Postmortem Changes

postmortem

_____________: after death

antemortem

__________________: before death

perimortem

_________________: around death

autopsy

________________: self-examination (human)

necropsy

_________________: death examination

cause of death, extent of disease

What does autopsy/necropsy hope to determine?

dissection, observation, interpretation, documentation

Necropsy involves a careful process of _______________, _____________, _______________, and ________________.

autolysis

___________: decomposition of cells that takes place after somatic death; Breakdown of the body by endogenous substances / enzymes by ITS OWN SUBSTANCES

Putrefaction

_____________: decomposition of organic matter by bacterial or fungal digestion

postmortem predation/scavenging

________________: animals feeding on bodies after death

decomposition

________________: Process by which dead organic substances are broken down into simpler organic or inorganic matter

autolysis, putrefaction

postmortem degeneration is the result of _________ and ______________

true

True/false: one of the main challenges of necropsy is differentiation antemortem cell death from postmortem cell degeneration

liver mortis/hypostatic congestion

______________: Gravitational pooling of blood on the dependent (down) side of the carcass

dependant side (down)

where is blood sent in hypostatic congestion?

pale-skinned, non hairy animals; organs on the down side

where do you see hypostatic congestion most?

0.5-2 hours

How long until hypostatic congestion starts?

blanches (to make pale/move the blood around)

What happens initially on palpation after livermortis has started?

8-12 hours

How long until liver mortis is "fixed" on one side?

smooth and shiny, lack of lamination, lack of attachment to endothelial surface of the vessel

Describe a postmortem clot.... (3 things)

RBCs at the bottom, buffy coat of leukocytes, clotted serum at the top

When blood settles in a dead body, what is meant by a "chicken fat" or "black currant clot"?

horses, high errythrocyte sedimentation rate

What species is a "chicken fat clot" common in?

Why?

chicken fat/black currant clot

What is this pattern?

inflammation

increased sedimentation rates indicate ____________ in the animal

anticoagulant rodenticide toxicity, hereditary coagulopathies

decreased sedimentation rates indicate...(2)

rigor mortis

generalized contraction of skeletal muscle

1-6 hours, 2+ days

When does rigor mortis start? How long does it persist?

Muscles need ATP to relax, run out of intracellular stores of glycogen after death

why does rigor mortis occur?

only autolysis, need complete breakdown of proteins, not just the corss-bridges

How is rigor reversed?

antemortem exertion, seizures, antemortem hyperthermia

What can cause accelerated rigor?

Aseptic

Autolysis is a [septic/aseptic] process

putrefaction

_____________: Involves the action of bacteria on the tissues or body

postmortem bacilli, fermentation

putrefaction is done by ________________ and can result in ____________.

severe softening, gas, not suitable for microscopic exam

Implies presence of __________ and ___________ in tissue

May suggest samples are:

true

true/false: another cahllenge of necropsy, is that there is limited data or evidence to hep determine the postmortem interval

long interval between death and necropsy

high ambient temperature

large body size

heavy hair or wool

continued fermentation in GI tract (equine and ruminants)

antemortem hyperthermia,

antemortem bacteria

what things INCREASE autolysis? (7, but she said to make sure we knew this stuff :.)

short interval between death and necropsy

rapid cooling of carcass postmortem (lower ambient temp/fridge)

thin animal (reduced fat/muscle)

High levels of tissue antibiotics

What can REDUCE autolysis? (4, again KNOW THESE)

20 minutes

Autolysis develops within ________ in the rumen or intestine

pH drops

what happens to the rumen postmortem that causes quick autolysis?

brain, spinal cord

_______ adn ________ are tissues quick to autolyze

dark neurons

handling artifact in brain tissue on necropsy

False; it retains the ability to contract

true/false: skeletal muscle once dead... is dead man, it doesn't move

mucosal sloughing

What is happening in this image?

Dark neurons

What are these?

bloating, rectal/vaginal prolapse, tissue softening/discoloration and gas bubbles

what are some postmortem changes you would see on a carcass that'd been lying out for a while? Like a cow by the road

putrefaction

What do we know we have if gas bubbles are present in dead tissue?

gaseous distension

result of increased gas producing bacteria in a carcass

Gi tract, diaphragm, entire carcass

what can rupture if the carcass is bloating

displacement of abdominal viscera, eversion of rectal mucosa through anus, vaginal eversion, phimosis, protrusion of the tongue

WHat else can bloating cause besides rupture?

postmortem rods

What are these?

gas producing bacteria

what caused this "swiss cheese brain"?

diffuse, pallor, soft/pulpy/gas filled tissue

Grossly, autolysis looks like what?

friable, reddish fluid, hydrogen sulfide, methyl mercaptan

grossly, autolysis causes tissue to be [tough/rubbery/friable], the tissue oozes __________________ and has a strong odor due to the _______ and _______________--

pale, nope, cadaver bacilli

Microscopically, due to autolysis, the tissues stain ____________.

Is there inflammatory response seen?

What bacteria is there?

errythrocytes not preserved, loss of tissue pattern, cells release from basement membrane

Describe the microscopic appearance of autolysis

autolysis

what is happening?

autolysis

what is happening?

water

what histological artifact?

frozen before fixation

What histological artifact?

hemoglobin imbibition

reddish discoloration of tissue from lysed erythrocytes; Leakage of hemoglobin from blood vessels after death;

intima, endocardium, surrounding tissues

where would you see hemoglobin imbibition

hemoglobin imbibition

what is causing his deep red pigment on this aorta?

hemoglobin imbibition

What is causing the deep red pigment on the top of this organ?

bile imbibition

_____________: Greenish discoloration from leakage of bile through the wall of the gallbladder or bile ducts

bile imbibition

what is the pigment in the gall bladder on the far right?

pseudomelanosis

_________________: Blue-green to black discoloration of tissues by iron sulfide deposits

false; pseudomalanosis is not melanin

true/false: pseudomelanosis and melanosis are both the same melanin pigment, just named for different stages of the animals life (or...death ig)

hydrogen sulfide from bacteria reacting with iron in hemoglobin

so if pseudomelanosis isnt melanin... what is it?

severe autolysis

what does pseudomelanosis signify?

antemortem; melanin deposits

is this a postmortem or antemortem pigment change?

pallor

_________: Postmortem pressure on organs can force blood out of tissues causing "Pale imprints" (like the ribs)

bacterial proliferation, liver

Pallor can also come from localized postmortem _____________ ________________- in the _______________

lens artifact

Chilling or partial freezing of the carcass can make the lens opaque and white

cataracts, lens artifacts are from freezing, and so revert to normal on warming (most of the time)

What is it important to differentiate lens artifacts from? and how can you do this?

traps blood in ridges, mimics intussusception

what patterns (2) does postmortem peristalsis cause in the intestines?

agonal breathing, hemorrhage, euthanasia artifacts, resuscitation artifacts

what are some examples of perimortem changes (4)

interstitial edema, tracheal foam

What changes does agonal breathing cause?

petechial hemorrhage

What perimortem change comes with electrocution?

splenic congestion, pulmonary congestion and edema, dicolored blood, coagulation of endocardium

what are the perimortem artifacts associated with Barbiturate euthanasia (4)

fractured ribs, cutaneous hemorrhage, hemorrhage around injection sites, collapse of lungs if on O2 or anesthetic gas

What are some of the artifacts of ressuscitation?

pseudomalanosis

What is this change?

pallor

What is this change called?

freezing

What is this artifact caused by?

postmortem peristalsis

what causes this change?

_____________: Greenish discoloration from leakage of bile through the wall of the gallbladder or bile ducts