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General teaching about disease


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Prepared by MD, Marta R. Gerasymchuk, department of pathop

Published in: Health & Medicine
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General teaching about disease

  1. 1. Classroom Etiquette: Turn off iPads and cell phones ! No tobacco use of any kind Be considerate of others: Take out what you bring in. Talk to me, NOT your neighbor! Remember for personal hygiene - cleanliness above all! Do not ask for release of classes, you are able go to the dean’s office and student’s clinic! NO:  Be Late (in case You are late - look above ↑ )  Plagiarism  Cheating  Allowing others to copy from you Penalties can be severe !!! REWORKS – every Monday at 4 p.m. (till last student)
  2. 2. Terminology Pathology – focus on physical changes in diseased organs and tissues Pathophysiology – abnormal functioning of diseased organs and how it applies to medical treatment and patient care
  3. 3. Pathological physiology is the science, which studies the general law fullness of disease genesis, development and the end.This is the science about the vital activity of sick organism.Pathological physiology is the study of the most common options of the disease genesis and development, while clinical sciences study specific items of disease prevention, diagnostics and treatment.Pathological physiology, as a science, solves the following problems: illness essence establishment; disease causes and it’s beginning conditions study; illness development, display, course and the convalescence mechanisms separate explanation; diseases prevention and cure general principles determination.
  4. 4. The pathological physiology is related to the othersciences. The following connections are:a) to the sciences, which study illness causing environmental factors (physics, chemistry, biology, microbiology, the social sciences), they are necessary for etiology studying;b) to the sciences, which study the organism properties and its vital functions (cytology, embryology, histology, the normal physiology, biochemistry, immunology, genetics), they create a base for pathogenesis study;c) to general theoretic sciences, which study an the disease (pathological anatomy, pharmacology), in common with pathological physiology create a total picture of the illness;d) to the clinical sciences, helping to determine the basic etiological and pathogenic principles of disease prevent, diagnostics and cure.The clinic arises the problems andgives the necessary material for theirsolvation to pathophysiologists.
  5. 5. The connect between the pathophysiology and other disciplines
  6. 6. Methods of Pathophysiolog y1. Clinical2. Epidemiological3. Anatomic4. Experimental The peculiarity of pathophysiological experiment is the reproducing of the experimental disease models upon laboratory animals with the purpose to establish the mechanisms of their genesis, development and in human organism.
  7. 7. • The experimental disease model is the artificial reproducing of disease up the laboratory animals, which has the same lines of the proper human disease.• Though an experiment up animals does not give us the full picture of the proper human disease, it enables to observe and to study the disease course the beginning to its completion, that is impossible in clinics. During the experiment one can control the environmental conditions, which influence upon the illness course and have the objective material for the scientific theories construction.• The experiment can be divided into the acute and the chronic one.• The acute experiment is based on the surgical intervention in animal organism. It examines the acute disorders in organism (shock, collapse, sharp breathing insufficiency, blood circulation insufficiency, etc).• The chronic experiment is a protracted one, shows the illness development dynamics. It is used for chronic diseases modeling (diabetes, atherosclerosis, arterial hypertension, ulcerous disease etc).
  8. 8.  Pathological physiology consists of such parts:► the general pathology and► the pathophysiology of the organs and systems. The general pathology unites such parts:► nosology,► pathogenic environmental factors action,► inner factors role in pathology, ► typical pathological processes,► the typical metabolic disturbances. The pathophysiology of organs and systems studies the general development of pathological processes in separate functional systems; the most widespread nosological forms are etiology and pathogenesis .
  9. 9. The general nosology includes such notions:healthdiseasepathological processpathological statepathological reactions
  10. 10. Nosology► Nosology (fr. Gk nosos, disease + logos, science) is a general science of diseases including the basic concepts and categories of pathology, classification and nomenclature of diseases, social aspects of pathology.► Nosology deals with many problems: building basic scientific terms, used in medicine: Health and Disease, pathological processes, conditions, pathological reactions, stages of a disease, its complications, and other terms which are of medical importance.► Development of nomenclature of diseases and their conditions.► Building a classification of diseases.► Laying the foundations for the general study of diseases.► Developing a theoretical conception of medicine.► Basic concepts of nosology:► Health, disease, normal, pathological reaction, pathological process and pathological conditions.
  11. 11. TERMINOLOGY• Etiology (fr. Gk aetia, reason + logos, science) is the science of causes and conditions of disease occurrence. Etiology studies general properties of pathogenic factors, basic categories of pathogenic factors, significance of conditions in occurrence of diseases, principles of etiotropic prophylaxis and etiotropic therapy.• Pathogenesis (fr. Gk pathos, disease + genesis, origin) is the science of mechanisms of development, course and outcome of diseases. The science of pathogenesis includes: mechanisms of stability of organism to the action of pathogenic factors, general mechanisms of development of diseases, mechanisms of recovery, mechanisms of dying, principles of pathogenetic prophylaxis and pathogenetic therapy.• Biological modeling is an artificial reproduction of disease processes in a living organism (in a cell, organ, entire organism).
  12. 12. TERMINOLOGY• A pathological reaction (fr. Gk pathos, affliction, disease; Lat. re- - against, actio - action) is an organism response to extraordinary irritant, which is sometimes a symptom of disease.• A pathological process is a complex of pathological and protective- adaptative reactions as a response to a damaging effect of a pathological factor.• A typical pathological process is a pathological process developing in accordance with the same rules, irrespective of reasons and localization.• A pathological function (fr. Gk pathos, affliction, disease; Lat. functio, activity) is a disorder of function of a cell, tissue, organ, system of organs and vital activity of organism).• A pathological reflex (fr. Gk pathos, affliction, disease; Lat. reflexus, reflected) is a disorder of functional activity of organs, tissues or systems, occurred with participation of CNS in response to pathogenic irritation of receptors and manifested as pathological reactions of organism.• A pathological condition (status pathological) is a stable abnormality of organism functions, a sluggish pathological process or the consequence of an earlier suffered pathological process.
  13. 13. Health is the condition of completephysical, psychic and social well-doing, but not only diseases or thephysical defects absence (WHCO –World Health Care Organization). In doctor’s practical activity determination is used, according to which health is the condition of a norm. There is a question: what is the norm? There are two approaches to this notion determination: the statistic and the general physiologic one. According to the first one, the norm is the condition, which is the most frequently observed among people. According to the second one, the norm is the biological optimum of the organism functioning and development. The second determination reflects the scientific approach to the notion which is “a norm”. However this approach remains still unrealized because of our knowledge and possibilities limitation.
  14. 14. Disease – loss ofhomeostasis, or when physicalor mental capacities cannot befully utilized (interuption,cessation or disorder in thefunction of an organ orsystem). The disease is disturbance of human organism vital activity under the influence of extraordinary factors of external or inner environment which is characterized by lowering of capacity for work and adaptation with simultaneous mobilization of protective forces.
  15. 15. • Stages of a Disease.1. The latent period or incubation period of an infectious disease. The incubation period of a disease lasts from some hours to some days or years. The patient must be isolated or hospitalized.2. Prodromal period of a disease. The patient develops generalized clinical symptoms of a disease (complaints of a headache, slight malaise, chills, rheumatic pains in his joints as well as muscular pains). The doctor can make a preliminary diagnosis in this period of disease development.3. Dromal period of a disease. It is marked by all clinical characteristics of a disease. In the dromal period the patient develops all specific clinical symptoms. The doctor has to make the final, basic diagnosis in this period of disease development.4. Outcome of a disease will be favorable or unfavorable. – recovery - complete or incomplete – recurrence – chronic disease –remission and exacerbation• Terminal state• preagonal state• agonal state• clinical death• biological death.
  16. 16.  The diseases endings are following: convalescence ( complete and incomplete), recurrence, into chronic form transition, the death. The convalescence is the process, which conduces to the violations liquidation, caused by an disease, and normal relations with the environment  restoration, for human beings – foremost the ability to work restoration. The full convalescence is the state when all the disease signs disappear and organism restores its adaptation possibilities completely. When the convalescence is incomplete the disease consequences are expressed. They remain for a long time or forever. The convalescence is provided by the urgent (emergency) and lasting protectively-compensational reactions of the organism. The remission is the temporal state improvement of the human being, which is displayed by the disease progressing slowing down or cessation, the partial reverse development or the disappearance of the pathological process clinical signs. The recurrence is the new disease display after its seeming or incomplete cessation. The complication is secondary as for reference to the disease pathological process. The transition in the chronic form signifies that disease courses slowly with the protracted remission periods (months and even years). So, many diseases acquire chronic nature in old age (chronic pneumonia, chronic colitis).
  17. 17. The terminal states are the boundary ones between lifeand death. This is also the dying, which include a few stages: pre-agony, agony, clinical death, biological death.► The preagony is characterized by the diverse duration (during hours, days) of deep violations of the vitally important organism functions. The dyspnea, the decreasing of the arterial pressure, the darkening down of the consciousness, which are observed in this period. Gradually the pre-agony gets across in the agony.► The agony is characterized by the gradual turning down of all organism functions. The agony lasts 2-4 minutes, sometimes more.► The clinical death is such condition when all of the visible sparks of life have already disappeared (the breathing and the heart work are ceased, however the metabolism still continues). The life can be restored on this stage.► The biological death is characterized by the irreversible changes in the organism.► The reanimation of the organism includes number of measures which are directed foremost to blood circulation and breathing renewal: heart massage,  artificial lungs ventilation, heart defibrillation. The indirect heart massage is widely used for the renewal of blood circulation, it can be used at once after the clinical death setting in any conditions and even not by specialist. The artificial ventilation of the lungs also must be started as soon as possible. The heart fibrillation is observed in the terminal period ordinary. In such cases the electric defibrillation is used. A single digit to 6000 V removes the fibrillation and promotes the renewal of the blood circulation.
  18. 18. Cause of a Disease• One of the most important and difficult questions is the problem of establishing the cause of a disease. The tactics of the physician and the success of treatment of various diseases depend on the correct solution of this problem. Pavlov believed that a problem of etiology is the least investigated problem of medicine. In the course of development of natural history the theory of etiology of diseases has been changing. Each etiological theory was influenced by the dominant ideas of the time it was formed at. The old theory could not account for new facts. There were two ways of doing research: either to deny the facts or to change theories interpreting them.• The ancient medicine gave rise to the idea of a causative agent as a major etiological factor. XVII –XVIII centuries witnessed the development of a new doctrine known as mechanical determinism.
  19. 19. Theories•The mechanical determinism of XVII-XVIIIcenturies was of great significance for thedevelopment of the theory of pathology. Within aframework of mechanical determinism some basicmethods of establishing causal connection (methodof isolation, method of similarity, method ofdifferences, method of attendant changes, method Louis Pasterof remainder) were elaborated. These methods arestill of great importance nowadays.• The important stage in the development of this scientific trend was elaboration of the theory of mechanical monocausalism.• The origin of this theory was prompted by discoveries of infectious pathology. Within a short period of time the causative agents of most widespread infectious diseases were discovered which was inspired by Paster’s idea that diseases may be caused by infectious agents. Many scientists overestimated the importance of microbes in the development of diseases.
  20. 20. Theories• Monocausalism was most fully reflected in the conception of Genle - Kock:• A certain microbe causes a certain disease, it can be found neither in healthy people nor in people suffering from other diseases.• A microbe can be isolated in a pure culture.• Pure microbial culture will cause the disease whose causative agent it is supposed to be in experiment.• This conception was of great importance as it channeled the research into discovering numerous microbes.• However, there was some clinical evidence which contradicted this conception. Firstly, the study of severe epidemics revealed that not all people get infected and develop a disease. Nor all of those infected die. Secondly, there was experimental evidence that a hen which is not subject to anthrax in ordinary conditions dies if its legs are kept in cold water for a while. Thirdly, milkmaids that had had cowpox did not catch smallpox during epidemics.• Finally, in 1884 Lefler discovered the fact of carriage of bacilli. He found virulent streptococci and pneumococci on the mucous membranes of the pharynx and on the tonsils of healthy people.
  21. 21. TheoriesLater a new theory of conditionalism gained popularity.The founder of that theory was Ferworn. He formulatedfive principles of this conception.1. The first of them is as follows. There are no isolated and absolute things. All processes or states are conditioned by other processes or states.2. There are no processes or states which are determined by a single factor. All processes or states are conditioned by a large number of factors (doctrine of multiple conditions).3. Every process or state is unequivocally determined by the sum of their conditions4. Every process or state is identical to the sum of their conditions.5. All conditions of any process or state are equally significant.• Conditionalism is a subjective idealism theory. Microbes alone can not account for the origin of infectious processes. But we should not underestimate the role of microbes in this process.
  22. 22. Theories• Another step in the development of the doctrine of etiology is constitutionalism. The founders of this theory believed that diseases may be caused by a constitution type. These types are as follows: normal, asthenic or hyperstenic constitution. Each type of constitution has its own peculiarities. People of asthenic constitution are subject to stomach ulcer and tuberculosis. People of hyperstenic constitution are likely to suffer from myocardial infarction or bronchial cancer. This theory is based on the theses of formal genetics and on genotype invariability. However, a genotype can change under the influence of many exogenous and endogenous factors. Therefore, this theory can not be considered true.
  23. 23. TheoriesThe next theory was elaborated by Zigmund Freud.This author distinguished three main systems in thepsychic (mental) structure of a person: the conscious,the subconscious and the unconscious. The latter is thehome for sexual instincts. • The conscious constantly suppresses these instincts. Freud believed that a daughter’s love for her father, a son’s love for his mother are manifestations of sexual instincts. Human consciousness constantly suppresses these sexual instincts. But having a high power charge they tend to struggle their way to consciousness. This results in the development of numerous diseases such as schizoprenia, epilepsy, neurosis, etc. • Zigmund Freuds conception had a great effect on the western medical science. It also gave rise to a new branch of medicine, i.e. psychosomatic medicine. The supporters of this branch of medical science suppose that diseases may be caused by psychological conflicts in childhood. Different pathological processes are conditioned by different stages of children’s development when disorders occur. • Under 6 months of age an infant seeks for his mother’s love and has a food instinct. Disorders at this age lead to bronchial asthma or ulcer. Under 3 years of age a child has an inclination for analysis. They often break their toys and other things. If parents forbid to do this a child gets aggressive and spasms of the muscular system occur. From 3 to 6 years a child develops a sense of self and sexual feelings. Disturbances at that age will result in hysteria and in various sexual disorders.
  24. 24. • Thus, we have outlined the main theories of etiology in medicine. Nowadays etiology is a theory of causes and conditions of a disease development.• A cause determines specificity and quality of the bodily reaction to a pathological process. A cause also determines connections and regularities of the processes. For example, tuberculosis is caused by Micobacterium tuberculosisIt is responsible for specific and morphological changes typical of it.• The following these underlie the modern idea of causality:• All natural phenomena have their own cause, there are no causeless phenomena.• The cause is material, it is independent of our existence.• The cause interacts with the organism. Changing the body, the cause changes itself.• The cause gives a new quality to a process. It is the cause that makes a pathological process special and unique.• Classification of causes:• Exogenous: physical, chemical, biological, psychic/mental and social.• Endogenous.• Conditions.• Psychic/mental conditions in childhood.• Urbanisation.• Industrialisation.• War.• Unemployment.
  25. 25. The diseases classifications are based on the following criterias:• 1. The etiological classification is founded on the cause community for the diseases group. For example, there are the infectious and uninfectious diseases. According to the same principle one can group the diseases caused by an intoxication (food, professional), genes violations and chromosomal mutations (hereditary diseases) etc.• 2. The topography-anatomic classification is based on the organ principle: the cardiovasculars diseases, diseases kidneys, diseases of nervous system etc. It is comfortable for practice. Besides, it corresponds to the modern specialization of the medical help. It combines with the classification of the functional systems: blood system, digestive system, musculosceletal apparatus diseases etc.• 3. The age and sex disease classification. There are the children’s diseases, the senile age diseases. The female genitals diseases are studied by the gynecology.• 4. The ecological diseases classification proceeds from the human dwelling conditions: the air temperature, the atmospheric pressure, the sun illumination.• 5. The classification according to the pathogens commonness: allergic and inflammatory diseases, neoplasms, shock, hypoxia.
  26. 26. The general etiology• The etiology is the learning of  disease beginning causes and conditions. The notions of causality and determinism are base of etiology.• A causality reflects an objectively existent phenomenas connection, when one phenomenon (cause) inevitably causes beginning of the other phenomenon (result) by the definite conditions. Any disease just like a phenomenon has its own cause. The beginning and the development of the disease are not by chance but subordinated to the definite lawfullness.
  27. 27. Classification of etiological factors They are exogenous (external) and endogenous (internal). The exogenous factors: a) physical – mechanical influence, radiation, high and low temperature, electric current, overloading, zero-gravity and others b) chemical – the inorganic and organic compound; c) biological – viruses, rickettsias, bacterias, Protozoas, helmints, Arthropodes d) psychic – a word e) social – society development level, traditions and others The endogenous factors: heredity constitution age sex organism reactivity
  28. 28. Categories of etiologyGenetic disease– genes are responsible for a structuralor functional defectCongenital disease– genetic information is intact, butthe intrauterine environment interferes with normaldevelopmentAcquired disease – disease is caused by factorsencountered after birth (biological agents, physicalforces, and chemical agents)Clinical manifestations – indications that the person issickSymptoms – unobservable effects of a disease reportedby the patientSigns – observable or measurable traitsSyndrome - a characteristic combination of signs andsymptoms associated with a particular disease.
  29. 29. Pathogenesis - sequence of events in the of development of a diseaseSequelae – lesions or impairments resulting from a diseaseAcute conditions – rapid onset, develop quickly, usually of short durationChronic conditions – longer duration onset may be sudden or insidiousDistribution of lesions may be: Local – confined to one area of the body Systemic – widely distributed throughout the bodyWithin an organ damage can be: Focal if there are only one or more distinct sites of damage Diffuse if the damage is uniformly distributedDiagnosis – identification of the specific diseaseTherapy – the treatment of the disease to either effect a cure or reduce the patient’s signs and symptomsPrognosis – prediction of a disease’s outcome
  30. 30. Risk FactorsThe risk factors are the factors combinations, the presence of which in people population statistically increases morbidity by definite diseases. The belonging of these or those conditions to the risk factors is determined by epidemiological methods, which envelop the large people contingent.So it was established, that the violation of blood plasma lipid composition, arterial hypertension, the age, belonging to male, obesity, hypodynamia, hereditary factors, stress are the atherosclerosis risk factors.
  31. 31. Adaptation and compensation The base of adaptation and compensation are the same mechanisms which are named protective -adaptation or protective-compensatory. The distinction between these notions: is adaptation develops in augmentation of the action intensity of usual factors environmental. The damage hasn’t happed yet, and the homeostasis indexes are coming to the extreme norm borders. The compensation develops in the action of the pathogenic factors when a damage takes place and the homeostasis indexes are beyond the extreme borders norms.
  32. 32. Adaptation and compensation in disease development 1. The stage of immediate adaptation and compensation. The mobilization of existing mechanisms and reserves begins and as a result of loading on functioning system unit increases, its hyperfunction develops. On this stage the events develop according to such scheme: the action of pathogenic factors → the violation of homeostasis → the perception of homeostasis violation → regulatory centers → immediate protective reactions (specific and unspecific) → the hyperfunction of proper structures, supporting homeostasis. 2. The stage of the long duration adaptation and compensation. The augmentation of systems power, responsible for adaptation and compensation is its base. It is reached by the augmentation of the structures amount, providing a hyperfunction, so hypertrophy develops. The hyperfunction → violation of intracellular homeostasis → activation of genomes → decrease of the proteins synthesis → cell hypertrophy.
  33. 33. The general pathogenesis• The pathogenesis is the study about the mechanisms of the development, the course and the end of disease. The pathogens studies everything taking place after the cause action.• It is necessary to mention the following questions in disease pathogenesis consideration:1) the role of etiological factor in disease development;2) the organism reactivity significance for the disease beginning and the course;3) the significance of the general and local changes and their correlation;4) the basic link of pathogens and causally-investigation intercourses;5) the significance of functional and morphological changes and their correlation in disease;6) the significance of nervous system functional changes for disease development. There are three variants of connections between a cause and a pathogens:1) Etiological factor initiates the pathologic process and then disappears, so the pathogenesis develops without etiological factor (trauma, radiation).2) The cause continues its action throughout all the period of the development of the disease (infectious disease), as consequence the etiological factor penetrates into pathogenesis, exist in it and influence it.3) Persistence of the cause agent, which causes the disease, is delayed in organism (healthy bacilli-carrier).
  34. 34. How does pathogenesis divide? (four periods of pathogenesis)• The pathogenesis is a new complicated process in the organism with the two quite opposite processes:• 1) "the measure against the disease" (by I.Pavlov) — it means the compensatory and protective reactions• 2) "pathologic process proper"• So, the pathogenesis is a unity of opposites, which always fight (law of dialectics). The doctor must find out pathologic process the proper and stimulate the protection. There are four stages of pathogenesis:• 1) latent period (incubation period of the infectious diseases); 2) prodromal one; 3) the period of expressed manifestations; 4) the outcome of the disease.
  35. 35. Local and Systemic in Pathogenesis• The study of pathogenesis of diseases proved that hare are neither purely local nor purely systemic diseases. The effectiveness of treatment depends on the correct understanding of this idea.• All diseases are local and systemic at the same time, which determines the development of processes. Dental caries can be treated using a stopper. If caries results from a systemic disorder of mineral and albumin exchange it requires a general treatment.• The correlation between local and systemic changes must be timely considered.• A local process, for example, a furuncle can develop as a result of the impairment of defense mechanisms of the organism which limits this process and makes it local.
  36. 36. Local and Systemic in Pathogenesis
  37. 37. Causally-investigation Relations The changes in organism which arise during disease development are in definite causally-investigation relations, it means that the same phenomenon of pathogens is the result of violations and cause of other. Such type of causally- investigation relations when the definite links  the pathogens over violation sequence bring to their heightening over so called “the vicious round ”. It supports itself the pathogens of the disease and redoubles its course. So, in pathogens of any shock lowering of arterial pressure has big significance that becomes cause of anoxaemia. The cerebral hypoxia brings to the oppression of vasomotor centre and greater lowering of arterial pressure (a circle locked). The main link of pathogens is the process which is necessary for a development of all the rest. The liquidation of the main link in time brings to removal of pathological process as a whole. The main principle of pathogenetic diseases cure is founded on it. So, in diabetes mellitus the insulin lack is the main link of pathogens. Its liquidation (the introduction of hormone) brings to disappearance of  other displays (hyperglycemia, glucosuria, polydipsia, ketonemia, comas). In  pathogens  specific and unspecific processes and mechanisms are always combined. The specific ones depend on the cause properties and determine the basic disease descriptions. A search of the specific signs lays in base of  diseases recognition (diagnostics).
  38. 38. Vicious circle Causes and consequences constantly change their places. The cause (etiological factor) causes the pathologic reactions (process) and than these reactions return to the first agent (etiological factor) and intensify it. So "vicious circle" is formed m pathogenesis For example, if arterial pressure decrease it causes the hypoxia and than vasomotor center depresses. It leads to the prolonged decrease of arterial pressure.
  39. 39. Nonspecific and SpecificSigns Every disease can have its signs that are typical of this disease only (for example, irradiation of the pain in angina pectoris), while other signs are typical of many diseases or even for all. This common nonspecific aspect of pathogenesis depends on the reactions of the organism developing in the course of evolution and is hereditary. There are five nonspecific reactions: Parabiosis. This is stable, non-spreading excitation, which occurs in damaged excitable tissues. It is important in pathogenesis of some forms of cardiac blocade. Dominant reaction. This is a condition of a stable rise of excitability of the group of nerve centers, which regulates the overall activities of the body. The dominating motivation gives rise to other dominants such as nutritional, sexual, etc.
  40. 40. Negative effect of changes of atmospheric pressure A man feels the effect of decreased atmospheric pressure during ascent on plane or in mountains, or the pilots flying in nonhermetically sealed cabin. The pathologic changes, occurring in it, are caused by two main factors: a) decrease of partial pressure of oxygen in inspired air; b) decrease of atmospheric pressure (decompression). The clinical signs of decompression syndrome are: pain in the ears and frontal sinuses because of expansion of air in these cavities, nasal bleeding, because of bursts of small vessels. Bursting of alveoli and vessels causes the gas bubbles to into the blood circulatory system (gas embolism, hypoxia, boiling of blood and other liquids, especially at the height of 1900 m). A man feels the effect of increased atmospheric pressure in water during diver’s or caisson works. The most important is the fact if of quick increase of atmospheric pressure (hyperbaria) so the rupture of lung alveoli occurs and additional quantity of gases dissolves in blood and tissues (saturation). Nitrogen plays a key-role in breathing with the compressed air. The quantity of nitrogen in the body can sometimes increase, especially in the organs, which contain a lot of lipids (nervous system). The first manifestation is a light excitement, like euphoria, the next are the phenomena of narcosis and intoxication. Not only nitrogen is toxic, but also oxygen (hyperoxia) realizes its toxic effect a little later. The hemoglobin molecule is blocked by oxygen and loses its ability to carry out carbon dioxide. The result is that oxygemoglobin practically does not dissociate and carbon dioxide is not removed. Toxic effect of high concentration of oxygen is similar to the effect of radiation. In both cases the formation of free radicals and peroxides with strong exudative abilities causes affection of DNA and tissue enzymes. The antioxidant therapy must be used, such as tocopherols, glutathione, ubiquinone and others, which suppress free radical oxidation. Decompression can be used which is a method of returning of the man into the conditions of normal atmospheric pressure and the excretion of the excess quantity of dissolved gases via blood and lungs (desaturation).
  41. 41. Pathogenic influence of electric current• Mechanism:• Electric energy is transformed into:• 1. Mechanical tearing off tissues and bones and even part of the body• 2. Thermal – temperature in place of penetration may be 120 °C and more – than burns arise• 3. Chemical – electrolysis may cause changes of biological potential of the different cells.
  42. 42. The effect of ionizing radiation• The rays of high energy (X- and γ rays), α and β-particles, proton possesses the ability to penetrate into the radiated environment and produce ionization.
  43. 43. The Effect of the Thermal Factors 1. The effect of the high temperature (when the air temperature elevation varies from 33 °C to 37°C, it is equal to the body temperature) is the development of the overheating (local effect – burn), or the effect of the low temperature – hypothermia. 2. Characterize overheating. There are two stages: 1) Compensation stage, when normal temperature is preserved. 2) Decompensation stage, when overtension of thermoregulation leads to its exhaustion. 3. Describe hypothermia. The effect of the low temperature on the body may result in the decrease of the body temperature and the development of pathological condition – hypothermia. There are two stages of overcooling: 1. Compensation stage is directed at limitation of the heat emission. 2. Decompensation stage or hypothermia proper.
  44. 44. Crush Syndrome Crush syndrome (CS) is a variant of traumatic disease. The main pathogenic factors in CS are:1) Pain syndrome2) Intoxication3) Psychoemotional stress4) Hypovolemia Characterize the clinical course of crush syndrome. There are three periods in the clinical course of crush syndrome:1. Early (to 3 days, with compression and decompression phases)2. Intermediate (from 8 to 12 days) with the prominence of acute renal insufficiency (ARI)3. Late (from 12 days to 1-2 months — the period of recovery with the prevalence of local syndromes.
  45. 45. Literature Basic:1. General and clinical pathophysiology / Edited by Anatoliy V. Kubyshkin – Vinnytsia: Nova Knuha Publishers – 2011.2. Pathophysiology, N.K. Symeonova. Kyiv, AUS medicine Publishing, 2010.3. Gozhenko A.I., Gurcalova I.P. General and clinical pathophysiology/ Study guide for medical students and practitioners.-Odessa, 2003.4. Essentials of Pathophysiology: Concepts of Altered Health States (Lippincott Williams & Wilkins), Trade paperback / Carol Mattson Porth, Kathryn J. Gaspard. – 2003. Additional:5. Robbins basic pathology, 7/e / Kumar et al. – Indian reprint, 2004.6. Pathological physiology / Yu.I. Bondarenko, M.R. Khara, V.V. Faifura, N. Ya. Potikha. ‑ Ternopil: Ukrmedkniga, 2006.7. Pathophysiology, Concepts of Altered Health States, Carol Mattson Porth, Glenn Matfin.- New York, Milwaukee- 2009 p.8. Stephen J. McPhee. Pathophysiology of Disease. An introduction to Clinical Medicine / Stephen J. McPhee, William F. Ganong // Lunge Medical Books/McGraw-Hill. – 5th edition. – 2006.9. foreign-students-englishstep-111.