Uveitis in Kittens: FIP or Not?

Cloudy eyes in a kitten can be a warning sign for feline infectious peritonitis (FIP). What happens when the eyes look like FIP and then… the kitten gets better? That clinical tension sits at the heart of our conversation with Hikaru Shiraishi and Drs. Karen Vernau and David Maggs. Their JAVMA article describes “undifferentiated resolving uveitis” in young cats, a syndrome that can mimic FIP associated uveitis at first glance yet improves with symptomatic treatment and careful follow up.

We walk through what uveitis actually is, why it matters so much in kittens, and how a set of real hospital cases pushed the team to look back systematically. You’ll hear how terminology changed the thinking: “idiopathic” implies an exhaustive workup, while “undifferentiated” reflects what clinicians often face in rescue, shelter, and budget limited situations. We also dig into the practical details that can help on the clinic floor, including which ophthalmic signs overlapped between groups and which findings leaned more toward FIP, such as fundic abnormalities and rubeosis iridis.

We also address the realities that make this topic so high stakes: the limits of coronavirus serology, the role of clinical pathology like globulins and bilirubin, and the weight of decisions that can lead to expensive antivirals or even euthanasia. Our biggest takeaway is a clinical mindset shift: FIP diagnosis is a weighted balance of evidence, and a thorough fundic exam plus a willingness to reassess over time can keep you from making a knee jerk call when a kitten might simply need a chance.

If you found this helpful, subscribe for more author behind the scenes conversations, share the episode with a colleague who sees urgent eye cases, and leave us a rating and review. What’s the hardest part of getting a good fundic exam in your practice?

JAVMA article: https://doi.org/10.2460/javma.25.07.0469

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Transcript

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Lisa Fortier 0:35

Welcome to Veterinary Vertex, the AVMA Journal's podcast where we delve into behind-the-scenes look with manuscript authors. I'm editor-in-chief Lisa Fortier, joined by associate editor Sarah Wright. Today we're discussing a really cool clinical implication manuscript where we're discussing a group of kittens that presented with uveitis that looked very similar to that that is caused by feline infectious peritonitis, but from which they recovered with symptomatic treatment only. Our authors are David, Karen, and Heikaro. Hey guys, thanks so much for taking the time to be here with us today and educate us a little bit more on how the inspiration for this manuscript.

SPEAKER_05 1:15

Thanks so much.

Lisa Fortier 1:16

Yeah, thank you.

SPEAKER_05 1:16

Thank you so much.

What Uveitis Is And Why It Matters

Lisa Fortier 1:18

David, let's start for you. For listeners who might need a refresher, why is what is uveitis and why is it such an important clinical finding in kittens?

The Kitten Cases That Sparked Study

SPEAKER_05 1:27

Yeah, thanks, Lisa. I suppose as the ophthalmologist in the group, I should take that one. But um, yeah, uveitis is it is inflammation. You can think of it as inflammation of any of the inside of the eye. So the the uveal tract, iris, cilly body, choroid, and then almost inevitably the retina as well. So the implications are pretty dramatic. Um, though, first of all, it's a painful disease. Uh, secondly, it's blinding, it can cause retinal detachment, uh, cataracts, glaucoma. And so all of those are serious enough, but then particularly in, for instance, the best example, FIP of kittens, it's a sign of one of the fatal systemic or previously fatal systemic diseases. So, so uh problems for the eye and a harbinger of things that are going on elsewhere in the body.

Sarah Wright 2:17

Karen, what prompted you and your co-authors to investigate this presentation of buveitis?

SPEAKER_03 2:22

Thank you. Uh, we were in the middle of this collaborative clinical trial at UC Davis uh when Hikaru was a pre-vet student and volunteering in ophthalmology. So I'll let him continue on with that.

SPEAKER_02 2:36

Yeah, so I have a story for this. Um, this start study actually started when I was still a pre-vet student at UC Davis, and then I was working/slash volunteering in the ophthalmology service at the teaching hospital. And then at that time, um, I was very new to the Ven A medicine. And then in fact, I didn't even know that I the ophthalmology would become such a strong interest for me. But uh, I remember seeing an orange kitten with uh FIP and UVitis, and then how striking those cloudy eyes looked. And then over time, I started seeing other kittens with um similar-looking eyes. And the book, they were cloudy too, but they came back for rechecks, and then their eyes were completely clear and then they were happy. And then as a student, I remember thinking, wait, did we somehow treat FIP with just eye drops? And then these experiences really sparked my interest or curiosity in both ophthalmology and research, and then eventually let us come together and look into these cases more systematically as a research project.

Lisa Fortier 3:43

Karen, at a at a high level, what questions, what was your hypothesis? What were you hoping to answer with this study design?

SPEAKER_03 3:51

Exactly. Our hypothesis was like was that despite um similar clinical presentations, that there were some differences between kittens with you know the resolving uveitis and FIP that may help differentiate these two um disease syndromes.

Sarah Wright 4:08

So, David, let's talk about how you approached answering the question. How did you define and characterize undifferentiated resolving uveitis in this group of kittens?

SPEAKER_05 4:17

Yeah, this is undifferentiated uveitis is is sort of a um a new term, and it was a new term to us. Actually, this is a chance for us to complement the JAVMAR uh review process. This was a situation where peer review really, really went well. Um, we had an excellent pair of reviewers, and one of them suggested the term undifferentiated and resolving uveitis. The resolving sort of self-explanatory, as um Hikara's just said, these kittens, some of them got better by themselves and all got better with drops. And so we'd called it an idiopathic uveitis, and that's what I was taught and have taught students for years. Turns out this review is exactly right. In the human literature, idiopathic is used for diseases and uveitis in this case, where a cause has been extensively looked for, not found, and so they remain idiopathic. In our case, these kittens were like most of the kittens that your listeners are going to be faced with. They're either adopted or orphaned or um, you know, rescue kittens, not a lot of not a lot of money floating around with them, and so they hadn't been extensively worked up. We really shouldn't have called them idiopathic. And the and the reviewer did a lovely job suggesting why don't you call this feeling undifferentiated and resolving uveitis? That's how it came about. And um, I I think it really helped us.

Lisa Fortier 5:47

Yeah, that's an important distinction. Carl, how else did these cases with this now called undifferentiated resolving uveitis, how did those kittens compare uh with terms with uveitis of with those that had feline infectious peritonitis?

SPEAKER_02 6:04

Yeah, thank you. I think that's a challenging and then also interesting part. Um at presentation, many of these kittens looked very similar clinically. For example, they could all present with cloudy eyes, squinting, or systemic signs like lethargy and then appetite changes. The main difference I think really became more apparent in how this uveitis behaved over time. And then the kitten with this uh resolving UVitis improved and recovered, whereas the kittens with FIP associated uveitis did not, and ultimately had fatal outcomes. Because our study was retrospective, and then we were able to look back at these two groups side by side. Um, we first identified kittens with uveitis, and then we identified two groups. We ended up like having 22 kittens with resolving uveitis and eight kittens with FIP associated uveitis. And by the way, by saying kittens, we mean cats that are were one year old or younger at the first visit, and then all had to be examined by our ophthalmology service at least once. Um but important part of this process was that the resolving cases were intentionally selected because how similar they look at the presentation. So rather than finding similarities, the most interesting part for for us was finding the differences between these two groups.

Ophthalmic Signs That Point To FIP

Sarah Wright 7:37

Yeah, very well said. So, Karen, now let's dig into what you found. Were there differences in signalment, history, or duration, or progression of clinical signs prior to presentation?

SPEAKER_03 7:48

There were some differences. I mean, one of them was the source. Like a lot of the undifferentiated kittens were, you know, from shelters or um stray kittens compared to the FIP kittens were from breeders. Um, as far as history goes, the kittens with the undifferentiated uveitis had a pretty short course, um, like one to two weeks, and the guys with FIP could go on for months and months. Um, one interesting thing we noted, um, Dr. Megs, maybe you can weigh on on this, is that those kittens that had unilateral disease could become bilateral with the um undifferentiated uveitis, but not with FIP.

Lisa Fortier 8:29

That's very cool. David, were there other clinical features other than this unilateral might or might not become bilateral that stood out as potential differentiators between the resolving and FIP associated uveitis?

SPEAKER_05 8:43

Yeah, there were, um, but a minority. And that makes sense when you think about it. Uh, Hikari did a good job of explaining that we actually selected these groups because they looked similar. And then we wanted to then in further analysis work out were there minor differences or differences that would in retrospect tell us that. So we looked at, I think, 21 or something like that, 21 different ophthalmic signs, uh, things as varied as, you know, ocular discharge through to vision disturbance, PLR disturbances, um, hyperemia, and then, you know, uh flair, all sorts of ophthalmic things that we grade and look at. Of those 21, 13 were identical between the two. The likelihood of the of the kittens experiencing them they could equally in both groups. And that's not surprising to us. It became really interesting. What were the other eight where there were differences? In in there was only one sign where we found that the kittens with undifferentiated ubiotis were more likely to show it than the FIP kittens, and that was interestingly episcleral hyperemia, so engorgement of those large vessels on the sclera of the eye. The other seven signs that differed were all seen more commonly in the kittens with um uh FIP than with um the undimperatiated uviatus. And I'll just quickly list them. They're corneal edema, dyscoria, or an un a non circuit, a non-elliptical pupil shape in the kitten, rubiosis iridus, ophthalmologists love all these fancy terms. It means a red iris or an inflamed and hyperemic and neovascular iris, along with that iridal congestion and thickening, posterior senecia, keratic precipitates, so where you see those white blood cells descended down and precipitated against the inner corneal surface, and then fundic changes. And if I could just highlight two of those of those seven that I think really make a difference. One is fundic changes. We saw abnormalities in the tepedum, the choroid, the retina, only in the kittens with FIP. We saw rubiosis iridus only in the kittens with uh FIP. And so these are two really important changes, I think, to look for uh as not unfortunately pathonomonic, but helpful in this sort of weighted balance, this syndromic sort of assessment of the kittens.

Lisa Fortier 11:21

Very cool. I I do love all the opso terms. You might know I'm an equine surgeon for decades, but if I had to do it over again, it would be opso.

SPEAKER_05 11:30

Well, you're there's never too late, please.

Sarah Wright 11:34

I'll just read about you guys.

SPEAKER_05 11:36

Okay, good.

Lab Findings And Limits Of Serology

Sarah Wright 11:37

Yeah, all these terms really bring me back to your ophthalmology. Rotation in the fourth year. That's cool. So, Karen, did clinical pathologic findings, including coronavirus titers, help distinguish between the conditions?

Clinical Stakes Cost And Decision Making

SPEAKER_03 11:52

I mean, they were pretty similar between the two groups. The only real difference are that kittens with FIP were the only ones that had elevated globulins and bilirubin. And regarding the coronavirus serology, there was no difference between the two groups.

Lisa Fortier 12:07

Karen, given this major implication in practice, especially given the weight of an FIP diagnosis for a cat and the owner, why is it distinguishing between these two causes of UVI is so clinically important for the veterinarian and the potential owners?

SPEAKER_03 12:23

Yeah, it's tough. I mean, differentiating these two is for sure a challenge. Um we just want to highlight, you know, a broad awareness of the syndromes is probably the first critical step, at least clinically. And, you know, looking at these together, it's just important that, you know, we as veterinarians um, you know, undertake a complex and comprehensive history taking and clinical evaluation to help differentiate the two. You know, if the a presumptively diagnose um a kitten having FIP, when in fact they have the undifferentiated type, then as veterinarians we're gonna present, you know, the owner or shelter or rescue group with um a worsening prognosis and discuss treatment options, which include, you know, expensive medication. I just treated my own foster kitten with neurologic FIP and just the drugs alone were$1,500. So that's not for everyone. Um, and of course, there's follow-up and blood work. So, you know, some owners or rescues or shelters may be deterred from going ahead with antiviral treatment and may even consider euthanasia. And of course, there's other causes of heveitis other than you know, FIP that may require a different treatment. Okay, Dr. Megs.

Sarah Wright 13:38

Yeah, I had a mentor during my internship that said don't round me a case unless you've done a retinal and a rectal exam. That's really stuck with me.

SPEAKER_05 13:47

Very wise advice.

Practical Diagnostic Approach For Clinicians

Sarah Wright 13:49

Yeah, exactly. You never know what you're gonna find. So, David, how should clinicians approach diagnostics when faced with a young cat with anterior uveitis and overlapping features?

SPEAKER_05 14:02

Yeah, sir, it still remains a dilemma. I don't pretend that our paper has answered that question. As you know, um, diagnosing FIP has been a dilemma for as long as we've known about FIP. And likewise, diagnosing F U R U, you know, uh the undifferentiated version is still a dilemma. There is no one diagnostic test for either disease. We all we all know that it's a weighted balance, you know, where we accumulate evidence and eventually get to a point where we feel like, okay, that's tipped the balance far enough that we now feel like that's the diagnosis and we're to the point of wanting to treat. I suppose if if if your listeners left with perhaps um a a couple of hints, we'd be really happy. One is that serology isn't the test. Um, still part of your weighted balance, but it's not going to differentiate them. We want to be really clear about that. Two is that a fundic exam is really critical. Um, I would say at this stage anyway, with our pilot study of 22 of the kittens with um um undifferentiated uveitis, that the lack of fundic abnormalities, the lack of fundic abnormalities would steer me very much towards um treating empirically and seeing if I got a response. Um and then I think if if your readers, if your listeners also left with just a knowledge of this syndrome, so that they didn't either um knee-jerk uh prescribe antiviral treatments or knee-jerk recommend um, heaven forbid euthanasia or plain to very poor prognosis, but we're willing to give the kittens a trial on a topical steroid. And that's all we're talking about here for these young kittens. I I guess we'd be really pleased if they came away with that. That along with knowing that it's a syndromic diagnosis.

Lisa Fortier 15:56

Very good. You kind of stole my thunder for the next question, but we're gonna um one word uh really important. So we've heard that serology may or may not be helpful. Always do a fundic exam uh and give the kittens a chance. Don't don't make a knee-jerk reaction to this diagnosis. Karen, uh what other important message do you want clinicians to remember from this study?

SPEAKER_03 16:20

I you know, I think I think David said it. It's just it's a syndromic diagnosis, and uh, we need to just treat them and give them a chance and just look at the whole picture and just make sure we're thorough with history and you know, we gotta do that phonic exam. Always worth repeating.

SPEAKER_05 16:38

One more thing we might say, which is that, you know, if a kitten who you assumed had FIP started to improve while on the antiviral therapy, we would have, I think, and until now said, oh, well, that's pretty much confirmation that it's, you know, FIP and doing well. Now we might have to hesitate and say, gee, I wonder if he's improving because he was going to improve anyway, and he's improving while he's on the antiviral instead of because he's on the antiviral.

Lisa Fortier 17:09

Hey, Carl, one last question. Uh, since you love research so much, what what are the future directions and what is our next manuscript coming our way in JABMA in this topic area?

SPEAKER_02 17:20

I wish I could do that more too, yeah. Um, I think future prospective research would be valuable because our study, like I said, was retrospective. Each kitten had different diagnostic workups, and then which is why we chose the term undifferentiated instead of idiopathic. And then I think a prospective study with like standard standardized or and more comprehensive diagnostics for both groups could help find like underlying causes and then tell whether it can be truly called as feeling idiopathic resolving uveitis rather than feeling undifferentiated resolving uveitis or furu. But at the same time, while ideally we would like every kitten with uveitis to receive comprehensive testings, but this isn't this isn't always possible. Um, it could be due to financials, or it could be just the possibility of um inconclusive test results. In many cases, we recognize that the finding, uh finding the definitive cause of feline uveitis is challenging. So we believe our studies uh reflects what the clinicians actually see in the real life. And then we believe that our study still provides meaningful uh information for them. And then lastly, um this study was really memorable and then it really had an impact for me what throughout my pre-ventery journey. And then I cannot um end this conversation without thanking all of them who contributed to this study and of course Ancline Kittens in this study and their caretakers too. So we're truly, truly grateful to be able to share this work with you all today. Thank you.

Lisa Fortier 19:05

Yeah, very cool. Um, always good to have good collaborators, even the kittens. I've read some things about AI uh looking at fundic exams and analyzing the vessels and that sort of thing. What's what's your opinion on that? Where are we in veterinary medicine?

SPEAKER_05 19:23

Yeah, to the best of my knowledge, we're not even starting down that road yet, but you're absolutely right. I mean, in the human field, um, screening in regional centers where they may not have an ophthalmologist visiting for diabetic retinopathy and that sort of thing is now being done by either photography and that photo being sent to an ophthalmologist. Or I understand, yes, you're right, AI image uh recognition in the same way as other images like radiographs. That would be a fascinating approach. It requires still that a good image of the retina is obtained, and that's the hardest part. I mean, once you show a veterinarian, here's a nice still image of the fundus, what do you think? They're well able to say whether it's normal or abnormal. It's the gaining of that image that I think as students and then as general practitioners, they really struggle with. And I know I used to be a real vet out there in the real world. It is hard.

Lisa Fortier 20:20

Do you know we have a manuscript category called technical tutorial videos?

SPEAKER_02 20:25

No.

Lisa Fortier 20:26

So it they're they're full manuscripts, they have a DOI, they go through peer review, but they're videos for things just like that that are difficult to do. So we would love to have a video, technical tutorial video on how to do how to get a good you know, even how you position the animal, the lighting behind them, all those things, the tips and tricks that you all know. We would we would really love to have that.

SPEAKER_05 20:51

That's a great idea.

SPEAKER_03 20:53

And we have a good technique in kittens who are not cats. Perfect. You do, they are not.

Lisa Fortier 21:00

Ponies are not horses either, Karen.

SPEAKER_05 21:06

But when it comes to ophthalmology, cats are small horses.

Sarah Wright 21:10

Okay. We actually was talking to someone else about that today, how um they think cats are like carnivorous horses, right, Lisa?

SPEAKER_05 21:21

That's a great way to say it. Yeah.

Sarah Wright 21:27

And then one more plug before I wrap up. So have you also heard of our journal awards as well?

SPEAKER_05 21:33

No.

Sarah Wright 21:34

All right, so Carl, looking at you, you're eligible. So our journal awards are for veterinary students, interns, or residents that are authors on manuscripts that are published in Java and AJVR. So as faculty, yeah, you can nominate your students or house officer for nominated. Yeah. Uh that are due mid March. So I'll follow some instructions. So for anyone listening to, if you've had a student or house officer, author a manuscript. And published art journals, please submit them for a journal award. It's a really great opportunity for them to help advance their career and to get recognition too.

SPEAKER_05 22:07

Well, that's great. I commend you for doing that because uh uh our pre-vet and our um house officer authors are just they contribute so much to the literature.

Sarah Wright 22:17

Yes. Well, David, Karen, and Hikaru, thank you so much for joining us today.

SPEAKER_02 22:21

Thanks for having us. Thank you. Thank you so much.

Sarah Wright 22:24

And for our listeners and viewers, you can read their article in Javma. I'm Sarah Wright here with Lisa Fortier. Be sure to tune in next week for another episode of Veterinary Vertex. And don't forget to leave us a rating and review on Epicle Podcast or every listen.