Feline Medical Emergencies: Part 2

In the July open access episode of Chattering With iCatCare, Yaiza Gómez-Mejías is joined once again by feline specialist Nicki Reed to continue navigating the high-pressure world of feline medical emergencies. This second part shifts focus towards managing other challenging, high-stakes medical crises frequently encountered in general practice.

They explore how to optimise positioning for the seizuring patient, why certain clinical markers can predict severe hyperkalemia in blocked cats before catheterisation, and how to spot the elusive signs of antifreeze toxicity. Nicki also breaks down the unique challenges of managing euglycaemic DKA following the rise of SGLT2 inhibitors and shares essential steps for making emergency referral transport as safe as possible.

For further reading material please visit:

Rational approach to feline medical emergencies: part 2

2024 RECOVER Guidelines

Host:

Yaiza Gómez-Mejías, LdaVet MANZCVS (Medicine of Cats), RCVS CertAP (Feline Medicine), iCatCare Veterinary Community Co-ordinator

Speaker:

Nicki Reed, BVM&S CertVR CertSAM DipECVIM-CA DSAM(Feline) FRCVS, Internal Medicine & Feline Specialist

Creators and Guests

Host

Yaiza Gomez-Mejias

Veterinary Community Co-ordinator @ International Cat Care

What is Chattering with iCatCare?

Welcome to Chattering With iCatCare, the official monthly podcast of International Cat Care, hosted by Yaiza Gomez-Mejias (Veterinary Community Co-ordinator). Each month, we chatter about cats and cat-friendly practices with industry experts and contributors to The Journal of Feline Medicine and Surgery. If you would like access to our members episodes become an iCatCare Veterinary Society Member and get in touch.

Yaiza Gomez Mejias: Welcome back to Chattering with iCatCare. I'm Yaiza Gomez, Veterinary Community Coordinator in International Cat Care, and we are back with Nicki Reed for part two JFMS Spotlight Review on feline emergencies. In the first part, we covered stabilisation and respiratory distress, and today she will be talking about other challenging emergencies that we see in general practice. Let's start with the seizuring cat. You mentioned that the head position is vital. When should we suspect an increased intracranial pressure? And how should we be positioning these cats?

Nicki Reed: Yeah, so raised intracranial pressure is harder to detect in cats compared to dogs. They don't do the classic Cushing response of increased blood pressure and slow heart rate. We might get a suggestion from altered mentation, lack of pupillary response, so really any kind of head trauma patient. For example, 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 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 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, 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.

Yaiza Gomez Mejias: When they're seizuring we obviously want to stop the seizuring whilst all this is happening, if you had to choose between midazolam and diazepam, would you have a preferred choice?

Nicki Reed: In terms of efficacy, I don't think that there's any evidence that one is better than the other. I'm always a little bit wary 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. If intravenous access is difficult because the patient is seizuring and you're maybe having to think about alternate roots, 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 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.

Yaiza Gomez Mejias: When should we consider intravenous lipids?

Nicki Reed: I think if you've got toxin access, you can establish whether or not it's one that is appropriate to use intra lipids for. If you've got a suspicion of a toxic agent, 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. 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 poor systemic shunts. So those would be my considerations for when to use it.

Yaiza Gomez Mejias: Any tips around use?

Nicki Reed: It ideally should be administered through a lipid filter because it can contain some little particles of lipid that could potentially cause a fat embolus. And

Yaiza Gomez Mejias: if we didn't have a specific filter for lipids, because we don't use that very often in general practice, could we replace that filter with something else?

Nicki Reed: 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. We always purchase the two together. It was a case if you had a seizuring patient that you couldn't manage and obviously you check 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 warn 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.

Yaiza Gomez Mejias: Let's talk about urethral obstructions, another very common emergency. When deciding if the cat needs treatment for hyperkalemia even before we try to pass the catheter, what should we be looking for?

Nicki Reed: 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 I would strongly suspect that cat is hyperkalemic and needs stabilisation before sedation or anaesthetic 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 a potassium above eight, I would be concerned if the heart rate was less than 160. Those cats need some form of stabilisation before adding in sedative drugs or anaesthetic drugs.

Yaiza Gomez Mejias: Should we be using the electrocardiogram as well?

Nicki Reed: Yeah. We can also sometimes find abnormal ECGs in cats that have normal mentation and a normal heart rate. We know that the ECG traces don't always correlate with the potassium values, but if you've got an abnormal ECG trace that indicates that there's an abnormal conduction there. If you add drugs into that equation that could 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.

Yaiza Gomez Mejias: Would you anaesthetise them for when they are not very stable?

Nicki Reed: There are times where we can, 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 premed. Then typically we would induce with something like propofol and get them intubated as quickly as possible and then get them “debulked” or unobstructed as quickly as possible. I think you're more likely to succeed with cats under general anaesthesia than under sedation. So I always tend to go to general anaesthesia to get the catheter passed as quickly as possible.

Yaiza Gomez Mejias: In the article you mentioned the epidural anaesthesia. Are there any tips you'd share with busy practitioners to improve their technique when using it for catheterizing blocked cats?

Nicki Reed: Yeah, so I'm very lucky because I have the benefit of anaesthetists who will do that for me and you maybe have to prioritise slightly if you've got quite an unstable cat, then I would try and prioritise getting the catheter as quickly as possible, or potentially even cystocentesis rather than spending time doing the epidural. Particularly if 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 and we know, unfortunately, that a lot of the males who do get obstructed are quite overweight.
If you've got a thin cat it helps you identify the landmarks. Practising on a cadaver can be challenging because it's very difficult to ask for consent. But if you were to practise on a cadaver, then use of radiopaque contrast medium, such as used for bladder studies, could help you delineate where you're administering your injection. So that could be a wee tip if you are wanting to practise this prior to going live, 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 can't hospitalise cats overnight, you might 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 interfere with their urination pattern when you send them home. It's different for us where 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.

Yaiza Gomez Mejias: Any other risks by doing an epidural?

Nicki Reed: 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 24 hours after the procedure as well.

Yaiza Gomez Mejias: You mentioned cystocentesis. In which cases are you more inclined to use that?

Nicki Reed: Yeah, so cystocentesis is a little bit, controversial as to whether or not it facilitates with your catheterization by taking some of the back pressure off if the bladder is very distended. One of the concerns is that if you have got chronic cystitis cases where the bladder wall is bruised and inflamed, your cystocentesis could cause urine leak and give you a urine abdomen potentially even rupture the bladder. If you have got a very full bladder, you've got a cat whose hyperkalemic and probably is azotemic as well and you're struggling to get a catheter in within about 10 minutes or so, I think it does let you buy some time because you're taking that back pressure off the kidneys and alleviating that postrenal obstruction.

Yaiza Gomez Mejias: It may help you calm down as well because you don't feel in that much of a rush.

Nicki Reed: That's true.

Yaiza Gomez Mejias: Yeah. In cats with azotemia and other signs compatible with kidney disease, we always have this question is this acute kidney failure? Is it acute on chronic, or is it end stage disease? How can we differentiate all these options?

Nicki Reed: True acute kidney disease is relatively easy to differentiate because these have generally been quite fit and well patients up until maybe 24, 48 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. 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 anaemia in your blood picture would also tend to suggest that those changes are chronic. 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 'em over the edge and that can often be something like an infection pyelonephritis. So we have a sudden deterioration and the worry in that situation is that yes, they might be thinner. Yes, they've got this history of weight loss, poor 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 as an acute on chronic problem and if we manage whatever has caused this acute deterioration, such as 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.

Yaiza Gomez Mejias: In an emergency setting, we may be just thinking of helping the animal to survive.

Nicki Reed: I think if it has had quite a good quality of life until the preceding 48 hours, I would definitely say 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 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. 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.

Yaiza Gomez Mejias: Antifreeze poisoning is another nightmare. Does microscopy help in these cases at all?

Nicki Reed: Yeah, I think we always need to bear in mind that 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 crystals and I think we need to remember that the crystals with ethylene glycol tend to be monohydrates rather than dehydrates that we associate with calcium oxalate stones. Ethylene glycol are monohydrate crystals, which can have various shapes, often described as picket fence ones, ones that look like hemp seeds, and there's also dumbbell appearance to them, so people may not recognise them. So microscopy, if you see it it very much lends support to your suspicion. If you don't see it, you can look at other things like is there any evidence of fluorescein around the mouth or urethra? Some of the antifreezes contain fluorescein. If not, there are samples that you can send away, but obviously that isn't a quick in clinic test the way that microscopy or the ultraviolet could be.

Yaiza Gomez Mejias: Yeah. Managing diabetic ketoacidosis used to be in regular insulin infused at a continuous rate. Is that still the case?

Nicki Reed: Yeah, it's still my 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 come on to the market. 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 DKA and then for the client to go home with the same bottle when they're managing their more stable diabetic.

Yaiza Gomez Mejias: With the rise of SGLT2 inhibitors, we are seeing euglycemic diabetic cats acidosis. How does the emergency treatment change when the glucose looks normal?

Nicki Reed: Yeah, so the glucose in these patients is often in the order of 12 to 15 millimoles per litre 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, actually that glucose indicates that their diabetes is quite well controlled, there's something else going on here. Whereas actually what's happening is that these drugs are causing loss of glucose out of the urine, but the patients are still producing ketones and are probably acidotic as well.
We need to manage these as we would any DKA patient with insulin. They've 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 hyperglycemic 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.
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.

Yaiza Gomez Mejias: Just before we wrap up, I hope you don't mind a last question. It is more general, but I see this coming up very often now that referral centres are so much more widely available in the UK. When you've worked in first opinion practice and you receive an emergency before referring it because your practice may close soon, or you haven't got the 24 hour care that you need to provide, you are meant to stabilise the patient first before sending it over. But what happens in these cases where you can't really? What's the degree of stabilisation that you are aiming for and what are the tips you'd share about making the transport to the referral centre as safe as possible?

Nicki Reed: I think it can depend on what condition you're dealing with 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. 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 centre 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's things that can make a huge difference, such as drainage of pleural effusions, controlling seizure activity can be more challenging. I've had vets or vet nurses come in the car with patients so that drugs can be administered or potentially things like your rectal diazepam can come in handy that the owners can use. I think it does depend on what the distance is going to be. It's always worth giving a call to the centre that you're referring to and say, this is the situation. What do you want me to do? 'Cause they can often give you advice that'll help you to stabilise the patient before it's transported.

Yaiza Gomez Mejias: 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, 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 and the now open access Journal Of Feline Medicine and Surgery and thanks for tuning in and we'll be back again next month.