Saturday at the Vet Clinic

 

When I started picking up the occasional Saturday shift at a local clinic, I insisted that I only wanted to see wellness clients. But not every pet that comes in just needs an exam and vaccines. Ears, skin, vomiting, and diarrhea cases began showing up on my schedule, although I am still able to duck lacerations and other cases that required suturing. (This clinic only does dentals and surgeries during the week, so that was never going to be a problem.) The reason is that I simply don’t trust my skills with cutting and suturing living animals. I’ve developed habits that help me do necropsies efficiently but these absolutely do not translate back into the GP world.

On a recent Saturday, things shifted quite a bit, taking me pretty far outside that wellness bubble. A regular client came in with their 14-year-old Chihuahua laterally recumbent and unresponsive. The dog was being treated for congestive heart failure, a chronic, progressive disease. The other vet working that day and the entire team of techs jumped into action, setting up for intubation, oxygen, placing an IV catheter, giving drugs, and performing chest compressions. It was impressively smooth and professional teamwork. Realizing that I could contribute nothing to that effort, and at best would only be in the way, I focused on the owner, collecting more history, giving her information, and helping her work through the many decisions that she needed to make quickly. I work with grieving owners all the time in my job at the lab and am comfortable communicating in that setting. Sadly, they couldn’t restart the dog’s heart.

Of course, I received training in how to treat these kinds of emergencies. But I haven't applied that  training in over 7 years. Like any specialized knowledge, if you don't use it regularly, it atrophies. 

But that wasn’t the only curve ball thrown on this day. The last appointment of the day, assigned to me, arrived around 5pm. The owner had taken the dog, a 2-year-old female pitbull mix, to a low-cost spay and neuter clinic two days earlier. The dog had developed severe bruising on her abdomen and was “dumpy” and lethargic at home, although she still had an appetite. The dog wasn’t messing with the spay incision site, which was a bit scabby but healing. However, there were massive, dark purple bruises on her abdomen and large pockets of fluid under the skin. Alone, these weren’t an emergency even though they looked scary. Large, deep-chested dogs can sometimes be difficult to spay and there can be trauma to the body wall, leaving bruises and subcutaneous edema. But it was the reported lethargy that set my spidey senses tingling.

I’ve seen the absolute worse cases of post-spay deaths presented for necropsy, including ligatures coming off, cutting but not ligating ovarian arteries, accidental avulsion of renal vessels, complete transection of the intestine (we still don’t know how this happened as one does not insert scalpels into the abdomen for a spay), and contamination of the abdomen or the incision site. There are lots of ways for spays to go wrong.

The dog’s physical exam was normal. The owner reported that the dog had pooped since the surgery. Still, the case just didn’t feel right to me. I said, I want to run full bloodwork. And it turned out that the dog had a severe, active infection. If the dog didn’t receive immediate treatment, it would probably have died. We sent the owner home with 14 days of a broad-spectrum antibiotic plus a steroid for inflammation and another drug to address pain.

Regular GPs see these kinds of cases every day. This was a normal Tuesday, or rather Saturday, for that clinic. 

I’m a decent diagnostician, and as I learn more about the pharmacy available at this clinic, I get more confident in selecting tests and treatments. But I still have a lot to learn. I am lucky that my forays into GP veterinary medicine are being supported by such a well-trained and compassionate team. 

Sample Wall of Shame

Under the umbrella of Pathology, the lab section that I supervise has two main functions: necropsy and histopathology.

Histopathology refers to both the study of disease in tissues and the process of preparing tissue samples so they can be examined under a microscope. Tissue samples are systematically collected during necropsies. Histopathology is one of the many tools we use to help determine the cause of death of an animal. Veterinarians (and doctors) also remove tissues during surgical biopsies and submit those for histopathology. In those cases, we are not necessarily looking for the cause of death but examining the tissues to determine if cancer is present, or to identify the cause of a persistent lesion or disease state in the animal.

Tissues slated for histopathological analysis must first be fixed. The most common fixative is formalin, an aqueous solution of formaldehyde. Formalin causes cross-links to form between proteins and makes tissues stiff. Formalin-fixed tissues don’t decay (they can degrade over time, but we will let this oversimplification go). Once the tissues are stiff, they can be cut into very thin slices and placed on microscope slides. The rule of thumb for proper fixation of a tissue sample is a 10:1 ratio of formalin to tissue.

But this post isn’t about what goes on in a histopathology lab. It’s about the containers that veterinarians choose to hold tissue samples and formalin that they then ship to us. I keep pictures of the more creative choices in a folder that I labeled “Sample Wall of Shame.” Here are some of the best. 

 

This container is for food, human food.

 

So is this one. It was sealed with packing tape and formalin leaked out during transport.

 

 

This vet submitted the uterus of a dog in a Gold Peak tea bottle. When collected at the time of surgery, the tissue undoubtedly went into the bottle easily. We had to cut the bottle apart to get the fixed tissue out. And yes, that is a zip tie that was used to close off part of the uterus. We still don’t know why.

 

This vet chose a pill bottle which does not have a liquid-proof seal. They thoughtfully folded the submission form into the same baggie as the pill bottle. Formalin leaked onto the submission form.

 

 

This vet chose a glass mason jar and opted to seal it with packing tape instead of wax film. Glass is an insanely terrible choice. And the submitter still didn’t have enough formalin for the size of the sample.

 

 

This vet used an appropriately sized, commercially prepared jar with sufficient formalin to fix the submitted tissue samples. They had marked one of the samples with a suture, a common way to differentiate multiple samples placed into one jar. Unfortunately, the suture caught in the threads when the jar was closed and most of the formalin leaked out during transport, contaminating other samples in the same shipping box.

 

 

There was not enough formalin in this commercially prepared jar for this large tissue sample. 

 

Why does any of this matter? Formalin can leak out of poorly sealed containers and contaminate submission forms, packing materials, and other samples in the same shipping box. Leaks expose shipping, receiving, and histopathology personnel to formalin, a carcinogen. Tissues that don't get fixed completely can rot, obscuring diagnostic details. Glass containers can break, creating sharps hazards. 

Sure, the commercially prepared jars that I showed in the last two examples cost money and some vets may want to cut costs where they can. But selecting any old container that comes to hand creates unnecessary risks, potentially ruins samples, and shows poor attention to detail and poor understanding of the requested diagnostic test. 

To be sure, this is not a problem unique to our lab. All diagnostic labs have to deal with improperly packaged samples. We wear PPE and use biological safety cabinets and fume hoods to handle samples to mitigate risks on our end. And of course we educate clients who submit samples like this as often as we can. 

Even so, I regularly add photos to my Sample Wall of Shame folder. 

 

 

Reminder

 Locum work, also called relief work, has always been a thing in both the human and veterinary medicine fields. Oddly, it seems like it's mostly nurses from the human side who do locum work, while it is DVMs who travel around in vet med. When the world turned upside down during COVID-19, locum work really took off to the point where it has become a solid career option for some veterinarians. 

Some assignments can last for months, such as covering maternity leave for a regular employee, while others consist of an occasional overnight or weekend shift. Some practitioners use locum work to travel widely, while others stick closer to home. There are companies who will find locum assignments for you (for a fee usually), or you can arrange them yourself through personal connections. 

Locum work can pay really well. DVMs covering overnights at an emergency clinic can earn over $1500 for a 12-hour shift. That's a car or student loan payment or money saved for a trip. You can be paid as a regular W-2 employee or as a 1099 contractor, which is a bit more complicated for tax reporting. You have to arrange DEA licenses for each location that you work at. And if you travel, you'll need a license to practice in each state. All of that is just bookkeeping. Quite manageable. 

Locum work isn't for everyone. It takes a certain personality and ability to walk into a strange clinic with pre-existing technical protocols and interpersonal drama and get right to work treating patients. To add to the stress, a DVM, locum or otherwise, is expected to be a team leader. It doesn't matter if you don't know where the bathroom is. A relief practitioner needs to both check their ego and take the lead. 

I've started picking up Saturday shifts at a local clinic. I only do one shift per month, and sometimes skip a month. The clinic is corporate, meaning it is owned by a much larger company, so I was hired as an hourly employee with W-2 wage and tax reporting. 

Why would I do this when I have a perfectly good job? There are lots of reasons! For starters, when I pick up a Saturday shift, one of the regular vets gets to spend that day with their family. Burn out is a problem in vet med. I'm helping out my colleagues.

While that sounds terribly noble, there is also a selfish reason that I'm doing it. I get to put my hands on living animals. I get to practice medicine. I absolutely thrive as a veterinary pathologist and am good at it, but working a Saturday in the clinic reminds me why I spent all that time and money getting the DVM degree. 

Because of the many bad habits I've picked up from being a pathologist, I told this clinic that I would absolutely not do surgeries, dentals, or even laceration or wound repair. I would only take wellness clients. I would be okay with giving vaccines, but no other sharp things should be put in my hand, ever. And they are fine with that! 

I see between 14 and 18 clients per shift, which is a lot. Each time I do a relief shift, my hands and brain remember physical exam skills that I learned in school but haven't had a chance to use since I graduated. Sure, we do physical exams before a necropsy but we are evaluating very different things about the animal in front of us.

 The owners I work with are in a different place too. They are bringing their pets in for wellness exams, vaccines, parasite preventatives, nail trims. Simple stuff. Basic health care. For the most part, they are relaxed and calm. It's a different world.  

There's another reason I'm doing this. I've already started to think about retirement from my current job. I'm still a couple of years out but now is the time to start planning. By keeping my skills up and my connections solid, I can step from my current job into part-time relief work without a break. I am grateful that I have that option. 

 

Occupational Hazards: Ballet With Knives

 Working in veterinary medicine comes with special occupational hazards. Like clinical vet med teams, the pathology team is regularly exposed to the usual array of body fluids. Our working environment is probably a bit more splashy than a typical GP office, however. I always wear a surgical cap to cover my hair when I'm on the necropsy floor.

Let's add in exposure to ticks, fleas, flies, fly larvae, beetles, ants, and other members of team arthropod. Except for the ticks, most of them don't have much interest in us. Many animal ectoparasites are evolved for just a few species. But not ticks, of course not, those little generalist fuckers. 

There is the potential for exposure to some fairly nasty zoonotic pathogens, including rabies. We are vaccinated for rabies and the lab checks our titers every couple of years. We mitigate risk by wearing PPE. When needed, we work with suspect tissues inside a biological safety cabinet. Knowing what pathogens might be differentials in a given case before we handle an animal is important too. That comes from training and experience. I always take the reptile necropsy cases because I find their anatomy and pathologies really interesting. But they can have some weird bacterial diseases that can make people pretty sick. 

An extra special hazard is exposure to intestinal gases. This isn't much of a problem for small animals, but large animals like horses and cows can become pretty bloated after they die. A couple of years ago, I accidentally pierced the rumen of a cow while leaning over the carcass and got a blast of moist, bacteria-laden rumen gas directly in my face. I said, uh oh. Forty eight hours later, I dragged myself into an urgent care with a raging case of conjunctivitis. They loved the backstory though!

Other hazards that are common to pathology are being cut with sharp things, including knives, scalpels, claws, and cut bone; slipping; being rammed by rolling tables; and being whacked in the head by the hoist hook or a flying hoof when a large animal carcass unexpectedly rolls or slips.

Of course there is the potential for sharp things and slippery stuff on the floor in an operating theater, but it's a matter of degree for the pathology team. We might have five people armed at the same time with wickedly sharp knives moving about in a relatively constricted space. And we are performing our ballet with knives ankle-deep in intestinal contents and blood. 

Communication is essential. We can't go waving knives and scalpels about willy-nilly. It's essential to know where everyone's fingers are before you start cutting something. Planning is part of our ballet too. We need to be systematic about how we conduct necropsies and how we handle animal remains. To the external observer, it may look chaotic but we don't rip open carcasses in a random fashion. 

I'm proud to work with a professional, efficient team that is conscious of safety, looks after each other, and gets the job done with a minimum of drama. 

You Are Served

 The lab regularly receives necropsy submissions from animal rescue groups, county and city shelters/animal control, law enforcement, vets, and owners that involve suspected abuse. I've been subpoenaed five times at work in cases that have made it as far as a trial. 

In all of these cases, I'd already been contacted by the prosecutor's office and was expecting the subpoenas, which come by email, but it's still a shock when they pop up. 

In one case, once the defendant took one look at the four witnesses lined up to testify for the prosecution, including me (I did the necropsy), another vet who treated the animal before it died, and two people from the rescue group, he asked for a plea deal right away. Showing up is important!

In another case, I testified in a county courthouse in northeast Arkansas. That was a simple trial in front of a judge. The evidence from necropsy was compelling--the same poison was found in vomit near the dog's head and in stomach contents from the dog. The guy was convicted.

Earlier this month, I testified in my first jury trial. Animal abuse was recently elevated to a felony charge in Arkansas, and the prosecutors worked really hard on this case. After doing the necropsy, I spent a couple of hours on phone calls with them, then another hour-long in-person meeting for trial prep. 

Trial day arrives. I was the eighth of eight witnesses for the prosecution. It was late in the day by the time I was called in, and everyone was tired. I was questioned for over 45 minutes! I was really stressed going in, but the prosecuting team's prep was good, and I think I did a good job of explaining emotionally difficult and technically complicated things to the jury. The prosecution used as evidence some of the necropsy photos that I sent to them. Even for me, it was jarring to see the photos splashed up on a giant flat screen beside me. I know the jury was shocked. I even acknowledged in a couple of my remarks that I knew it was hard to look at photographs like that. I was prepared. I am good at my job. It was still a relief to be dismissed. 

The prosecution team texted me the next morning--jury voted to convict, defendant sentenced to serve 2.5 years. 

Veterinarians deal with death every day. Nothing is routine--each case brings its own burdens. Animal abuse cases are particularly hard on the entire team. I didn't expect that being an expert witness would be part of my job here at the lab. But I made this career change in order to do more meaningful work, and sitting in a court room talking about difficult topics is just one of the meaningful things that I do now. 

Never A Dull Moment

The samples and cases submitted to the veterinary diagnostic lab are inherently unpredictable. No appointments need to be made, although we do ask that clients call the lab before bringing in a large animal for necropsy. With a few exceptions, we accept submissions directly from owners and commercial entities. The result is that there is nothing like a normal day to day routine at the lab. My section, Pathology, which includes necropsy and histopathology, is particularly prone to unexpected surprises. 

Surprise! There's a dead goat in the cooler on the dock, on top of two neonatal calves, all dropped off over the weekend. And the goat has no paperwork with it....

Surprise! There's a dead chicken in that box on the counter, shipped without any ice packs, literally creating a stink in the Receiving.

Surprise! It's 2pm, and Tyson just arrived with 36 live broiler breeder hens from three different farms, and didn't call ahead!

Pathology has no routine or predictability at all. We have to be ready to accommodate whatever comes in. In just the past week, I've had to deal with several cases that nicely illustrate how unpredictable my job is.

We have an incinerator to dispose of the tissue waste we generate. The incinerator occupies a fair bit of my management time each week. It is touchy (won't start if it is raining, or right after it has rained, for example). It is also a dangerous piece of equipment. We burn around 4,000 lb of animal remains a month, and use a forklift to hoist bags weighing as much as 1300 lb into it. But remember that unpredictability factor? In December, we burned just over 9000 lb due an unusually high number of horses submitted for necropsy. I was scrambling to keep the propane tank filled during the last two weeks of the year. 

The incinerator lid is raised by cranking up two bottle jacks, one on each end. The jacks and the lid roll back as a unit on a track, exposing the interior of the incinerator. A week ago Friday, one of the jacks failed. It had been leaking hydraulic fluid, and I knew it was on its last legs. So when the techs came back and reported they couldn't get the lid opened, I drove to the incinerator (it's in a secure fenced maintenance yard across from the lab), measured the existing jacks (their labels had been scraped off by the incinerator manufacturer so they could be painted black), and drove to AutoZone to get two more. On Tuesday, one of my techs and I ripped out the old jacks and rammed in the two new ones. Good thing I'm handy with tools.

On top of that, I was scrambling to get more propane. Our walk in cooler was full because we didn't burn on the Friday as we often do to clean it out for the next week because of the jack issue. I usually call or text the propane delivery driver directly but he wasn't answering on Monday. It's pretty useless to call the company directly. But our director still has the business card of a "customer experience" rep at the propane company who helped him set up the tank back in 2018. One call to that guy and we had a full tank of propane (1000 gallons) the very next day. 

A young boa was submitted for necropsy that week. Against the usual backdrop of dogs, cats, cows, and chickens, I quite enjoy these unusual species. Even if I am not on necropsy duty that day, I always take these cases when they come in. They are challenging to handle, and their anatomy and pathologies are always interesting.

On Wednesday morning, I get this picture via text from a veterinarian friend.

That is a very sick calf with green snot coming out of his nose and eyes. Poor little guy. I actually received three photos of the calf, along with this text: "what tests?"

I had to laugh. This particular vet is young, but very good. He works really hard to help his large animal clients. And obviously, we have a lot of mutual trust and respect since he knows he only has to text me to get an immediate response. 

I first replied "gross" then I suggested some testing options and the samples needed, and let him know what I thought should be prioritized in case the client couldn't afford or didn't want to run everything I recommended. 

I had another vet call me on Thursday morning to tell me about a horse she had seen that had large bleeding ulcers in its mouth. Uh oh, a short list of differentials, at least one of which was reportable, came to mind. I've worked with this vet before so we chatted for a while about the case. I told her, I've got to escalate this so hang tight and I will get back to you. I texted the state vet. He happened to be in his office, and came right down to mine. He said, get her to email everything including pictures. She did, and I forwarded all of it to him and to the USDA APHIS vet in charge. They eventually decided it was not a disease issue that needed their involvement, and passed the entire mess back to me and the vet who called me. 

I get calls like this from vets and animal owners/producers daily. Since taking this job, I've worked very hard to make the lab a resource for reliable information and assistance. The result is that I spend many hours each week helping other vets and animal producers and owners, calling, texting, emailing, gathering information. By now, most of the practicing vets in the state have worked with me, and they just call me directly. It also helps that I have a solid relationship with my state and federal colleagues. 

Finally, it was Friday, and I was taking a breather in my office thinking the crazy week was almost over when the state vet pops in. We have a situation, he says. New developments, he added. I thought he was still talking about the horse with the oral ulcers. He said, oh no, something entirely new.

Turns out a brown bat had gotten into the atrium of the building and people were running around in panic while others were trying to catch it. The atrium of the building divides the building into two halves, the lab side and the Department of Agriculture admin side. All of us on the lab side have been vaccinated for rabies as a requirement of our job. Nobody on the admin side has received this vaccine. 

I told the state vet, I'm on it. He and I rushed towards the atrium, only to be met by two admin folks coming towards us with a very small bat trapped in a very large net someone had rounded up from Forestry. Neither of them had gloves. Oy.

I asked repeatedly, any human contact? Any spittle, blood? Any scratches or bites? Negative, negative.

Since the bat was secure for the moment, I had them follow me back to our necropsy area. We ran into the lab director on the way, and I told him, just keep moving, don't look, everything is under control. I put on gloves, grabbed a plastic sample transport container out of necropsy, and maneuvered the bat (stunned into immobility or injured) into the container. I closed the lid, and sent them on their way. 

As a general rule, we don't accept live animals for necropsy. As a result, we don't keep euthanasia drugs at the lab. That's partly because we don't want to euthanize animals here, and partly because we don't want the hassle of maintaining DEA licenses and keeping inventory and so on. However, we do accept live poultry. We use CO2 gas to euthanize them. While this is not recommended for euthanasia of mammals, it was my only option and was how I euthanized the bat. Within an hour of the state vet showing up in my office, the bat had been euthanized, packaged with completed paperwork, and was on its way to the Department of Health for rabies testing. 

Admittedly the bat was kind of unusual, but most of the rest was just a normal week for the lab. Never a dull moment.

The Neighbor Poisoned My Dog

 Here at the lab, we hear this a lot from distraught pet owners when they submit their pets to us for necropsy. It is by far the most common history we get from these owner-submitted cases. We rarely hear this when vets submit companion animals, probably because they've already heard it from the owner and filtered it out for us. 

About the only thing these cases really have in common is that the pet died suddenly with no clinical signs of illness. 

And that is absolutely devastating to many pet owners. 

Sadly, the most common diagnosis (cause of death) in these cases is heartworm in dogs and feline hypertrophic cardiomyopathy in cats. 

 Heartworm is completely preventable, but monthly parasiticides are expensive. Some owners try to save money by using natural products (don't work) or buying off-brands at the grocery store (don't work). Others aren't aware that they need to give heartworm treatments every month, and in Arkansas, pretty much year-round. They don't know that each treatment kills the microfilaria in the dog's blood that he became infected with in the PREVIOUS month. 

It's always a shock to open a dog's heart and see worms spill out. 

We also see a lot of caval syndrome, which is advanced heartworm disease. The worms migrate out of the heart into the pulmonary vessels and into the vena cavae. While heartworm disease is more or less treatable, caval syndrome is ultimately fatal.

Dogs can have clinical signs with heartworm disease, such as cough and exercise intolerance, but often there is just acute death with no warning. 

Most owners accept this diagnosis with quiet sadness, but we've had a few who absolutely fought us, and insisted that we run many other tests. We've learned the hard way, and ask them to pay for those tests in advance. 

Feline hypertrophic cardiomyopathy is a harder diagnosis for owners. It is genetic in some pure breeds but most often our cases are for your Standard Cat, a mixed breed, short- to medium-haired tabby. We've seen some spectacular cases in which there certainly would have been a detectable heart murmur when the cat was alive...but many owners don't get regular preventative vet care for their cats. And cats are notoriously fractious patients in general. 

There have been some good studies that demonstrated that a normal adult cat heart should weigh 17 g. We had a memorable case in which the heart weighed 45 g, although weights between 20 and 30 g are more typical. The left ventricular walls thicken so much that there is almost no central space left in that chamber, so the volume of blood that gets pumped out with each contraction gets smaller and smaller. And the heart often becomes stiff and fibrous. 

 This disease can cause acute death in cats as young as 2 years, which is always a sad finding. There's no good way to prevent it other than not breeding animals that have it. The tests required to diagnose it are quite expensive, and out of reach of the regular pet cat owner.

I've only had one case where the owners thought the dog had been poisoned, and sure enough, it actually had been. But in that case, the dog was found next to a dead (also poisoned) cat, vomitus containing poisoned hot dog pieces near his head, and similar hot dog pieces in his stomach. I ended up testifying in court about this case. It's never a fun day when you get a subpoena at work, but eventually, the neighbor was successfully charged and convicted. 

There's really no uplifting message here. People do their best but their pets sometimes still die. Our job is to navigate the path between finding out why and informing the owners in a way that is sensitive to their loss but also helps them make different choices in the future. 

How'd I Do?

 The horse gut is an amazing and complex thing. They have a single stomach like us, although it's only partially glandular like ours. The real magic happens in their cecum and very long colons. They have a right ventral colon, a left dorsal colon, and a right dorsal colon, plus a regular colon called the descending colon. Their cecum is an enormous blind sac located between the small intestines and all of these colons. 

Depending on the particular pathologies involved, it can be kind of difficult to identify the various parts of the horse's gut during a necropsy. The best way is to remove the entire digestive tract from stomach down, cut all of the ligaments (thin sheets of tissue that hold it in a particular shape), and stretch it out. 

Yesterday I had a foal who died from not one but two intestinal ruptures. For accuracy in my report, I wanted to figure out exactly what parts were affected. Because everything in the foal's abdomen had been marinating in intestinal contents and bacteria for a couple of days, there was a lot of autolysis (post-mortem changes). And there was necrosis of various parts of his gut associated with ulcers and hemorrhage that preceded the two ruptures. Tissues were delicate and friable. Everything was coated in bits of partially digested feed and greenish, bloody fluid. 

We of course took pictures but those can be hard to interpret, and sometimes the techs don't get those loaded onto the server for a couple of days. After I had extricated his gut and stretched it out, I made a quick sketch, labeled some key bits, and marked the areas of the ruptures. Here's the result:

 

"Colon" is the descending colon, RDC is the right dorsal colon, PF is the pelvic flexure (a distinctive anatomical feature of the horse gut), "base cecum" is where the cecum opens into the right ventral colon, J is jejunum, D is duodenum, and "stom" is the stomach. That bit sticking off the stomach would be the esophagus. The heavy black bars are the two rupture sites.

Compare this to a diagram from one of my vet school textbooks:

 

I think I produced a real masterpiece!

Notice how I positioned the stomach to the right, descending colon to the left, the same way as in the picture. That's because we necropsy ruminants and horses from a left lateral position, meaning their left sides are down on the table. This creates the same right lateral view of the intestines as shown in the picture. I'm pretty sure I would struggle to identify things if I had to look at them from the left aspect. 

Consistency is important when doing necropsies. If we examine tissues in the same order every time, we are much less likely to miss problems.

Each One A Puzzle

Every necropsy case is a puzzle. To find the solutions, my colleague and I have considerable agency to select the tests that we want to apply. At one end of the spectrum is the shotgun approach: collect every type of sample (tissues, swabs, fluids) and run every test available. But where's the fun in that? Not only does this approach lack elegance and waste resources, it isn't intellectually pleasing. It's lazy diagnostics. It's more challenging by far to build a list of differentials based on signalment and history, modify that list based on gross findings from the necropsy, then thoughtfully select specific tests that will rule in or rule out your top differentials for the cause of death. 

Sometimes the necropsy itself is the only test we need. That is informally referred to as "grossing out" a case, meaning we are able to determine a definitive cause of death of an animal during the gross examination conducted during the necropsy, and the case is closed out with no further testing. Necropsies are meticulous and require a lot of careful examination, and the word "gross" in this context means we aren't using any special diagnostic tools beyond our eyes and fingers. For example, when we find heartworms in a dog who died suddenly or who had clinical signs like fainting, low energy, or coughing, and there are no other major findings such as pneumonia or masses in other organs, we gross that case out. 

While it can be satisfying to close a case based only on the necropsy, it is even more satisfying to identify a pathology during necropsy and verify it with just a handful of carefully chosen tests. Those cases give us a lot of validation. We've had several cases like this recently.

A beef cow-calf operator brought in a yearling cow. The cow was petite, quite pretty. She'd been sick for a couple of days and had not responded to his treatments. He'd lost several from his herd in the past few days, all with similar clinical signs. All of the sick or dead cows were yearlings or older--he hadn't lost any nursing calves. That was interesting. Based on my initial conversation with him, it sounded like a toxicity event and not infectious disease that was killing his cows, and he agreed. We went through the list of the usual suspects--paint cans, old batteries, sheds with old bags of fertilizer, rusting 50-gallon drums containing mystery liquids--cows are both curious and relatively indiscriminate eaters. Nothing really fit though. So into necropsy I went. 

Even if you think you know the answer, which I did not in this case, you still approach every necropsy systematically to make sure that you don't miss anything important. Heart, lungs, and spleen looked good. But the liver was moderately autolyzed. Autolysis refers to post-mortem changes that occur in tissues due to cell death and bacterial activity. The state of the liver didn't match the other tissues. I couldn't find anything wrong with the liver that would explain this, such as liver flukes or evidence of a bacterial infection in the liver. This was a symptom of something else, not the primary problem.

Next, I examined her gastrointestinal system. The rumen was filled with 20-30 L of a thin liquid slurry of finely shopped feed. Her abomasum, her glandular stomach, was red-black inside and contained a couple of liters of cloudy red-brown liquid. The rest of her intestinal tract was empty. All three of these observations were a surprise. Her rumen should have contained layers of material--a mat of feed at the bottom, a slurry on top, and a gas cap on top of that. Sure, this stratification gets a bit mixed up when animals are moved and transported after death, but the basic components can be identified at necropsy. I only saw slurry, and far too much of it. Her abomasum should have normally contained feed. It shouldn't be bloody. And she should have had digesta scattered all along her gut and feces in her colon. All of this added up to an animal that had stopped eating and had developed ileus, or a cessation of the normal peristalsis of her gut. She had continued to drink water, thus the rumen was distended with liquid. Cows can develop ileus as a result of torsion or displacement of the abomasum, heavy parasite load, blockage of the rumen by a foreign object (baling twine and plastic bags in cow rumens are common incidental findings, but they can sometimes cause problems), chronic diarrheal disease, or something called vagal indigestion related to dysfunction of the vagal nerve and rumen function. There was no evidence of any of this, so the ileus was a symptom, not the primary problem.

Next, I examined her kidneys. Kidneys are often the first tissues in a cow to autolyze, which refers to the post-mortem changes in tissues due to bacterial activity and cell death. This cow was very fresh so I didn't expect to see autolyzed kidneys. Normal cow kidneys are not quite as dark as our own but they fall well into the range of what we might call "kidney colored." Her kidneys were golden brown and covered with bloody pinpoints. The same pinpoints were visible inside in the renal cortices. These distinctive lesions are textbook examples of oak toxicity. Leptospirosis, an infection caused by bacterial spirochetes, was definitely a differential. But my other observations fit oak toxicity better. Oak toxicity is caused by tannins in leaves and acorns. It can cause hemorrhage in the glandular stomach, which was likely the precipitating cause of the ileus (the cow didn't feel good so she stopped eating), and liver necrosis, which set the liver up to autolyze faster than surrounding tissues. And it causes pinpoint hemorrhages in the kidneys.

I called the owner back and surprised him by asking about oak trees that might be in or around the pasture. Turns out that during stormy weather a couple of weeks prior, wind had knocked down several branches from an oak tree in the middle of the field. The producer had observed several of his cows eating leaves from the fallen branches. He didn't think much of it because he thought oak toxicity was only caused by buds or acorns, and we are past the time for the first and not yet into the season for the second. He gave them new forage and cleaned up the branches. I told him that young leaves and their stems are toxic too, and that unfortunately the damage had already been done. Nursing calves didn't eat any leaves so they weren't affected. And the leaf-eating had occurred long enough ago that no leaf remnants were in the rumen of this cow. I told him to expect more mortalities in the handful of cows that were still sick.

There is no bench test for oak toxicity. Diagnosis is made by gross findings and distinctive microscopic changes to the kidneys. I had to wait a couple of days for the tissues to fix in formalin, another day for trimming, and another day to cut and stain the slides. But eventually, I had the slides in my hand. Textbook case. 

My colleague recently had a similar puzzle that he quickly solved. A breeder had submitted two French bulldog puppies, only 7 days old. She had already lost most of the litter. When this kind of thing happens in pure-bred dogs or cats, breed-specific genetic or congenital abnormalities top the differential list. That list is of course rather long for French Bulldogs and other brachycephalic breeds, especially since breeders are selecting for ever more extreme deformation of the faces of these dogs. I recently did a necropsy of an adult female Bulldog whose nasal openings were positioned so far back on her head that they were over her molars, not in front of her incisors. Selecting for extreme body deformities often comes with unanticipated deformities in critical things like hearts, skeleton, and brains. Oops.

But back to the puppies. For high litter mortality, you also have to consider canine parvovirus, which can be transmitted through the placenta. Ideally, the dam should have been vaccinated for parvovirus and she would have passed antibodies to her puppies when they nursed the first time or two, but the number of people who refuse to give vaccines to their dogs is growing. She could have been infected during pregnancy, and infected her puppies in utero. Canine herpesvirus is a bit more insidious. There is no vaccine. It can also be passed to the puppies in utero and often results in abortion in those cases, but the more common route is post-natal infection. It can result in high mortality in young puppies. Dogs older than about 8-12 weeks usually only get mild disease from herpesvirus, but they shed virus in all of their body secretions. Keeping it out of a kennel is a matter of biosecurity--wash hands and shoes, quarantine new additions, segregate animals of different ages, clean surfaces. 

My colleague approached the necropsy with his usual care. Nothing significant turned up until he looked at the kidneys. The kidneys of both puppies had many small hemorrhages inside and out. Textbook example of canine herpesvirus infection. He was so excited by this finding that he called me down to necropsy to take a look. Definitive diagnosis of canine herpesvirus is available with a PCR test. It of course came back positive, and he closed the case with no further testing. We made slides of the kidneys for our own learning because they were such good examples of this disease. You could see inclusions comprised of many viral particles (far too small to see individually) in the nuclei of the cells lining the renal tubules.

Two interesting puzzles: cases of multifocal renal hemorrhage and nephritis identified at necropsy of two different species. When we combined our gross observations with signalment and history, we were able to land on diagnoses quickly. Two puzzles that we got a lot of satisfaction from solving!

Small Acts of Kindness

I got these flowers today at the lab. They were sent by a veterinarian out in the wilds of southwestern Arkansas whom I've never even met. She called the lab yesterday, almost in tears, worried that she had screwed up a case, second-guessing all of her decisions, and needing to talk to someone about necropsies. Receiving sent her to me.

I spent over 30 minutes on the phone with her. The clients were being difficult, accusing her of killing their dog. She did an in-clinic necropsy and found many dozens of heartworms in its heart and vessels of its lungs. She was worried that she did something wrong. I assured her that she did everything right. I told her that the outcome would have been the same if she had sent the dog to the lab for necropsy. I thanked her for trying to find the best answers for her patient and the owners. 

Today she sent me flowers and a short note.

It is these small acts of kindness that we give each other that get us through.

We Are All Partners In This

Despite being barely two years out of vet school, I apparently project an air of confidence and competence to my veterinary peers. I've been thinking about this ever since my conversation with Dr. M that I mentioned in my last post. It's absolutely true that I don't know everything about vet med. I've got a lot to learn. But I bring so much more to the table--years of experience with scientific writing, public speaking, and critical thinking. And my own personality contributes a lot as well--I have always had a habit of calling things like I see them.  

On Tuesday, one of the regional USDA-APHIS vets emailed me to see if I could help them out. They felt like they were not fully prepared to conduct poultry necropsies if there was an FAD event in Arkansas. 

FAD means Foreign Animal Disease. There is a very long list of FADs that are of concern to the USDA, but in the poultry world, we are mainly talking about HPAI (highly pathogenic avian influenza) and vNDV (virulent Newcastle Disease Virus). If either of those were to appear in Arkansas, it would be devastating to the poultry industry here. Containment and sampling are critical. It is far beyond the scope of my blog to talk about the training that USDA-APHIS and USDA-accredited veterinarians receive (I have Category II accreditation), but if there was a disease outbreak, USDA and other federal agencies would run the show. Their people would go into the poultry houses and conduct necropsies and collect samples which would then be sent off to the various national labs. 

So back to my vet colleagues, who reached out to me for help. The vet that emailed me asked if I could run a workshop for them, a wet lab with hands-on instruction in poultry necropsies. Sure, I said, that sounds like fun. I mean, what else would I say? I love teaching. I love working with poultry. I put in a lot of effort during vet school to gain knowledge and experience in poultry vet med. Only 2 or 3 vet schools teach about poultry, so most vets never even touch a chicken during school or during practice. 

The only problem was that I can't predict when poultry cases come into the lab. We needed birds for this workshop. Then I had an idea. We do a lot of serology testing for the big poultry companies in Arkansas. Most of them regularly send us necropsy cases too. But one of the bigger companies hasn't used us much for necropsies in the past. However, since I joined the lab, their regional rep has been sending me tough cases that really allow me to stretch my diagnostic skills. He never fills out the history on the submission form, instead preferring to call me up and chat for half an hour about what is going on at that particular farm. 

My idea? I emailed him, told him that USDA wanted a workshop, that I was happy to run it at the lab, and would he be willing to donate birds? He didn't hesitate. He immediately grasped the larger picture--if USDA vets are better prepared for a FAD event, his company would directly benefit. We are all partners in this. 

A flurry of emails ensued, and the workshop was arranged for Friday. I downloaded the training manuals that the USDA vets use so that I could see what they were being instructed to do, and I wrote a brief outline for the workshop to ensure that they would learn how to collect the samples they needed to collect.

I told them, if there is a FAD event, you will be working in some seriously adverse conditions--taped into PPE head to toe, kneeling in hot, dusty poultry houses surrounded by dead and dying birds. I told them I was going to show them tricks and efficiencies to quickly collect the samples they needed, and to make sure they were diagnostic. And then I proceeded to do just that. 

 

Me on the left. These are broiler breeder hens. They lay eggs that are hatched to become broilers, which become chicken nuggets.

It was a great workshop. I can assure you those vets know a hell of a lot more about poultry anatomy now than they did when they woke up on Friday morning. They know how to hold and use scalpel blades without cutting themselves. They know how to get blood samples my way (my way is heresy, to be sure, but it works, it's amazingly fast, and the samples are just as diagnostic as those obtained the traditional way). They know how to perform tracheal swabs on live and dead birds. All of this delivered in less than 3 hours. It was so successful that I will run another one in May for the four vets that couldn't make this one.

To be sure, this was quite a professional accomplishment for me. My USDA colleagues valued my expertise enough to ask me to share it with them. I am empowered in my own job such that I can use state resources for this kind of activity without seeking permission (although I let the upper levels know what I was up to). I really value my personal relationships with lab stakeholders, and the effort I put into them paid off nicely.

We are indeed all partners in this.

Absurdly Alice

Here are some (slightly edited) conversations I've had at work in the past few days.

Backstory: One of my favorite vets called me up to get my opinion on a recent case he submitted last week. He knows now that our reports are strictly factual--we observed this, we measured that. But on the phone or in person, he is also aware that I will share any and all theories that my colleagues and I might have about the cause of death of the animals in his cases. That's what he called me to get--the crazy theories and speculations. 

Many of his clients are cow-calf operators in the southwest part of the state. It's a long haul for those producers to bring a cow or calf into the lab so he often does field necropsies and sends us what we call "a box of parts." After a fair bit of coaching from me, he sets the bar pretty high with his submissions, generally collecting diagnostic samples for most of his cases. He sends fresh tissues and feces and rumen contents knotted up in disposable obstetric sleeves, and cuts off pieces of affected tissues and drops them into a container of formalin. Pretty much every time he sends us a BOP, the container he uses is a large bottle that used to contain 500 tablets of cephalexin, an antibiotic that can be used in food animals. Since he submits cases almost weekly, well, that's a lot of cephalexin. 

Me: So, another fabulous field submission from Dr. M. I have to know, what's up with the cephalexin bottles? 

Dr. M: Well, it's a big bottle.

Me: I know, but why do you have so many empty ones? What do you do, give them out like M&Ms?

Dr. M: Yes, exactly, everyone that comes into the clinic gets some!

Me: Like Oprah! Cephalexin for you! And cephalexin for you too! Cephalexin for everybody!

This same vet submitted the headless, legless torso that I mentioned in my previous post. That came up in today's phone call too.

Me: Um, so why did you cut the head off? Why?

Dr. M: The calf wouldn't fit in the container and...

Me (interrupting): ...hahaha!

Dr. M: ...it wouldn't fit and the courier was getting upset, needed to leave...

Me: ...so you cut off the head but you so thoughtfully left the tail! You left us a handle!

(Me and Dr. M cackling like chickens)

Backstory: I'm on a committee at the lab that handles quality management issues. We are only a committee of three. We had an event that needed to be assigned to one of us. 

Committee leader: Which one of you will take this?

MBF and I look at each other. 

Me: Rock paper scissors?

MBF: Sure. But I'm terrible at this. My wife always wins.

Me: I'm glad to hear you and your wife have a healthy process for conflict resolution.

MBF: So, on 1-2-3-go?

Me: Yes.

MBF: 1-2-3...

And on "go", I throw out paper. 

MBF: No! After I say go!

Me: Oh. Okay.

MBF: 1-2-3-go...

And I throw rock as he throws scissors.

Me: I win!

Always setting a high bar for professionalism! 

Backstory: I was approached by our local colleagues in USDA APHIS about leading a wet lab for them in poultry necropsy and diagnostics. They wanted to be better prepared in case of a disease outbreak. Sure, I said, I can do that. But we need some birds, and waiting for a regular submission is not really a workable solution. I have developed a good relationship with a high level guy in one of the broiler breeder companies in Arkansas. He submits crazy cases that keep me on my toes. I decided to ask him to donate birds for the wet lab, either spent hens scheduled for slaughter or birds from a problem farm. He'd get a full report and diagnostics at no cost.

Me: I have an unusual request. blah blah wet lab blah blah USDA blah blah warm fuzzies all around. I only need about 10 live birds.

SL: Sure! But how will we get them to the lab? 

Me: I'll bet we can get one of those USDA folks to pick them up from your folks. And I almost forgot, they wanted some deceased birds too. Can we get a few of those? 

SL: How many dead ones do you want?

Me, reading the email asking me how many dead ones I wanted: This is a strange email conversation. I want five dead ones.

SL: It's always a strange email conversation in this business. Done!

My job challenges me in many ways. I would never have expected days that leave me feeling like Alice in Wonderland.

Surprise!

I've discussed before about how we approach each necropsy case with a list of differentials for the cause of death. Before you even see the animal's remains, you can posit a decent list just on signalment (age, sex, breed) and clinical history, if one is provided. The time of year and the weather can suggest a few differentials too. And I'd say that, for most cases, our differential lists don't change much, other than to usually get a lot shorter. 

Then there are the surprises. 

Oh, a calf was sent in for necropsy? It's wrapped up and packed in a styrofoam box, and Receiving won't open it up, of course. They leave that for us in Necropsy. The box seems small but maybe it was a neonate? Surprise! We opened the box to find a single, long-ago melted ice pack and a trash bag. Inside the trash bag was a torso. A calf torso, minus the head and four legs, removed to reduce weight and thus reduce the shipping cost. They thoughtfully left the tail, however. But because the torso was shipped without enough ice, and because they had removed the head and didn't take quite enough care when removing the legs, fluids produced by rotting tissues had mixed during shipping with the diarrhea that had oozed out of the anus and blood that seeped from everywhere else to create a foul ichor, a marinade that penetrated all crevices of the torso. Except for a PCR test for mycoplasma pneumonia, the tissues were not usable for anything else. 

We see many dogs who died from heartworm infections. These cases make me angry because it was a completely preventable death. And we can often predict which cases these will be: owner-submitted, large breed, intact male dogs are vastly over-represented. Even if you are expecting to find heartworms in the heart, there are always the surprises, in which you find literally hundreds of worms packed into the heart, worms in the pulmonary arteries and even in the smaller vessels deep in the lungs. By far the worst are the dogs who died of caval syndrome in which the worms migrated upstream, back out of the heart into the caudal vena cava. Surprise! It's a plug of worms thicker than a broom handle blocking the largest vein in the dog's body. 

We handle about a dozen legal cases per year. They are always difficult since most involve animal abuse of one form or another. But we have a process that we follow, and focusing on the process helps us get through them. But there are the cases that take unexpected turns and become legal cases based on our findings at necropsy. Last year, I had a medium sized, mixed breed dog submitted for necropsy. I started by conducting a thorough physical examination. Surprise! That looks like a projectile entry wound! I ripped off my gloves and called the vet listed on the submission form and asked her, why didn't you mention that the dog had been shot? Turns out she never even saw the dog, just directed the owners to take it to the lab when it died suddenly. I took the dog over to the Crime Lab for radiographs, identified the location of the projectile, and retrieved it later during necropsy--a 9 mm slug.

And of course there are always rare congenital anomaly cases that you really just can't predict at all. The animals may have died as fetuses, or lived for a few days or even years. But they did die eventually and ended up on our necropsy table. Surprise! This Hereford calf fetus is missing most of its brain. Skull is normal, brain, not so much. Surprise! This 10-day old Angus calf doesn't have a rectum or anus! Its colon ended about 6 cm too early. Surprise! This obese 6 year old cat that died after a vet visit had two tracheas! Two tracheas all the way down, one going to the left lung lobes and the other to the right lung lobes. It also had feline cardiomyopathy, which was not a surprise. Surprise! This pure bred cat that has been genetically selected to have defects in how it makes collagen so that it will have folded back ears has malformed collagen everywhere else too, including the heart, blood vessels, skin, liver, kidneys, ligaments holding vessels in place. Nothing was normal in that cat. It was like working with a Picasso vision of a cat necropsy. A 10 month old German Shepherd pup, purchased at great expense by a breeder hoping to use him for stud work, was a "poor doer" from the start with vomiting, diarrhea, and poor growth. Surprise! The poor pup had two kidneys but they were very small. Under the microscope we could see that the usual renal structures had not formed, and the kidneys were mostly not functional. He had full thickness, bleeding ulcers in his stomach from the uremia, because the non-functional kidneys were unable to remove urea from his blood.

We approach every necropsy case with a plan, a list of differentials and tests we might want to run. We also need the flexibility and knowledge to modify that plan on the fly based on what we find, whether we expect it or not.

At Last

Yesterday, we received notice that agricultural workers and veterinarians (and their staff) could at last sign up to get the COVID19 vaccine in Arkansas. As a veterinarian who works for the Arkansas Department of Agriculture, I was in line at last.

After some quick computer work, I was set up. I somewhat randomly chose a local pharmacy about 5 or 6 minutes from the lab. Although it may have been a bit overkill, the pharmacy sent me multiple email and text confirmations and reminders. I'm okay with that. I looked at each one of them with a smile.

I got my shot today at 9:50am. The pharmacy is in a somewhat upscale strip mall on the western side of Little Rock. They set up the vaccine clinic in an empty storefront in the same strip mall, and it was a straightforward experience. The storefront didn't even have finished walls, it was just a big, empty, concrete-floored space. Plenty of room for social distancing. 

Which vaccine did I get? Does it really matter? For the record, I got the Pfizer-BioNTech vaccine. And I have a confirmed appointment for my second shot in three weeks. My colleague Xie got his shot today too, and he got the Moderna vaccine. Science for the win!

Reactions? My arm hurts. Eh. Tetanus boosters are far worse. After one of those fuckers, I can't lift my elbow higher than my waist for a couple of days. But here's the thing. Rabies and tetanus--they will kill you. As a veterinarian, I'm happy to line up for the vaccines and titer checks (my rabies titer is checked annually, at no cost to me, at the lab) and boosters. COVID19 is now just another check box on the list.

I'm quite over-committed at work right now, yet I feel like a huge weight has been lifted from me.

Disposition of Remains

 The lab director and I often talk about lab activities that would make good PR photos and short articles in the Department of Agriculture and State Veterinarian newsletters. The Pathology section of the lab almost never makes the cut (heh, unintentional pun there). There is no way to make a necropsy visually palatable for public consumption. There is no way to make slicing up hunks of formalin-fixed cow liver into thin sections to make microscope slides fun. And there is a very important component of our section that we can't ever discuss--the incinerator.

I didn't anticipate becoming an expert on incineration as a part of this job, but so it has come to pass. While the monthly totals vary wildly, our small lab incinerates about 25 tons of animal remains a year. Somebody has to be in charge of that, and that somebody is me.

The lab building was constructed around 1973 or 1974, and there is an incinerator built into the necropsy floor. I've been told tales of former pathologists who would perform necropsies on cows and other large animals hauled up on the hoist directly over the old incinerator. Fortunately, that generation isn't in charge anymore, because while it may be efficient, that sort of thing is fucking appallingly sloppy. By the time I arrived at the lab, the old incinerator was being decommissioned and the new one starting up.

The new incinerator is a stand-alone unit attached to a very large propane tank, located in a fenced lot across the street from the lab. It took almost six months of nearly weekly crises to get that damned thing up and running. I made significant contributions to that success, and consider it a professional achievement that I mention on my resume. 

If you were paying attention, you may have noticed that I mentioned the incinerator is across the street from the lab. So how exactly do we get those 25 tons of animal remains over there? It involves very large woven plastic sacks designed to hold many hundreds of pounds, large containers, a truck, and a forklift. It required a lot of planning and training to work out the details. We had to consider optics (can't be hauling bloody bits and leaking bags across the street) and safety while still designing a process that would work.

I know how many pounds we incinerate per time unit, how many gallons of propane we use per hour, the cost, in propane, per pound of material incinerated. Based on observations of burn efficiency, I developed a simple formula to calculate the number of hours we need to run the incinerator per 100 lbs of load. I analyze temperature logs of every incineration event. I have the cell phone number of the propane delivery driver. I arranged forklift operation and safety certification for 10 lab personnel, including myself. I have been on top of the incinerator messing around with one of the thermocouples a dozen different times. I wrote instructions on how to trouble-shoot the controller on wet days. I have chipped ice out of the tracks that the lid travels on to get the incinerator open. I have spent hours out there in all weather with various repair and maintenance guys learning how the burners work. I made worksheets for the technicians to collect the information that I need to fill out official logs related to our operating permit, and when those worksheets proved to be a bit too complicated, revised them and revised them again until everyone can use them correctly.

I expend mental and physical energy on the incinerator nearly every week. The skills I've gained seem fairly esoteric, but they are actually part of the general problem-solving aspects of my job. Incineration of animal remains is an important contribution made by the lab to general public health, but we'll never be able to "showcase" it.

Head Count

 I performed 259 necropsies in 2020. This represents 63% of all necropsies that we did at the lab last year. Officially, I only do necropsies on Mondays and Tuesdays, so you'd think I'd end up with two-fifths of all the cases, certainly not more than half. But Mondays can be quite busy, and Fridays can be quite slow. And because I'm the supervisor of the Pathology section, I will sometimes take cases that come in on other days that are of interest to me.

One third of those necropsies were avians. And because this is Arkansas, by avians I mean chickens. Okay, we had a peacock, goose, and macaw, and a couple of quail cases. But by far, most of our avian cases are chickens. About half were backyard birds (single bird necropsies) and the other half were commercial chickens--broiler breeders who lay eggs from which broilers are hatched, broilers, and table egg laying hens. Commercial poultry cases generally include 10 or more birds per case. I did 57% of all the poultry necropsies. I see a lot of chicken innards.

Previous occupants of my position had necropsy case turn-around times of 20, 60, even 100 days or more. That's astonishing. There is no justifiable reason for this, even if you wanted to run every test available (and some of them did!). When I started this job, my case turn-around time was around 20 days. Within 3 months, I had dropped that to 10 days, and I maintained that throughout 2020. My colleague and I work very closely together, and since we have similar approaches to selecting diagnostic tests for each case, his turn-around time for 2020 was also 10 days. 

This is a useful metric, but it's more than just a number. Short case turn-around times mean vets and food animal producers get information about herd and flock health issues when it is still useful to them, allowing them to implement effective treatment plans. I don't treat, and I don't prescribe. My job is to diagnose. If I do that job well, it has a direct impact on animal health, food safety, and public health. No pressure or anything, though.

Let's take a look at September. There were 22 working days that month. I was on the necropsy floor for 9 days and ended up taking 16 necropsies. Here's a list of my cases from that month:

• pure-bred Highlander cat with severe cardiomyopathy which we ended up deciding was congenital
  
• puppy with parvovirus
• backyard guinea hen with no determined cause of death
• dog with heartworm
• kitten with the blood parasite Cytauxzooon, spread by ticks
• puppy that died of bacterial sepsis
• another puppy with parvovirus
• alpaca with right-sided heart disease and intestinal parasites too numerous to count
• another kitten with Cytauxzoon
• cow with an intussusception in its small intestine; this is when part of the intestine gets entrapped inside an adjacent part, like one of those finger trap toys; very bad
• calf with aspiration pneumonia; it actually died of bacterial sepsis, not the pneumonia
  
• calf with necrofibrinous pleuropneumonia; very bad
• goat that had so many blood-sucking worms in its stomach that it died of anemia and malnutrition
• kitten with bacterial pneumonia
• another kitten with Cytauxzoon
• backyard chicken with a bacterial infection in its mouth and crop, bacterial pneumonia, and coccidia in its gut
  

Some types of cases are seasonal. Ticks are more active in the summer, so we see an increase in cats that died from the Cytauxzoon felis blood parasite. Small ruminants with anemia died from infestations of the strongyle Haemonchus contortus until proven otherwise. Calves pretty much always have pneumonia until proven otherwise.

Knowing about these kinds of patterns helps us develop a list of differentials for each case. I make a short list for each case before I even change into scrubs, based on chatting with the submitting vet, the owner, or reading the history they provided on the submission form. Sometimes the signalment alone is enough to suggest some differentials (signalment to a vet usually means species, breed, age, sex, and breeding status). I modify my differential list based on gross findings during necropsy, and I select diagnostic tests that will help me rule in or rule out one or more things on the list. 

Sometimes cases can be closed using necropsy findings only. The cow with the intussusception is an example. I ran a fecal egg count as a courtesy to the producer, but her cause of death didn't represent a herd health problem. Just a case of bad luck for that cow. 

Necropsy findings in some cases can reduce the differential list down to just a couple of things. The calves with pneumonia are examples. It was obvious at necropsy that they had pneumonia, but was it viral? Bacterial? Multi-factorial? I could just order all the tests but that is lazy pathology, bad science, and a waste of money and resources. It is far more challenging to select the "right" tests for each case. 

And sometimes we just can't determine why an animal died. Or rather, we can't reduce the "why" down to one thing we can verify with testing or observation. 

In a way, I'm still in vet school. I learned something from every one of those 259 cases--technique, differentials, diagnostic tests, how disease develops and presents itself.

Whatever Dr. A. Thinks Necessary

There's a handful of vets who call me to ask for advice. Not for every case they handle, of course. They are excellent clinicians who see hundreds of cases for every one they might call me about. But they are all convinced that I can help them solve their particularly tough cases. I get calls from these vets once or twice a month, often when they are standing in a field looking at a sick cow or in their clinic with the sick pup in front of them. They've all learned that they will get far better diagnostics if they call me before they collect any samples.

I'll admit that I have found answers in some cases only by sheer luck. But the truth is, I am a careful observer, I think quickly on my feet, I am happy to toss crazy ideas back and forth, and I'm not afraid to be wrong. I also have time that these clinicians simply don't have to dive into all kinds of resources--the internet, my vet school lecture notes, textbooks, consultations with vet school classmates and teachers (I have my own advice network!), and so on. This combination means that, in fact, I am pretty good at my job.

Although it amazes me every time they ring me up to ask me what I think, I'm rather proud that I can apply my knowledge to help my colleagues out.

So I couldn't have been more pleased when one of my favorite vets, who regularly calls me up to chat about difficult cases, sent in this submission form along with the samples that I had advised her to collect, writing on the Tests Requested line, "Whatever Dr. A. thinks necessary."

That's an incredible gift of confidence and trust she gave me. After all, it's her client--she's the one who is treating the animal. But she willingly made me a partner, because in the end, she and I do in fact share the same goal--improve animal health.

Let's Take A Look At Some Dog Food Labels

 I get asked quite often what I feed my dogs. I am quite willing to share that information. Purina, Hills, and Royal Canin are all good choices. I feed Archie a regular Purina diet, the cat gets a Hills prescription diet to prevent urinary blockages, and Azza thrives on Royal Canin's Ultamino hydrolyzed protein diet. The prescription diets made by these three companies are incredibly useful for a wide array of diseases. Nothing magic here, we know that diet can reduce and delay clinical signs of many types of disease for both people and animals. A managed diet can improve performance. It can help a beef cow put on more weight faster, and can help a "no antibiotics ever" broiler chicken have a healthier gut to reduce bacterial infections. 

But the important point is that all three of these companies conduct feeding trials using real dogs to determine the nutritional profiles of their foods. Other companies analyze samples of their food in a lab only, for example burning it in a crucible to determine protein content. These kinds of assays are certainly useful, but they provide no information on bioavailability of important nutrients. Only feeding a living animal the actual food can tell you if that protein can be digested and used by the animal. If a dog food label says "food is formulated to meet the nutritional levels established by AAFCO," that food has only ever seen the inside of beakers and test tubes, not the inside of a dog. Grain-free? "Human-grade" ingredients? "Natural"? All marketing. All bullshit. All to make you, the human with the credit card, feel good. 

So this windy opening sets the stage for Archie's current situation. He got a stick jammed in the roof of his mouth a month ago or so, and some pieces of it broke off and were left behind in the tissues around his left upper molars. His bad breath prompted me to take a look in there...where I found this nasty hole in the roof of his mouth surrounded by friable, brown (necrotic) tissue. It bled when I touched it. I managed to get a large piece of stick out of the hole but even after starting some antibiotics, things weren't improving as much as I would have liked.

Of course, my imagination immediately went to the worst case scenario--abscess, lysis of the bony palate, formation of a fistula (an inappropriate hole between two spaces), damage to the roots of those huge molars. All Very Bad Things. I had to get a referral to another vet to get some dental radiographs made since my vet doesn't have dental rad equipment (it's specialized). That vet flushed a couple more small pieces of stick out, and helped calm my worst fears. She added a second antibiotic to go after the anaerobic bacteria, and recommended that I feed Archie a canned diet for two weeks to give the roof of his mouth a rest. 

Archie had not shown any evidence of pain or reluctance to eat or play, but he's a pretty stoic dog in general. Two weeks of canned food seemed reasonable. Except that I haven't calibrated any canned diets. I have no idea how much canned food to feed him. 

See, I feed Archie a calculated number of calories per day, including treats. He currently eats 1 cup of Purina Pro Plan Performance 30/20 Chicken and Rice kibble per day, divided into two meals, plus two tablespoons of plain yogurt, between 20 and 40 g of frozen green beans, and 10-20 kcals of treats. I adjust this basic plan for training and trialing days when he gets lots more treats. The kibble has 484 kcal/cup, so on most days Archie consumes around 510 kcal.

Let's examine three canned food options. Rachel Ray's Nutrish dog food comes in small plastic tubs. It looks and smells like human stew. The lamb and rice stew label says to feed an adult dog 1.5 tubs per 10 pounds per day. Archie weighs about 24 pounds so according to the label, I would need to feed him THREE tubs per day. Each tub is calculated to contain 244 kcal. Let's do the math, shall we? If I gave Archie THREE tubs of this stuff a day (not sure I could get this volume of food into him, but he certainly would give it a go), he would consume 732 kcal each day. If I give him the chicken and rice stew at the recommended volume, at 290 kcal/tub, he'd be getting 870 kcal per day. That is astonishing!

I also bought some Canidae Small Breed canned food. The chicken, salmon, and pumpkin recipe, which looks and smells as gross as that sounds, contains 123 kcal/can. The label recommends 2 cans per 6 lb of weight, so if I follow those recommendations, Archie is supposed to eat EIGHT cans of this per day. EIGHT! That's 984 kcal per day. OMG, that's even worse than the Nutrish stew. That's almost TWICE the numbers of calories that Archie needs each day.

ProPlan Focus canned food is my third example. If fed as recommended, Archie would need to eat 1.5 13-ounce cans per day of the (large breed) chicken and rice formula (their "small breed" options are grain-free and I don't feed grain-free). That comes out to about 475 kcal per day, which is in line with what he actually needs. So not only is the Purina food tested on real animals, the feeding guidelines are reasonable, not grossly over the top.

Here's the bottom line. Read labels. Don't be fooled by marketing. Measure your pet's food and calculate kcal per serving (can, cup, etc.). Are they healthy now? Figure out how many calories they eat per day--including all treats. Kibble is always going to be more nutritionally dense than canned food, which is mostly water. The volume of canned food will always be more than the equivalent kilocalories of dry food. And consider feeding Purina, Hills, or Royal Canin.

The Messy Matrix of Post-Mortem Diagnostics

 I was texting with a vet school classmate last night, and mentioned that we take radiographs of some of our necropsy cases. You take post-mortem rads? She was clearly surprised. After thinking it over, I realized that it does sound odd to a GP vet that we would do that.

There are three types of necropsy cases for which radiographs can be quite helpful. The first type is gunshot suspects--we want to see if there are any metal fragments in the body and where they might be. The second type is abuse suspects--we want to look for, and document, any bone fractures. Animal rescue groups and municipal shelters and animal control usually submit these two kinds of cases, but I've had vets submit gunshot cases directly. In one memorable case, I discovered what looked like projectile entry wounds on a dog when I was examining it before starting the necropsy. But the submission form didn't mention a thing about gunshots! So I called the vet, and she admitted that she had not seen the animal herself. The neighbors had taken the dog to the vet, but it unfortunately died on the way, and the vet clinic passed the dog directly on to the lab without a thorough examination. Using the radiographs that I made, I was able to find a lead pellet lodged in the descending aorta that was the cause of the animal's death. The third type of case is a more generic legal case in which radiographs are another diagnostic tool. Racehorses sometimes fall into this category. They are usually insured to the gills, and we are asked by owners or the racetrack vet to perform a complete necropsy, even though, for example, the fractured cannon bone in a front leg is the obvious problem.

Our veterinary diagnostic lab does not have any radiographic equipment. So we rely on the generosity of the State Crime Lab which is literally next door to us. We all get gold stars for the inter-agency cooperation, but I try not to abuse the privilege. They are a busy lab. The State Crime Lab handles cases of humans who died under suspicious circumstances. Which means they have dead people there. Lots of dead people.

When I need rads for a necropsy case, I text one of the techs at the Crime Lab and set up an appointment. For small animals, we get rads before starting the necropsy. One of my techs and I will load our case, double bagged, into the back of a vet lab truck and drive next door. We back up to the dock of the Crime Lab and unload our case onto one of their gurneys. A human-sized gurney. We then follow the Crime Lab techs into a large, walk-through cooler where they store their cases. Dead people, each one enclosed in a body bag. It's super fucking creepy, and after the shock of my first trip through, I keep my eyes forward and try not to glance around. I've seen that cooler room stacked with literally dozens of bodies. Super. Fucking. Creepy. One of my techs refuses to even go to the Crime Lab, and I don't blame him for a second. 

We keep our cases bagged at all times out of respect for our Crime Lab colleagues. They don't want to see what is in our bags any more than we want to see what is in theirs. 

Their xray room is just beyond the cooler room. They have a very nice rig, all digital, quite similar to what I've seen in vet clinics, except that the table is human-sized. I bring a flash drive with me.

Taking clear, diagnostic radiographs of humans and animals is both a science and an art. There is a balance between resolution, energy of the beamed particles, and radiation damage to the patient and techs. But since neither lab is dealing with living patients, there is a lot less fiddling and more just blasting some xrays and taking a look at the result on the monitor. We don't use radiographs to FIX a problem, we use them to FIND a problem.

Horses represent a unique situation since the Crime Lab doesn't have a hoist, or any facility that could deal with such a large animal. We usually remove the part of the horse that we are interested in, most often the leg. But I did have a case in which the racetrack vet insisted that we do a more thorough examination of the caudal (neck) vertebrae. Without going into a lot of detail, my techs and I removed the neck, all seven caudal vertebrae plus the first two thoracic vertebrae, and bagged that up to carry to the Crime Lab. The rads revealed an old, poorly healed fracture in C7 and a new fracture in C2 that happened when the horse fell over as it was dying. It died from something called EIPH, exercise-induced pulmonary hemorrhage, a progressive, chronic disease. In this case, all of the horse's lungs filled up with blood very rapidly. That's a lot of lung, and a lot of blood. But that C2 fracture wasn't compatible with life either. Once we got back to the necropsy floor, we used the radiographs to precisely section the neck and photograph the fractures directly. Very interesting case that was greatly enhanced by post-mortem rads.

Working up a necropsy case requires an array of qualitative and quantitative diagnostic tools--gross examination (sight, touch, smell), bacterial culture, PCR tests, radiographs, even blood tests. The art comes in navigating the messy matrix of making a good differential list, obtaining the right samples, and selecting the right diagnostics for each case. Sure, anybody can run all the tests on every case, but what's the purpose of that? It is far more challenging, and satisfying, to find the most elegant path through the matrix.

"Well, Didja Skin'Em?"

 Some of the lab's clients are rather ... colorful. My favorites are the guys that run small beef cow/calf operations. I learned years ago how to schmooze with just about anybody, and some of these crusty old guys can get downright chatty with the right schmoozing. I never fail to learn something new and useful. Maybe I learn a new word, or get more detail about a management procedure. It's always a lot of fun. In fact, I see the time I spend talking to them on the phone or in person as part of my job, not an interruption.

There are two important reasons for this. Firstly, I can always get a more detailed history from them directly than they will ever write down on the submission form. I get them to tell me all kinds fascinating details about how they are managing, or in some cases, mismanaging their herd. And secondly, I'm building their trust in the lab. Building their trust in me and my team's ability to help them solve their problem. 

We recently had a guy bring in a couple of young pigs, about 5 or 6 months old. Yeah, I know, pigs aren't beef calves. But this guy was cut from the same cloth. It wasn't my day in necropsy but I always get called when producers show up because everyone in the lab knows that I like to chat with them. I was standing on the dock, looking down into the bed of his truck at two dead pigs. Body condition looked good. They were clean, well kept. But certainly dead. And he was telling me and my colleague that the entire pen of nine pigs was sick. I let him talk on until he mentioned staggering. Ah ha! I asked him, were any of them dog sitting (that means sitting back on their haunches like a dog) or head pressing (that means pressing their head into a corner)? Yes, he said, all of them. Head tremors or seizures? I asked. Yes, that too. Turns out he had some nice videos of these exact behaviors, which he showed me on his phone. How about the water supply? Hoses and spigots still working? Tanks full? Oh, well, yeah, it seems that he did have a bit of trouble with the water supply in that pen when we had a freezing spell a few days earlier. Only that pen affected? Yes, only that one. 

They literally teach you about this in vet school: water deprivation leading to sodium toxicity and death in pigs. The videos were magnificent--I had him send them to my work cell right away. The water deprivation leads to an electrolyte imbalance that affects the brain. The neurological signs I asked him about are considered textbook signs of the sodium toxicity.

I was so excited to get this case for us to work up that I never let him feel bad about killing his pigs. I gave him some advice about how to save the remaining pigs, and thanked him for bringing the case. He called me two days later and reported that he had followed my advice and saved the remaining pigs in the pen. With some ingenious sample collection, my colleague and I were able to make a convincing argument that it was indeed sodium toxicity that was the problem. We considered other differentials such as pseudorabies (also called Aujesky's disease) and rabies that could cause the same neurological signs, but we tested for and eliminated the first and rejected the second as reasonable (unlikely to affect an entire pen at the same time). In the end, it was a solved case and a happy client!

At the other end of the spectrum is the old guy that called up a few weeks ago wanting to bring in a calf that had died overnight. He had lost five or six calves in a 24-hour period. My brain was spinning out a list of possible differentials when he said, I think they were shot. Oh, okay, I said, we can take a look and see if that is the case. Odd differential, as I was thinking about things like lightening strike or infectious agents that can kill several animals at the same time. But sure, getting shot is possible too. 

So I did the necropsy on this calf and didn't really find much of anything except that it had a lot of intestinal worms. Those absolutely can kill a calf if the parasite burden is high enough, but the calf was in good flesh and it wasn't a definitive finding. I found nothing else that was particularly helpful or diagnostic as to the cause of death. And as is my usual procedure, I called the producer to let him know this. He started yelling at me, saying, I brought that calf in so you could prove it was shot! I told him that there was no evidence that it had been shot. He replied, well, didja skin'em? I paused, trying not to laugh, and said, sir, I did a complete, thorough necropsy and there was no evidence of any projectile trauma in this calf (no, we don't skin animals for most necropsies). 

By this point, I have unfortunately seen quite a few animals with gunshot wounds and I am confident in my ability to identify that. Definitely no gunshot in this case. But this old crank managed to get the county sheriff's office involved and they contacted the lab director for more information last week. We sent them the final report and I thought that was the end of it. 

But no, no, my year will not end so quietly. This cranky old guy is bringing us another calf today. One of seven more that died last night. He still thinks they are being shot! I'll try again to find a cause of death. I hope this calf tells us a better story, although I suspect that he won't be satisfied with anything less than being presented with the bullet that killed the calf.