Postmortem changes
Physico-chemical changes
independent (!) from the fatal disease take place immediately or shortly after death progress in a fairly orderly fashion strongly influenced by unpredictable endogenous and environmental factors
General pathology
Postmortem changes Mechanical effects
Estimating the time of death Separating from the real lesions!
Cooling off algor mortis
No metabolic process
no heat production = thermo-equalization
Subcutaneous fat tissue
In dogs usually 1C/hour
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 )
Pale colour - pallor mortis
Blood is settling to lower parts of the animal
Skin and mucous membranes are pale Contraction of the small blood vessels
Desiccation exsiccatio postmortalis
Due to evaporation Skin
nasal plate,rostral plate
Not easy to recognize in animals
Hair and pigmentation!
Mucous membranes Cornea Also in alive animal
necrotized skin
Not an infallible sign of death
anaemia!
Mumification
Soaking maceratio
Skin, organs filled with fluid Foetuses
- complete dehydration of the tissues - dry heat and/or air current - desert, chimney - Function of the putrefactive bacteria is also hampered
aseptic autolysis
Carcasses staying in the water Also in living animals
flows on the skin!
Discharge
Stiffness - Rigor mortis
Occurs in all the three kind of muscles
Voluntary and involuntary muscles
Nystens 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
Rigor mortis
Heart muscle
Standstill in diastole looks like systole Develops fast (30 minutes) Lasts for 1 day
Onset and duration of RM
Rapid and short
High environmental and/or inner temperature Prolonged muscular activity Young and elder animals Septicaemia, wasting diseases
Smooth muscles
Quick process (10-15 min.) Lasts for 1 4 hours
intestines, arteries, spleen
Delayed
Asphyxial death (notably by carbon monoxide poisoning) Severe hemorrhage, cold surroundings
Fails to develop
In case of degenerative muscle changes
Development of stiffness
N: ATP inhibits the activation of the linkage between the 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
Stiffness - rigor mortis
Irreversible development of those linkage
Resolved by the autolysis
Postmortem clot Cruor postmortalis
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
Blood clot in the heart
PM blood sedimentation, lividity sedimentation,
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
Imbibition
Discoloration Forms: From the blood
hemoglobin aorta ! 24 hours - permeable
From the gall bladder
bile pigment imbibition
Self softening Autolysis
Autolytic ferments of the cell in the cytoplasm
endogenous enzymes
Autodigestio (self digestion)
Gastromalatia
Gastric juice
Oesophagomalatia
Postmortem destruction - putrefaction
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
Rate of putrefaction
Rapid
Obese (retaining the body heat) Warm environmental temperature Hyperemic organs Widespread infection Injuries (portals of entry) Oedematous tissues
Slow
Lean Exsanguination (dehydration)
Emphysema postmortalis hepatis
Honey-comb pattern Honey-
Postmortal tympany
Sulph-hemoglobin SulphReaction of Hb (hemoglobin) plus H2S (hydrogen-sulphid) greyish-green, paling off on air
Pseudomelanosis
H2S + Fe (from Hb)
PM Wax Adipocere
Saponification In wet, clayey soil Fatty acids and Ca++ Form soaps, impregnate soft organs Sweetish odour
Iron-sulphide
Adipocere
Post mortem changes
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
General aetiology
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
Causes of the cellular damage
External causes
Physical Chemical
Intoxications
Biological
Viruses, bacteria, fungi, protozoa
Inadequate supplements (malnutrition)
Internal conditions (predisposition)
Physical effects
Forms
Traumas
Open wound or covered lesion Superficial (excoriatio) or deep (denudatio)
a. b. c. d. e. f.
Mechanical effects High and low temperature Electricity Radiant energy Climate and weather Inadequate supplements
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
Luxation
Dislocation
Forms of the wounds (vulnus) vulnus)
On the surface (open w.) Inside the body
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) Bleeding (haemorrhagia) Split (ruptura) Perforation (TRP) Trituration (conquassatio) Compression
SURGICAL WOUND !!!
Covered lesions sometimes without outer signs on the surface!
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Bleeding in the brain tissue
Rupture
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Trituration
Sequelae of traumatic effects
Local effects
Lesions Tissue damage Portal of entry!
General effects
General effect of a local infection
tetanus, gas-phlegmone
Loss of blood
Bleeding out
Functional disturbances
fractures, luxations
Embolism
fat, bone marrow
Traumatic shock
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Bleeding, Bleeding, haemothorax
Loss of function
Lesions in the tissues
Microscopical
Fibrillary ruptures
Macroscopical
Ruptures (ruptura) Fractures (fractura) Luxation (luxatio) Fissure Concussion (commotio)
Locus minoris resistenciae - sick animals - bad condition - nutritive problems
brain, spinal cord, bone marrow bony capsule!!!
Fracture
open (fr. aperta) or covered (fr. optecta) special appaerance
Infraction - bone fracture marked by a small line 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
Tumor
Tumor
Vital reaction
Did it happen in life? Edges of the wound
Hemorrhages at the surrounding tissues After soaking it disappears!
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