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.