[00:00:02] Introduction: Welcome to All Cats Considered, a podcast from the Feline Veterinary Medical Association.
Here we interview professionals from across the veterinary world and take deep dives into the latest evidence based research developments, studies and guidelines that improve feline health and well being.
We are the home for veterinary professionals seeking to enhance the care of cats through high standards of practice, continuing education and evidence based medicine. In each episode you'll hear interviews with a variety of experts in our field covering a wide range of topics and the latest developments in feline health. We'll share the key points you need to know to improve your patients care.
Let's dive in and listen to this week's experts.
[00:00:45] Gómez-Mejías: So hello again. Welcome back to Chattering with icatcare. I'm Yaiza Gómez-Mejías, Veterinary Community Coordinator in International ICAT Care and we're back with Nikki Reed for part two of her JFMS Spotlight review on feline emergencies. In the first part we covered stabilization and respiratory distress and today she will be talking about other challenging emergencies that we see in general practice like epilepsy, urethral obstructions, acute kidney failure. So thank you so much Nikki for sticking around. Thank you.
[00:01:18] Reed: Thank you Yaiza.
[00:01:20] Gómez-Mejías: Let's start with the Let's start with the seizuring cat.
[00:01:22] Reed: Yeah, sure, sure.
[00:01:24] Gómez-Mejías: You mentioned that the head position is vital. When should we suspect intracranial pressure? Like an increased intracranial pressure and how should we be positioning these cats?
[00:01:37] Reed: Yeah, so raised intracranial pressure is harder to detect in cats compared to dogs. They don't do the sort of classic Cushing response of increased blood pressure and slow heart rate. We might get a suggestion from altered mentation, lack of pupillary response. Really any kind of head trauma patient, for example, or a cat who's been seizuring for a period of time, you might suspect that it could be there. And in that situation, you're best to raise the head above the level of the shoulder, level of the body. Although I find it easier just to put the entire cat onto something like a board and raise it at an angle of about 20 to 30 degrees to the horizontal. I think if you try to raise the head by placing, for example, a rolled up towel under the head, what tends to happen is you raise the sort of shoulder to the neck level and then the neck bends and the head dips down at the level of the neck. So you need to make sure that you're not doing that and also potentially putting pressure onto the jugular vein, the carotid artery in that area.
Just raise the entire body, or at least the body upwards from the shoulder right up to the head.
[00:02:47] Gómez-Mejías: When they are seizuring.
We obviously want to stop the seizuring whilst all this is happening. Is there any feline preferred first line choice drug? If you had to choose between midazolam and diazepam, would you have a preferred choice?
Yeah.
[00:03:04] Reed: So in terms of efficacy, I don't think that there's any evidence that one is better than the other.
I guess I'm always a little bit weary about the possibility of an idiosyncratic reaction to diazepam causing liver failure. And therefore, if I have access to midazolam and diazepam, my preference would probably be for intravenous midazolam.
However, if intravenous access is difficult because the patient is seizuring and you're maybe having to think about alternate routes, rectal diazepam is available and I would use that as an option.
Midazolam can also be given onto the nasal mucosa. There are some special devices that are available for aerosolizing that, but if you're stuck in practice, you could just use one of the attachments, one of the nozzles that's used for kennel cough administration, for example, and use that to spray the midazolam onto the nasal mucosa if you didn't have intravenous access.
[00:03:59] Gómez-Mejías: Ah. And what are those devices like?
[00:04:03] Reed: The official ones are very similar to what we see for the kennel cough nozzle, which is why in my basic Blue Peter School of Veterinary Medicine, if you haven't got the perfect article, I think it would be a perfectly appropriate substitute to use.
[00:04:21] Gómez-Mejías: Brilliant. Thank you. When should we consider intravenous lipid?
[00:04:26] Reed: I think if you know you've got toxin access, you can fairly easily establish whether or not it's one that is appropriate to use intralipids for. If not, if you've got a suspicion of a toxic agent, for example, a perfectly healthy cat that was fine in the morning and went out and may have eaten something, it wouldn't be unreasonable to use it. Another situation where it can be used. Well, it has been used in dogs for this purpose. I haven't come across any case reports in cats, but it has also been used to address neurological complications of Hepatic encephalopathy associated with port systemic shunts. So those would be my considerations for when to use it.
[00:05:08] Gómez-Mejías: Any tips around the tubes?
[00:05:12] Reed: Ideally should be administered through a lipid filter because it can contain some little particles of lipid, if you like, that could potentially cause a fat embolus. So we always use a lipid filter on it as well when we're giving it.
[00:05:26] Gómez-Mejías: And if we didn't have a specific filter for lipids, because we are not, we don't use that very often in general practice, could we replace that filter with something else?
[00:05:39] Reed: Yeah. So I have been asked before about whether or not we can use the blood filters. I think they capture different particle sizes, so it may not be entirely appropriate, but it may be better than nothing.
Similarly, if you don't have the filter but you've got the lipid, I mean, we always kind of purchase the two together. And it was a case. If you had a seizuring patient that you couldn't manage, and obviously you checked that it wasn't due to low blood glucose or low calcium, other things that you could address, then I guess as long as you warned the owner it was a slight risk, you might be better to risk giving the intralipid without a filter than not give it and potentially have ongoing seizures.
[00:06:19] Gómez-Mejías: That's very helpful, thank you.
Let's talk about urethral obstruction. Another very common emergency when deciding if the cat needs treatment for hyperkalemia.
Even before we try to pass a catheter, what should we be looking for?
[00:06:39] Reed: So the main warning signs would be on your clinical examination.
If you've got a cat who's got obtunded mentation, bradycardia and hypothermic, then yes, I would really strongly suspect that that cat is hyperkalemic and needs stabilization before sedation or anesthetic drugs are added into the protocol. There is a strong association between a heart rate less than 120 and hypothermia below 37.5. Of these cats having potassium above 8, which is quite a significant increase.
But I would be concerned if the heart rate was less than 160. Your potassium may not be quite as high as that. But again, I think those cats need some form of stabilization before adding in sedative drugs or anesthetic drugs.
[00:07:27] Gómez-Mejías: And should we be using the electrocardiogram as well?
[00:07:32] Reed: We can also sometimes find abnormal ECGs in cats that have still got normal mentation, for example, and a normal heart rate.
We know that the ECG traces don't always correlate with the potassium values. But again, if you've got an abnormal ECG trace, that indicates that there's an abnormal conduction there. And if you add drugs into that equation that could in themselves cause abnormal conduction problems, then you could exacerbate the problem. So, yes, if you've got access to the ECG, get that on them. As well.
[00:08:04] Gómez-Mejías: Thank you so much.
Would you anesthetize with them with when they are not very stable?
[00:08:11] Reed: Yeah. So there are times where we could, despite our best efforts, we can't get the potassium down as low as we would wish.
We will often have used an opioid to provide analgesia, which we can use as part of the pre med. And then typically we would induce with something like propofol and get them intubated as quickly as possible and then get them deblocked, if you like, or unobstructed. There's so many words that people use for that as quickly as possible. And I think you're more likely to succeed with cats under general anesthesia than under sedation. So I always tend to go to general anesthesia to get them. Get the catheter passed as quickly as possible. Yeah.
[00:08:52] Gómez-Mejías: And in the article you mentioned the epidural anesthesia.
[00:08:57] Reed: Yeah.
[00:08:58] Gómez-Mejías: Are there any tips that you'd share with GP practitioners to improve their technique when using it for catheterizing blocked cats?
[00:09:05] Reed: Yeah. So I'm very lucky because I have the benefit of anesthetist who will do that for me.
And I think, you know, again, you maybe have to prioritize slightly if you've got quite an unstable cat, then I would try and prioritize getting the catheter in as quickly as possible or potentially even cystocentesis, rather than maybe spending time doing the epidural. You're not doing it frequently and you're slick at the procedure.
I think if you're wanting to start doing this, I would definitely say start with a thin cat rather than an overweight cat. We know, unfortunately, that a lot of the males who do get obstructed are quite overweight. But certainly if you've got a thin cat, it helps you identify the landmarks.
Practicing on a cadaver can be challenging because it's very difficult to ask for consent in these situations. But if you were to practice on a cadaver, then use of some radiopaque contrast medium, such as used for bladder studies, could help you delineate where you're administering your injection as well. So that could be a wee tip if you are wanting to practice this prior to going live, shall we say. But, yeah, I think most people do pick up the technique relatively easily.
I tend to prefer it if we're leaving indwelling urinary catheters in as well, because I think it makes it more comfortable for the cat for several hours after the initial unblocking procedure. I think if you were maybe in the situation where you can't hospitalize cats overnight, you might just have to have that conversation with the owners if you're taking the catheter out to send them home.
Because there is the possibility that the epidural in itself may kind of interfere with the urination pattern when you send them home. So it's different for us where we're. We've got them in the hospital with an indwelling catheter, we might not appreciate that they actually are a little bit dysuric as a result of the epidural.
[00:11:03] Gómez-Mejías: Any other risk that we take by doing an epidural
[00:11:06] Reed: I mean, there's always the potential for infection. So, again, you need your good aseptic technique. And some cats could potentially be left with a degree of ataxia for sort of 24 hours after the procedure as well.
[00:11:22] Gómez-Mejías: And you mentioned cystocentesis. In which cases are you more inclined to use that?
[00:11:29] Reed: Yeah. So cystocentesis is a little bit sort of controversial as to whether or not it facilitates with your catheterization by kind of taking some of the back pressure off if the bladder is very, very distended. One of the concerns about it is that if you have got these chronic cystitis cases where the bladder wall is really quite bruised and inflamed, your cystocentesis could effectively cause urine leak and give you a urine abdomen, or worst-case scenario, potentially even rupture the bladder. But I think if you have got a very full bladder, you've got a cat who's hyperkalemic and probably azotemic as well, and you're really struggling to get a catheter in within say about 10 minutes or so. I think it does let you just buy some by some time because you're taking that back pressure off the kidneys and alleviating that post renal obstruction, it
[00:12:23] Gómez-Mejías: may help you calm down as well because you don't feel in that much of a rush.
[00:12:28] Reed: That's true. That's true, yeah.
[00:12:31] Gómez-Mejías: In cats with azotemia and other signs compatible with kidney disease, we always have this question that always arises. Is this acute kidney failure, is it acute on chronic or is it end stage disease? How can we differentiate all these options?
[00:12:49] Reed: Yes, I think true acute kidney disease is relatively easy to differentiate because these have generally been quite fit and well patients up until maybe 24, 40 hours beforehand. They're in good body condition, they have generally had good appetites up until that point, and then something has caused their acute kidney injury.
Similarly, chronic kidney disease, we often have a history over several months, even years from the owners of increased thirst, decreasing appetite, weight loss, presence of anemia on your blood picture would also tend to suggest that those changes are chronic.
I think the most challenging one is probably the acute on chronic patient where they could have had some degree of chronic kidney disease, often stage one or stage two iris, and then something happens that tips them over the edge and that can often be something like an infection, pyelonephritis. So we have a sudden deterioration. The worry in that situation is that yes, they might be thinner, yes, they've got this history of sort of weight loss per appetite, but they've got disproportionately high values that might be inclined for somebody to say this is end stage kidney disease and be more inclined to suggest euthanasia as opposed to this is an acute on chronic problem. And if we manage the whatever has caused this acute deterioration, such as, you know, infection, or maybe they've had some NSAIDs that may well be reversible and they can actually go back to having a good quality of life. So they're the challenging ones that people might be tempted to say is end stage kidney failure, when perhaps it actually isn't.
[00:14:26] Gómez-Mejías: Which should be our goal in the emergency situation, because obviously you're talking about prognostic information, we're talking about long term progression or long-term outcome. But in an emergency setting, we may be just thinking of helping the animal to survive.
[00:14:47] Reed: I mean, I think if it has had quite good quality of life until the preceding 48 hours, I would definitely, you see, you know, this isn't an end stage cat that needs that decision made to put it to sleep there and then. And I would always try and give them the benefit of fluids for 48 hours to see what effect that has while we try to establish what the cause of that acute kidney injury has been, you know, and monitoring for an improvement in the azotemia. If you're not winning after 48 hours, you maybe have to be a bit more negative in your prognosis. But if you start to see values coming down, then I think that gives you encouragement to give them a bit more time.
[00:15:25] Gómez-Mejías: Yeah, Antifreeze poisoning is another nightmare. Can Microscopy help in this case is at all?
[00:15:35] Reed: Yeah, I mean, I think we always need to bear in mind that we may, we may get negative results because it can depend on the dose of ethylene glycol that's been ingested and the timeframe in terms of where are we with the metabolites that go on to produce the, the crystals and I think we need to remember that the crystals with ethylene glycol tend to be monohydrates rather than the dihydrates that we associate with calcium oxalate stones. So I think we're all quite familiar with the square that has the St. Andrew's Cross in the middle of the box and attributing that to calcium oxalate stones. But what we might see with the ethylene glycol are monohydrate crystals which can have various shapes, often described as kind of picket fence ones, ones that look like hemp seeds, which you may or may not be familiar with, and more of a kind of dumbbell appearance to them. So people may not recognize them. So definitely microscopy, if you see it, it very much lends support to your suspicion. If you don't see it, you know, you can look at other things like is there any evidence of fluorescein around the round the mouth or urethra from some of the antifreezes contain fluorescein.
If not, there are samples that you can, you can send away, but obviously that isn't a quick in clinic test. The way that microscopy or the ultraviolet light could be.
[00:16:54] Gómez-Mejías: Managing diabetic gut acidosis used to being regular insulin infused at a continuous rate. Is that still the case?
[00:17:05] Reed: Yeah, I mean it's still my sort of go to.
I think probably because we're familiar with it, we know how to adjust it in relation to the glucose values that we're getting.
But we have had a few more options that have come onto the market which certainly a few years ago were kind of required because regular insulin became unavailable. And I guess the beauty of Glargine, for example, if people are on a little bit tighter budget, is that it can be used both for the intravenous route during the decay and then for the client to go home with the same bottle when they're managing their more stable diabetic.
Whereas if you open a bottle of regular insulin, usually the client gets charged for the whole bottle because you can't guarantee when you're going to see your next dka. And then they also have a bottle of intermediate acting insulin for them to go home with, which can add to the cost.
And also obviously with the soluble insulins, we're changing the bags of saline quite regularly. So it is an expensive trip. And using the one form of insulin can help save a little bit of cost. Although in the grand scheme of things it's probably not a huge amount, but, but, but it can help and it is good to have some options if we don't have regular insulin available.
One of the things that, that if you don't sort of stock regular insulin, a little tip is that maybe we don't tend to use insulin for the first couple of hours anyway, because we know that the glucose value will come down with fluids alone.
So if you don't have regular insulin and your neighbors don't have either, you could potentially just write a prescription and get the client to get some glargine from a local chemist and then you can use that if you're struggling for an idea as to what to do. Because we know that subcutaneous licensed insulins aren't really going to be very effective. They're too slow in onset, we can't control them nicely and they're not well absorbed in a dehydrated patient. So that would be my route, rather than using a subcutaneous insulin that you have in the fridge, is to get the client to get something that we know we can use for DKA.
[00:19:17] Gómez-Mejías: That's very helpful. And with the rise of SGLT2 inhibitors, we're seeing EU glycemic diabetic acidosis as well. How does the emergency treatment change when the blue glucose looks normal?
[00:19:33] Reed: Yeah, so the glucose in these patients is often kind of in the order of 12 to 15 millimoles per liter. And you may not be thinking necessarily about the clinical signs relating to DKA in these patients.
Even if you know that they've been previously diagnosed as diabetic and they're on an SGLT2 inhibitor, you might think, oh, well, actually that glucose indicates that their diabetes is quite well, well controlled. There's something else going on here.
Whereas actually what's happening is that these drugs are causing loss of glucose out in the urine, but the patients are still producing ketones and are probably acidotic as well. So we need to manage these as we would any DKA patient with insulin. They've effectively failed that trial as to whether they're an appropriate candidate for an oral medication.
Their body is telling you that they need insulin, so we need to get that on board, but we often have to match that with higher levels of glucose because the SGLT2 inhibitor is still on board, it's still causing glucose loss out through the kidney so these patients can become hypoglycemic if we just substitute glucose at our normal rate, because some is being excreted in the urine, but some is also required for the insulin to act on. So we need to give higher levels and sometimes a 5% solution for giving that as a constant infusion isn't adequate, they may be needing 10% solutions. And then we start getting into situation of that strength is quite hyperosmolar and can be quite irritant to veins. So we may need to consider jugular lines, for example, to administer it.
[00:21:12] Gómez-Mejías: Thank you. Just before we wrap up, I hope you don't mind asking me asking a last question. It's more general, but I see this coming up very often now that referral centers are so much more widely available in the UK.
When you work with in first opinion practice and you receive an emergency before referring it, because you may close, your practice may close soon or you haven't got the 24 hour care that you need to provide, you're meant to stabilize the patient first before sending it over. But what happens in these cases where you can't really. What's the degree of stabilization that you're aiming for and what are the tips you share about making the transport to the referral center as safe as possible?
[00:22:04] Reed: I think it can depend a bit on what condition you're dealing with, for example, and also the distances that are going to be involved because we can get referrals from four or five hours away as opposed to somebody who maybe only has to go 20 minutes down the road. And if it is just a short distance, then yes, sometimes it may be better to risk the short journey and have it arrive at the center where there's better facilities.
But if it is going to have to be a long distance, then I think you do have to consider what could happen on the way there. Obviously there are some things that can be addressed that can make a huge difference, such as drainage of pleural effusions, for example.
Controlling off seizure activity can be a bit more challenging. I've had vets or vet nurses come in the car with patients so that drugs can be administered or that's where potentially things like your rectal diazepam can come in handy that the owners can use.
So I think it does depend a little bit on whether what the distance is going to be. And it's always worth speaking, you know, giving a call to the center that you're referring to and say this is the situation, what do you want me to do? Because they can often give you advice that will help you to stabilize the patient before it's transported.
[00:23:22] Gómez-Mejías: Yeah, that sounds very sensible. Like managing expectations around the case and checking, always communicating with the person you're going to refer the case to.
Yeah, well that's. That was very helpful. Thank you so much. You've given us so many practical tools to take back to our clinics. Thank you so much for sharing your expertise and for writing such a comprehensive guide for the feline veterinary community. To our listeners remember that the latest evidence is at our fingertips in the now open access The Journal of Feline Medicine and Surgery. And thanks for tuning in. We'll be back again next month.
[00:23:58] Conclusion: Thank you for listening to this episode of All Cats Considered. We hope you enjoyed this interview. For more information on the topics discussed in this episode, please head over to catvets.com podcasts and explore the links in the show notes. Don't forget to subscribe to this podcast on your platform of choice so you won't miss any episodes as we release them. Have thoughts or ideas about the interview you heard today?
Share them with us by leaving a comment. Comment on our Facebook page or shoot us an email
[email protected]. Thank you again for joining us today.
