Postmortem changes • Physico-chemical changes – independent (!) from the fatal disease – take place immediately or shortly after 4. Postmortem changes – progress in a fairly orderly fashion – strongly influenced by unpredictable endogenous and environmental factors General • Estimating the time of death • Separating from the real lesions!

Cooling off – Subcutaneou • No metabolic process s fat tissue – no heat production = thermo-equalization In dogs usually 1°C/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 Desiccation - exsiccatio postmortalis

• Blood is settling to lower parts of the • Due to evaporation animal • Skin – Skin and mucous membranes are pale – nasal plate,rostral – Contraction of the small blood vessels plate • Not easy to recognize in animals • Mucous membranes – Hair and pigmentation! • Cornea • Not an infallible sign of death – anaemia! • Also in alive animal – necrotized skin

1 Mumification Mumified dog in a tree

- complete dehydration of the tissues - dry heat and/or air current - desert, chimney

- Function of the putrefactive bacteria is also hampered http://www.newsweek.com/photos-strange-phenomenon-left-dog-stuck-tree-almost-60-years-without-rotting- 784863

Mumified dog in a tree Soaking maceratio • Skin, organs filled with fluid • Foetuses – aseptic autolysis • Carcasses staying in the water

• Also in living animals http://www.newsweek.com/photos-strange-phenomenon-left-dog-stuck-tree-almost-60-years-without-rotting- 784863 – flows on the skin!

2 Discharge

Stiffness - Rigor mortis • Occurs in all the three kind of muscles • Heart muscle – Voluntary and involuntary muscles – Standstill in diastole – looks like systole • Nysten’s rule – Develops fast (30 minutes) – first investigation in 1811 – Lasts for 1 day • Skeletal muscles • Smooth muscles – 2-4 hours the beginning – Quick process (10-15 minutes) – 5-8 hours becomes general – Lasts for 1 – 4 hours – 24-48 hours starts to disappear • intestines, arteries, spleen – 48-60 passes off

3 Onset and duration of RM Stiffness - rigor mortis

• 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

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

4 PM blood sedimentation, lividity

• 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

5 Self softening Autolysis Autolysis • normal • Autolytic ferments of the cell in the cytoplasm – endogenous enzymes • autolysed • Autodigestio (self digestion) – Gastromalatia • Gastric juice – Oesophagomalatia

Postmortem destruction -

• 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)

6 Emphysema postmortalis hepatis

Postmortal tympany Honey-comb pattern

7 Sulph-hemoglobin

Reaction of Hb (hemoglobin) plus H2S (hydrogen-sulphid) greyish-green, paling off on air

Pseudomelanosis

• H2S + Fe (from Hb)

• Iron-sulphide

8 PM Wax - Adipocere Adipocere • Saponification • In wet, clayey soil • Fatty acids and Ca++ • Form soaps, impregnate soft organs • Sweetish odour

Post mortem changes Topics • Cooling off – algor mortis • Pale color – pallor mortis • 5. Traumas and their consequences • Desiccation – exsiccatio postmortalis • 6. High temperature as cause of disease • Soaking – maceratio postmortalis • 7. Low temperature as cause of disease • Stiffness – rigor mortis • Postmortem clot – cruor postmortalis • 8. Irradiations and electricity (also • PM blood sedimentation – hypostasis postmortalis lightning) as cause of disease – Livores mortis • 9. Inadequate oxygen and water supply • Discoloration - imbibition • Selfsoftening – autolysis (selfdigestion – autodigestion) • 10. Inadequate nutrient supply. Starvation • Postmortem decomposition – putrefaction • Grave wax - adipocere

General aetiology Causes of the cellular damage • Stimuli from the environment: physiological • External causes (causae efficientes) • External causes + internal conditions – Physical • Causes of diseases – Chemical – Absolute – relative cause • Intoxications – Monocausalis – pluricausalis – Biological » causa essentialis (dominating) – Clostr. perfringens D • Viruses, bacteria, fungi, protozoa » causa auxillaris (helping) – decreased motility – Inadequate supplements (malnutrition) » causa occasionalis (occasional) – overfeeding – enterotoxaemia in sheep • Internal conditions (predisposition) – pneumomycosis in newly hatched chicks – causae predisponibiles

9 Physical effects 5. Traumas and their consequences • Forms a. Mechanical effects – Open wound or covered lesion – Superficial (excoriatio) or deep (denudatio) b. High and low temperature • Causes – force, high sudden pressure c. Electricity – tension (stretching) d. Radiant energy – torsion • dilaceratio, pulling, extension e. Climate and weather – penetration into tissues – explosion (detonation) • fragment cause wounds • pressure changes tear or rupture of the tissues – ultrasound • pseudocavitatio, heat production

Luxation Consequences

• depend on – causing agent – strength of conjunction – type of organ or tissue • soft tissues • bones, head

Forms of the wounds (vulnus)

• On soft tissues (open w.) • Inside the body – abrasion (v. abrasum) – bleeding (haemorrhagia) – contusion (v. contusum) – split (ruptura) – laceration (v. lacerum) – perforation (TRP) – incision and cut – trituration (crumbling) (v. scissum et caesum) (conquassatio) – puncture (v. punctum) – compression • penetration, perforation • gun-shot (v. sclopetarium) – Covered lesions – bite (v. morsum) sometimes without outer signs on the surface!

– SURGICAL WOUND !!!

10 11 Bleeding in the brain tissue Rupture

Trituration

Sequelae of traumatic effects

• Local effects • General effects – Lesions – General effect of a local infection – Tissue damage • tetanus, gas-phlegmone – Port of entry! – Loss of blood • Bleeding out – Functional disturbances • fractures, luxations – Embolism • fat, bone marrow – Traumatic shock

12 Bleeding, haemothorax

Loss of function Lesions in the tissues • Microscopical disruption of the – Fibrillary ruptures Achilles tendon • Macroscopical – Ruptures (ruptura) Locus minoris resistenciae – Fractures (fractura) - sick animals – Luxation (luxatio) - bad condition – Fissure - dietetical problems – Concussion (commotio) – brain, spinal cord, bone marrow – bony capsule!!! – not always seen with naked eyes

13 Dislocation of the broken ends 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 (rarefied) – cachectic animal

Vital reaction

• Did it happen in life? • Edges of the wound – Hemorrhages at the surrounding tissues – After soaking it disappears!

6. High temperature Physical effects as cause of disease • Mechanical effects • Local effect of burning • High and low temperature – Burning (combustio) • Narrow temperature zone – Categorized by the severity of the lesions • Less sensitive to too low • C. erythematosa (1st) partial depth (epidermis) • C. bullosa (2nd) • C. escharotica (3rd) • Electricity complete depth • Radiant energy - irradiations • Carbonization (4th) – Radiant heat, hot liquid, steam, gas, solid • Climate and weather substances (live coal, melted metal) • General effect - hyperthermia

14 Degree of burn is influenced… Inhalation burns • … by the temperature • … by the duration • Destruction of airways and lungs • … by the quality of substance – mucous membrane of nasal and oral cavity, upper respiratory system • paraffin – water – gasses soluble in water form acids or base and cause • 60 °C – 50-52 °C edema • … by the extension of burn • chloride, sulphur dioxide, ammonia • … age of the animal • swelling, inflammation – pneumonitis (nitrogen oxide) • in 24-48 hours Effect can be • secondary infections – loss of epithel – external (skin) or internal (trachea, esophagus) – Pseudomonas aeruginosa, Staph. aureus, candida

Appearance of the burns

• C. erythematosa (1st degree) – hyperaemic area, vasodilatation, edema • C. bullosa (2nd degree) – vesication, denaturation of proteins, pain • C. escharotica (3rd degree) – coagulation of the tissues, hemostasis, thrombosis, pale, insensible • Carbonization (4th degree) – tissues are charred

15 General effects

• Circulatory disturbance, shock … (immediate) – edema (permeability of the blood vessels) – pain, hypovolaemia, hyperkalaemia, autointoxication • Necrosis, enzymatic lysis of proteins – increased local osmotic pressure • Hemoconcentration, desiccation • Degeneration of parenchymal organs – catabolic enzimes continue to work – liver, kidney, heart, bone marrow! (anaemia) • Hyperkalaemia (potassium released from the cells) – 2nd day: oliguria, anuria (degeneration of tubular cells) – 3rd day: polyuria (later no water retention ability) • Toxaemia

General effects of burning Hyperthermia necrosis • Extremely increased internal temperature of the body • Hyperthermia (failure of physical heat regulation) degeneration /from 1. day/ hyperkalaemia – High (and humid) environmental temperature (heart, liver, kidney, bone marrow) – High own heat production (pyrogens) heart failure – Heat loss is inhibited • Consequences poliuria /from 3. day/ – damage of vasomotor centrum, low blood pressure, spastic muscle contractions, kidney insufficiency, hyponatraemia… • Pathologic findings autointoxication /from 7. day/ oliguria /for 2 days/ – Quickly developing rigor mortis, incompletely clotted blood, early putrefaction – hemostasis in internal organs, brain edema, meningeal hyperemia and hemorrhages in the hypothalamus anaemia /from 7. day/ • Heat stroke (> 43°C)

Lesions Sunstroke - Insolation • Heat spasms • Infrared (ultraviolet?) radiation of sunshine – electrolyte loss (sweating) – Longlasting or strong impact of sunshine • Heat distress – Vasodilatatio in the skin of the head – most often seen, collapse – Vasodilatatio in the collateral brain vessels, – failure of cardiovascular compensatory hyperemia mechanisms after hypovolemia – Brain and meningeal edema – death – usually solved by itself – Rare in animals (haircoat!) • Heat stroke – vasodilation, hemostasis, necrosis, DIC

16 7. Low temperature as cause of disease

• Local effects – Contraction of vessels, local ischaemia • Metabolic and waste products (lactic acid, histamin) • Irregular vasodilatation! - hemostasis – Frostbite (congelatio) • C. erythematosa (1st) – bluish-red, swollen • C. bullosa (2nd) –vesication, edema • C. escharotica (3rd) – necrosis • C. gangrenosa (4th) – – Not only at freezing point - wet, windy surroundings! • Piglet with diarrhea, protruding body parts (ears, tail, testicles) • General effects – Gangrenous lesions, necrosis • Toxaemia

Hypothermia

• Failure of the heat regulation – around 35oC – Weather (cold, windy, wet…) – Exhausted, starving animals • Predisposing factors (diarrhoea, bleeding…) • 27-30 oC: vital functions come to standstill • 20-25 oC: death • Endangered species: pig, rabbit, dog

• Brown fatty tissue: great metabolic activity!!!

Defence mechanisms Baby pig disease • Acute hypoglycemia of the newborn pigs • Against falling body temperature – Fatal if untreated – Contraction of muscles – Cold, starvation • Shivering – Vasoconstriction in the skin – Increased metabolism • Labile glycogen reserves are used up • In newborn or young animals – Shallow and quick respiration – Heat regulation is not perfect – Body surface is relatively large

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