Classification of edema by etiology and pathogenesis
"Classification of burn states: etiology, pathogenesis, symptomatology and treatment of burns"
student 12 gr. ІІІ courses FVM
Burns(Combustio) - damage to tissues under the influence of hightemperature, radiant energy or chemicals. Depending on the cause that caused the burn, thermal, chemical, radiation (see Chapter X) are distinguished, and with combined effects - thermochemical and other burns.
Thermal burns. In agricultural animals, burns are most often observed in fires in cattle-breeding premises, and in domestic animals (dogs, cats) - due to scalding with steep boiling water, hot milk, oil and other liquids. In wartime, thermal burns are possible with the use of incendiary shells, flame throwers, incendiary mixtures, and the like.
The degree of severity of a thermal burn depends onthe temperature of the physical agent, the duration of its action, the dimensions of the burned surface and the depth of tissue damage. The deeper the tissue damage with a burn, the more the burned skin surface, the heavier the burn. In addition, in determining the severity of the burn, the condition of the affected animal, its age, and the possibility of pyogenic infection should be taken into account.
To determine the severity of the burn, usedetermination of its degree according to the accepted classifications and the dimensions of the surface of the damage. In our country there is a classification of burns, adopted at the XXVII Congress of Surgeons, which provides for the division of burns according to the depth of damage to four degrees: the first - skin hyperemia; the second - the formation of bubbles; the third degree is divided into two types - the third A (damage to the superficial layers of the dermis) and the third B (necrosis of the deep layers of the dermis); the fourth degree is characterized by the necrosis of the skin and tissues located deeper than its own fascia - muscles, bones, tendons, joints.
It should be noted that in practice,it is necessary to observe more often the combination of different degrees of burn in connection with the unequal force and the duration of the effect of the damaging factor on various parts of the skin surface.
First degree burn. Clinically, it is characterized by asepticserous inflammation, acute burning pain, arterial hyperemia and more or less impregnation of the affected area with serous inflammatory exudates. Redness is noticeable on the unpigmented skin. Acute pain, as in inflammation, is caused by exudate accumulated in the intercellular spaces, which presses on the sensitive nerve endings, irritating them with both mechanically and chemically formed toxins in the breakdown of proteins. Simultaneously, it has an immediate effect on the nerve endings of the temperature factor, Burns of the first degree, representing the slightest degree of damage on a limited surface of the skin usually passes without a trace - the hyperemia and pain gradually disappear, the serous effusion dissolves, and the epidermis peels off.
Second degree burn. It is characterized by more severe damage,when the phenomena of acute serous inflammation appear even brighter in connection with the lesion of the epidermal and papillary layers of the skin. In this case, carnivorous animals and swine form blisters as a result of the accumulation of inflammatory effusion between the corneal layer of the epithelium and the papillary layer of the skin. This is a characteristic sign of this degree of burn, which occurs soon or a few hours after the injury. Bubbles have different sizes, at first they are filled with a transparent serous or yellowish liquid. Subsequently, in connection with an increase in the permeability of the vessel wall and the release of leukocytes and coarsely dispersed proteins (fibrinogen) of blood serum and lymph, the swollen fluid becomes turbid.
The contents of uninfected blisters graduallyresolves, and exfoliated epidermis together with dried exudate forms a crust under which the newly formed epidermis grows. The healing proceeds according to the type of planar epithelization and is completed by the complete restoration of the affected area of the skin. When the blisters are infected, purulent pustules are formed. In this case, the course of the process is complicated, and the recovery occurs with the formation of a flat scar.
Often bubbles burst and from them followsabundant exudate, and the exposed surface appears wet, red and very painful. In the absence of infection, the surface quickly becomes covered with the newly formed epidermis. When bacterial contamination occurs skin ulceration, which, healing with the help of granulation tissue, usually give dense scars disfiguring the affected surface, and in the joint area - resistant contracture.
Third degree burn. It is characterized by coagulation necrosispart or all of the skin thickness to form a scab. Clinical signs of burns of the third and third degrees do not have a bright distinctive picture, which makes it difficult to recognize these lesions early. Local changes for third-degree burns are varied. Depending on the type of burn-causing agent, a surface dry light-brown or whitish-gray soft scab is formed. Since the phenomena of exudation and necrosis are combined, in some places there are bubbles.
Primary clinical and morphological changesat deep burns of the third B degree are manifested by coagulation (dry) necrosis. Under the direct effect of high temperature, blood plasma and tissue proteins coagulate, colloid falls out. At the same time, vessels are damaged, thrombosis and clotting of blood occur. All this causes the necrosis of all layers of the epidermis or the entire thickness of the skin and underlying tissue. The damaged skin becomes a dry, compact, insensitive mass (dry necrosis).
Burns with flames burned surfacegets dark, almost black. The surrounding skin, where there are phenomena of first and second degree burns, are sharply painful. At the border of the deadened area, a demarcation inflammation appears that separates gradually living tissues from the dead. At the site of tissue rejection, defects of different size and depth are formed, depending on the nature of the necrosis that has occurred, which are covered with a granulation tissue.
In the case of extensive deep burns resulting fromblood vessels and nerves are damaged blood supply and trophism are violated, which leads to a slowing down of the regeneration process. Epithelialization also proceeds very slowly. The extensive scars formed are covered with a thin epithelium, their surface is often ulcerated, especially in places prone to external irritations (friction, tension, etc.). Often there are long-lasting non-healing burn sores. All this leads to the formation of excessive scar tissue, which causes functional disorders. With burns of the limbs in the joint area, scarring can occur, and with burns in the head area, eyelid twists and so on.
During the rejection of dead tissues, a purulent inflammation may develop, leading sometimes to severe local and general events.
Fourth degree burn. Characterized by charring the entire stratumskin, subcutaneous tissue, fascia, muscle and even bone. When burns in the abdomen may damage the internal organs. This is observed with prolonged exposure to a heat agent of high temperature or by direct contact with a flame. The question of the advisability of treating animals with burns of the fourth degree should be solved separately in each specific case.
Pathogenesis. The severity of a thermal burn depends not only onits degree, but also the vastness of the burn damage to the skin, the general condition and age of the affected animal (very young and old animals suffer a more severe burn), the possibility of affecting the upper respiratory tract with hot air, gas or superheated steam, and developing post-burn intoxication. Even with first degree burns, with extensive skin lesions, severe intoxication may occur, aggravating the course of the burn disease.
A complex of general pathological changes,arising in the body with burns, is defined as a burn disease that manifests itself in the form of burn shock, toxemia, changes in the nervous system, parenchymal organs, cardiovascular system, blood morphology and biochemistry, and septicotoxemia.
Clinical signs. Burn shock manifests itself in the form of turbulentexcitation (erectile stage), lasting up to several minutes, which is replaced by oppression (torpid stage). In the first hours after the burn, the temperature of the body decreases by 2-3 ° C, which is explained by the violation of heat regulation, suppression of metabolism and cardiac activity (pulse weak, filiform). Reflexively falls blood pressure. In the subsequent drop in blood pressure and deterioration of hemodynamics contribute to an increase in the permeability of the walls of blood vessels and the release of a large amount of liquid part of the blood (plasma) into interstitial spaces, plasmorrhea in the affected area, leading to dehydration and a decrease in the volume of circulating blood. In this connection, the number of erythrocytes, leukocytes and percentage, the hemoglobin content in the blood increases. The blood thickens and becomes more viscous.
Along with these phenomena already in the first hours afterBurning, an aggravating effect on the condition of a sick animal is exerted by the resorption of toxic products of tissue necrosis, which is defined as the toxic phase of the development of a burn disease. So, according to NA. Fedorova et al. (1979), extremely active proteolytic enzymes and toxic abnormal proteins, burn toxins with antigenic properties, accumulate in fired tissues and blood. The introduction of them to healthy animals, as well as the transplantation of burned skin, caused in the experiments the same symptoms as in burned animals.
The totality of the listed phenomena leads tocirculatory disorders in the parenchymal organs, especially in the liver, lungs and adrenal glands, to the disturbance of oxidative processes in the cells and tissues of the body. The biochemistry of blood changes drastically-an alkaline reserve falls; and the heavier the burn, the more alkaline-acid balance changes to the acidic side. Developing hypochloremia, hypocalcemia and hyperglycemia. The content of potassium and nitrogen sharply increases due to the mass death of cells and the absorption from the surface of the burn of products of tissue decay. In the urine appears protein and increases the sugar content. In severe cases, hematuria is observed.
In the future, burn disease leads tosignificant functional and morphological changes in the central nervous system, parenchymal organs and gastrointestinal tract. As studies show, burned people and animals have hyperemia of the meninges, cerebral edema, hemorrhages in the nerve nodes, pericardium, hemorrhages and ulcers on the mucous membrane of the stomach and small intestines. There are degenerative changes in the liver, spleen and kidneys, as well as pulmonary edema. The adrenal glands are significantly enlarged, hemorrhage and destruction occur in the brain tissue.
The barrier function of the liver deteriorates,ventilation - of the lungs and excretory - of the kidneys. The latter is manifested by oliguria and anuria. Disturbance of digestion. Deterioration of hemodynamics is accompanied by a decrease in hematopoiesis. All this further exacerbates the metabolic disturbance and causes the development of decompilation of acidosis, as in the blood and tissues non-oxidized products and toxic substances from the lesion centers accumulate. Reduction of the skin excretory function and the ability to neutralize the toxic substances formed in the body strengthens histolytic and metabolic toxemia.
The totality of functional andmorphological changes leads to a weakening of the body's resistance and the development of local and general infection. As a result, a septic phase of the burn disease occurs, which often ends with the death of the animal.
Forecast. With burns, it depends on the degree of "vastness(approximately, they believe, burns of the head of animals make up about 6% of the entire surface of the body, the dorsal part of the neck, withers and back to croup-17%, the ventral part of the neck, chest and abdomen - 20%, thoracic extremities-15%, pelvic extremities and croup - 22%, genital area - 4%), age and type of animal, the general condition of the body. With the first degree burns, the prognosis is usually favorable, the second and third degree burns are limited, the prognosis is often more favorable, and for extensive lesions (up to 50% of the body surface) - from questionable to unfavorable. Very young and old animals suffer severe burns, so their prognosis is less favorable. Greater resistance to burn damage is found in cattle than in horses. In cattle, even with burns of the second - fourth degree with les bole; e 50% of the body surface is possible with appropriate treatment. Recovery Extensive burns in pigs are often accompanied by a deep torpid shock with a fatal outcome.
Treatment. It depends on the degree and size of the burned surface, the location of the burn injury, as well as the conditions under which medical assistance is provided.
First of all, eliminate the damaging effecthigh temperature, and then prescribe treatment. With extensive burns, based on general functional disorders and local tissue damage, treatment should be comprehensive (local and general) aimed at eliminating or reducing pain reactions and normalizing the function of the nervous system in order to prevent burn shock. They support cardiac activity and limit the permeability of capillaries, reduce or eliminate burn intoxication, accelerate the rejection of necrotic skin and tissues, create favorable conditions for the regeneration and prevention of infection.
Local treatment. With limited first and second degree burns, the treatment is mainly aimed at eliminating the pain reaction, reducing acute inflammatory phenomena, permeability of the capillary walls, preventing excessive serous effusion and the formation of blisters. Locally apply cold in the form of a bubble with ice or cold lotions with soda, boric acid, tannin or sprinkling the burnt surface with clean cold water. Periodically wet the affected area with alcohol rectificate. Painful tension is reduced when ointments with 0.5% menthol, as well as lanolin, petrolatum or zinc-petrolatum are applied to the burn surface. At the same time, take care not to accidentally damage the formed burn blisters, so as not to create a gateway for infection. The contents of the bubble gradually dissolves, in its place a crust is formed, after the rejection of which a new thin stratum corneum is visible. Thus, healing can take place without complications.
When forming large bubbles to avoidaccidental damage and exposure of the burn surface with a thin needle and syringe at the base of the bladder make a puncture, the contents are aspirated, followed by the introduction of 1-1.5 ml of a 5% solution of novocaine with 5% ephedrine and 0.25% solution kanamycin. The exfoliated horny layer falls off, adheres to the damaged surface of the skin and protects it.
In order to prevent infection,When carrying out any interference on the burned surface, strictly observe the rules of aseptic and antiseptic. To do this, the entire area of the burn and the adjacent areas of healthy skin are thoroughly cleaned of mechanical impurities, dry, sterile swabs remove charred hair, the skin along the circumference of the burn and its entire surface is treated with rectified alcohol, iodine gasoline or alcohol ether, cut with scissors flaps of broken bubbles, and then repeatedly abundantly moistened with a 5% solution of potassium permanganate. The latter thickens the skin, disinfects it, reduces the plasmorrhoea, binds and fixes toxins on the wound surface of the burn. On the naked from the blistering places a dense crust forms, which creates rest to the wound, protects it from secondary infection and gives a favorable course of epithelization.
Of tanning antiseptic substances besides potassiumpermanganate 10% aqueous solution of tannin, 2% solutions of methylene blue, diamond and malachite green in 3% alcohol solution of tannin, 10% aqueous solution of silver nitrate, etc. are also applied.
Some authors for protection and dryingburned surfaces are recommended to use a variety of powdered antiseptic substances - xerobes, dermatol, streptocid with penicillin, bismuth with starch or absorbent dressings - chalky, gypsum with the addition of antibiotics and sulfanilamide preparations to the components. Powders together with the detachable form a protective crust , which absorbs toxic substances well from the burned surface, protects against unnecessary traumatization and infection, creates favorable conditions for healing. After the sequestration of the dead tissues, ointment is prescribed - xerogram ointment, synthomycin emulsion, Vishnevsky liquid ointment, fish oil, etc.
Careful treatment of the burned surface with second degree burns in most cases provides primary healing and excludes additional treatment.
With third and fourth degree burns, medicalmeasures in the first day remain the same as with second-degree burns (hypothermia, normalization of acute inflammatory phenomena, pain relief, use of tanning antiseptics, prevention of infection, etc.). Along with this, considering the greater degree of damage to the skin and underlying tissues, most authors consider it advisable to use early necrotomy with subsequent skin transplantation or suturing.
In order to accelerate the rejection of dead tissuedamp aseptic dressings with various antiseptics are applied to the affected surface, vaporization is applied for 30-40 minutes up to 2 times a day, followed by application of 10% salicylic ointment, hypertonic solutions of middle salts, liquid Olivkov to the affected skin. In places of rejection of dead tissues, solidifying synthetic films and films of canned biological materials (collagen, fibrinous) can be used to protect the affected areas from the effects of the external environment and prevent infection. To accelerate the granulation appoint applications with Balsamic ointment Vishnevsky and sintomitsinovoy emulsion, ointment Olivkov (xerobean ointment with digitalis) and Konkov, as well as physiotherapy (ultraviolet irradiation, irradiation with a lamp of solux, paraffin applications,
With extensive burns in order to accelerateand the prevention of the formation of excessive scar tissue on the granulating surface make a transplantation of small pieces of auto skin (1X1.5 cm) according to the method of P.F. Simbirtseva. In addition, it is necessary to constantly monitor and regulate the process of epithelization and scarring so that they are premature aging of the granulation tissue and scarring of its degeneration. On this basis, the granulating surface is occasionally subjected to vaporization or paraffin applications are applied to it. According to P.F. Simbirtseva, with the aging of granulations, good results are obtained by the application of the skin, preserved with 2% chloracid, which not only freshen the granulation tissue, but also promote the resorption of the developed scar tissue. In order to prevent the development of extensive scars and the formation of keloids, we recommend tissue therapy, the use of enzyme preparations (ronidazum, etc.), pyrogenal.
General treatment of animals with extensive burns inThe first hours from the moment of damage should be directed primarily to the elimination of pain reactions and the prevention of burn shock. As painkillers, subcutaneously morphine, hexenal or pantopone, an intravenous 10% solution of sodium bromide with a dose of caffeine or a 0.5% solution of novocaine.
The first day after the burn to remove acutepain, capillary permeability restriction, plasmorrhoea, edema formation and acceleration of the rejection of coagulated tissues, depending on the localization of the burn injury, repeated regional neocaine blockades epipleural, with an interval of 2-3 days, according to V.V. Mosin, paranephrenic, according to I. Ya - Tikhonov, M.M. Senkina, cranial or stellate sympathetic nodes, etc. With limited burns of the extremities, short and circular novocain blockades can be used. In these cases, it is advisable to inject the novocain solution with a therapeutic dose of antibiotics.
When blood is thickened, the best results aretransfusion of plasma or serum of convalescent animals (from animals who had recovered from burn disease). These drugs contribute to the binding of toxins, improve the concentrating ability of the kidneys, normalize diuresis, relieve hypoproteinemia and shock conditions, reduce pain.
According to NA. Fedorova and S.V. Skurovicha, the use of serum or plasma convalescent in the first hours after a burn provides an easier flow of the burn disease and curing the local process in a very short time.
To combat intoxication, you can dobloodletting followed by transfusion of compatible blood. The best results are the transfusion of large doses of serum or plasma, as well as repeated administration of significant amounts of physiological glucose solution, a 40% solution of hexamethylene tetramine (urotropine).
Given that sick animals experience(oliguria), and sometimes even completely stops (anuria), it is also advisable to administer to the body by any means (copious drink, intrarectal, subcutaneous or intravenous injection of physiological sodium chloride solution) of large quantities of liquid (large animals up to 10 -15 liters per day). This prevents dehydration of the body, thickening of the blood and provides a more successful washing out of toxins from tissues and excretion through the kidneys, as well as the removal of acidosis.
To combat acidosis intravenously injected 4%solution of sodium bicarbonate (1000-2000 ml of large animals 2 times a day). Such therapy should continue for a long time, until the toxemia phenomenon disappears.
Sensitization is recommended to be removed by intravenous30% solution of sodium thiosulfate (50 ml in large animals, 3-5 ml in small animals), and 10% solution of calcium chloride to normalize the permeability of the walls of the vessels and cell membranes and the ratio of K and Ca. Apply antihistamines - diphenhydramine, etc.
In order to mobilize defensive forces, improvefeeding the body and reducing the acidosis of animals with burn injuries provide easily digestible vitaminized, alkalizing fodder. Large animals in the diet are injected with sprouted grain, a bolt from bran with the addition of baking soda, root vegetables. In addition, to raise the regenerative-regenerative processes and the antitoxic function of the liver, it is advisable to administer parenterally B vitamins, ascorbic and folic acid in combination with methyluracil or pentoxy, and to maintain the supply of the heart muscle and the necessary level of liver glycogen, a daily intravenous infusion of 20% solution of glucose with ascorbic acid.
Chemical burns. They arise in cases of exposure to chemicals on the outer covers of the animal's body and mucous membranes in case of improper use and negligent storage of chemicals. These include acids (nitric, sulfuric, hydrochloric, arsenic, chromic, carbolic, etc.), quicklime, salts of heavy metals (silver nitrate, zinc chloride, copper sulfate, etc.), alkalis (sodium hydroxide or potassium hydroxide, ammonia and other).
At the basis of the damaging effect of the listedchemical substances lies in the fact that three direct contact with living tissues they enter into a compound with the proteins of the protoplasm of cells, change its normal colloidal state and chemical composition, causing cell death. In this case, some of them (acids, salts of heavy metals) coagulate the proteins of the protoplasm of cells, taking away their water, others (alkalis) - dehydrating the tissues, dilute them. Clinical manifestations of chemical burns, the degree and nature of tissue damage depend on the type, concentration of the chemical and the duration of its action. When exposed to weak solutions of acids and the short-term effect of their strong concentrations, usually only inflammatory reactions occur, similar to thermal burns of the first and second degree, hyperemia and the formation of blisters.
Continuous contact of strong concentrationsacids and salts of heavy metals causes coagulation of proteins and dry tissue necrosis. At the same time, under the influence of acids, a limited dense surface scab is formed from the salts of heavy metals due to rapid dehydration of the tissues. With burns with sulfuric acid, a scab of black color appears, nitric - yellow, and under the influence of silver nitrate - a brown color. Alkalis and substances of alkaline action, like acids, take water from the tissue, but they do not roll proteins, but they dissolve, causing saponification of fats and moist (colliquated) tissue necrosis. Therefore, these substances easily penetrate into the thickness of tissues and produce deeper damage, forming a soft whitish color of the scab. As the destructive action of the chemical continues, the volume of the scab gradually increases. Rejection of the scab occurs more slowly than in burns with acids and heavy metal salts, and is often accompanied by bleeding. As a result, alkaline burns are slowly cleared from dead tissues and their healing is sluggish.
Changes in the general state of the body during chemical burns depend on the type and degree of chemical damage.
Treatment. In the case of chemical burns, it is primarily directedto the possible rapid removal or reduction of the concentration of the chemical agent and to neutralize it, and subsequently to accelerate the regeneration. The best results in this case are the flushing of the injurious substance with a copious stream of water followed by neutralization with chemical means. As chemical neutralizers apply: for burns with acids - alkali (2-3% solutions of ammonia, 5-10% solutions of bicarbonate soda, milk, chalk powder, burnt magnesia, ash, etc.), with burns with alkalis and quicklime - weak solutions of acids (2% solution of acetic, citric or boric acid).
In the future, attention is drawn to the prevention of secondary infection. The main treatment is carried out in the same way as thermal burns.
Thermochemical burns. This is a kind of combined damage to the outer covers of the animal's body, which usually flows heavier than chemical ones. The peculiarity of these burns is that along with the damaging effect of high temperature, the chemical agents themselves have a strong toxic effect on the body. So, phosphorus and phosphorus-containing self-inflammable liquids, hitting the skin, are inflamed and absorbed into the body, causing severe intoxication. Consequently, the overall response and severity of local damage with thermochemical burns will depend not only on the degree and area of the burn, but also on the toxicity and the amount of chemical absorbed into the body. Of the general disorders with severe phosphoric damage, shock, toxemia, acidosis, liver damage, leukocytosis, bilirubinemia in the blood and erythrocytes in the urine can be observed.
Treatment. First of all it is necessary as soon as possibleto extinguish the burning of phosphorus, and then to neutralize its unburned particles. This is achieved by abundant washing of affected areas with water or a 5% solution of copper sulfate or a dense application of lotions moistened with this solution, as well as powdering with talcum, chloric lime or applying gruel from it. In the absence of these tools, dry sand can be used. The most successful combustion of phosphorus is quenched by using special antiphosphorus pastes and solutions that convert it into a bound neutral state.
Given that the extinguished phosphorus can againit is necessary to remove it from the surface of the skin, to cut off the hair, then re-treat the affected area with lime or a solution of copper sulfate. Further treatment is carried out, as with conventional thermal burns. However, it should be remembered that with fresh phosphoric damages, the use of ointment dressings is contraindicated because of the risk of absorption of phosphorus into the body. When appointing a general treatment, taking into account the possible damage to the liver, recommend a diet of foods rich in carbohydrates.
The first aid for burns with melted bitumen provides for immediate removal with napkins moistened with gasoline.</ i> 1. Private veterinary surgery / K.I. Shakalov, B.A. Bashkirov, E.I. Povazhenko and others L. Agropromizdat, 1986. - 478p.</ H2>