Etiology: term, definition, concept, classification. The role of causes and conditions in the occurrence, development and overcoming of diseases. Theoretical and practical significance of the study of etiology. General etiology
2. The concept of "etiology". Causes and conditions for the occurrence of diseases. Etiological factors external environment. Ways of introduction of pathogenic factors into the body and ways of their distribution in the body.
Under etiology one should understand the doctrine of the causes and the complex of adverse conditions (external and internal), in the presence of which the cause can manifest its pathogenic effect and cause the development of the disease.
Cause called a factor disease-causing and giving it fundamental, as a rule, specific features, without the influence of which the disease is impossible. There are external (exogenous) and internal (endogenous) causes of the disease.
Endogenous causes associated with heredity, constitution, etc. Reason large group so-called hereditary diseases are various kinds genetic defects.
Factors of an unusual nature for an organism that it does not encounter in everyday life (virulent microorganisms, toxins poisonous snakes, insects, other poisons), as well as habitual factors that differ in unusual strength or duration of their action are called pathogenic orpathogenic. Adaptation to the action of such factors is impossible or requires special conditions (training, hardening, vaccination, etc.)
Along with the cause of the disease in its occurrence and development importance have conditions that encourage and discourage it. They can be external and internal.
The factors contributing to the occurrence of diseases include malnutrition, hypothermia, overheating, high air humidity, rapid temperature changes, overwork, previous diseases, hereditary predisposition, pathological constitution, early childhood and old age, social environment.
As an example of conditions preventing disease development, you can call a balanced diet, an organized daily routine, fitness, hardening. Hereditary, racial and constitutional factors matter, namely species immunity, hereditarily determined resistance to certain types of pathology.
Ways of introducing pathogenic factors into the body: alimentary, parenteral, airborne, placental, contact-household, transmissible.
Pathways for the spread of pathogens in the body: by continuation, by contact, through the blood and lymphatic vessels, through the nervous system.
3. Objective and subjective signs of diseases. Symptoms and syndromes.
Subjective symptoms- these are the sensations of the subject due to the disease, for example, pain, nausea, increased fatigue. Of course, the symptoms can be felt and described in many different ways. different people or by the same person but in different situations.
The accuracy of the description of subjective symptoms is influenced by the instrument by which the data is usually collected; To improve the reproducibility of the results, standardized interview methods and questionnaires were developed. However, the identification of symptoms during an interview is influenced not only by the wording of the questions, but also by the interviewer himself and the interview environment.
Objective symptoms are manifestations of a disease that the examiner (usually a doctor) can observe, such as a rash or swelling. The confirmation of signs is influenced by the subjective judgment of one researcher (or several researchers). Such subjectivity is inherent in the results obtained by auscultation (listening) of the heart and lungs or by palpation (palpation) of the abdominal organs. It is also noted in radiographic studies, including the interpretation of an x-ray, and in the morphological study of tissues.
Accuracy such surveys depends on the degree of consistency between the actions of different researchers (interpersonal variability) and on the consistency of different studies conducted by the same person (intrapersonal variability).
Each disease is characterized by its typical clinical Symptoms and Syndromes.
Symptoms(symptoma - sign) - these are signs of a disease (a sign of a pathological condition or disease) detected during clinical diagnosis. Many of them are named after the scientists who described them: Bekhterev's symptom, Botkin's symptom, Vasilenko's symptom, etc.
All symptoms are divided into: 1. subjective(when pathological manifestations are felt by the patient himself) and Objective symptoms(changes revealed during the examination of the patient by a clinician). 2. Early and Late Symptoms - according to the timing of the appearance in the course of the disease. 3. Specific and non-specific(for a specific disease) Symptoms. The presence of a symptom specific to a particular disease increases the likelihood of correct recognition of the disease, although it is not enough for the absolute certainty of the diagnosis.
Syndrome(Greek syndrome - accumulation, confluence of signs of the disease, running from syndromos together; synonymous symptom complex) - a set of symptoms united by a single pathogenesis; sometimes the term syndrome denotes independent nosological units or stages (forms) of a disease. Currently, more than 1500 syndromes are known.
The concepts of "syndrome", "symptom" are not equivalent to the definition of the disease as a nosological unit. However, the word "syndrome" is often included in the name of a particular nosological unit. For example, Itsenko-Cushing's syndrome (disease) or prolonged compression syndrome (disease).
Factors that influence the occurrence and development of diseases are called conditions for the onset of the disease. Unlike causative factor conditions are not necessary for the development of the disease. In the presence of a causative factor, the disease can develop without the participation of some conditions for its occurrence. For example, lobar pneumonia, caused by pneumococcus of strong virulence, can develop without a cold, without weakening the diet and other conditions. There are conditions that predispose to the disease or contribute to its development and prevent the occurrence of the disease and its development. Conditions that promote or hinder the development of diseases can be internal and external.
To internal conditions contributing to the development of the disease include hereditary predisposition to the disease, pathological constitution (diathesis), early childhood or old age.
To external conditions contributing to the development of diseases include malnutrition, fatigue, neurotic states, previously past illnesses, poor patient care.
To internal conditions that prevent the development of diseases, include hereditary, racial and constitutional factors. These include, for example, human species immunity to certain infectious animal diseases. A person does not suffer from the plague of dogs and cats, pneumonia of cattle and many other infectious diseases of animals. People with sickle cell anemia do not get malaria.
To external conditions that prevent the development of diseases, refer to good and balanced diet, proper organization working hours, physical education, and in case of illness - good care for the sick.
The establishment of the main etiological (producing, specific) factor, the identification of conditions that predispose to the disease or contribute to its development, and the conditions that prevent the onset of the disease and its development, is absolutely necessary for the development of effective measures for preventing diseases, reducing morbidity and improving the health of the population.
3. Pathogenic environmental factors.
We start talking about one of the most important sections pathological physiology. The rapid development of technology in the XIX and especially in the XX century. unexpectedly came across the fact that the practical implementation of new achievements is sometimes hampered not by technical difficulties, but by the creation of such conditions that a person can hardly endure. That is why modern pathology raises the question of the action of so-called extreme factors. Under this term, we will further understand the influence of factors that have a detrimental effect on the body of an animal or a person, in connection with which, if death does not occur, then there are severe conditions, in which the disease essentially does not have time to fully develop.
3.1 The effect on the body of low temperatures.
Despite the extensive literature on the problem of action low temperatures, there is still no unity in views on the essence of this process. extreme states possible both with frostbite and as a result of a general cold injury - freezing. They have a specific pathogenesis that is not repeated in any of the other human injuries. There are two types of cold effects on the body:
1) acute cold injuries (frostbite and freezing):
2) chronic cold lesions (chill, cold neurovasculitis).
Factors that influence the occurrence and development of diseases are called conditions for the onset of the disease. Unlike the causative factor, the conditions are not mandatory for the development of the disease. In the presence of a causative factor, the disease can develop without the participation of some conditions for its occurrence. For example, croupous pneumonia caused by pneumococcus of strong virulence can develop without a cold, without malnutrition and other conditions. There are conditions that predispose to the disease or contribute to its development and prevent the occurrence of the disease and its development. Conditions that promote or hinder the development of diseases can be internal and external.
To internal conditions conducive to the development of the disease, include hereditary predisposition to the disease, pathological constitution (diathesis), early childhood or old age.
To external conditions conducive to the development of diseases, include malnutrition, overwork, neurotic conditions, previous illnesses, poor patient care.
To internal conditions that prevent the development of diseases, include hereditary, racial and constitutional factors. These include, for example, human species immunity to certain infectious animal diseases. A person does not suffer from the plague of dogs and cats, pneumonia of cattle and many other infectious diseases of animals. People with sickle cell anemia do not get malaria.
To external conditions that prevent the development of diseases, include good and rational nutrition, proper organization of the working day, physical education, and in case of illness - good patient care.
The establishment of the main etiological (producing, specific) factor, the identification of conditions that predispose to the disease or contribute to its development, and the conditions that prevent the onset of the disease and its development, is absolutely necessary for the development of effective measures for preventing diseases, reducing morbidity and improving the health of the population.
3. Pathogenic environmental factors.
We begin a conversation about one of the most important sections of pathological physiology. The rapid development of technology in the XIX and especially in the XX century. unexpectedly came across the fact that the practical implementation of new achievements is sometimes hampered not by technical difficulties, but by the creation of such conditions that a person can hardly endure. That is why modern pathology raises the question of the action of so-called extreme factors. Under this term, we will further understand the influence of factors that have a detrimental effect on the body of an animal or a person, in connection with which, if death does not occur, then serious conditions arise in which the disease essentially does not have time to fully develop.
3.1 The effect on the body of low temperatures.
Despite the extensive literature devoted to the problem of the action of low temperatures, there is still no unity in views on the essence of this process. Extreme conditions are possible both with frostbite and as a result of a general cold injury - freezing. They have a specific pathogenesis that is not repeated in any of the other human injuries. There are two types of cold effects on the body:
1) acute cold injuries (frostbite and freezing):
2) chronic cold lesions (chill, cold neurovasculitis).
Word " etiology" means the doctrine of the cause (from the Greek. aitia- the reason logos- reason, teaching). In ancient times, this word also meant the doctrine of diseases in general (Galen).
In the modern sense, etiology is the study of causes and conditions. occurrence and development of diseases.
Causes - diseases
The cause of the disease is called the factor that causes the disease and gives it specific features. For example, the reason radiation sickness is ionizing radiation, the cause of an infectious disease is pathogenic microbes. Often, however, the onset of a disease can be linked to the influence of not one, but several factors. For example, lobar pneumonia occurs not only under the influence of human infection with pneumococcus. Colds, fatigue, negative emotions, malnutrition and other predisposing conditions also contribute to the disease. It is easy to understand, however, that without infection with pneumococcus, all of these factors will not be able to cause lobar pneumonia. Therefore, the cause of this disease should be considered pneumococcus. Based on the foregoing, the cause of the disease should be understood as such an effect, without which the development this disease impossible.
However, it is sometimes difficult to establish the cause of the disease (some tumors, mental illness). It has been established, for example, that a stomach ulcer develops both from coarse food and from a state of neurosis, dysfunctions of the autonomic nervous system, endocrine disorders. These and many other observations gave rise to ideas about the polyetiology of the disease. According to this idea, each disease can develop under the influence of not one, but several equivalent causes. This position is incorrect. It arose as a result of the lack of our knowledge about the causes of certain diseases and their variants. From a methodological point of view, this idea is adjacent to conditionalism - a doctrine that is inherently subjective-idealistic.
As mentioned, each disease has its own cause, peculiar only to it. With the accumulation of knowledge about the causes of all types and subtypes of diseases, their prevention and treatment will improve.
Many diseases, as their true causes are known, break up into new subspecies, each of which has its own separate reason. For example, until recently there was a disease "bleeding" (hemorrhagic diathesis). As the causes of individual manifestations of this disease were established, new completely independent forms of the disease were revealed, characterized by bleeding (scurvy, hemophilia, hemorrhagic purpura and etc.). Likewise split into independent diseases with its causes, neuro-arthritic diathesis (gout, rheumatism, non-infectious polyarthritis, etc.).
There are external and internal causes of diseases. To external reasons include mechanical, physical, chemical, biological and social factors, to internal - heredity, constitution, age, gender. It should be pointed out that the formation of internal causes in the process of evolution is also formed in close interaction with the external environment. Therefore the title " internal causes» diseases to some extent conditional. It meant that the this person the disease developed without visible influences of the external environment.
Conditions for the emergence and development of diseases
Factors that influence the occurrence and development of diseases are called the conditions for the occurrence of the disease. Unlike the causative factor, the conditions are not mandatory for the development of the disease. In the presence of a causative factor, the disease can develop without the participation of some conditions for its occurrence. For example, croupous pneumonia caused by pneumococcus of strong virulence can develop without a cold, without malnutrition and other conditions. There are conditions that predispose to the disease or contribute to its development, and conditions that prevent the occurrence of the disease and its development. Conditions that promote or hinder the development of diseases can be internal and external.
The internal conditions that contribute to the development of the disease include a hereditary predisposition to the disease, a pathological constitution (diathesis), early childhood or old age.
External conditions that contribute to the development of diseases include malnutrition, overwork, neurotic conditions, previous illnesses, and poor patient care.
Internal conditions that prevent the development of diseases include hereditary, racial and constitutional factors. These include, for example, human species immunity to certain infectious diseases animals. A person does not suffer from distemper of dogs and cats - pneumonia cattle and many others infectious diseases animals. People suffering sickle cell anemia do not suffer from malaria.
External conditions that prevent the development of diseases include good and rational nutrition, proper organization of the working day, physical education, and in case of illness, good patient care.
Wide network preventive measures in our country, the organization of mass physical education classes by radio, the correct organization of the diet, the alternation of the regime of work and rest, the wide network of resorts and rest houses provided to the working people in our country, are the most important factors reduction of morbidity and improvement of the population.
On some methodological perversions in the understanding of causality in pathology and medicine
In the medicine of bourgeois countries there are various perversions in the understanding of causality in the development of diseases. The main ones are as follows.
Mechanical causalism (from lat. cause- reason). According to this understanding, the disease develops in full from the impact of any one cause, according to the principle "cause equals effect." From this point of view, the entry of a pathogenic microbe, such as Mycobacterium tuberculosis, into the body is a necessary and sufficient reason for the development of tuberculosis as a disease (action) in all its known forms. This, of course, is not true. Mycobacterium tuberculosis is indeed the cause of tuberculosis, but a number of other conditions are necessary for the implementation of its pathogenic effect (features of the profession, nutritional status, reactivity, neuroendocrine system, living conditions, etc.). These conditions determine the form of the disease - acute, chronic, focal, widespread, latent, overt, etc.
Similar considerations apply to all other infectious diseases in which a microbe is the cause, but the form of the disease is determined by a number of conditions. All these conditions create a chain of cause-and-effect relationships, which in turn represent “only moments of worldwide interconnection, connection (universal) interconnection of events” (V. I. Lenin).
When studying causality, we always artificially simplify, isolate from the general interconnection of events and causes the one that is the main cause of the disease, but we do not believe that the cause (disease-causing factor) is equal to the action (disease). In fact, between the action of a disease-causing factor and the picture of the disease, there is in full long row events or mechanisms of disease progression.
Conditionalism (from lat. condition- condition). This is a direction in the understanding of causality, according to which in the development of the disease there is generally no main cause that determines the occurrence of the disease. The disease develops under the influence of a combination of a number of equivalent factors - conditions.
Conditionalism was developed in biology by Verworn (1907) and in medicine by Hansemann (1912). The combination of conditions for the development of the disease, in their opinion, is determined not objective factors the patient's environment, but the condition of the patient himself, his consciousness, his behavior, his personality. The patient, according to this teaching, creates his own illness. It is easy to see that the ideological roots of this trend go back to the philosophy of subjective idealism of Hume and Berkeley.
From the point of view of conditionalism, for example, the reason that a person fell and broke his leg is not the fact of injury from a fall, but a combination of suitable spatio-temporal and other factors.
The patient broke his leg because he fell on a stone (one condition), thought (second condition), was upset (third condition), etc. In fact, these conditions may matter, but do not replace the main cause - a blow. You can stumble, but not fall. You can fall, but not get such a blow that will cause a broken leg, etc.
The doctor’s conditional way of thinking does not allow him to “clearly aim” (I.P. Pavlov) at the cause of diseases and, thus, does not contribute to preventive direction in medicine.
"The theory of factors". This is one of the variants of conditionalism in medicine and pathology in bourgeois countries at the present time. According to this theory, human diseases arise as a result of the combined action of many equivalent factors on him - poor living conditions, malnutrition, negative emotions, infections, etc. A sick person cannot work well, his earnings decrease. Supporters of this theory say: “People get sick because they are poor; they are poor because they are sick.” The theory of factors does not take into account main reason the emergence of diseases under capitalism, which, as a system, is the main cause of the disease of the working people. The "factor theory" is beneficial in a bourgeois society, as it distracts workers and health authorities from the main cause of morbidity under capitalism.
Factors that influence the occurrence and development of diseases are called conditions for the onset of the disease. Unlike the causative factor, the conditions are not mandatory for the development of the disease. In the presence of a causative factor, the disease can develop without the participation of some conditions for its occurrence. For example, croupous pneumonia caused by pneumococcus of strong virulence can develop without a cold, without malnutrition and other conditions. There are conditions that predispose to the disease or contribute to its development and prevent the occurrence of the disease and its development. Conditions that promote or hinder the development of diseases can be internal and external.
To internal conditions conducive to the development of the disease, include hereditary predisposition to the disease, pathological constitution (diathesis), early childhood or old age.
To external conditions conducive to the development of diseases, include malnutrition, overwork, neurotic conditions, previous illnesses, poor patient care.
To internal conditions that prevent the development of diseases, include hereditary, racial and constitutional factors. These include, for example, human species immunity to certain infectious animal diseases. A person does not suffer from the plague of dogs and cats, pneumonia of cattle and many other infectious diseases of animals. People with sickle cell anemia do not get malaria.
To external conditions that prevent the development of diseases, include good and rational nutrition, proper organization of the working day, physical education, and in case of illness - good patient care.
The establishment of the main etiological (producing, specific) factor, the identification of conditions that predispose to the disease or contribute to its development, and the conditions that prevent the onset of the disease and its development, is absolutely necessary for the development effective measures prevention of diseases, reduction of morbidity and improvement of the population.
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Novosibirsk 2006
Reviewer: Tutorial is devoted to one of the most important sections of pathophysiology - general nosology. The manual discusses the main issues of etiology and pathogenesis. Represented
Stages of development of pathophysiology
First period (1542-1863). Fernel (J.Fernel, 1497-1558) pointed out the connection between physiology and pathology in his treatise De naturale parte medicine (1542). Elements of the general (universal)
Subject and tasks of pathophysiology
Pathophysiology is a science that studies the vital activity of a diseased organism. Otherwise: the main patterns of occurrence, the mechanism of development (pathogenesis) and the outcome of the disease (recovery
Modern methods used in the experiment.
In the process of cognition, a scientific experiment performs the following main functions: 1) by isolating individual properties and sides of the subject makes it possible to penetrate into its essence, to reveal it
Typical pathological process.
One of the areas of pathophysiology is the study of typical pathological processes. Processes to varying degrees and in different combinations take place during various diseases and enter their pathological
Stages of the disease and its outcomes.
In the development of the disease, one can distinguish next periods: 1. Latent or hidden (incubation); 2. Prodromal; 3. Full development of the disease or the height of the disease;
GENERAL ETIOLOGY
The word "etiology" means the doctrine of the cause (from the Greek aitia - reason, logos - reason, teaching). In ancient times, this word also meant the doctrine of diseases in general (Galen). In modern
PATIENT ENVIRONMENTAL FACTORS.
We begin a conversation about one of the most important sections of pathological physiology. The rapid development of technology in the XIX and especially in the XX century. unexpectedly came across the fact that the practical implementation of new
The effect on the body of low temperatures.
Despite the extensive literature devoted to the problem of the action of low temperatures, there is still no unity in views on the essence of this process. Extreme conditions are possible both with frostbite and
Frostbite.
Frostbite is local damage from cold and are represented by three varieties: 1) frostbite that occurs when exposed to temperatures close to zero or moderately low, 2)
Freezing
Freezing - the general cooling of the body - is a violation of the thermal balance in the body, leading to a decrease in body temperature. According to E.V. Maistrakh with this pathology
The effect on the body of high temperatures.
Thermal injury is a serious medical, social and economic problem. High temperatures render local (burns) and general ( burn disease, overheating) damage
Burn disease.
The pathology of burns is not limited local changes fabrics; an extensive and deep burn causes versatile, long-term and severe functional disorders internal organs and org systems
Overheating.
Overheating (hyperthermia) is a temporary increase in body temperature as a result of a violation of the mechanisms of thermoregulation and inconsistencies in the processes of heat transfer and heat generation. When impossible
The effect of radiation on the human body.
The development of life on Earth has always taken place in the presence of radiation background environment. From outer space, penetrating radiation passes, which reaches the earth down to great depths. Sun Spanish
The effect on the body of electric current.
First systematic; research on electrical injury began in the late 19th - early 20th centuries. Electricity occupies a special place among pathogenic irritants. First, he cannot stay
Influence of the state of the body and environmental factors on electrical injury.
Cardiac arrest due to: 1) cardiac fibrillation; 2) spasm coronary vessels; 3) lesions of the vasomotor center; 4) increase the tone n
Hyperbaria.
The first information about the stay of people under high blood pressure belong to distant times. However, only with the development of industry did this pathology go beyond the purely theoretical sphere into practice.
Hypobarium.
It should be noted that a slight hypobaria has an effect on human body influence only with a rapid fall atmospheric pressure: it affects the pressure of gases in closed cavities and in cavities,
mountain sickness
mountain sickness is a variant of exogenous hypobaric hypoxic hypoxia. It has long been known that climbing to great heights causes disease state, typical with
Barotrauma.
This pathology occurs with a rapid change in atmospheric pressure in the direction of both lowering and increasing it, as well as with rapid pressure fluctuations (an example is a shock wave during an explosion
shock wave action.
The main ideas about the mechanisms of the damaging effect of a shock wave were formed among representatives of medicine simultaneously with the use of explosions in practice. The first mention of damaging e
The effect of a shock wave on the body.
The body of an animal or a person is deformed in the direction of the shock wave. The deformation has a damping character and is associated with overload in time. The greatest changes in this pathology are noted
Overloads.
Acceleration occurs when the speed or direction of a body changes. The amount of acceleration, measured in m/s2 or a multiple of the speed of a free-falling airborne
GENERAL PATHOGENESIS
Pathogenesis (from the Greek pathos - suffering, genesis - origin) is a section of pathological physiology that studies the mechanisms of the development of diseases. The study of the most common
Protective-compensatory processes.
An important expression of every disease are reactive changes on the part of cells, organs and systems that arise, however, always secondary, in response to damage caused by pathogens
The main link and "vicious circle" in the pathogenesis of diseases.
In the development of diseases and pathological processes, it is extremely important to determine the main, leading or main link in the chain of disorders that occur in the body - change (one of the pathogens).
general pathological significance.
General pathogenesis diseases is a universal mechanism of life dysfunction on different levels integration of the organism (molecular, cellular, tissue, organ and organism).
SANOGENESIS
Sanogenesis- (Latin sanitas - health, Greek genesis - origin, the process of formation), means "development of health." Sanogenesis - the doctrine of the mechanisms of maintaining health and challenges
REACTIVITY AND RESISTANCE OF THE ORGANISM
Ideas about the reactivity and resistance of the body began to take shape even in times ancient medicine. Indications about them can be found in ancient Chinese and ancient Indian medical literature. O
Resistance, definition of the concept, types and forms.
Resilience is a property solid body resist various influences (general definition used in the technical literature). In the biological and medical literatures
Relative resistance.
This is understood as the relative immunity of the body to the action of a damaging factor, which either appears or disappears in the process of life. For example, immunity to influenza, disappearing
Primary or hereditary form of resistance.
Secondary or acquired form of resistance, which can also be: active, resulting from adaptation; passive - transfusion of antibodies to which
The ratio of reactivity and resistance.
The question of the relationship between the concepts of reactivity and resistance is very important. I will repeat in the definition of these concepts. Reactivity is understood as the property of a living self-regulatory system to respond to changes
Mechanisms that determine reactivity and resistance.
What factors or mechanisms determine reactivity and resistance? 1. In our opinion, the first place should be put hereditary factors, because in on
Reactivity and resistance in phylogenesis.
As has been shown, reactivity is inherent in every living organism. In the process of evolution, along with the complication of the organization of living beings, the forms and mechanisms of reactivity became more complex. The easier it is to organize
PATHOPHYSIOLOGY OF HEREDITARY DISEASES.
To date, the international program "Human Genome" has almost been completed. The human genome has been almost completely sequenced, that is, a sequence of 3 billion base pairs has been read, from
Etiology of hereditary diseases
At present, it is generally recognized that the cause of diseases of hereditary genesis is the action of factors that can change, and irreversibly, the genetic code of hereditary information, i.e. call
Genetic diseases.
A gene can mutate, resulting in a change or total absence squirrel. In this regard, allocate individual forms genetic diseases. So, a violation of the synthesis of a structural protein leads to the appearance of porosity.
Methods for studying hereditary pathology
Among the methods for studying hereditary pathology, there are classical ones: genealogical, population-static, twin and experimental. Cytological, biochemical and
Fundamentals of population genetics and ecogenetics.
Back in 1908, the English mathematician G. Hardy and the Viennese doctor V. Weinberg theoretically showed that in sufficiently large populations of freely interbreeding organisms, in the absence of selection and any use
