopy, and fluoroscopic contrast studies can be slightly preferable to radiographic contrast studies because we get that dynamic aspect of it that we don't get with with plain radiographs where we just get that snapshot.
So, as I said before, cystoscopy is absolutely fantastic for being able to evaluate for our urethro vesicular junctions, and the still image you can see on the right there is a dog with an ectopic ureter. So essentially we see two openings as we go down the urethra. And just as an aside, not related to urine incontinence really, but the image on the right there, a nice example of a urethral tumour, so a urethral urothelial carcinoma, what we used to call transitional cell carcinomas, and we can see those, we can sample those very nicely with cystoscopy.
Now, one thing I often flag when it comes to thinking about urinary tract disease is that in many cases, when we are investigating or managing urinary tract disease. We actually see two parts of this. We see whatever the underlying disease might be, and then it's really common that we get complications associated with that.
So when we're seeing patients with urinary incontinence, infection is a very common complication of that. And along with infection could sometimes come things like polyps and, you know, things of, of that nature. So it is important that when we think about these diseases, that we're thinking about disease and any potential complications at the same time.
Equally, sometimes what we see is the complication, and what we then have to look at is what is the underlying disease, if that makes sense. So, actually, these are patients who present to us for recurrent urinary tract infections. Nobody's.
Picked up the fact that they have low level urinary incontinence. So just try and make sure that when we're approaching urinary tract disease, that we think about those things together, you know, that we don't kind of just think about them in isolation, we try and join up those dots. So, as I said before, we kind of think about urinary incontinence in this way.
We're thinking in our examination, in our localization, is this a bladder problem? You know, is there too much bladder tone or too little bladder tone, so detrusor dysfunction or detrusor hyper excitability? Or more often, is this urethral, you know, is there too much urethral tone, I, you know, this patient can't urinate and is getting overflow incontinence or as is most common, is there too little urethral tone, and therefore, as the bladder gets fuller, we're getting leakage.
Now, again, a little bit like we were talking about with disease and complication. There can be combinations of these, but of course if you have, for example, too much urethral tone or urethral obstruction, and therefore your bladder becomes over distended, you will progress to a point where your bladder tone, your detrusor tone is abnormal. So dogs or cats who've been obstructed for a period of time will then frequently develop detrusor dysfunction.
So we have to, we may have to manage multiple components of that at the same time. Again, we have to think about, you know, what comes first in that situation, but it's not, not an uncommon situation for us to be in. So let's talk about the presentation of this that is most common, and that is animals who present with decreased urethral tone.
These are the poster children for urinary incontinence. These are most often the middle aged and older dogs, female dogs who come in with classical urine incontinence at rest, you know, the, the ones that we think are most likely to be USMI. And, and I say that is the most common functional cause of that presentation.
Be aware, neurogenic diseases can look similar to that. As I said before, we typically expect to see that in dogs who would also have other neurological defects. So, you know, if you don't have other neurological signs, we probably don't have to worry too much about that as a possibility.
There is a huge amount of overlap, however, with that and anatomical causes. They tend to present in a very similar way. So dogs with ectopic ureters or other anatomical concerns such as vestibular vaginal septal remnants, and those often go hand in hand with ectopic ureters, we may see those presenting in a in a similar way.
So when we diagnose USMI. We need to make sure there is compatible clinical history, we've thought about some form of diagnostic imaging to exclude an anatomical cause. And therefore, this essentially becomes a diagnosis of exclusion.
Now in you or I, you may have seen these things performed, they will often look at evaluating your urethral pressures, so urethral pressure profiling. You'll see these tests described in dogs as well. However, they are not very clinically accessible and they are generally not very helpful in the patients in which we would like to evaluate.
They're really a research tool rather than something that we use in clinical patients. The reason for that. You need to anaesthetize dogs in general to be able to put these pressure catheters into their bladder or into their urethra.
As soon as you anaesthetize a dog, you of course affect their urethral tone. So they're not clinically very relevant tools for us to use, but you will see them described from time to time. How are we going to manage patients where we identify that they have decreased urethral tone?
Well, the vast majority of those will be managed medically. We have different groups of intervention. If you look at the consensus on these things, most people these days will reach for alpha agonists first, phenyl propanollamine, so propyin, most commonly used brand of of that product, and that is generally the the route that we would go down first.
There are other approaches, so looking at hormonal-based approaches, oestrogen replacements, which in the UK is generally estriol. There are other oestrogen replacements available elsewhere within the world. Again, most people tend to reach for alpha agonists first, not necessarily based on efficacy, actually don't have great comparative studies between these different groups, more based on potentially adverse effects profiles.
So we do see a few more adverse effects with hormonal therapies than we might with things like alpha agonists. Other drugs, so things like GNRH analogues, again these are reported in medication refractory patients, but they're not going to be used very commonly. Combinations, absolutely.
So if we look at success rates for using any of these medical interventions, they're broadly quite similar. You know, 70, 80% of patients will respond to a single agent if we're. On the right track with the diagnosis.
If we combine these, anecdotally, we push that up a little bit more. We probably think around 90% of patients would respond if we use combinations. And we think that they may be a bit synergistic, but again, this is based more on anecdote than actually any, any evidence base.
So, what I tend to do, we start with alpha agonists. If those are not enough, we probably add in an oestrogen replacement, and we use those things in, in combination. If you're using those and there is no response, I guess just double check that your diagnostics have been thorough enough and we have excluded other possibilities, or we may then have to think about surgical intervention.
Just to mention of male dogs, we don't see huge numbers of male dogs with urinary incontinence, as I mentioned before, that long urethra, the tone generated by that long urethra makes male dogs relatively, unlikely to, to. With your incontinence, but we will see it from time to time, and they can be more challenging to to manage. We will sometimes treat them with some of the conventional therapies that we've already discussed in female patients, particularly the alpha agonists, but their response rates tends to be lower.
One treatment that I've found useful in some patients that don't respond to other medical interventions is the use of testosterone. This is reported in male dogs with USMI. It is most commonly in older castrated male dogs, and testosterone does have some impact on urethral tone.
The challenge of testosterone has to be delivered by injection, so these are then dogs who end up often having monthly injections of of testosterone to try and maintain the effect. Again, anecdotally, it also sometimes becomes less effective with time. So, you know, male dogs can certainly be more tricky when it comes to to USMI.
If medical treatments are ineffective, what else can we do? Well, if we were giving this presentation, I guess 15 years ago, our classical surgical approaches, so culpo suspension or urethropexy, were probably pretty much all we had in that situation and. There are still some dogs who will have those kind of conventional surgeries, but they are reasonably invasive interventions and they can have their own, you know, potential issues with them, mainly, you know, making that urethral tone too great, which is then something that would require further surgeries.
So things that have then gained more interest in in the last 5 or 10 years. Placement of hydraulic occluders, if you haven't seen these yet, they are a cuff that is placed around the urethra. There's a little port that is then buried underneath the skin of the groyne and attached to that cuff with very small tubing.
That allows you then to place a needle through the skin into that port and slowly inflate the cuff, so we can essentially slowly apply more pressure to the urethra. And I suppose for most of us, those have probably become the the surgical intervention that we advise in in most patients if they haven't responded to medical therapy because they're more adaptable for us. There are still some downsides with them.
There are patients, for example, who have developed, you know, fibrous reactions around those cuffs leading to urethral obstruction, but they are a useful intervention. Submucosal injections of bulking agents, most commonly collagen or occasionally some of the newer products for these things, are something that we again use from time to time. The problem with submucosal injections of bulking agents is that the benefit of them is relatively short-lived in most patients.
So if we go and inject collagen, submucosally into the urethra of a dog, we expect to see an improvement in their incontinence, but in most cases it only lasts 6 to 12 months and then we may have to repeat that treatment. So for me, whilst that can be a useful intervention, I think we have to be quite selective about the kind of patients that we use that in. So I would consider it in older patients where, you know, they may have other comorbidities if urine incontinence is a particular challenge for them, knowing that, you know, they.
Our patients who maybe are not going to be with us for for years and years and therefore, actually, if we can manage their incontinence for 6 or 12 months, that may be all we kind of need to achieve. I don't generally advise them in young patients. I think that the benefit of, of that intervention is too short-lived for that to be something that's useful.
And just to mention, you know, when I would tend to think about suggesting surgical intervention in patients with urinary incontinence, so mostly it is when medical management has failed, or we have a lot of side effects with medical management that's kind of prevented us continuing it for a period of time. Times that I think we definitely should not think about surgery, so not in very young dogs, you know, not before the first season, for example, assuming that they're kept in tyre, you know, we need them to be fully grown. We should allow them to have seasons.
We know that seasons can have an impact in terms of urethral tone, so you know, make sure we select our patients appropriately. And of course, young individuals potentially slightly more likely to have had an anatomical cause that we don't want to have missed. So we need them to have been investigated fully.
We also would try to avoid doing these in very obese patients, you know, and try and make sure that they lose weight first or it can be very challenging. So a short chat about ectopic ureters, by far the most most common congenital cause of urine incontinence, and we will still see this with relative frequency in a in a kind of referral population, so we tend to see 2 or 3 dogs a month with urinary incontinence due to ectopic ureters. Most dogs present with this very young before about 6 months of age, and they have relatively continuous incontinence.
So they leak when they're lying down, but they may also drip when they're walking around the house. They can usually still urinate normally as well. Just remember, there can be atypical cases.
Occasionally we identify ectopic urities in dogs who present to With recurrent infections, and they've never been observed to have urinary incontinence, but maybe have very low grade incontinence. How are we going to diagnose it? Cystoscopy by far the best tool for us to use as we've already spoken about in females.
In males, we probably still use CTIVU often. Supplemented with cystoscopy, but actually as cystoscopic abilities are getting better, that becomes a more viable option for us to use potentially as a as a sole modality. Please don't CT female dogs to exclude ectopic ureters.
It is a waste of money. Please put that money towards the the intervention to correct these things. What does this look like when we perform cystoscopy?
So. You can see straight away in this patient comparing it to the previous one, that there was an extra band of tissue sitting over the vagina, we call that a vestibular vaginal septal remnant. We see that in the vast majority of dogs with ectopic ureters.
Here we are as before, finding our way down the urethra and straight away there in front of us, we can see an ectopic ureter. So urethra is on the left, ectopic ureter is there on the right. So cystoscopy very definitive in these situations in terms of being able to evaluate that.
There is an ectopic ureter, this is an intramural ectopic ureter, and then we can see the other urethral opening just there, which is also probably a little bit caudal. Here's another example of a vestibular vaginal septal remnant, that band of tissue that sits over the opening of the vagina. And we do tend to treat those at the same time as we treat ectopic ureters because we think they may be able to contribute to incontinence.
They're kind of tethering open the urethra. Here's another example. I think you've just seen the the normal urethral vesicular junction on our right, so on the dog's left.
And as we come back through the urethra, there's a very small ectopic ureter there, slightly stenotic open. Just caudal to the bladder neck, so just behind where it ought to be. In male dogs, ectopic ureters will often be very stenotic, so they can be quite difficult to see in contrast to female dogs where they're usually very large and very obvious.
So again, just a reminder you can see the image on the left there, a nice example of that vestibular vaginal septal remnants are that extra band of tissue. So normal ureters at the the top in the middle there and an obvious ectopic ureter in that patient on the bottom right. How do we treat dogs with ectopic ureters?
Well, by far, the majority of these patients will be treated now with cystoscopic laser ablation. All intramural ectopic ureters, which is the vast majority of ureters that we see, can be treated in this way. So we identify our ureter, we pass here a urethral catheter into that ureter via the working channel of our cystoscope, so that we've got a catheter within the ureter.
We then go back in, we pop our laser fibre down the working channel of our cystoscope, which will then appear in just a moment in the image, and you can see essentially this extra band of tissue that is sitting between the urethra at the top and the ureter at the bottom, and that is the band of tissue that we want to then cut away. So there's our laser fibre. And we're going to then just use little pulse cuts to cut away the tissue that shouldn't be there.
And we do that all the way down to the bladder neck and so we hope that we move that opening pretty much to the same, same level as our normal urethro vesicular junction on the other side. Or of course if they're bilateral, we try and just get them into the bladder, so the other side of, of what we perceive to be the the bladder neck. You can see there that it's a, you know, a slightly slow process, just cutting away these bits of tissue that we don't want to be there.
So there's our UVJ now that we've created within the bladder, pretty much at the same level as the other side. So we've achieved most of what we want to do. There's always a little tendency to do just to smidge more.
We're all perfectionists. But probably we were already OK from that point of view. And then as I said before, if this is a patient, as the majority of them are that have a vestibular vaginal septal remnant, we will ablate that at the same time using the laser.
And they can come in a variety of forms. Some of them are just a very fine piece of tissue that we can, you know, very quickly. Get rid of some of them can be a very long band, even resulting in something that we call a dual vagina when they're a long band of tissue that essentially separates the vagina in half.
But all of those forms can then be successfully ablated using the laser. Now, in terms of outcomes of laser ablation, it is as good as, if not potentially slightly better than the, the outcomes that we saw with conventional surgical techniques, so things like reimplantation. But the risk of complications is significantly less with laser ablation than with those conventional surgical techniques where we used to see, you know, issues such as stenosis around the site of, of reimplantation leading to obstruction.
What we can sometimes see is potentially things like chronic infections, occasionally polyps, although it's not something we recognise very, very commonly. I guess we talk about things like urinary tract perforation, very, very infrequently observed. What is really important in dogs with anatomical causes of incontinence to remember is that however you correct that, there will be around about 30% of dogs who will still be incontinent afterwards, and that's because they have concurrent urethral sphincter mechanism incompetence.
So we may have Made them normal anatomically, but they may still be incontinent. Hopefully that incontinence is less severe than it was before and it's more likely then to respond to medical interventions or whatever, but we have to be really careful with our client conversations around these things so that we warn them that that is a possibility. And I will say that is a very frequent cause of complaint after managing dogs with ectopic ureters because we, you know, don't.
I guess get that job done well enough, the education point with our clients, so they still come back saying, hang on, my dog's gone through all of this treatment, it's still incontinent, so we have to be really careful with that communication around those situations. So before we finish, we'll talk about just a few of those other forms of urinary incontinence that we may see a little bit less commonly. So, increased urethral tone, or paradoxical forms of incontinence, so when we get overflow incontinence, we probably see this most commonly in our cats who get urethral spasm, potentially as part of, you know, idiopathic cystitis type complexes.
But equally, we can see it with neurogenic disease, so typically upper motor neurone disease, whereby we don't get appropriate relaxation of our urethra. And then in this condition that we call reflex dysynergia, relatively poorly understood condition predominantly in dogs where we don't get appropriate relaxation of the urethra. It's important, of course, that we exclude anatomical causes such as your lithiasis or neoplasia, which may be able to look the same as those.
So that's where we need cystoscopy, retrograde studies, these kind of interventions. How are we going to manage these? Well, we're going to look at drugs to try and relax the urethra, so thinking about things like alpha receptor antagonists, so prazocin, tamsuacin.
Obviously be aware in cats, the evidence around some of these is a little bit conflicting as to whether these are useful things in obstruction or whether they might increase the risk of obstruction. In dogs where we have increased urethral tone or failure to relax, we do typically use alpha receptor antagonists. Tamsuacin, slightly more selective for the urethra than prazoin and maybe, maybe be preferred.
But remember, and I'm not sure whether I emphasise this enough, but of course the urethra is made up of different types of muscle. We may also need to look at skeletal muscle relaxants such as diazepam. We don't tend to use diazepam in cats, but more so in dogs, and diazepam can be useful as an additional medication if we're trying to get decent relaxation of the urethra, maybe combinations.
And of course at times, we end up having to do, you know, more physical interventions in these situations. So obviously if we have a physical obstruction, surgery, stenting, these kind of interventions, if we don't get a good response to medical management to try and relax this, then think about placement of things like a cystostomy tube. We use quite a lot of these locking loop cystostomy tubes that are placed percutaneously under the guidance of ultrasound and.
Be very useful either as a temporary or sometimes as a permanent intervention in patients with challenging to manage urethral disease. So some dogs with reflex dysinergia don't respond to medical intervention, end up needing things like cystostomy tubes. Now, just to mention then of, of atonic bladder diseases, so flaccid bladder type diseases.
Again, the most common reason that we see this is so-called myogenic causes. So because we've had an issue maybe with urethral tone, we end up with, you know, chronic obstruction and over distension of our bladder, therefore leading to dysfunction. But we can also see this as part of neurogenic diseases, as we've spoken about before.
Now, if we need to try and improve bladder tone, there are medical interventions that can help with that, most commonly things like beanyol and there's also some experimental evidence that perhaps metoclopramide can be useful from a bladder point of view. It is really important that we only use those things if there is no obstruction in the urethra, so either if we've removed a physical obstruction or we've relaxed the urethra appropriately to be able to do so. And what about overactive bladders?
So we do see this from time to time, and again it's a common thing for us to, I guess, confuse for other forms of, of incontinence. So that can be with inflammatory bladder disease. So some dogs.
Who have infection, you know, I said to you before, dogs with infection don't develop incontinence. That's true, but sometimes they can develop forms of incontinence or urge incontinence. Dogs who have very inflamed bladders may struggle to retain in a, in a normal way.
I guess the most frequent example that we have of bladder overactivity is in puppies, you know, who have what you might call an excitable bladder. So they're the dogs that when you, you, you know, have a visitor at the house, they pee on the floor or squirt little bits of urine when they're jumping up to say hello. Most of those dogs, they grow out of it, don't they?
You know, they kind of mellow with age, but we occasionally see this persisting with time. And in those situations, we might try drugs such as oxybutynin, which again helps with detrusor relaxation. So they can be useful things to use.
We also occasionally see this in in dogs with, for example, chronic infection of the bladder as a as a sequel to that disease. So worth just bearing that in mind as a slightly atypical presentation of urinary incontinence. So we're just about coming to the end of the session, talking about incontinence.
I hope that that has helped just to kind of plant some seeds and things to think about when it comes to to incontinence. The real take home message for me is just to remember this idea that not all incontinent dogs have USMI. Yes, a good chunk of them will, a good chunk of them will, and we generally have very good medical interventions for those, but don't forget potentially anatomical causes and don't forget these atypical presentations of urinary incontinence.
And actually if we're careful with our history taking, if we're careful with our clinical examination. We can start to understand some of those patients even before we've started to do anything from a diagnostic point of view. So ask the questions, do the careful examination to try and localise the incontinence more accurately, and you will have much more success with these patients.
If we always assume that dogs have USMI and we immediately reach for the bottle of of phenyl propionol. I mean at that stage, we will have, you know, poor response to those interventions than if we're more selective and we, we define those patients more accurately. So, you know, is this genuinely, urethral disease, too little urethral tone, or actually, could it be one of these other localizations that are going to take me in a different direction?
Ideally then, we're gonna pursue the kind of diagnostic test that we've already spoken about, exclude those other causes until we're left with, with a diagnosis of SMI. If you're interested in in urinary incontinence, there's a great ACI consensus statement that was published relatively recently in the last couple of years that has a really nice overview of pathophysiology of urinary incontinence and talks about many of these interventions in more detail. It's relatively long, 25, 30 pages, something like that, but it's a, it's a good read if you see lots of patients with urinary incontinence.
If you do have any queries, feel free to ping me an email. My email is on the screen there, always happy to chat about dogs with urinary tract disease. Incontinent dogs are one of my passions, improving, the management, the interventions, the treatment of dogs with urinary incontinence, I think is, is something that we can all try and strive to do.
So even if you're not local to us, if you have challenging urinary tract diseases, and you, you want to pick my brain about them, always delighted to, to do so. Otherwise, thank you for your time and enjoy the rest of your days.