Post Mortem
In veterinary medicine the death of an animal
patient is often thought of as the end of a medical
case. However until a thorough post-mortem examination
is completed, the case is not closed. In
fact, the post-mortem examination (autopsy, necropsy)
is a very useful and necessary procedure
in the diagnostic process as it often defines the
cause of death.
Why do a post-mortem examination? A good
post-mortem has five benefits:
- Benefit to the owner/breeder:
- It may reveal deficiencies in husbandry
practices which can be modified or
corrected.
- It may reveal hereditary and/or congenital
(birth) defects which may influence
future breeding decisions.
- By pinpointing the underlying disease
process or processes, it allows the initiation
of treatment for similarly affected
individuals in a litter, household,
kennel, etc.
- The results of a post-mortem exam may
facilitate the development and implementation
of a preventive medicine/
husbandry program in the kennel to
avert future deaths if possible.
- Benefit to the attending veterinarian:
- A specific diagnosis, in many cases, leads
to a specific treatment.
- It can reveal individual kennel problems
and these can serve as a starting point
when future disease problems occur.
This avoids time consuming trial-anderror
treatments and allows specific
treatment and preventive measures to
be started earlier.
- It adds to the experience and learning of
the veterinarian.
- Benefit to the breed:
- It may reveal breed-specific problems.
- It will provide useful information to other
breeders and veterinarians.
- It allows accumulation of specific information
concerning the deaths of individuals
in that breed and allows for
statistical analysis and compliation of
data.
- Benefit to humans:
- Since animals live with and amongst humans
it may reveal zoonotic diseases
which may be transmitted to people.
This allows public health personnel to
be notified and act to prevent human
exposure and disease.
- We now know the close relationship genetically
between animals and humans.
More and more we are finding the same
hereditary and genetic diseases in animals
and people. The results of the post
-mortem examine may facilitate the development
of animal models for human
disease which can lead to new treatments
for both animals and people.
- The post-mortem examination often results in
“closure” for the owner, the veterinarian
and other people involved in the death of
an animal.
What constitutes a thorough post-mortem examination?
The post-mortem examination consists of the
following categories:
Gross pathology
Histopathology
Toxicology
Microbiology
Parasitology
Virology
Clinical pathology
Gross Pathology
This consists of the examination of every organ and
system, including the brain and spinal cord. By visual
examination, the veterinarian is looking for obvious
abnormalities in organ appearance and the
relationship between organs. The body is examined
for trauma due to vehicles, bite wounds, lacerations,
wounds caused by projectiles, burns,
chemicals, etc. Many bacterial and infections as
well as cancer will often produce characteristic
changes in organ appearance – these often determine
the direction of the rest of the post-mortem
exam. All too often the examination ends here. It
must be pointed out that the gross appearance of
an organ can be misleading and degenerative
changes following death can be misinterpreted
-- it isn’t always like a CSI episode.
That being said the gross exam is useful in
revealing the following broad categories of
problems such as neoplastic changes resulting
in tumors, potential bacterial and viral diseases,
foreign objects, trauma, congenital or
hereditary defects.
Histopathology
This microscopic examination of tissues is very
important and useful. Many disease problems
and processes are not visible to the naked eye
and not obvious on the gross exam. Tissue
samples are harvested from suspicious areas
as well as the liver, spleen, intestinal tract,
kidneys, pancreas, lymph nodes and lung.
Additional samples might include heart muscle,
skeletal muscle, nervous system, the eye
and bone. These samples are sent to a veterinary
diagnostic laboratory and it may take up
to several weeks for the results to be reported.
Histopathology will often give the definitive
diagnosis so it is a very important procedure
to do.
New procedures have entered the field with
the advent of immunohistochemistry staining,
Congo Red staining, etc.
Toxicology
Although not commonly done, the toxicological
examination is done in those cases where
poisoning, whether intentional or accidental,
may be involved. In these cases blood, stomach/
intestinal contents and samples of the ingested
material are sent to the laboratory for
analysis.
Microbiology
Here samples are taken for bacterial culture.
The causative organism is identified and
tested against various antibiotics to determine
its susceptibility. Most commonly the lungs,
trachea, urinary tract and reproductive tract
are cultured. Cultures can also be done on
intestinal contents, any discharges or abscesses.
Time is especially critical in this
phase of the post-mortem exam – upon the death
of the animal normal bacteria from the gut invade
the tissues and will obscure the results.
Parasitology
This aspect of the post-mortem involves the examination
of the lungs, intestinal tract and heart
for evidence of internal parasites. Many parasites
are only visible under the microscope and not all
are picked up on routine fecal exams.
Virology
This phase of the post-mortem examination is
perhaps the most difficult and costly. Viral isolation
requires special laboratory equipment, special
tissue culture media for growing viruses and
time. Viral isolation can take 4 weeks or longer.
Special transport media is necessary for shipment
of samples, although many times a local human
hospital can be helpful. Electron microscopy is
also used to identify viruses which require special
processing. Typical tissues cultured for virus isolation
in clued the liver, kidney, lungs and intestines.
Clinical pathology
Included in this category is routine blood testing
which can be hampered due to storage conditions
of the body, time after death, and many other
factors. Newer methodologies include DNA/RNA
analysis, PCR techniques, serology, and other
testing procedures.
Up to this point we have addressed what goes
into a thorough post-mortem examination and
why we perform one. I will also say that many
veterinary hospitals and veterinarians are not
equipped or have the time and staff to do a thorough
post-mortem examination. Often the exam
is shortened to a rapid dissection of the body with
harvesting of samples from appropriate tissues.
Now I’d like to address the breeder/owner’s responsibility:
- Cost – as one can imagine, a good postmortem
examination is a costly procedure.
It takes time to do a thorough exam, laboratory
costs are high and the techniques
involved are complex. A rough estimate
would be in the hundreds of dollars.
- Time – the time to decide to do a post-mortem
exam is before the animal dies. This allows
the veterinarian to obtain fresh samples as
soon as possible and optimizes the chances
of getting useful results.
- If an animal should die at home and a veterinarian
is not available, don’t freeze the
body. It is much better to refrigerate the
body. This prevents freezing artifacts which
confuse the pathologist examining the tissues.
The death of a pet is traumatic both for the owner
and the veterinarian. Too often, the post-mortem
examination is rushed at the last minute or, worse
yet, forgotten. It is important to communicate your
wishes to the veterinarian early so the necessary
procedures can be scheduled rapidly, samples obtained
quickly and the examination performed efficiently.
The Chinese Shar-Pei dog breed has a genetic predisposition
to an autoinflammatory disorder known as Familial Shar-Pei
(FSF). It is an heredofamilial episodic fever disorder characterized
by a high temperature (typically greater than 105° F)
lasting 12-36 hours, often with a swollen, painful hock joint
(Swollen Hock Syndrome, SHS which can occur in 40% of the
FSF dogs) and systemic reactive amyloidosis leading to kidney
failure in about 15% of these dogs. There currently are no
diagnostic blood or DNA tests available to screen for or diagnose
this disorder.
As part of the research into the genetics of FSF the Health
Committee of the Chinese Shar-Pei Club of America, Inc. has
asked owners whose dogs have died or were euthanized in
kidney failure to have a necropsy done and to request Congo
Red staining (CRS) of the tissues submitted. Congo Red
staining is the “gold standard” for the presence of amyloid.
Unfortunately, H & E staining of tissue specimens for the
presence of amyloid is not as accurate or reliable as CRS. The
Health Committee and the CSPCA, Inc. ask that any veterinarian
and/or laboratory receiving a request from a Shar-Pei
owner to have CRS done on submitted tissues to please comply
with that request. If the laboratory is not equipped to do
CRS please inform the owner so that other arrangements can
be made. We hope the CRS results can be used by breeders
to evaluate and modify their breeding programs until definitive
blood screening procedures for FSF can be developed and
made available to the fancy. |