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GeneralGeneral pathologypathology
Postmortem changes
Mechanical effects
PostmortemPostmortem changeschanges
• Physico-chemical changes
– independent (!) from the fatal disease
– take place immediately or shortly afterdeath
– progress in a fairly orderly fashion
– strongly influenced by unpredictableendogenous and environmental factors
• Estimating the time of death
• Separating from the real lesions!
CoolingCooling offoff –– algoralgor mortismortis
• No metabolic process
– no heat production = thermo-equalization
• Depends on
– Hair, subcutanous fat tissue
– Temperature of the surroundings
– Zone (tropical, temperate)
• Increased PM temperature
– Overtemperature (heat stroke, septicaemia)
– Spastic muscle contraction (tetanus, strychnine or
DiNitroOrtoCrezol poisoning )
SubcutaneousSubcutaneous
fatfat tissuetissue
In dogs
usually 1°C/hour
PalePale colourcolour -- ppallorallor mortismortis
• Blood is settling to lower parts of the
animal
– Skin and mucous membranes are pale
– Contraction of the small blood vessels
• Not easy to recognize in animals
– Hair and pigmentation!
• Not an infallible sign of death
– anaemia!
DesiccationDesiccation
exsiccatioexsiccatio postmortalispostmortalis
• Due to evaporation
• Skin
– nasal plate,rostralplate
• Mucous membranes
• Cornea
• Also inalive animal
– necrotized skin
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MumificationMumification
- complete dehydration
of the tissues
- dry heat and/or air current
- desert, chimney
- Function of the
putrefactive bacteria
is also hampered
SoakingSoaking
maceratiomaceratio
• Skin, organs filled
with fluid
• Foetuses
– aseptic autolysis
• Carcasses staying in
the water
• Also in living animals
– flows on the skin!
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DischargeDischarge StiffnessStiffness -- RigorRigor mortismortis
• Occurs in all the three kind of muscles
– Voluntary and involuntary muscles
• Nysten’s rule
– first investigation in 1811
• Skeletal muscles
– 2-4 hours the beginning
– 5-8 hours becomes general
– 24-48 hours starts to disappear
– 48-60 passes off
RigorRigor mortismortis
• Heart muscle
– Standstill in diastole – looks like systole
– Develops fast (30 minutes)
– Lasts for 1 day
• Smooth muscles
– Quick process (10-15 min.)
– Lasts for 1 – 4 hours
• intestines, arteries, spleen
OnsetOnset andand durationduration ofof RMRM
• Rapid and short– High environmental and/or inner temperature
– Prolonged muscular activity
– Young and elder animals
– Septicaemia, wasting diseases
• Delayed– Asphyxial death (notably by carbon monoxide
poisoning)
– Severe hemorrhage, cold surroundings
• Fails to develop– In case of degenerative muscle changes
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DevelopmentDevelopment ofof stiffnessstiffness
• N: ATP inhibits the activation of the linkage betweenthe actin and myosin
• Muscle tissue becomes anoxic after death– Oxygen dependent processes cease
– Ca ++-pump stops, Ca++ reaches the sarcoplasm
– Level of ATP is maintained by anaerobic glycolysis
• Increased amount of pyruvic and lactic acid
• Myosin-ATP-ase liberates energy
– Muscle glycogen becomes depleted
– Cellular pH drops to 6 - COAGULATION of actomyosin
– Level of ATP falls below critical level
RAPID RIGOR
• Irreversible development of those linkage– Resolved by the autolysis
StiffnessStiffness -- rigorrigor mortismortis
PostmortemPostmortem clotclot
CruorCruor postmortalispostmortalis• Dark red, smooth, fleshy
with glistening surface
• Not attached to the intima!
• Trombocytolysis– cruor sanguinis – red clot
– crusta lardacea – chicken fat clot
• After death blood clots in
15-30 minutes
– Heart, large blood vessels
• No clotting in small blood
vessels - fibrinolysin
BloodBlood clotclot
inin thethe heartheart
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PM PM bloodblood sedimentationsedimentation, , lividitylividity
• postmortem hypostasis
• Effect of gravity on the blood fluid – in 1 hour!
– Also in the organs (lungs, kidney …)
• livores mortis
PM spots
dark purple
• Changing
position
– Special
pattern
ImbibitionImbibition
• Discoloration
• Forms:
• From the blood
– hemoglobin – aorta !
– 24 hours - permeable
• From the gall bladder
– bile pigment imbibition
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SelfSelf softeningsoftening
AutolysisAutolysis
• Autolytic ferments
of the cell in the
cytoplasm
– endogenous enzymes
• Autodigestio
(self digestion)
– Gastromalatia• Gastric juice
– Oesophagomalatia
PostmortemPostmortem destructiondestruction -- putrefactionputrefaction
• Decomposition products
– Activity of saprogenic bacteria
• Suffocation supports the putrefaction
– blood remains liquid
• Intestine – v. portae – liver
• Dissolution into gases, liquids and salts
– Ptomaines (neurine, muscarine, putrescin)
– Gas production – stomach distension
• Under 5oC putrefaction stops
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RateRate ofof putrefactionputrefaction
• Rapid– Obese (retaining the body heat)
– Warm environmental temperature
– Hyperemic organs
– Widespread infection
– Injuries (portals of entry)
– Oedematous tissues
• Slow– Lean
– Exsanguination (dehydration)
EmphysemaEmphysema postmortalispostmortalis hepatishepatis
HoneyHoney--combcomb patternpatternPostmortal tympany
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SulphSulph--hemoglobinhemoglobin
Reaction of Hb (hemoglobin) plus H2S (hydrogen-sulphid)
greyish-green, paling off on air
PseudomelanosisPseudomelanosis
• H2S + Fe (from Hb)
• Iron-sulphide
PM PM WaxWax --
AdipocereAdipocere
• Saponification
• In wet,clayey soil
• Fatty acidsand Ca++
• Form soaps,impregnatesoft organs
• Sweetishodour
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AdipocereAdipocere PostPost mortemmortem changeschanges
• Cooling off – algor mortis
• Pale color – pallor mortis
• Desiccation – exsiccatio postmortalis
• Soaking – maceratio postmortalis
• Stiffness – rigor mortis
• Postmortem clot – cruor postmortalis
• PM blood sedimentation – hypostasis postmortalis– Livores mortis
• Discoloration - imbibition
• Selfsoftening – autolysis (selfdigestion – autodigestion)
• Postmortem decomposition – putrefaction
• Grave wax - adipocere
GeneralGeneral aetiologyaetiology
• Stimuli from the environment:
physiological
• External causes + internal conditions
• Causes of diseases
– Absolute – relative cause
– Monocausalis – pluricausalis» causa essentialis (dominating) – Clostridium perfringens D
» causa auxillaris (helping) – decreased motility
» causa occasionalis (occasional) – overfeeding
CausesCauses ofof thethe cellularcellular damagedamage
• External causes
– Physical
– Chemical
• Intoxications
– Biological
• Viruses, bacteria, fungi, protozoa
– Inadequate supplements (malnutrition)
• Internal conditions (predisposition)
PhysicalPhysical effectseffects
a. Mechanical effects
b. High and low temperature
c. Electricity
d. Radiant energy
e. Climate and weather
f. Inadequate supplements
TraumasTraumas
• Forms– Open wound or covered lesion
– Superficial (excoriatio) or deep (denudatio)
• Causes– force
– high, sudden pressure
– dilaceration• pulling, extension, torsion
– explosion (detonation)• Fragment cause wounds
• Pressure changes tear or rupture of the tissues
– Ultrasound• Pseudocavitation, heat production
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LuxationLuxationDislocationDislocation
FormsForms ofof thethe woundswounds ((vulnusvulnus))
• On the surface (open w.)– abrasion (v. abrasum)
– contusion (v. contusum)
– incision and cut(v. scissum et caesum)
– puncture (v. punctum)
– laceration (v. lacerum)
– bite (v. morsum)
– gun-shot (v. sclopetarium)
• Inside the body– Bleeding (haemorrhagia)
– Split (ruptura)
– Perforation (TRP)
– Trituration(conquassatio)
– Compression
– Covered lesionssometimes withoutouter signs on thesurface!– SURGICAL WOUND !!!
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BleedingBleeding inin thethe brainbrain tissuetissue RuptureRupture
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TriturationTrituration SequelaeSequelae ofof traumatictraumatic effectseffects
• Local effects
– Lesions
– Tissue damage
– Portal of entry!
• General effects
– General effect of a localinfection
• tetanus, gas-phlegmone
– Loss of blood
• Bleeding out
– Functional disturbances
• fractures, luxations
– Embolism
• fat, bone marrow
– Traumatic shock
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BleedingBleeding,,
haemothoraxhaemothorax
LossLoss ofof functionfunction
LesionsLesions inin thethe tissuestissues
• Microscopical
– Fibrillary ruptures
• Macroscopical
– Ruptures (ruptura)
– Fractures (fractura)
– Luxation (luxatio)
– Fissure
– Concussion (commotio)
– brain, spinal cord, bone marrow – bony capsule!!!
Locus minoris
resistenciae
- sick animals
- bad condition
- nutritive problems
FractureFracture
• open (fr. aperta) or covered (fr. optecta)
• special appaerance
– Infraction - bone fracture marked by a smallline that shows up in X-ray examination
– newborns, metabolic disorders, tumors
• Minor trauma can cause it
– strenght of the bone decreases
– cachectic animal
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Hematome Hyperemia
TumorTumor
VitalVital
reactionreaction
• Did it happen in life?
• Edges of the wound
– Hemorrhages at the surrounding tissues
– After soaking it disappears!