Nathalie DowgrayWelcome to the June episode of Chattering with ISFM. I'm Nathalie Dowgray, Head of ISFM and host of this month's podcast. First up this month, we have part two of my interview with Professor Clare Rusbridge, and we're talking further about neuropathic pain in cats. And then Dr Kelly St Denis from AAFP is going to be speaking with Dr Julien Guillaumen on his clinical spotlight article, feline aortic thromboembolism, recent advances and future prospects.
You gave some fantastic case studies in the paper, but with a number of those, I also noticed that actually, while we achieved in the first outcome successful management, there were often then flare ups when maybe other disease conditions occurred, and that may have led to the medications being difficult. So these aren't necessarily straightforward for the owners. How do you manage those initial discussions with them, but then also that longer term sort of role in monitoring the quality of life?
Yes, I'd say that the biggest burden that caregivers have is giving medication. Some of these medications that we use for neuropathic pain are better to be given sometimes three times a day, and that may inform my choices. For example, pregabalin, one of the gabapentinoids, is about five times more bioactive than gabapentin, and I prefer it for cats because it can be given twice daily, which is much less effort for the owners.
And there are some cases where we'll use quite unusual drugs for pain. You wouldn't expect phenobarbital, for example, to be useful for a pain condition. And I'm not sure that it necessarily is for dogs, but it does seem to be useful in some cats, especially with feline oral facial pain. And phenobarbital can in some circumstances be given once daily.
So if I have a very challenging case, then I will consider that perhaps a poor choice you might think because of the side effects, but sometimes a low dose of a once daily drug of a small tablet, which the owner finds easier to hide in food is going to be better than them struggling to give capsules three times a day. There are some options for giving topical medication. For example, we can apply things like tramadol to formulations to the ear and topical amitriptyline also exists.
But the problem with that is that they are very poorly absorbed. And so they're definitely not an option for many cats. So I think the first caregiver burden is really that they can struggle to give medication. And it can be difficult for them to find solutions for that. And sometimes it can be so difficult that you have to have the euthanasia discussion, that the quality of the life of the owner and the cat are just so poor.
The quality of the life of the cat, because they are miserable with the condition and miserable having medication. And the owner just can't cope. So I think, although we focus on treatment in the article, I think we have to also acknowledge that euthanasia plays a role in some of these cases because it can be a difficult situation. As far as quality of life tools, I think they definitely will have a place.
It's challenging sometimes to find one that is suitable for chronic pain and chronic neuropathic pain. And so if people are asking what I would tend to use, it would be the AWAG. That is a pretty useful tool for looking at quality of life and the impact of the disease and monitoring over time.
Nathalie DowgrayIt's useful to know what works and we're still, I think, at the stage of developing good health related quality of life tools for cats. It's a growing area of interest. You also, within the article, created this really lovely treatment algorithm as well. And I have to say I do love an algorithm. In terms of a reference guide as well, I think it's really helpful. And I wanted to just ask a few questions about some of the drugs.
The first one was around the anti nerve growth factor monoclonal antibodies. We've only had them available for the last sort of three or four years. And some people listening to this podcast, it only might just be coming available in your country. So I was just really interested in how you've been using them in your work with pain cases and which ones that you've found them the most useful for.
Yes, I think this is probably the most exciting development in pain management that has come out in recent years. And obviously the big advantage of these drugs is that they're given by injection and they can be given once monthly, much less challenging than giving tablets daily. I think it's important to state that this is most indicated for peripheral neuropathic pain.
So what it's having an effect on is affecting the way that information about pain is translated through the peripheral nerve and the dorsal nerve root ganglia, where the cell body of the nociceptor is. And so it affects changes in that cell nucleus. So I wouldn't expect these drugs to work on central neuropathic pain, only in peripheral neuropathic pain, and people say, Oh, isn't it for osteoarthritis. Actually, the mechanism is through the nerve.
And so theoretically, it could work for any condition with peripheral neuropathic pain. So the conditions that I have used it on successfully in cats, most notably feline oral facial pain syndrome, which is a challenging condition to treat. Related to that is dental pain. Now, I consider those two separate.
Yeah, feline oral facial pain is a syndrome of mutilation that cats probably have an inherited tendency to, having abnormal processing of information and it's triggered by teething and other oral lesions, which you wouldn't normally expect to cause pain. I would normally expect severe periodontal disease to cause pain, but sometimes those cats can be left in a lot of pain despite having dentistry. So they were in a lot of pain beforehand. They have dentistry.
A lot of cats are discharged from dentals having had extensive dental work with barely any or no oral medication Just imagine if you had that work done. I know I'd be a complete baby. I have seen some cases that where the cat has had some chronic pain relating to tooth problems, and I've used these anti NGF monoclonal antibodies successfully in that. One of the examples I'm thinking about was a cat that had chronic pain related to its upper canines.
And I was referring to a veterinary dentist to deal with that because that's quite a complex surgery and there was a long waiting list. So I had to manage that cat's pain for quite a long time. So that was one sort of example. I've also used it successfully for lumbosacral disc disease in the cat.
So I think going forward, I would consider it for any neuropathic pain syndrome in a cat where the pain is peripheral as opposed to central and lumbosacral disc disease I regard that as peripheral because the nerve roots are being compressed.
Nathalie DowgrayNo, that makes sense. Yeah, and it is definitely exciting and obviously with these drugs came out they've been licensed in cats and dogs for osteoarthritis, but it's that bigger piece as well that we're now starting to explore a little bit more.
It should be said that all drugs used for neuropathic pain in cats are not licensed. So you need to make that, those discussions with their caregivers that you're not giving a licensed medication.
Nathalie DowgrayYeah, no, that's important to consider. And now over to Dr Kelly St Denis and she's speaking with Julien Guillaumen on feline aortic thromboembolism.
When I was reading through this, one of the things I always forget about is this potential side effect or sequela of FATE is acute kidney injury, which you have a lot of really good information in here about, but I wondered if you would talk a little bit about that aspect of FATE as a sequela from the problem, how that happens, what you do to monitor.
That's something that I didn't know that came out of the paper that we published a few years ago. Again, funded from Morris Animal Foundation, and I like medical history, and so I'm gonna start, I'm going to start all over in, in 1953, but the first case report in cats is actually from a French veterinarian, I guess the first case report that I can read, and I can only read in two languages, and so it was published in 1953 in, in, from France. Dr Collet described the syndrome.
I think it was a necropsy, but so talked about it. And then, we didn't have a lot of things that was in a big scale until the eighties. And so, In 1980, Paul Pion, who was a cardio resident at QC Davis, is now better known for founding VIN, but before founding VIN, Paul was a, a cardiology resident and he treated a lot of those cats in the 80s. I talked to him a few times, and that's kind of what he told me. And he did a lot of formalising.
At that time, when he published the case theory, there was actually no, no retrospective studies in the 80s on ATE cats, which I think is fascinating. The first kind of larger case series was in the 80s when he used TPA, and he said we didn't expect those cats to get complications. So when we gave TPA and they got complications, we thought that it was because of the TPA and because we had nothing to compare with. And so that's how TPA got its bad reputation as a thrombolytic.
And then in the 90s, there have been a couple of more retrospective studies, usually from the East Coast, looking at ATE cats, and they do basically say the same thing in terms of 30 or 40 percent survival rate, all those type of things. And, but they don't really, they didn't really go into the details about why those cats died.
And to the point that when I designed my study with the cardiology team at Ohio State University, while I was there at that time and then other people, we also did not expect those cats to die very quickly in a way. And so I think our study was the first one that reported why they died and, and the complications associated with treatment. Which again was acute kidney injury and probably more acute kidney injury than reperfusion injury to be very honest.
And so that's something that I was not expecting and treating those cats, having those grants, being able to treat a lot of those cats. That's something that we saw.
Yeah, and so it seems like based on what I read in your articles that there's the, maybe there's a concern that cats that have pre existing kidney disease may be at increased risk of that acute kidney injury if they have a FATE episode. Is that what I'm reading correctly?
Yes, I know. Again, that's for me a little bit more of a clinical experience. So most of the cats are old, right? I think the average is about 8 to 10 years old. They have chronic kidney parts in necropsy or ultrasound if you do those things. And when I have a cat that has an ATE, the first thing I'm going to look at, it's going to be its admission creatinine value.
Right.
If it is 3, or if it is 0.8, I think my suspicion is that the ones that are coming with a creatinine of 3 are going to be more likely to get into a more rapid acute kidney injury compared to the one that is coming in with a creatinine of 0.8, right. I looked at that spreadsheet for a very, very long time and I've treated a decent amount of those cats and this is my clinical impression. I'm going to be very careful with those cats. A lot of those cats are dehydrated as well.
In our study, we had cats that came in with a PCV of 55 and a total protein of 10. And when they are in congested heart failure. So, you know, they are coming in with a PCV of 55, a total protien of 10, a creatinine of 3, and in congestive heart failure, at some point I'm going to have to switch from Lasix to IV fluid. And we are all very scared by giving IV fluids to a cat who is in severe HCM. So, that's why I say it's tricky. That's why I say it's not an easy clinical management.
Sounds like a crazy balance to do when you do start being what's going to roll out for that individual patient.
One of the things I wanted to mention, Dr St Denis as well, is that even if they develop acute kidney injury, it's not a death sentence because in our study, we found that around 40 percent of them will survive their complications. And so, you know, I have a cat that, you know, did develop a KI, creatinine goes up 5, 6, 7, but with time, judicious fluids, then they kind of go back to, to their baseline.
Brilliant. Okay. That's good to know. Again, like, like I said, that wasn't something I was really aware of, and I think it's partly because I've been in general practice for so long, and most of these patients don't make it very far in general practice, as we discussed, for a variety of reasons. So hopefully we can start seeing that change.
Nathalie DowgrayThank you for listening. If you're an ISFM member, don't forget you can access the full version of this podcast and all the other ISFM member benefits including congress recordings, monthly webinars, the monthly clinical club, the discussion forum, and much much more at portal.icatcare.org. Later on this month we will be dropping the recordings from our annual congress in Malta so do look out for those.
If you're looking for more free CPD from ISFM, we do also have an open access webinar this month from Paulo Steagall. That's going to be going live on the 24th of July. And following on from our updated non steroidal guidelines, Paulo's going to be talking about non steroidals, what's new. We'll be back again next month with another episode so if you don't want to miss out, do make sure you're signed up to Chattering with ISFM on your preferred podcast platform.