Dr. Tim Evans, a diplomate of the American College of Theriogenologists and of the The American Board of Veterinary Toxicology, joins Dr. Andy Roark to talk toxins! Dr. Evans tells stories from practice as a toxicologist as he walks through the most common nephrotoxins we see in veterinary medicine today. This episode is not to be missed!
This episode is brought to you by Hill’s Pet Nutrition and the Hill’s Veterinary Academy
LINKS
The Hill’s Veterinary Academy is a one site solution for educating the entire veterinary team. On the HVA, you can find FREE RACE CE from leading specialists and experts, patient-centric education beyond nutrition and flexible, on-demand content that fits your schedule.
Hill’s Veterinary Academy: https://na.hillsvna.com/
To learn more about the nutritional management of pets with kidney disease, check out the Chronic Kidney Disease Inside Scoop video on Hill’s Veterinary Academy. This video shows you how Hill’s new Prescription Diet k/d ActivBiome+Kidney Defense uses the gut-kidney axis to help pets with kidney disease.
Chronic Kidney Disease Inside Scoop video: https://na.hillsvna.com/en_US/resources-2/view/87
ABOUT OUR GUEST
Dr. Tim Evans is a diplomate of the American College of Theriogenologists and of the The American Board of Veterinary Toxicology. Dr. Evans was the Toxicology Section Head in the Veterinary Medical Diagnostic Laboratory at the University of Missouri for almost twenty years, until November 1, 2022, and he now wears several new hats at the University of Missouri, including Associate Professor in the Department of Biomedical Sciences, MU College of Veterinary Medicine Public Engagement & Continuing Education Coordinator, and MU Extension Specialist in Animal Health & Veterinary Toxicology. Dr. Evans received his DVM from the University of California, Davis in 1982, and he earned both his MS (1996) and PhD (2002) from MIZZOU. He has been described as “intimidatingly enthusiastic,” especially when it comes to teaching veterinary professional students, and he was recognized as the April 2009 Nerd of MIZZOU and Nerd of the Year in 2010. Dr. Evans was also recognized as a William T. Kemper Fellow for Excellence in Teaching in 2013 and was MIZZOU’s 2015-2016 recipient of the Governor’s Award for Teaching Excellence. Dr. Evans also has a superhero alter ego, THE ANTIDOTE, the enemy of ALL things toxic, who periodically makes appearances in the classroom. Tim has been married to his extremely patient wife, Debbie, for 41 years, and they have two adult children, Andreya and William.
EPISODE TRANSCRIPT
Dr. Andy Roark:
Welcome everybody to The Cone of Shame Veterinary Podcast. I am your host, Dr. Andy Roark. Guys, this is a fun, fun episode. I have the amazing Dr. Tim Evans with me. Dr. Tim Evans is a boarded theriogenologist and also a boarded toxicologist. He is a professor at University of Missouri’s College of Veterinary Medicine, and darn, he is fun. I think you guys are going to love this episode. I love getting to meet Tim and my team still talks about getting to work with him. So he is super fun and this is one of those episodes where there’s somebody who, gosh, they know their stuff and they’re just telling stories, and it is awesome.
And so if you learn from stories and examples and anecdotes and you soak that stuff up and it sticks in your brain, I got something great for you today ’cause you’re going to learn some stuff. This is my favorite way to learn. Anyway, this is a wonderful episode. It is brought to you ad-free by Hill’s Pet Nutrition and their Hill’s Veterinary Academy. Guys, if you’ve not checked out the Hill’s Veterinary Academy it is a amazing site for educating the entire veterinary team. Have a look at it, there’s some links down in the show notes you definitely want to check out. Let’s get into this episode.
Kelsey Beth Carpenter:
(singing) This is your show. We’re glad you’re here. We want to help you in your veterinary career. Welcome to The Cone of Shame with Dr. Andy Roark.
Dr. Andy Roark:
Welcome to the podcast. Dr. Tim Evans, thanks for being here.
Dr. Tim Evans:
Well this is great. I dreamed about being on the Cone of Shame.
Dr. Andy Roark:
Nightmares.
Dr. Tim Evans:
Absolutely dreamed about it.
Dr. Andy Roark:
Oh, my gosh, you are too kind. For those who don’t know you, you are a veterinary toxicologist. You are at the University of Missouri’s College of Vet Medicine, you are also their public engagement and continuing education coordinator.
Dr. Tim Evans:
Yeah, that’s a mouthful, isn’t it?
Dr. Andy Roark:
It is. I had to write that one down. I was like, “I’m not going to remember that.” But yeah, it’s great.
You are so much fun. I am super glad to have you here. It’s time for a quick refresher for me, and I realized this last night when I was having a cookout at my house. And I had a bunch of friends that were over and we were doing shish kebabs, and one of the kebabs hit the ground and my goofy dog snatched a big hunk of onion off the end of the kebab before I could get there. And I thought, “Oh, well, that’s not good.” But how bad is it? Let’s think.
And so I thought that you and I could get together and start to talk about some… We should get into toxins, is what I was thinking. So anyway, we’re due for a review on nephrotoxin. So that’s what I wanted to get in today, I was thinking about, let’s think about kidney disease. The A to B to C there is winding and convoluted, but that’s how I got here.
Dr. Tim Evans:
Yeah. Well on the onions, I mean, eventually if you have severe enough of a dosage… And again, a lot of it, in veterinary toxicology, I mean, everything is toxic. Okay? You watch the TV, you listen to the… Everything is toxic. Britney Spears is toxic, Taylor Swift is toxic, something’s toxic.
Dr. Andy Roark:
Something’s toxic.
Dr. Tim Evans:
But everything is toxic.
But I think it all really comes down to the level of exposure. How much is an animal exposed to? So that comes down to how much onion, how big the dog, and is it just a one shot deal? The dog counted to five, got what it was, ate it, probably not a problem. If that’s your daily routine that you have people come every day… I mean, we had some folks years ago, they decided they were going to grill steaks every evening. And they felt bad for their Great Dane. So they went ahead and grilled onions for their Great Dane. Now does that sound like a fair exchange? The dog wants a steak and they’re grilling onions.
So they gave it onions and for approximately a month, six weeks, two months, it got grilled onions every night. And then the dog started acting kind of lethargic. And they brought him in, the dog was anemic. And then incidentally they get this history. And all we’re trying to do when we’re talking about our patients is we’re trying to get a history, we’re trying to get… What’s the examination? We want to come up with, what are the problems? And then we want to figure out, how do we fix things?
Well this dog was anemic and then the story came up with the onions. And luckily onions will destroy red blood cells, as homolysis. That can cause hypoxia, it can also affect the kidneys. A lot of these things that are out there, and again, everything is toxic if there’s enough of it. You can potentially go ahead and get some adverse changes in the case with onions and the red blood cells, possibly in the liver, in the kidneys. But it all comes down to how much.
And again, this was a Great Dane. Usually when I get a phone call and someone says, “Hey, I got a Great Dane, it got into something,” I’m thinking, “Well it’s going to have to get into a whole lot of something to be a problem.” I mean, most of the time when we’re talking to our colleagues, if someone tells me they got a Shih Tzu or a tiny little Chihuahua or something like that and it gets into something, I start listening pretty carefully because the possibility of that being a problem goes much higher. Then when you’ve got a Lab, which goodness, they eat everything, or you’ve got a Great Dane. So…
Dr. Andy Roark:
Yeah. That makes sense to me. It still makes sense, your old nutrition history for the win is trying to tease that out. Do you have questions when you’re looking for toxins, ways that you like to ask questions to pet owners that you feel like get them to tip their cards a little bit? It’s amazing to me how often I’ll say, “Well what does she eat?” And they’re like, “Oh, nothing. Just regular stuff.” And 35 minutes later the onion story will come out and I’m like, “Well why didn’t I get this early on?”
Dr. Tim Evans:
Yeah, and I think that’s one of the things that makes it a bit hard in veterinary medicine sometimes, in that medicine generally have gotten to the point where you got 15 minutes to figure out what’s going on.
We had a situation over at the Veterinary Health Center where an owner of some really… A very good owner had, I believe, Retrievers, running dogs all the time. She brought this dog, the dog was acting kind of depressed. She thought maybe it was a problem with a dewormer that she had used and then they got some blood work. And then the dog, they found something that… It was an older Golden Retriever, they thought possibly there might be a problem like some type of cancer or something like that. You get into a referral center and we’re looking at everything in the world and trying to figure out what’s going on.
And so we got people working on this part of the dog and people working on this part of the dog. And they said, “She still thinks it could be some kind of poisoning, and she said she wanted to know if you’d come over and visit.” And a guy like me at the time, I was in the diagnostic lab, I mean, actually being allowed into the hospital… I mean that’s like, whoa, that’s like being on the Cone of Shame, Andy. That’s like being on the Cone of Shame.
So I got in and I sit with the client, we’re talking about it and she said, “Well the dog was acting kind of drunken and it just…” She thought that it could’ve been this dewormer. And then she’d had a lot of workers working around the house and they’d had a bunch of vehicles and all of this. She said, “Well what kinds of things can cause this kind of behavior?” And so I’m going down the list of things and there’s the ivermectins, the macrocyclic lactones, that class of drug. And then I’m getting in, “Well, and then there’s alcohol. There’s bread dough, yeast decides to rise in the animals so then you get ethanol.”
And then I said, “Well there’s always ethylene glycol. I mean, were there any dripping radiators or anything like that?” And she said, “Well they had a bunch of vehicles there.” She said, “Well how do we figure out if that’s the problem?” I said, “Well you got a complete blood count, you got a blood panel this morning. We went ahead, we got a urinalysis.” So we go ahead and we’ve got some blood work on the animal. We got a CBC, we got a chemistry panel looking at liver, kidney, a variety of different organ systems. And then we get a urinalysis. Okay, we can look at those results when we get them and that can give us some idea if we’re concerned about a possible exposure to ethylene glycol, maybe that could have occurred.
So we go ahead at the end of day, we get the blood work, we’re all thinking this chance of it being ethylene glycol is next to nothing. And all of a sudden what we do, we get the urinalysis and we’ve got calcium oxalate monohydrate crystals, we’ve got an increased anion gap. And this dog, and it was not something on the radar, had gotten into ethylene glycol. Excellent owner, breeder, made sure that everything was just right. But when you get a lot of people and a lot of things happening, who knows? And ethylene glycol is generally pretty sweet and it doesn’t take a lot. This was an older dog. And unfortunately this dog ended up going into renal failure. I mean, yeah, those are the kinds of things.
And so everything is toxic, but again, it depends on the amount. And sometimes it’s the simplest things. Years earlier I’m in the VHC, the second time they let me in it, and then there’s this Great Dane. And this Great Dane is in there, and the Great Dane had had surgery on its spine. They thought it was a wobbler, they were going… I was there for another reason, but they were taking the pictures and pinching it. And this dog all of a sudden goes ahead and he just takes his head, and it just kind of looked like this right at you. He looked like my roommates my first year of that school, on a Saturday morning. It just looked like that.
And I said, “Could this dog have gotten into ethylene glycol?” And the residents looked at me and they said, “Dr. Evans, you always think it’s an intoxication.” I said, “I can’t help myself.” So I was working on my PhD at the time, writing my dissertation. So I was working into the wee hours in my office, and so I’m running on this dissertation. And all of a sudden I get this phone call and it’s from the people over in the ICU and they said, “Dr. Evans, Dr. Evans, this is amazing. We went ahead, we looked at the blood work on the dog. The dog had an increased osmo gap, and just at that point in time he vomited and this fluorescent green fluid just was all over the floor. Dr. Evans, you were right.”
And I said, “Well, yeah.” He said, “Whoa, okay.” So they said, “Well can we test it to see whether it’s… It’s the fluorescent green.” I said, “Yeah, I’ve got a really expensive test for that. We’re going to take that vomit and we’re going to see if it freezes. Okay? And I’ll know pretty quick.” Didn’t freeze. Okay? That’s what it was.
So those kinds of things, I mean, we started out with a Great Dane and onion and now we’re a Great Dane with ethylene glycol. And it’s funny, when you talk about trying to go ahead and get a history you never know when that pearl of information is going to pop up that actually gets you thinking. A dog had surgery, so great, and it was a wobbler, had to be something was going like that. The fact that this dog had probably drank a half gallon of antifreeze seemed to not be in the cards.
So again, there’s a lot of things that people don’t recognize that are around the house, that are in our homes that potentially can be problematic. And again, oftentimes it’s just people’s natural to think that it’s somebody else possibly trying to poison their pet, when its actually just things that are around the home.
Dr. Andy Roark:
Yeah. Stepping back real quick, the frozen vomit test, is that written down somewhere? Can you look that up or is that an actual diagnostic test? Or did you just-
Dr. Tim Evans:
No, it’s a Dr. Evans. It’s antifreeze, does it freeze?
Dr. Andy Roark:
Okay, all right.
Dr. Tim Evans:
So there [inaudible 00:14:40].
Dr. Andy Roark:
My head kind of exploded for a moment. I was like, “I’ve never heard of this test.” And…
Dr. Tim Evans:
I think these cases are good illustration of things that we find around our house that are potentially a problem. Some of them you got to consume a lot of. Okay? For ethylene glycol, a dog has to consume about four to six mils per kilogram. And that’s pure ethylene glycol. So let’s figure, if it’s half ethylene glycol it’s got to be close to 10 to 12 mils per kilogram. Let’s figure you got a 20 pound dog, 10 kilogram, that’s close to 120 ounces. I mean… Yeah, close to 120, not ounces, 120 mils. We’re talking four ounces. Okay, got to do the math there. It’s four ounces, that’s a pretty good amount of ethylene glycol and that’s a 20 pound dock. Go ahead and take a 100 pound dog, you’ve got quite a bit.
And again, it’s the one thing. And students, vet students love math. They love math. So do veterinarians, actually.
Dr. Andy Roark:
So there’s a right answer, yeah.
Dr. Tim Evans:
Yeah. But again, we have to get the calculations. And so we add that all together and then we go ahead. When we talk about intoxications we talk about, how are we going to go ahead and treat it? Well we’re going to remove from the source, we’re going to stabilize, supportive care and then we’re going to try and prevent it. In the case of ethylene glycol what you’re left with most of the time with treating is, we’re going to use ethanol or we’re going to use 4-methylpyrazole. People call it fomepizole.
I had a student who one day in the parking lot said, “Dr. Evans, I want to do emergency medicine and you taught me about 4-methylpyrazole, 4MP, but you never taught me about fomepizole.” I said, “Okay, let’s just… 4-methylpyrazole, fo-me-pi-zole. There you go. Okay?”
Dr. Andy Roark:
“You were just taught about it.”
Dr. Tim Evans:
Yeah. But again, and you could get 4-methylpyrazole or ethanol, Everclear. I mean, I’m in Missouri, you go to your corner liquor store and there’s a variety of protocols you use. But you give the animal IV ethanol, a 30% solution, a bolus dose. Then you keep it on a continuous infusion for a period of time with, if you could get 4-methylpyrazole, fomepizole. You dose a number of multiple doses, but you’re doing that to prevent the animal from making some of the more toxic metabolites of ethylene glycol. Okay?
So that’s how we address that. But you got to get after it quick. And if the dog or the cat is already in kidney problems there’s not a whole lot you can do. That’s the unfortunate part. So that’s that aspect we kind of talked about. How do we work up a case? How do we talk about these things? How do we treat something like ethylene glycol? Let’s go to another common problem that would affect the kidney, let’s talk about grapes and raisins in dogs. Okay?
So for some reason never in my mind did I think, “I got a dog, I’m going to give it a treat. Let’s give it a grape.” I just never quite occurred to me that that was… Well a lot of people like giving grapes and raisins to dogs. I mean…
Dr. Andy Roark:
Oh, I get it. I totally get it. It’s a perfect little treat size. You’re there, you’re eating it. It’s mostly water. You go, “How could this be bad?” And I totally get it. I totally get it.
Dr. Tim Evans:
Yeah. Well see, that’s why you are where you are as the host of the Cone of Shame, and I’m a toxicologist.
So we’ve talked about for probably… I mean, it’s probably been close to 15 years where the animal poison control center brought attention to the fact that they were seeing problems with grapes and raisins. And some animals seem to be particularly sensitive. I mean, some animals, it takes a boatload of grapes, maybe less in the way of raisins. But some dogs, little dogs, you get a box of raisins and they go into renal failure. So that’s an interesting… In that case we’ve got different kinds of intoxications where we have differences in sensitivity of different animals.
And in this case some animals are much more sensitive dogs, it’s a dog thing. In my mind it’s a dog thing. You’ve got grapes and raisins, and particularly raisins, because whatever it is… We didn’t know what the toxin was but now the belief is that tartaric acid or potassium bitartrate are somehow involved in that. We don’t know how, and we don’t have really a way to test for it, but they can… What happens is the dog gets into it, they start vomiting and then they end up with the tubules in the kidney, which play an important role in what the kidney does, basically are damaged. And then we get into renal failure and kidney failure.
And so this is one of these things that I tell people, “Just don’t give grapes and raisins to your dogs.” And I was trying to get my hair cut yesterday ’cause I was coming on the Cone of Shame, and my regular barbershop, they were closing in 10 minutes. And so I went to a new barbershop and the lady there says… And I was dressed, don’t ask me why, but I had an emu shirt on and wearing my tiger striped pants, okay? Wearing my tiger striped pants. It doesn’t leave much to the imagination of where I work.
And she says, “I have a dog, I have a French bulldog.” And I said, “Wow.” And she says, “If you could tell me anything, you said you’re a toxicologist, if you could tell me anything, what should I not do?” I said, “Well, don’t give it grapes, raisins, don’t give it chocolate, don’t give it those kinds of things. It’s a dog, get dog treats for the dog, okay?” So then she asked about grapes and raisins, “Well grapes and raisins, I always think that…” And she said that, she said, “Well they’re so much fun and when they eat them they explode.” And I said, “No, that’s a less than ideal thing to do.”
Now again, how many times do we get phone calls from somebody who says, “Oh my gosh, my Great Dane ate one grape?”
Dr. Andy Roark:
One grape.
Dr. Tim Evans:
Well that’s probably not going to be a problem. But what we do need to recognize is, has that dog ever had that kind of poisoning before? Has that dog had grape and raisin intoxication? If it’s had it before then yes, maybe one grape, particularly multiple raisins, might be an issue.
And I think this brings us back to a lot of things, and you know, dealing with pets and with organ function, I mean, the kidneys, we don’t really know they’re not working until they’re really not working. And so we go ahead and we see an elevation in the blood urea nitrogen or the creatinine, and we go, “Oh my gosh.” But we don’t always…
And a good example of this grape and raisin analogy. You talk about in dogs, I believe it’s a dog thing. Anecdotally some people say, “Well there may be cats.” There’s been reports of cats having kidney problems and they’ve ate one raisin. Okay? Well as you and I both know, cats are basically chronic kidney disease waiting to occur. I mean, I love cats.
Dr. Andy Roark:
Oh yeah, no.
Dr. Tim Evans:
My best friend is a cat, but I’m not giving it… I’m watching out for his renal function. But what happens is a cat eats a raisin and then the cat’s not feeling well, and somebody goes ahead and does the blood work and they see the cat has renal disease. And now it’s got to be because it ate the raisin, not just because it’s a cat.
And that brings us to the point of going ahead, and when we get our patients that come into clinics I always think it’s a great idea to get baseline blood work. Dog’s coming in for a puppy check, or even a dog’s coming in for its annual shots, whatever, getting that blood panel and looking at, are we seeing any type of changes in the red blood cells, white blood cells? Are we seeing anything in the blood chemistry indicative of potential liver disease or kidneys? Something like that. That gives us some baseline information that we can go back and then go ahead and figure out.
So when I’m talking about cats and grapes and raisins, and I don’t think that’s a thing. On the other hand we’ve got cats and true lilies, that’s a thing. And so I think a lot of this is trying to organize those thoughts and put them in. And again, teaching veterinary students, I’m trying to get them to think in terms of a system of how do you look at things and put it together? And in the case of cats and lilies, true lilies… Lily is like Smith of the plant kingdom, okay? Everything’s a lily. But the true lilies, the Lilium genus, the Hemerocallis genus which is your Easter Lily, Asiatic Lily, all of those other lilies, and then your Day Lily, those potentially can be associated with kidney disease in cats. Even the pollen, even the pollen is enough to cause a problem.
We don’t know what the toxin is. We know that if the cat eats even a tiny bit that it’s a potential problem. You go ahead, you take it to the veterinarian, you go ahead, you put the animal on fluids. Usually we put it on IV fluids for about ideally 72 hours, sometimes we can get away with less. But it’s an emergency. I mean, it’s like the Great Dane and one grape, not an emergency. The cat who’s got yellow pollen all over its face from… And it just happens to be Easter or it’s prom, everyone at prom time’s got to have lilies, and then we go from there.
And so those are the kind of things that we take [inaudible 00:27:43].
Dr. Andy Roark:
All right. Dr. Tim Evans, you are amazing. Do you have any favorite resources before we go that you love for people who are like, “I want to brush up on toxicology,” or, “This is really an area of interest for me?” Anything that you like to point people towards?
Dr. Tim Evans:
Well, I would say that I think the poison control websites, particularly the Pet Poison Helpline and the ASPCA Animal Poison Control Center, great websites, phone apps. Certainly you can call for a consultation, but they’ve got lots of free resources that can answer a whole lot of questions. And there’s a number of pretty good textbooks out there that give us some good information. And yeah.
So I love what I do. I hope I met your requirements for maybe coming back to the Cone of Shame again. So…
Dr. Andy Roark:
The stringent requirements for return visit. I think so. I think you’ve far exceeded what I hope for. This has been wonderful. I appreciate the heck out of you. Guys, thanks for tuning in and listening, everybody. Take care of yourselves, be well.
And that’s it, guys. That’s what I got for you. I hope you enjoyed it, I hope you got tons out of this episode. Thanks to Dr. Tim Evans, he is so fun. I so enjoy getting to sit down and talk to him. Thanks to Hill’s Pet Nutrition for making this episode possible.
Guys, if you want to get into the actionable treatment steps coming out of this episode, if you’re like, “Hey, I really want to get into management of these conditions. Hey, I really want to get into the latest in therapeutic intervention for nephrotoxins.” I got you covered. Head over to Hill’s Veterinary Academy and check it out. They’ve got a video called The Inside Scoop, and I linked all this in the show notes. But guys, everything that you need to address these issues to get into treatment and ongoing management of the things we talked about today is right there for you.
So anyway, go and check that out. Links for all this stuff down in the show notes. Gang, take care of yourselves. I’ll talk to you soon.
