Thursday, May 14, 2009

Rotation #1: Necropsy

My first rotation as an official fourth year veterinary student is Necropsy- where "all our clients are sad and all our patients are dead," as summed up by one of the pathologists. Necropsy (Latin for "study of the dead") is the animal version of an autopsy (which literally translates to "study of self", which is a little weird... think of it as "study of the dead human"). The Minnesota Veterinary Diagnostic Lab offers necropsy services to clients of the Veterinary Teaching Hospital as well as to the general public. A necropsy is a thorough examination of a dead animal, including the external anatomy and internal organs. We examine everything grossly (using just our eyes and hands), and then take samples to make histologic slides to examine everything microscopically. Sometimes, depending on the case, we also submit samples to look for bacteria, viruses, fungi, and parasites.

So why exactly do we perform necropsies? There are a few reasons... Sometimes it's just because an animal's owner wants closure about why their animal died. They come home and find the pet dead, or the pet suddenly developed disease and had to be unexpected euthanized. For some people, knowing what happened is an important part of the grieving process.

Sometimes, a veterinarian requests a necropsy because his treatment didn't work, or he recently performed surgery on the animal. In that case, they are looking to see if they did something wrong (did my sutures come loose? did I misdiagnose the disease?). Knowing what went wrong can help improve how they handle cases in the future.

For people with breeding kennels or farmers with herds of animals, a necropsy can help determine if an infectious agent was the cause of death. Knowing that one animal was infected with a certain bacteria or virus can help them change their management protocols, provide treatments to their other animals to keep them from getting sick, or help guide treatment of other sick animals on the farm.

Last, there are the CSI-type cases. I think my neighbor poisoned my dog, or I think the horse you sold me had a congenital defect that caused its death, or my cat died as soon as I switched brands of food so I think the food is toxic. In these cases, we take lots of photos and make sure our notes are extra clear, because it's not unusual for them to end up in court.

Sometimes we can find a cause of death. Sometimes we find evidence of disease, but not necessarily anything that explains why the animal died. And sometimes we come to conclusions like we did today- "We can find no abnormalities in this animal, so clearly it is not dead." A lot of times, death comes without leaving any obvious evidence why- heart rhythm disturbances, electrical abnormalities in the brain, electrolyte problems in the blood... Unfortunately we all too often can't find any particular cause of death.

Aside from necropsies, pathologists also work with biopsy samples, like tumors that have been surgically removed, or diseased tissue, like inflammatory bowel. They are the ones who can tell you what type of tumor that animal had, which has serious implications for the animal's cancer treatment and prognosis.

Overall, I think necropsy has been useful. It's a great review of anatomy, if nothing else. Pathology is also the intersection of clinical science and basic sciences, so we've had to synthesize everything we've learned over the past two years. For example, when we read in the clinical history that a dog has been on prednisone (a steroid) for the past three years, we have to consider what changes that drug would have made in the dog's body (a big liver) and why (because prednisone makes the liver cells prone to storing glycogen). It can be really exciting to make a diagnosis of a strange disease, or to put together a puzzle of how the history, clinical signs, and necropsy findings fit together. But, I'll be glad to move out of the D-Lab and into the hospital, where our patients are alive!

Next rotation, starting Monday, is Emergency and Critical Care.

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