Well, thank you so much for having me this evening. It genuinely is a pleasure. This evening, I have the opportunity to speak to you all about respiratory disease in dogs and cats with a particular focus on the use of inhaled medicine.
And over the course of the next 45 minutes or so, we'll talk about three diseases that we see pretty commonly in our profession. Each of which is a non-infectious disease that responds very well to anti-inflammatory medication. The first we'll talk about is canine chronic bronchitis.
Chronic bronchitis in a dog is defined clinically. It's a disease that causes a chronic cough every day. After you've ruled out other causes of cough, and that may sound a little particular, but it really is a disease of exclusion.
So for example, if a dog presents to your clinic with a chronic daily cough, You have to make sure the dog doesn't have pneumonia or heart failure in an older patient, or malignancy in some parts of the country, some parts of the world, heartworm infestation. Certainly in small breed dogs, we're all aware of dogs with tracheal collapsing cough. And finally, another common phenomenon that causes a daily cough in dogs is interstitial fibrosis.
To understand a little more completely, chronic bronchitis is commonly expressed in our profession as COPD, chronic obstructive pulmonary disease, but it, it's really, it confuses the issue of chronic bronchitis because COPD is actually a disease that involves bronchitis and emphysema, and it's a disease in people almost exclusively assigned to people who smoke cigarettes. Our patients don't smoke cigarettes and if they're exposed to it, they still don't get emphysema, and that's relevant because emphysema is the part of COPD that makes people hypoxemic and exercise intolerant. Typically, our patients really actually don't get that.
Now, in talking about COPD, I'll just make one graphic reference on the left, you see a postmortem lung specimen that's been fixed and formula of the human lung. And on the right is an equivalent size formal and fixed specimen of a patient who smoked for about 40 years, and I think even grossly, you can tell the profound difference between both lung surfaces. The reason I brought up the fact that chronic bronchitis isn't really COPD is because there's one other disorder that we confuse with bronchitis and they both cause chronic daily cough.
In this case, it's chronic fibrosis. But actually, chronic fibrosis in dogs is a disease of the lung itself, the interstitial of the lung, while disease of chronic bronchitis is a disease of airways. The reason that's relevant is because diseases of the lung can cause low oxygen content or hypoxemia, whereas diseases of the respiratory tree tubing system, chronic bronchitis.
And dogs really don't interfere with oxygenation very, very well. And finally, to make that last point, if a dog has fibrosis, it typically will not respond to corticosteroids, whereas a dog with chronic bronchitis almost always does. So I would say, briefly, if you have a patient that you think the patient has chronic bronchitis and it doesn't respond to reasonably high dose steroids, it's worth rethinking the diagnosis.
To make the diagnosis of chronic bronchitis really is pretty straightforward because it is a clinically-based diagnosis. It involves the obvious history and physical exams and chest radiographs, and then whatever else you need to rule out common causes of cough where you live. So, for example, I live in New Mexico, lung parasites are extraordinarily uncommon, but in the southeastern part of the United States, lung parasites are much more common.
So the diagnosis in fact of chronic bronchitis involves having a daily cough for 2 months. That's a little bit arbitrary, but that's been the way that it's been defined in human medicine and in canine medicine for years now. Dogs that cough with chronic bronchitis make mucus.
But you don't see the mucus because they don't spit. So typically, the history in addition to a chronic daily cough will involve some combination of gagging or choking or swallowing at the end of the cough because the patient is bringing up mucus to the back of the throat. Other than that, dogs with chronic bronchitis should appear to be pretty normal.
So if we have a dog with chronic cough, they should generally be in good health. We may or may not hear crackles on auscultation, but if we don't, that doesn't mean the dog does not have chronic bronchitis. On the other hand, if we hear wheezing in the dog, for which we suspect chronic bronchitis, that's consistent with the diagnosis, but it means the dog may have a more advanced form where airways actually collapse.
Chest radiographs in dogs with chronic bronchitis are the only typical test we tend to run, and they tend to look something like this. And I can show you if you can see as I'm showing you the pointer. And we look over here, the trachea is obvious, but immediately you can see the cranial lobar bronchus and secondary bronchi, as I'm pointing them out.
And that really is very unusual in a healthy patient. You really just shouldn't see that. And of course, caudally or distally, you can see airway walls as well.
If you look a little closer in this patient, you can also see, as I point out here, what are called doughnuts. So in addition to airways lining, alongside the X-ray, there are airways that are facing us. So if you think of a tube pointing at you, the round part of the tube is what you're seeing right now.
If the tube were on its side, you'd see these airway walls and we call those tram lines and doughnuts. It just means that the airway walls are thick with mucus or cellular to be exudate, and that makes them thick enough to see. Airways, airway walls and normal dogs are really very thin, and you shouldn't see them normally on an X-ray.
This is a case where a dog has chronic bronchitis that led to bronchiectasis, which I'll show a picture of in a moment, which led to pneumonia. So if you follow the trachea down to the carina, you can see an enormous craniallo or bronchus and then evidence of pneumonia, with their bronchograms. So this is the patient that originally had chronic bronchitis, developed secondary bronchiectasis, and that led to infectious pneumonia.
If you look As I circling now, that's an airway endoscopically with the appearance of bronchiectasis, and on the right is a cross section of the lung. It simply means with end-stage bronchitis. Two airways that are next to each other have their airway walls that break down in such a fashion that the two airways become one big airway, and that's the problem because the normal defences of the airway, including cilia, etc.
Are lost when these airway walls get broken down, and these patients really are very prone to secondary bronchial infection with bacteria. So if we say the diagnosis based on clinical findings, and we say the common lab tests really don't confirm bronchitis cause the CBC won't tell you and blood chemistries won't tell you, then what are we looking at? Well, we're looking at other things in a dog with a daily cough that could cause a cough.
So, for example, Here's a, a picture and on of the carina of a very small dog, so I apologise for the resolution. But the blue arrow was pointing out that this dog's left main stem bronchus is collapsing. Because the dog has heart failure, and just below that airway would be anatomically where the big left atrium would sit.
On the right side of the dog, the airway is normal. So heart failure can certainly cause a chronic daily cough. This is the dog with a piece of plastic stuff in its trachea.
I think that's a pretty good resolution X-ray, and you can imagine that this dog may be coughing every day. Here's a dog with a broken off piece of an endotracheal tube. So after the dog was intubated for a spa, when it got extubated, something happened and the endotracheal tube was broken off, that too can cause a daily cough.
And finally, here's a piece of what we would call a grass on, which just means when grass grows the seed, it can produce these long thin fibres which dogs can inhale and also can cause a daily cough. So, the point of this is simply that, and finally, I'm sorry, this is the parasitic nodule. In the bronchi of a dog in the southeastern United States, that's called asterosteride, which also can cause a daily cough.
But the point of the conversation is just that if a dog comes to you with a daily cough for a couple of months and is otherwise healthy and you rule out other common things that can cause a cough, as we just talked about, you can back into the diagnosis of chronic bronchitis. Once you've done so, you can ask yourself what are the common kinds of treatments that we might imagine would occur with chronic bronchitis, and I've listed them on the slide, but I'll go through each of them in a little more detail. Typically, when dogs have a chronic daily cough, some of us feel that it's appropriate to use antibiotics.
I'll only make the point that chronic bronchitis in the dogs have been very well studied and very well published for many, many years, and what's pretty clear is that bacterial infection does not typically play a role in chronic bronchial disease. That to say that if you culture the airway, just with this reference, Peterson Journal of Veterinary Journal of Medicine, one of many studies, you culture the airway of adult with chronic bronchitis, you'll find bacteria, but if we cultured each other's airway right now, we likely would find bacteria, which just means those bacteria are commensal, our airways are not sterile, and they don't really cause a problem. So the take home messages, dogs with daily cough or otherwise well.
If we think they have chronic bronchitis, likely do not have a bacterial infection. Cough suppressants are appropriate when you're treating the underlying disorder of chronic bronchitis because chronic bronchitis is an inflammatory disease. So what you're not seeing is the accumulation of mucus.
If you treat the dog with chronic bronchitis appropriately with anti-inflammatory medications, it's appropriate to use cough suppressants as well, so that the dog can get some relief and some sleep, and the owners can get some sleep. But if the only thing you treat is with cough suppressants, it's really probably not a standard of care, cause you're not treating the underlying inflammation, you're not treating mucus accumulation, and the dog likely will get worse. How about bronchodilators?
It's common in our textbooks to suggest the dogs with chronic bronchitis should get Aminophylin, theophyine, breathing, etc. Understand that dogs with bronchitis do not bronchoconstrict, and I say that because we actually study that. This is one of the very few papers in our literature that actually looked at dogs with chronic bronchitis while they're awake.
We did pulmonary function testing before and after bronchodilators, and it turns out that as a species, dogs just don't bronchoconstrict very much. People certainly do, cats do, horses do, but as a species, dogs do not bronchoconstrict in a clinically significant way, so I really don't ever advocate using bronchodilators for this disorder. Antihistamines are used, but there's really no reason to think that's gonna work either.
This is not a histamine-related or generated disease. Anticholinergics like atrophy also probably have no place in this disorder. Eucalytics would work if we can get it into the patient by breaking down the mucus to make it less thick, but typically when we give something like acetylcystine, by aerosol tends to be very irritating to airways.
To give it intravenously, it only lasts for a very few hours. So it tends to be not a treatment that I use very often. Which leads to steroids.
In anti-inflammatory drugs are the absolute mainstay of treating dogs with chronic bronchitis, and they tend to respond beautifully to them. I gave you on the slide one of a number of protocols to treat chronic bronchitis initially when you first see the patient. And if you see the very high dose at the top, 1 milligramme per kilogramme twice a day, it's really to make sure that your diagnosis is correct.
If the dog has chronic bronchitis, it really should stop coughing at this dose. And then I've shown you just one of many ways to start lowering the dose. At some point, as you lower the dose, the symptoms will reappear and that's the lowest dose you can get away with.
So, if that were in a big dog, 5 milligrammes of prednisone every other day, you'd be fine. But typically, in my experience, the amount of corticosteroids we need to control the cough in dogs typically causes the side effects we're aware of, of increased thirst, urination, behavioural changes, changes in in coat, perhaps urinary. Urinary infections, etc.
And those are the things we really try to avoid. So once we've decided that the amount of steroids that we give for this disease is causing too many side effects, that's the beauty of introducing the inhaled steroids. The history of this is actually pretty interesting, I think.
They've been used in human medicine for many, many, many years. When I was at the University of Chicago on the pulmonary faculty, they were used in infants and small children with asthma and other sorts of, acute bronchiolytic or viral infections, believe it or not, and in the picture above, you can see mom giving a child an inhaled drug. And when I was at the faculty, I thought, well, why couldn't we do this for dogs and cats?
So we actually have been using inhaled medications in dogs and cats for over 20 years. The most infectious, the most effective treatments, as I mentioned, have been injectable oral corticosteroids, but we know the side effects associated with them, most obviously increased thirst, increased urination, increased hunger. So we started using metre dose inhalers.
Of course, the problem with metre dose inhalers is trying to get them into patients. Now, the two classes of drugs that we use are corticosteroids and bronchodilators. For this talk on chronic bronchitis, we'll just focus on corticosteroids.
It's the most effective treatment that we have in addition to Injectable and or corticosteroids, but the advantages, and it's the same advantage in people, it's why they're used in people as well. It's because the molecule is so big, it doesn't get into the bloodstream. It doesn't get into the systemic circulation, and of course, the beauty of that is there are literally no side effects associated with the use of inhaled steroids.
Now, I've been a veterinarian for 30 years. I really try to avoid the use of the word always or never. But in my experience, the side effects associated with inhaled steroids are so trivial, I don't even usually list them because they're so mild and in apparent to the client.
Now, the reason it's effective is because with the spacer combination, I'll show you in a minute, that really uses the plastic chamber that allows the inhaled medication to get into the patient. The particle size is so small, it's allowed to get into the lower airways and there have been studies that we've done using labelled pharmaceuticals by inhalation to prove that when you give drugs to dogs and cats this way, it gets into the lower airways. This particular chamber, made by Breathe Easy and by Trudell is specifically made for dogs, and there's another one called the Aerocat made for cats.
And the reason it's worth mentioning this is that these chambers are designed to get the inhaled medication into the patient, and sometimes these inhaled medications are a little expensive depending on where you get them. So the most effective delivery system you can have becomes the least expensive for the patient if you need less drugs. And the most effective for the patient cause the most gets in it.
And it so happens that the aerodo and the aeroca are specifically designed to get the maximum amount of drug into the patient, and that's why they exist. They were specifically designed for dogs and for cats. The way that these chambers are made is specifically so that the inhaled medication doesn't stick to the inside of the chamber.
And that typically is one of the biggest problems with these chambers for dogs and cats. If you use the ones made for people, it's a different size, etc. And the inhaled medication tends to get stuck on the inside of the chamber and doesn't go into the patient.
So, this is the way it looks, but I will say, as we're online right now, the mask that comes for the cat perfectly fits the cat's face. So when you order an arrow cat, it comes with the mask that fits the cat's mouth and nasal cavity perfectly. This picture, I have to say a little bit misleading.
Apologies to breathe easy and Trudell. Typically with the dog, there snout is a little longer. So typically the mask you would use would be the mask you would use to give oxygen to any of your dog patients in the treatment area if they come with trouble breathing.
Whatever size oxygen mask you would use in the treatment room will fit perfectly on to these spaces in this area that I'm using for the Point to right now. Well, going the wrong way. Just give me one second, I apologise.
So, the mask that you would use would fit right there and it would fit right onto the aerodo. Otherwise, the system actually works really, really well. And overwhelmingly, dogs are comfortable putting this mask on.
So how do we do that? Well, remember, once we decided that we have had an effect on the oral corticosteroids, but it's causing too many side effects, the drug we use is a drug called fluticasone. In different countries, there are different trade names.
So in the United States, it's called Flovent, but there are different trade names in different countries. The dose is bimeter dose inhaler that we use is 110 mcg, not milligramme in a puff. In other countries it may be listed as 125 mcg, and typically if you put one puff into the spacer and let the dog breathe so 7 to 10 times, it will inhale all the medication.
Now, how much we give these guys, and we'll talk about this a little more in the next talk as well, is a function of two things, the size of the dog and the response to therapy. And just as in people, there's no absolute dose per dog or per size. It's really trial by response to therapy with the one other caveat being sometimes this is expensive.
So typically, in a dog less than 25 pounds, if I use fluticasone and I give one puff into the spacer and I let the dog breathe in 7 to 10 times, if I do that twice a day, it has the effect of having about 10 milligrammes of prednisone into the patient. And that's usually a pretty effective dose in smaller dogs. In bigger dogs, they may have to go to as much as 220 mcg with 2 puffs twice a day, which is a much higher dose, and as you can see on the slide, 880 mcg, which is very effective for larger dogs.
The only limitation is the cost. In Madrid last week, I was there, the cost of one of these inhalers was $49 so it would last a month and that would be a maximum dose. Typically, in smaller dogs, One canister will last 2 months, and at $49 a canister, turns out to be $25 US on a monthly basis.
And for our, our clients, it tends to be a little more reasonable. The patient is already on systemic steroids, when you start the inhaled medication, continue the systemic steroids for about 10 days as you wean off. The reason for that is that the inhaled medication may take as much as 10 days to have a full effect.
The patient is not on systemic steroids, I begin using it over a 10-day weaning period as I start the inhaled medication so that after 10 days, I can stop the oral medication because at that point, the inhaled medication would have reached full effect. Remember, chronic bronchitis in people or in dogs is not a curable disease, but it's very treatable. It tends to be very slowly progressive in dogs.
It tends to be most responsive in seasonal dogs that actually have an ear sniff or infiltrate. And it tends to be least responsive in dogs with wheeze because that means the chronic bronchitis has reached a structural problem in the airways themselves, so they're collapsing. But typically, dogs with chronic bronchitis will respond beautifully to corticosteroids and then when you switch them to the inhaled steroids, they continue to respond beautifully with the advantage that there are no side effects associated with this.
That's the first part of the talk. So that's chronic bronchitis. I think the plan for the seminars for me, rather than to take questions right now is to switch to the second part of the talk.
So if you give me just a moment, I'll do just that. The second talk I'd like to present is a little unusual in that most of the textbooks that we use don't really approach chronic rhinitis in quite the same way as I'm going to speak today. So I hope this is helpful to you.
When we see dogs and cats with chronic nasal discharge, chronic sneezing, chronic poor rubbing of their nose, there are lots of things, as we know, that can be the cause. Certainly acute infections, the fungal organisms and viral organisms, and even bacterial organs can cause nasal discharge in dogs and cats. So can foreign bodies.
In dogs more than cats, sometimes tooth with abscesses can cause this. There are things that go on in the back of the nose in cats are facetious when I say weirdness, but they are unusual things. I mentioned for completeness, but not very common.
Certainly in older dogs and cats, nasal masses, neoplastic masses can cause symptoms of nasal disease. And then, a very, very common disorder is lymphocytic plasmacytic inflammation which will spend The bulk of our time talking on the next 15 minutes. But the controversial thing I want to share with you is that the primary cause of chronic nasal symptoms in dogs and cats is never bacteria.
So let me say that again. The primary cause of chronic nasal symptoms in dogs and cats, the primary cause is never bacteria. And if that sounds a little peculiar, think to yourself, in your life, For the life of anyone in your family, has anyone had a primarily bacterial infection of their nose on a chronic basis.
And historically, when I ask that question, the answer is, in fact, always no. So, let's dig into that a little more cause certainly, when we see patients with chronic nasal symptoms and we give them antibiotics, they get better for some period of time. So what actually do I need?
Well, in a young cat with chronic nasal symptoms, the two most common things you're gonna see are herpes virus and in fact, lymphocytic plasmacytic rhinitis. In an older cat, of course, the other thing that can happen is cancer or neoplastic disease. In a young dog, the most common cause of nasal discharge is actually not allergy.
It's a foreign body or sometimes depending on where you live, it can be a fungal infection with vagillosis. And again, if you biopsy the nasal cavity of these dogs, it's lymphocytic plasma cytic rhinitis. You can call that analogy because lymphocytes and plasmacytes are part of the allergic phenomenon, but technically, this is actually an inflammation caused by lymphocytes and plasma cells.
In the older dog with nasal discharge, of course, we also have to consider neoplasia. Typical signs actually for us in the clinic are pretty straightforward. When you see a dog or a cat of nasal discharge and history of sneezing, we tend to see a dog or cat that also has noisy breathing and maybe snorting, sometimes they paw their face, etc.
But the anatomic diagnosis that it's in the nose is usually pretty straightforward. In evaluating these patients, unless we're willing to put them under anaesthesia, typically it's a combination of inspection, feeling the nasal cavity, listening to each nostril, and then imaging of some kind. I will share with you that when you have a dog or cat with nasal discharge, if you take a culture from the front part of the nose, it's universally unrewarding because you get all the commensal bacteria that are normal in the nasal cavity.
Similarly, doing cytology and the discharges of the nasal cavity will almost always show you some combination of white blood cells, but rarely will it show you anything that explains the actual aetiology of the disease. So, if we're considering a young cat, we certainly, especially when it comes out of a shelter, we'll consider viral infections, and one of the viral infections we see is calicivirus associated with that ulcers in the tongue, and we're all familiar with that. The thing that they, at least in part of the world that I live in, that is the most common for cats coming out of shelter environments is always feline herpes virus.
Now remind ourselves that we get a form of herpes virus and it's seen as at least the English translation is chickenpox in the states, and then it reprodes or disappears and comes back years later as shingles. And that's because the viral. Particles live in the nerve trunk or the nerve shape of the body, and it tends to become very quiet and then for reasons that aren't always clear, it may be because as an adult we have steroids or bad stress that will recrudes and it can cause some pretty serious side effects depending on where it shows up.
Now, acyclovir is a drug. That can be used, but I won't talk about that today because I want to make sure if we do talk about herpes virus, we have a little more time. So for this point, I'll just say that the most common drug that people use is lysine.
And in most of the lectures I give, if I ask, have people use the lysine, most people's hands go up. The problem with lysine is that every study that's been done, that's double blinded. And placebo control demonstrates conclusively that LIine does not help cats with respiratory associated herpesvirus.
If they have the ocular form. If they have herpes retinitis, it tends to be very effective. But in the respiratory form, there have been enough studies that have been done in a double blind placebo fashion to demonstrate that Llysine really is not a very effective strategy for herpes.
If you use it and it works, you should continue, but if you're open to the literature, the literature is pretty clear that it actually doesn't work very well. So if I say that bacteria never the primary cause of chronic nasal signs, then what are the primary problems and what happens if we just use antibiotics? Well, this is a series of three pictures from the nasal cavity of the normal cat on our left and in the middle and the right, the nasal cavity of two cats that had lymphocytic plasmacytic rhinitis, and they were given antibiotics.
And again, the problem is an inflammatory disease, not a bacterial infection. The reason why antibiotics work for some period of time is straightforward. With lymphocytic plasmacytic rhinitis or cancer, for example, The normal commensal bacteria in the nasal cavity, normally that just line the nasal cavity and don't cause a disease now are allowed to invade the mucosa and cause a secondary bacterial infection.
And when we use the antibiotics, the secondary bacterial infection is cleared, but then the symptoms come back because the primary problem is in these patients, often lymphocytic plasmacytic rhinitis. One of the complications, if you look at the back of a cat's nose, if it's not treated appropriately, meaning if it's given antibiotics, but not anti-inflammatory drugs, is that the back of the nasal cavity called the kani starts to get more and more narrow. And on the picture on the right, It's called choanal stenosis.
Let's remind ourselves that this is a picture blown up about 100-fold. The openings in the back of the nasal cavity for this cat that's been treated with antibiotics for 2 years, the opening of that nasal cavity is less than the thinness of the smallest coin that you have. And so that's a consequence that means the cat will have nasal discharge for the rest of its life because it can't drain the back of the throat.
And finally, when we use multiple antibiotics for these patients, what happens is they tend to have the ability to form pseudomonas, which is a very resistant organism, and in fact, in the absence of any antibiotic therapy, it's rare to find pseudomonas. So only when we've used many antibiotics over the course of months to years, do we have the ability for this organism to invade and become a very difficult player to try to eradicate. The real problem, if you think about it, for dogs and cats with nasal disease is imagine if you have a cold or an allergy.
And someone ties your hands behind your back, so you can't blow your nose. Well, that's what we see with dogs and cats with nasal discharge. They can't blow their nose, they can't force themselves to sneeze, so the nasal discharge in the nasal cavity either goes to the back of their throat or drips out the front, but they can't clear their nose on their own.
And again, if we talk about the primary causes of chronic nasal discharge, as we look at this list, the common things in cats that are young turn out to be herpes virus or lymphocytic plasmacytic infection, invasion, and in the older cats, you can have neoplasia. In the dog with nasal discharge as they get older, it tends to be either a nasal mass or this disease called lymphocytic plasmacytic quaitis. The best way to think of this, I think, is to consider the sort of inflammatory bowel disease but of the nose.
And all I mean by that is dogs with inflammatory bowel disease get a lymphocytic plasmacytic inflammation of the GI tract. Well, nasal inflammatory disease shows up as lymphocytes and plasmocytes, and we call those nasal allergies in people are seasonal rhinitis, but that's typically what's going on in lots of these dogs and cats. It's common enough, we don't really know the cause.
We can't identify inhaled allergens or irritants, and we don't know if there's a hypersensitivity to bacteria or fungi or in the case of cancers, herpes. These are all speculations. We do know if you look at the top left, that's what normal nasal respiratory epithelium looks like in the dog, and in the bottom bigger picture, you can see the disruption of the nasal epithelium and in the semucosa, all the infiltrates of cells, and it's typical for an inflammatory response.
But the problem is We have secondary bacterial infection. We have mucosal congestion, mucus accumulation, and sometimes we get nasal remodelling with this disease. So what do we do with the dog or cat with chronic nasal discharge if we think it probably isn't cancer, especially if it's a little older, and we're pretty much thinking this is probably the disorder.
Well, for the secondary bacterial infection, you actually do use antibiotics for about 1 week or 10 days. And both dogs and cats, for the people who are listening to the webinar, you know what your favourite antibiotic is and in this case, it'll be effective because in these cases, the bacteria that are involved are commensal. The staphs, their streps, the E.
Coli, the Bordetella, the pasturella, and they tend to respond to most of the common antibiotics. So, you'll clear the nasal cavity of the bacterial component. The second problem is nasal mucosal congestion and mucus accumulation.
When we have a stuffed up nose or our children have stuffed up noses, we consider using nasal decongestants. And so, I'm showing you a proprietary drug. It's called little noses in the states.
It's just a dilute form of phenylephrine, which is a nasal decongestant. A very simple way to use a nasal decongestant in our patients is to take 1 cc of epinephrine and dilute it in 9 ccs of saline. That gives you a 10 to 10,000 concentration of epinephrine.
And in the absence of significant blood pressure problems, for example, it's pretty simple to give this to dogs and cats. The method I found to be most appropriate is to point their nose towards the ceiling and drop 1 or 2 drops of this solution on a nostril. Let them keep their head up for a second to inhale that drug, and then you've treated one nostril.
If you go ahead and do that with the 2nd nostril, you do that twice a day for about 3 days. Their nasal mucosa is shrunken down. They can breathe much better, and since you've already put them on the antibiotics, they're not making the secondary mucos mucus because of bacteria.
So, The antibiotics and the decongestants clear up the nasal cavity, but we still have to deal with the underlying disorder of lymphocytic plasmacytic infiltrate. And here again, we come to inhale steroid, which is the most effective form and in people, it's the treatment of choice for seasonal rhinitis. You can buy this over the counter.
And again, the dose that's most effective for dogs and small cats is 110 mcg, one puff given twice a day. When you put the puff into the chamber, you allow the dog or cat to breathe for 7 to 10 times, that gets all the medication into the nasal cavity, and this is a brilliant treatment for this disease in these patients. The reason we use fluticasone rather than other inhaled steroids, is it's the most potent.
It lasts the longest And it's the least likely to be absorbed systemically. So, what's the combination of treatments with lymphocytic plasmocytic rhinitis, dogs and cats with chronic nasal discharge that don't have cancer or foreign body, etc. You treat the secondary infection with antibiotics for 7 to 10 days.
You treat the congestion with anti. Inflammatory decongestants? And then you start the patient on inhaled steroids using the chamber that I'm showing you now at the bottom, which is the one used for cats.
There's an arrow dog made for dogs, and this is for people who have had dogs and cats with nasal discharge from this disease for years. This is absolutely in 30 years of being a respiratory specialist, the most effective and safest way to treat these guys. Now, the owner should be prepared that this is A therapy that they have to use for quite a while.
There's no cure, but we decrease the clinical signs to very acceptable levels. These patients may need to be on lifelong treatment and sometimes they have unpredictable relapses, but in general, using this approach, you can keep patients symptom-free for weeks to months. And remember, we're not using antibiotics for a long period of time, so we're not getting involved in all the complications of multiple antibiotic use.
And just to sum up, and then I'll take questions. If you get involved in respiratory medicine, you get involved in being interested in nasal disease, you start doing rhinoscopy, you have lots of opportunities in other situations you might not have imagined. This happens to be a zoo with an Egyptian sand cat, and it's in Chicago and the cat had lymphocytic plasmacytic rhinitis, and we're doing a rhinoscopy now.
We're gonna do a biopsy and confirm the diagnosis. So, for now, I think that we complete the presentation, I'm very happy to take questions at any point. Phil, thank you very much.
That was absolutely insightful and certainly stimulated a lot of good thoughts on reassessing the way we handle these cases. Just a quick thing, folks, just to remind you that tonight's webinar is free to access thanks to the kind sponsorship of Breathe Easy with those inhalers that Phil has been showing us. So, yeah, really good to support those companies that support us.
Well, we had a lot of questions coming through at different times through this. I will try and remember or put them in context. I'm sure you will be OK to answer them anyway.
But one of the questions when you're talking about dogs coughing and gagging and that sort of thing, one of the questions that came through is, is there any medical treatment for tracheal collapse? The question is, is there a medical treatment for tracheal collapsing, it's a simple answer and it's a complex one. The simplest way to approach this is if you recognise when you do a lot of endoscopy and you see lots of patients like this, you realise again, this is not an infectious disease.
This is actually a structural disorder of the cartilage that causes the trachea to become very rubbery, and then when the patient coughs, the trachea actually collapses and touches the top and bottom. The reason that's important for therapy is that if we remember the dogs don't bronchoconstrict, we're really not using bronchodilators at all. The cause of the cough is structural, and when the mucosa at the top of the trachea and the mucosa at the bottom of the trachea touch when the trachea collapses, it causes erosions in the mucosa.
So you're desperately required to stop that cough, and that requires sometimes very high doses of cough suppressants for short periods of time. If you can work with the owner to find a dose of a cough suppressant like hydrocodone, that'll stop the cough for a five-day period. That will allow the mucosa to heal cause the blood supply is so good and then you need much lower doses of cough suppressants long term to control that cough, but it is a structural problem.
It's a problem of the cartilage within the trachea itself, and the only medical treatment is really to try to control the cough. Excellent. Yeah.
Another question that came through, and this was when you were talking about COPD and smokers and that sort of thing. Is there any studies or have there been any studies that have been done with the effect of air pollution on our pets? That's a, it's a great question and the answer is yes and no.
If we remind ourselves that the particles of air pollution actually drop at some point down, our patients literally are lower to the ground than we are and get covered with more of the pollutants than we do, although we don't see it, they tends to be a higher concentration of pollutants that they're breathing in than we are. The pollutants that our patients tend to inhale have variable effects as they do in people. They, they, they, it's hard to quantify what amount of pollution, what kind of pollution will cause the problem.
Certainly, there's certain kinds of pollutants in people that lead to asthma attacks. Lots of pollutants cause coughing. But to cause chronic bronchitis itself in people and dogs, it's, it's a much more complicated story and just briefly, it's clear in people.
That you have to smoke cigarettes to get chronic bronchial disease and emphysema. Our dogs and cats don't have to smoke cigarettes, obviously, to get that, so we don't know the ideology, but we certainly know in any dog that's coughing for any reason, any cat that's coughing for any reason, if they're exposed to high levels of air pollutants, the coughing will get worse. So I don't think that was a complete answer to your question, but it's as much as I know.
OK. There was a question that came through from Amanda, and she wants to know if you have an animal, an elderly patient, for example, that is on NSAIDs, where you can't initiate treatment with oral steroids, would the inhaled steroids still be as effective? So, I, Amanda, thank you for asking that question.
I should have actually brought it up. For the patients that are on NSAIDs or diabetics, for example, for which steroids are relatively contraindicated, the inhaled corticosteroids are the perfect answer we've been waiting for because they don't get into the bloodstream, they don't have any coincident effects if you're already on NSAIDs or you're diabetic or you're on other steroids for other reasons. In fact, In fact, patients, children that get bronchiolitis from viral infections in the face of an active viral infection, they still get inhaled steroids to control the secondary inflammation.
So this drug, this form of drug given this way, corticosteroid inhalation, are very effective in a myriad of situations, and it's a brilliant use of the drug and the application when patients are taking NSAIDs or they're diabetic, for example. Excellent. Jas asked a question and said the use of the mouthpiece and the aeroca and aerodo, you know, all great goes over the mouth and nose.
But what happens if these animals are dysne and they are mouth breathing? That's a perfect answer, a perfect question. So, two things.
The first is that the inhaled steroids are not rescue drugs. If a patient with chronic bronchitis is dyspneic, he probably doesn't have chronic bronchitis. I think that's an important point to make.
So this is the disease, chronic bronchitis, for which inhaled steroids are very effective. But if the patient has heart failure or pneumonia or something else, this really isn't the appropriate drug or treatment. For nasal disease, once you clear up the nasal congestion with decongestants and a short-term use of antibiotics, they should not be dysneic.
So the situation in which a patient might be dysneic that I didn't get a chance to talk about is feline asthma. In those cases, and it's interesting, I actually have a movie but on a webinar, it's hard to show this of a patient having trouble breathing with asthma, for whom we use the spacer and mass combination. With the drug called albuterol, which is the bronchodilator that you would use or I would use or our patients use because if they can take 3 or 4 breaths of that, their dyspnea due to bronchoconstriction will usually resolve within about 30 seconds, which is exactly what you or I do if we have asthma and we're getting very wheezy.
We take a few inhalations of the albuterol and the wheezing goes away so we can see a doctor to find out what's going on. So in that situation with feline asthma, you actually can apply the mask for 3 or 4 or 5 breaths, and they will resolve the bronchoconstriction pretty quickly. But other than that, the steroid is really not a drug you ever want to use in a dyspneic patient.
Excellent. Davina's got a, a question. I'm going to read it exactly as she's written it.
She says, sorry, but I missed the 1st 5 minutes and came in at the time when you were talking about heart failure causing a cough. We are told over and over again by cardiologists that heart failure does not cause a cough and that this view is outdated. Should we now include heart failure again in our differential diagnosis of chronic coughing?
Well, thank you for that question. It really is a hotly debated question and with great respect to my cardiology colleagues, I broncho, I've bronchoscoped multiple dogs early in my career that had a big left atrium and normal airways, and the only place where there is erosion of mucosa is at the base of the left stem, the left main stem bronchus, which is where the left atrium is causing collapse. And it's such a recognised thing now that people are being taught in multiple universities, how to put stents in the left main stem bronchus alone, not tracheal stents, but tracheal claps.
But stents in the lane left main stem bronchus to keep that from collapsing in the face of heart failure. And I have treated so many patients that came in for bronchitis and in fact had a big left atrium and when you control the pressure within the left atrium of cardiac drugs, so the pressure in the left atrium goes down, the collapse of the left. The bronchus resolves and then the cough goes away.
So with all great respect to the cardiologist, this is not an outdated phenomenon. In fact, there are a number of people who are writing papers now to demonstrate bronchoscopically and in terms of CT, the focal collapse of the left main stem bronchus with the left atrium that's enlarged. So I guess I would just have to lightly disagree.
Excellent. Audrey has a two-part question. The first part question is, do you see fungal infections around the mouth and intra-orally?
With the, the flu to cause zone therapy, sorry. Sure. So when inhaled steroids first came on the market, there were two concerns.
One, the potential of growth retardation in children, and that proved to be completely untrue. And the other that does happen in people is to rush. And the organism for that is can candida or candidiasis in the back of the throat occurs in some small percentage of people and it causes hoarseness in their, in their voice, and sometimes it has to be treated.
And when I first started using this form of medication about 20 years ago, I was Very aware to look for any change in the oral flora or the development of thrush in my patients, and I never saw it or documented it. I can only guess why. I don't have data.
I can just tell you why. I think they don't develop it. It's because the oropharyngeal bacteria of the dog and the cat is just very different of the oropharyngeal bacteria people, and the bacteria in the posterior harynx of people allows the growth of commensal.
Candida, and it just doesn't allow dogs and cats. That may not be true in terms of why they don't get it, but I'm reasonably confident saying that dogs and cats do not get thrush when they've used this form of medication for a long period of time. OK.
The second part of Audrey's question, she says, in our country, we only have fluticasone 50 milligramme and 250 milligramme available. Would you start on 50 milligramme for a small dog or is this too low? And what about the dose for cats?
The lowest dose I've ever been able to use that was effective in cats and small dogs is the 110 mcg given twice a day to store. So if you have a 50 mcg dose, you can simply apply two sprays into the chamber and let them breathe 7 to 10 breaths, and they're getting a 10 100 mcg dose. Lower than that, I've never found to be effective.
There is one paper that a researcher showed that at a much lower dose of Flovent in an experimental model of asthma, you can get rid of theosinophils, but I won't repeat much more of that because it really isn't relevant to the clinical problem. So to answer the question specifically, the lowest dose of I think that'll be used in cats and small dogs is 100 or 110 mcg given twice a day for some period of time. The 250 dose, the only downside to using that is cost.
Again, you're not gonna hurt a patient clinically by using too much. In people, and I'm not saying physicians do a better job than we do, but if they suspect you have asthma, they'll put you on a 250 or a 500 mcg umtic cell dose of something called Advair. And it's completely arbitrary what they use.
So in our patients, for me, I use the highest dose I can use to begin with, to prove that it's gonna be effective. Excuse me, the only downside is the cost. So, I found in different countries, the online pharmacies are wildly variable pricing for these kinds of things.
OK, Caroline has asked, is memethazone as effective as fluticasone? So there are a number, as a number of people in the audience know, of different kinds of inhaled corticosteroids. Including the deanide, among others.
The reason Fluticasone was chosen, when we first started introducing this into our profession, is because It was and still is, as far as we know, the single most potent anti-inflammatory corticosteroid by inhalation that can be chosen. The second is it has the longest duration of that action of the inhaled steroids that are available. And the third, Because that that's least likely to be absorbed of all the inhaled corticosteroids.
Because remember, even if you inhale these things properly and the patients inhale properly, about 70% of the inhaled steroid winds up impacting on the back of the pharynx and that gets swallowed. Well, if it gets swallowed, and it's exposed to the stomach because theoretically get absorbed, but the fluticosum molecule was so large and negatively charged and lipid insoluble that it simply doesn't get into mucosal. Now, that does not mean that other forms of inhaled steroids don't work.
We chose fluticasone and have all our experience using platicasone because of the reasons I mentioned. But if there are other forms of inhaled steroids that are available that are much less expensive, there's no harm in trying to see if you can develop protocol to use those. We have another question that's come through which says, is there any way for us to tell or diagnose lymphoplasmocytic rhinitis without cytology?
So it's a great question. This is technically a biopsy-driven diagnosis, and when I see patients, I have the great fortune that my clients are coming to me as a specialist. They tend to be very committed to the kinds of diagnostics that I recommend.
So I typically will do an anaesthesia, endoscopy, biopsy, etc. But absent that, In a younger dog, the only other differentials really are, if you see fungal rhinitis, you have to consider it, and if they're in areas where they run and play in the grass, you have to consider a farm body over this palate. Those things would require a brief anaesthetic and rhinoscopy to confirm or deny.
And in older patients, you do have to be concerned about cancer. Now, there are techniques in radiographically, not just CT but radiographically, you can distinguish whether or not patients have fungal disease, cancer, etc. But it still involves anaesthesia.
So if the patient's going to be anaesthetized, you will make a definitive diagnosis. Absent that. If the dog or cat's been given antibiotics for quite a while now, and you'd like to try a different methodology on the assumption that it's a specific plasma cytic rhinitis, what I suggested is pretty benign therapy.
If you give an antibiotic for 17 days, a decongestant, and then an inhaled steroid, and the patient gets better, that's a trial by, that's a diagnosis by responsible therapy. OK. I'm, I'm sifting through.
There's loads and loads of comments still coming through, just saying how fabulous this webinar has been, how informative, how much people have learned from it. So, as Anthony always likes to say, if we were in an auditorium, you would be hearing thunderous applause at this time. Well, you're very, very kind.
There may be some howling in the back of one of my dogs is having a moment, but I apologise for that. There's, there's loads of questions coming through. Why, I'm gonna paraphrase a whole lot of them coming together.
Your comments on nebulizing strokes, steaming of, of cats especially, but generally in rhinitis cases. Well, you know, I, I was taught, when I was a child, when I had a cold by my mother to, get a pot of boiling water and put my head over the pot and put a towel over my head to inhale the steam. And I think that was a great idea 50 years ago.
I still think that's a great idea. So if you have the ability to expose a dog or cat to a lot of steam, whether it's in a shower or in any other fashion or a nebulizer, I think that's very effective locally to try to moisturise the nasal cavity and humidify and liquefy some of the secretions and if nothing else. The nose to sneeze.
So those are brilliant things to do. They cost no money and they're very, very safe. They don't get to the underlying problem of why the mucus is being made, which is why they're very helpful from a clinical point of view, but don't really solve the problem, and they won't get rid of the problem on their own.
I hope that's helpful. Excellent. Folks, we could be here all night.
Unfortunately, we have come to the end of the webinar. I would just like to do two things. First of all, again to our sponsors, Breathe Easy.
Thank you so much for your sponsorship to allow us to have access to a Speaker of Phil's quality. It really is fabulous. And Phil, to you, thank you for taking your time, this afternoon in, spending time with us, for us the evening, to impart your knowledge and, and to bring us this.
We really look forward to having you on the webinar vet again. Well, it's been my absolute pleasure and I really did enjoy the opportunity to chat about this. Excellent.
Folks, from my side, that's it for tonight to Paul, my controller in the background who makes things happen seamlessly. Thank you for all your help and from myself, Bruce Stevenson, it's good night everybody.
