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Physical effects
• Mechanical effects
• High and low temperature
• Narrow temperature zone
• Less sensitive to too low
• Electricity
• Radiant energy - irradiations
• Climate and weather
• Local effect of burning
– Burning (combustio)
– Categorized by the severity of the lesions
• C. erythematosa (1st)
• C. bullosa (2nd)
• C. escharotica (3rd)
• Carbonization (4th)
– Radiant heat, hot liquid, steam, gas, solid
substances (live coal, melted metal)
• General effect - hyperthermia
6. High temperature
as cause of disease
complete depth
partial depth (epidermis)
Degree of burn is influenced…• … by the temperature
• … by the duration
• … by the quality of substance• paraffin – water
• 60 °C – 50-52 °C
• … by the extension of burn
• … age of the animal
Effect can be
– external (skin) or internal (trachea, esophagus)
Inhalation burns
• Destruction of airways and lungs– mucous membrane of nasal and oral cavity, upper
respiratory system
– gasses soluble in water form acids or base and cause edema
• chloride, sulphur dioxide, ammonia
• swelling, inflammation
– pneumonitis (nitrogen oxide)• in 24-48 hours
• secondary infections – loss of epithel– 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 necrosis of the tissues, hemostasis, thrombosis, pale, insensible
• Carbonization (4th degree)
– tissues are charred
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 burningnecrosis
degeneration /from 1. day/ hyperkalaemia
(heart, liver, kidney, bone marrow)
heart failure
poliuria /from 3. day/
autointoxication /from 7. day/ oliguria /for 2 days/
anaemia /from 7. day/
Hyperthermia
• Extremely increased internal temperature of the body
• Hyperthermia (failure of physical heat regulation)
– High (and humid) environmental temperature
– High own heat production (pyrogens)
– Heat loss is inhibited
• Consequences
– damage of vasomotor centrum, low blood pressure, spastic muscle
contractions, kidney insufficiency, hyponatraemia…
• Pathologic findings– Quickly developing rigor mortis, incompletely clotted blood, early putrefaction
– hemostasis in internal organs, brain edema, meningeal hyperemia and
hemorrhages in the hypothalamus
• Heat stroke (> 43°C)
Lesions
• Heat spasms
– electrolyte loss (sweating)
• Heat distress
– most often seen, collapse
– failure of cardiovascular compensatory
mechanisms after hypovolemia
– usually solved by itself
• Heat stroke
– vasodilation, hemostasis, necrosis, DIC
Sunstroke - Insolation
• Infrared (ultraviolet?) radiation of sunshine
– Longlasting or strong impact of sunshine
– Vasodilatatio in the skin of the head
– Vasodilatatio in the collateral brain vessels,
hyperemia
– Brain and meningeal edema – death
– Rare in animals (haircoat!)
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) – gangrene
– 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
• Against falling body temperature
– Contraction of muscles
• Shivering
– Vasoconstriction in the skin
– Increased metabolism
• Labile glycogen reserves are used up
– Shallow and quick respiration
Baby pig disease• Acute hypoglycemia of the newborn pigs
– Fatal if untreated
– Cold, starvation
• In newborn or young animals
– Heat regulation is not perfect
– Body surface is relatively large
Topics
• Irradiations and electricity (also
lightning) as cause of disease
• Inadequate oxygen and water supply
• Inadequate nutrient supply. Starvation
8., Irradiations and electricity
as cause of disease
Electricity as cause of disease
• Touching/biting a wire or hit by lightning (bolt)
• Electric shock – death: electrocution
• Animal effect – the effect on the animals
• Influencing factors:
– current intensity, voltage, duration, earthing
– resistence of the body (skin, wet ground)
• The higher the voltage the less the resistance!!!
• Alternity current more dangerous than direct current!
• Medium amperage cause disturbances
– Brain – loss of consciousness, heart failure – cardiac arrest
Common Kestrel
(Falco tinnunculus)
Pathology
• Entry: current marks and arboreal patterns– m. arrector pili
• Cavity between str. corneum and str. spinosum
• Electrolytic effect (direct current)– Coagulation necrosis of tissues
• Metallisation – dispersed metallic particles
• Spastic contractions (nervus vagus)
• Mechanical changes – secondary shock wave– fractures of bones, ruptures…
HE. 200x
HE. 400x
HE. 100x
HE. 200x
HE. 100x
HE. 400x
Radiant energy• Electromagnetic rays
– Ultra-short waves (microwaves - warming)
– Infrared waves (warm surface radiations)• Capillary dilatation – increased metabolic pr.
– Visible rays (physiological effect)
– Ultraviolet rays (biological - path. effect!)• Endangered organs: eyes, skin (pigments in animals!)
• Cancerogen effect
• Photosensibilisation
– alkaloids (eg. photodynamic substances) in the food…
• Photochemical reactions (producing vitamin D)
• SUNLIGHT – dermatitis solaris
Radiant energy• Ionizing rays - positive or negative charges
– Effect: dose, ionization, penetrability
– Cosmic rays
– Particular radiations (alpha, beta, proton, neutron,
deuteron rays)
• Alpha: greatest ionizing ability – low penetrability
• Beta: lower ionizing ability – higher penetrability
– Electromagnetic rays (X- and gamma rays)
• ionizing ability – high penetrability: biological effect!!!
– Abnormal cell division
Irradiation sickness
• Phase I (initial phase – after 1-2 hours)– dizziness, vomiting, exhaution, anorexia, nervousness
– alopecia
• Phase II (latent phase) – 1-2 days without signs
• Phase III (sickness – after a week)– Bone marrow lesions: hemopoietic insufficiency
– No phagocytosis, no antibody production
• Phase IV (break down - 4-5 months after)– diarrhea, anemia, kidney & liver failures etc.
– malignant tumors
DEATH
Lesions• Lymphocytes
– lymphopenia, smaller lymphonodes
• Bone marrow
– hypoplasia
• Testicles, ovaries
– atrophia, fibrosis
• Lens
– opacity
• Skin
– ulcers, tumors
• Cartilage
– retarded growth, malformation of the legs
• Fetus
– developmental anomalies
Climate and weather
• Climate and weather have direct and indirect
effect on the diseases
– Condition predisposes for certain pathogens
• Meteoropathology
– Hot front, cold front
– is there any connection between fronts and diseases? -
outbreaks
• Colic in horses
• Erysipelas in pigs
External causes of diseases• Physical effects
• Chemical effects
• toxicosis
• Biological effects
• Infectious agents
• Virus, bacteria, fungi, prions, protozoa
• Inadequate supply
• Oxygen, water, nutrient
9., Inadequate oxygen and water
supply
Disturbances in oxygen supply
• Suffocation (asphyxia) – lack of air
• Hypoxaemia – insufficient saturation of the blood
– Hgb saturation decreased (O2 decreased, CO2 increased)
– Hgb is incompetent for oxygen change (CO poisoning, nitrit poisoning)
– Hgb amount is less (hemolysis, anaemia)
– Intracellular respiratory enzymes are inhibited (cyanide poisoning)
– Paralysis of respiratory and/or vasomotor center
– Mechanical obstacles in the circulation and/or breathing
• Obstruction, compression, pneumonia, pneumothorax, pressure, paralysis
• Hypoxia - insufficient saturation of the tissues
• Hypercapnia – increased CO2 level in the tissues
Pathology of the suffocation
• Dark, unclotted blood
• Petechial hemorrhages
– serosal membranes, larynx, trachea, heart
• Acute lung hyperemia and edema
• Acute dilation of the heart
• Acute emphysema
• Differentiate from septicaemia!
Unclotted blood
Dilated stomach
Stomach torsion
Disturbances in water supply
• Exsiccosis, dehydration
– Lack of water intake
• Fluid loss never stops – eg. evaporation
• Relatively high mineral content, pH shift
– Increased fluid loss
• Vomiting, diarrhea, perspiration
• Pathological changes:
skin, eyes, etc.
• Hyperhydratio (water toxicosis)
– Normal kidney
– Loss of minerals and electrolites
10., Inadequate nutrient
supply. Starvation.
Disturbances in nutrient supply
• Total starvation (Inanitio completa)– No food intake (energy, protein)
– 40-50 % of the body: death (Cachexia)
• Partial starvation, malnutrition (Inanitio incompleta)– Food supply is not adequate
– Deficiency diseases
• Obesity, overfeeding (Obesitas)– Surplus of feed or feed components
– Continuous or occasional (dilation and rupture of the stomach)
– Other causes (lack of movement, hormonal disorder)
Obesity
(obesitas)
Incomplete starvation, malnutrition
• Causes
– Feed
• Quantity or quality (ingredients)
– Normal feed, but
• Inadequate food uptake
• Pathological lesions of the digestive tract
• Digestion - Maldigestion
• Absorption - Malabsorption
• Deficiencies
– Increased need
• Consequence: deficiency diseases
Complete starvation• Age
– young more sensitive
• Causes
– Lack of nutrients
• First glycogen is used up, than fat, proteins
• Consequence: autointoxication
– increased fat and protein catabolism ketonaemia
Cachexia
Oedema cachecticum