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.