Yummy! Vegetative Endocarditis with a side of Pericarditis.

Before I start this post, I would encourage anyone who does NOT have a warped sense of appropriate dinner conversations, like many in the medical field, to not consume ANYTHING while reading this one… You have been warned. 

I was asked to perform a necropsy (animal autopsy) on a dry cow at one of my herd checks the other day. This cow was a middle aged cow that had been dried off a month ago.  She went down in the stall, looked thin, unthrifty and did not even seem to have the energy to get up to eat.  She was housed in a separate facility with all the other dry cows.  

Refresher: a dry cow is a cow that is due to have a baby in 2 months. The last two months before they calve, the cow stops milking and the udder is allowed to regenerate and renew itself for the next lactation. 

Since this cow seemed to be sick, she was brought up to the herdsman on the farm so that she could be treated with the appropriate medications.  The herdsman gave her a bottle of calcium in the vein, and pumped her stomach with alfalfa meal and energy to keep the bugs in the rumen alive.  She was kept outside on the lawn, where she would have adequate footing and wouldn’t be at risk to slipping on concrete and further injuring herself. When the herdsman went out to check her a couple hours later, she was found dead.

To start a necropsy, we lay the cow so that the left side is down on the ground. We then cut back the front leg, then the back leg to allow full exposure of the inside of the cow. The abdominal cavity is opened and the right rib cage is removed.  When I removed the rib cage of this cow, I noticed severe hemorrhaging and bruising around the lower lungs and heart.  There was excessive scarring of the heart, to the sternum. The lungs looked relatively healthy. Based on what I was seeing, I decided to take out the lungs and heart in one chunk.  The picture above is the pericardium of the heart in my cow. This is the sack that the heart sits in. Normally there is straw colored fluid in the sack, preventing friction as the heart beats. A normal pericardium is very thin and pictured to the left. 

When I peeled back the thick pericardium to gain access to the heart, I was greeted with the lovely picture below and to the left.  The yellowish stringy material is all scar tissue.  You can also see the severe bruising on the inside of the pericardium.

I then opened up the right ventricle and examined the atrial-ventricular (AV) valve, following with the left ventricle. These valves are also normally very thin and smooth. The long strings seen in the picture are normally there and help with the movement of the valve. What are not normal, are the large chunks on the valve, seen in the circles.  This is where the “vegetative” term comes into play. 

Circles are the vegetative lesions on the valves

These large vegetations are colonies of bacteria that have taken up residence on the AV valves. In order for the bacteria to get to the heart, the cow had to have had bacteria in her blood; a term we call septicemia.  In adult cows, diseases such as pneumonia, mastitis (infection of the udder), metritis (infection of the uterus), or acidosis (decreased pH in the rumen) can all result in septicemia.  The herdsman could not recall any of the previously mentioned diseases in this particular cow. 

Now as I mentioned, the pericardium was also diseased. This is termed pericarditis. Pericarditis alone is most commonly caused by “hardware;” sharp pieces of metal that have been ingested and have poked through the lining of the stomach, through the diaphragm and into the pericardium.  Cows are non-discriminate eaters, so they will not pick around a nail or scrap of metal, when they take a bite of food. To try to minimize hardware disease, many cows are given a magnet, which sits in the reticulum or bottom of the rumen to catch any metal they may eat. 

In this case, I could not find any signs of hardware when I examined the stomach and diaphragm.  I suspect that the septicemia that caused the endocarditis was severe enough to also cause the pericarditis.  
 

Endocarditis is usually treatable with long term antibiotic therapy. Because there are several different kinds of bacteria that can cause endocarditis, a blood culture would be needed, to find the right antibiotic for the job.  Treatment can take up to 3 weeks and can be very expensive. And sometimes we don't know what is really wrong with them, until we perform a necropsy and find this! 

As disgusting as you may, or may not, find this, it really is awesome when a necropsy reveals such wonderful lesions and an obvious cause of death.  Because I’m one of those with a warped sense of appropriate topics for discussion at the dinner table, all this talk of vegetation has made me hungry... Til next time!!!!  :-)