Why a Post Mortem Exam?
by MaryDee Sist, DVM
There is no way we can have an idea of what life threatening health problems exist in Salukis if dogs are not fully examined before and even after they die. Our Saluki Heart Pathology study has turned up an unexpected array of problems found during the post-mortem examinations. People often attribute sudden death to a cerebral aneurysm (rupture of a blood vessel in the brain) or a heart attack (infarct) or a stroke. All of these are very rare causes of death in dogs. In over 50,000 necropsies performed at Michigan State University's Animal Health Diagnostic Laboratory, none of the dogs died of aneurysms or rupturing of a major blood vessel. A heart attack or stroke occurs when heart or brain tissues die because a clot blocks the blood flow nourishing the tissue in the area. These don't occur often in dogs because they have very good collateral circulation. There is just no way to know what caused the sudden death without performing a post-mortem examination.
A full post-mortem examination includes both a visual or gross and a microscopic examination. This needs to be done before there is much autolysis or deterioration of the body and keeping the body cool can slow this process. Freezing can destroy microscopic architecture, so tissues are preserved with a formalin solution. Small sections of the preserved organs or tissues are then imbedded with wax, sliced very thin, stained and placed on slides for microscopic or histopathologic examination. Other diagnostics are often useful, such as viral serology or bacterial culturing if an infection was suspected or toxicology if a poisoning could have been a contributing factor to the demise of the animal.
The most complete necropsies are performed at Veterinary teaching hospitals or schools or state diagnostic laboratories. If that is not possible, a veterinarian experienced in performing post-mortem examinations on dogs can do a gross or visual examination. Someone trained in microscopic examinations or a pathologist needs to do the histopathological examination. At the time the gross examination is done, tissue samples of anything that looks abnormal and small sections of the major organs should be taken and preserved in formalin solution. These sections can be sent to the diagnostic laboratory at a veterinary college or laboratory, like Antech Diagnostics, or even a human laboratory for examination. But it is better to have a veterinary pathologist who examines numerous dog tissues perform the microscopic examination.
A veterinarian who does a field post and finds nothing on the visual inspection should not conclude that the cause of death could not be determined. Microscopic examination can often determine the cause or at least rule out certain causes. Examinations made by doctors with the most experience looking at various organs generally provide the most useful information and conclusions.
I have been very fortunate to work with a pathologist at Michigan State University's Animal Health Diagnostic Laboratory, Dr. Thomas Bell, whose special interest is in examining hearts. He is very thorough and even though he might only have the heart to look at, he can often tell about certain changes in the body as a whole.
I have included AHDL's necropsy form, histopathologic specimen form and a serology form to show what a full post-mortem examination might include. I also have a sample form that I use as a check sheet when doing a gross post and recording what samples I take for microscopic examination.
I'll include examples of 2 Saluki cases to show how a complete examination was needed to determine the cause of death.
I was sent a heart that was harvested from a dog that had symptoms of heart failure. A full post was done by a pathologist, and he concluded that the dog died of cardiomyopathy (meaning something wrong=pathy in the heart=cardio) because he found no other obvious problems. However, when Dr. Bell examined the heart microscopically, he found that the dog did not have the lesions of primary cardiomyopathy where the heart muscle fibers fail. The dog had an infection of the sac that surrounds the heart and that put enough pressure on the heart compressing the heart muscle that it failed secondarily. Pericarditis was the cause of death.
Another example is from a fairly young dog who had been completely healthy. She died in her sleep. From the findings of our Saluki heart pathology study, one could surmise that the dog died of a cardiac hemangiosarcoma that had ruptured causing the dog to bleed internally. However, a post was performed and there were no lesions found grossly in the heart. Dr. Bell's microscopic examination showed that the heart muscle fibers in the conduction system were fibrotic. This scar tissue could not transmit the electrical impulses that are needed to regulate the heart beat and the dog died of an arrhythmia. Microscopic examination of the lungs and liver sections showed that the changes were very acute and nothing could have been done to change the outcome.
At AHDL a gross post-mortem examination on a Saluki sized dog starts at around $75. Histology fees depend upon how many tissues are examined and start at $55. There is usually a disposal or cremation fee that can range from $25 to up to $150 for an individual cremation. Cultures, toxicology, mineral analysis, serum titers, etc are all extra charges.
To ensure the future health of our Salukis, we need to have our dogs examined and share these finding with other fanciers. Though the thought is not pleasant, having the dog examined after death can yield information as to what health problems are of concern to the continuation of our ancient breed.
MaryDee Sist, DVM Salukihealth@aol.com