Necropsies Solve Mystery of Animal Deaths

May 7, 2017 / Diagnostic Laboratory / Disease / Public Health / Toxicology

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Necropsies, the equivalent of human autopsies

In every murder mystery, there is a scene where the coroner interprets markings, bruises, and injuries on the dead body to estimate a time and cause of death.

What most people don’t know is that a similar process occurs in veterinary medicine. Necropsies, the equivalent of human autopsies, are performed by both primary care veterinarians and specialized veterinary pathologists to determine an animal’s cause of death.

Dr. Ian Sprandel is a veterinarian pursuing specialization in pathology at the University of Illinois Veterinary Diagnostic Laboratory in Urbana. As a pathologist, he performs necropsies on animal patients from the college’s Veterinary Teaching Hospital as well as on animals sent from clinics, farms, and zoos in the surrounding area.

“The purpose of a necropsy is to determine a cause of death,” Dr. Sprandel explains. “Sometimes this is a direct cause of death and sometimes it’s a morbidity, which means it led the animal to be euthanized.”

A major challenge for pathologists is determining if changes in the body are caused by the inciting disease, or if they are simply incidental. Older animals will have age-related changes, such as cysts in the kidney or loss of muscle mass. Some changes are post-mortem changes, which means they occur naturally in a deceased animal.

Necropsies, Step by Step

Dr. Sprandel walks us through a typical necropsy.

“First, we perform an external exam, similar to a physical exam done by a veterinarian at a clinic,” he says. “Next, we systematically open up the body and examine all the organs while they are still in the body cavity. This helps us to see displaced or twisted organs. Then we collect tissue samples of every major organ.”

These tissue samples are saved in case further tests are needed or the pathologist decides to look at the tissue under a microscope. Tests are frequently done based on certain lesions or injuries the pathologist sees in the body.

“After collecting the samples, we remove each organ, examine the surface, and incise it at regular intervals to look for internal lesions. Once again, samples are collected and preserved, in case they are needed later,” says Dr. Sprandel.

These samples need to be stored in a special solution to prevent tissue deterioration, which could alter or thwart a diagnosis.

“We are able to successfully reach a diagnosis about 75 percent of the time, based on examining the body, looking at tissue through a microscope, and performing more specific tests based on our list of possible causes of death,” he reports. “However, that doesn’t mean the other 25 percent of cases are a complete failure.”

Even if a definitive cause of death isn’t reached, pathologists are able to rule out many possible causes. In addition, there are some diseases or fatalities that don’t cause any injuries to the body at all, like certain heart problems or types of epilepsy.

There are also lesions the doctors see on a regular basis. “In young animals, we see a lot of congenital abnormalities, which makes sense because if an animal is born with a defect, it won’t live very long. Old animals typically have neoplasia or age-related disorders, such as kidney failure in cats,” Dr. Sprandel says.

Benefits of Necropsies

Getting a necropsy done is not expensive, considering all the expert analysis and testing that is included. Prices usually range between $100 and $200. Pet owners can receive the remains back for burial or can have the body cremated after completion of the necropsy.

When asked if necropsies are beneficial, Dr. Sprandel responds with a definite yes.

“In farm (production) animals, finding a cause of death is important for herd health—you want to keep the rest of the animals on the farm healthy.”

For small animal owners, determining a cause of death can help with peace of mind. “Necropsy can provide answers and closure for the sudden death of a pet, or it can help assure owners that it was, in fact, time to euthanize a pet with failing health.”

Necropsies are also very important for monitoring diseases in a community. If pathologists observe an increase of a certain bacteria or virus in the caseload, they can alert primary care veterinarians and increase preventive treatment for these conditions in the population. In that way, necropsy of a pet that succumbed to an infectious disease can potentially save future pets from the same fate.

A Bit Morbid, But Rewarding, and Even Exciting

Dr. Sprandel admits that the job can be a bit morbid at times. “But it’s a very rewarding job and it contributes exponentially to the veterinary field and public health,” he says. “It can also be a very exciting and unpredictable job.”

During his time as a pathology resident, Dr. Sprandel has performed necropsies on a variety of species, including porcupines, catfish, hawks, snakes, lemurs, toads, and giraffes.

“One time we received a deceased tiger for necropsy. Turns out the tiger was, in fact, alive!”

If you have questions about necropsies, speak with your local veterinarian.

By Danielle Engel

Featured photo by L. Brian Stauffer