Exam 1: Morphologic Appearance of Postmortem Changes

Question 1

true or false: autolysis is the degradation of cells by enzymes not normally present in the tissues and occurs pre-mortem

Answer 1

FALSE: self-digestion/degradation from NORMAL cell enzymes POST-MORTEM;

occurs after somatic cell death

Question 2

What causes somatic cell death?

Answer 2

Total diffuse hypoxia

Question 3

In what organs will autolysis occur more quickly? why?

Answer 3

GI tract, pancreas, gall bladder, kidney, liver

because they have more enzymes

Question 4

Cool environment and refrigeration can delay autolysis except where? why?

Answer 4

the forestomach in ruminants (the rumen); the equine cecum and ascending colon;

these organs have a large number of microbes and ingesta will continue to undergo fermentation even after death (in addition to autolysis)

Question 5

Why isn’t freezing a carcass recommended?

Answer 5

Now you have to determine:

1. Changes caused from freezing/artifacts
2. changes caused by the actual lesions
3. changes caused by autolysis

Question 6

What is rigor mortis? When does it occur?

Answer 6

stiffening of muscles after death.

Occurs 1-6 hours after death and lasts for 1-2 days

Question 7

What should you do if an animal has been dead for 8 hours and rigor has not set in?

Answer 7

DO NOT PERFORM A NECROPSY; likely anthrax – look for bacillus in blood from a clip of the ear or tail

Question 8

True or false: animals with more stress (or a fever) will have a faster onset of rigor mortis?

Answer 8

True

Question 9

What is Algor Mortis?

Answer 9

Cooling of the body after death. For animals time of death can be determined using a hole in the skull. However, temperature is affected by wool, environment and other factors

Question 10

How does bacillus anthracis prevent rigor?

Answer 10

the bacteria produces cAMP which inhibits muscle stiffening and relaxes the muscles

Question 11

What is livor mortis?

Answer 11

the same this as hypostatic congestion. Gravity pulls blood to the lowest point after death. This will cause a variation in color, particularly in bilobed organs like the lungs. It will also show which side the animal was lying on when it died.

Question 12

What is this a picture of?

Answer 12

Livor Mortis aka hypostatic congestion

Question 13

Where do we expect to see a lot of post mortem clotting

Answer 13

in the heart

Question 14

You see a blood clot that is dry and dull in color and firmly attached to the vesell wall. What type of clot is this?

Answer 14

Pre mortem blood clot

Question 15

You see a blood clot in the heart that is very shiny and slips out easily, it is in the perfect shape of the vessel it was in. You also notice that it has different colored components in a layered appearance. Is this a pre or postmortem clot?

Answer 15

Post mortem clot – chicken clot

Question 16

What type of clot is this?

Answer 16

pre mortem clot (thromboemboli or muralthrombi)

Question 17

What type of clot is this?

Answer 17

Post mortem clot

Question 18

What is hemoglobin imbibition? Where is it expected to be found?

Answer 18

Red staining of tissues, especially heart arteries and veins. Will also penetrate adjacent tissues.

Question 19

What change is present in this tissue?

Answer 19

Hemoglobin imbibition

Question 20

What change is present in this image?

Answer 20

Hemoglobin imbibition

Question 21

When hemoglobin imbibition is present in fat, what type of autolysis is it?

Answer 21

Advanced autolysis

Question 22

You are doing a necropsy on an animal and notice lots of reddened areas in the tissues. However, the level of autolysis in the animal is very mild. What is happening?

Answer 22

The reddening was caused by a pre-mortem change, possibly erythrolysis

Question 23

What is bile imbibition?

Answer 23

yellow staining of tissue adjacent to bile (near the gall bladder or the small intestine).

Question 24

How can you distinguish Bile Imbibition from Icterus?

Answer 24

Icterus causes a diffuse yellow staining of mucosa. Bile imbibition will only affect areas adjacent to the bile

Question 25

What is shown in this picture? Is it a normal post mortem finding?

Answer 25

Bile imbibition. Yes but it may also be a premortem change (not as common)

Question 26

What is shown in this picture? How do we know that this is not peritonitis?

Answer 26

Bile Imbibition:

yellow loops of intestin, distended loops indicating autolysis along with other color changes indicating hemoglobin imbibition

Question 27

Is bloating a normal post mortem change?

Answer 27

Yes

Question 28

How can you tell the difference betwen ruminal tympanny and post mortem bloating?

Answer 28

In ruminal tympanny there MAY be a bloat line – white line caused by congestion and blockage of blood flow.

there is not bloat line in a post mortem bloat

Question 29

What is shown here?

Answer 29

Bloat line indicating tympanny (pre-mortem bloat)

Question 30

What causes clouding of the lens?

Answer 30

cold temperatures of the carcass – refrigeration. Makes it difficult to differentiate from cataracts so use age of animal to help diagnose them

Cats 10+, Dogs 7-8

Question 31

What is pseudomelanosis? Where do we expect to find it?

Answer 31

greenish black discoloration of tissues post mortem;

found in areas in contact with the gut (kidney, liver, spleen, gut wall) – becomes more advanced with more autolysis (may eventually get to lungs)

Question 32

What is the discoloration shown here?

Answer 32

pseudomelanosis. note that there is not a definitive line but rather a gradation of black discoloration

Question 33

What is the black discoloration shown here?

Answer 33

pseudomelanosis. Notice the friable edges of the spleen indicating autolysis

Question 34

What changes are shown here?

Answer 34

hemoglobin imbibition, bile imbibition and pseudomelanosis indicating autolysis