Etiology

ETIOLOGY (literally, the doctrine of cause), a term used exclusively in medicine to mean the doctrine of the 'causes' of diseases. Under the general banner of etiological factors are usually included both the grounds and causes of diseases, as well as various accompanying conditions favorable to their emergence, and finally various precipitating factors for the manifestation of one disease or another. Attempts to distinguish between all these factors, which differ so much in their theoretical and practical significance, although they do occur, but due to incorrect methodological premises, do not lead to any satisfactory results. Thus, for example, Martius came to the conclusion that the only cause of any disease is the constitution of the patient, whereupon Bauer aptly remarked that according to this theory, the cause of a burn is the skin itself. Bauer himself distinguishes between optional and obligatory conditions and causes, recognizing the role of cause only for such a factor that cannot be replaced by any other; he refuses to consider pneumonia to be caused by a cold, since in some cases trauma or another factor may be present instead of a cold. Levit distinguishes between the producing cause and the revealing and contributing (or predisposing) factors, seeking the former in the genotype or phenotype, classifying infection, stroke, and the activity of endocrine glands as revealing factors, and sex, nationality, socio-domestic and professional conditions as predisposing factors. Obviously, here too there is a mixing of factors of different significance. There are also such pathologists who, following Vorworn, slide into conditionalisim, recognizing all sorts of conditions for the emergence of phenomena as equivalent and refusing to distinguish between cause and other conditions. Finally, quite widespread is the division of etiological factors into exogenous (mechanical, physical, chemical, biological) and endogenous (genotypic, constitutional, autointoxications, etc.). It is quite clear that this mechanical classification based solely on external characteristics not only cannot help clarify their role in the origin of diseases, but can only hinder this. All this is not accidental. Attempts to understand the essence of the etiology of diseases are as old as medicine itself. Already at the dawn of humanity, at the earliest stages of the development of medical science, people were not satisfied with merely applying various empirical methods of treating diseases, but also asked questions about what happens in the sick organism (pathogenesis of the disease) and why this happens (etiology of the disease). At various historical stages, the answers to these questions underwent countless changes depending, on the one hand, on the growth of knowledge about nature (physics, chemistry, biology), and on the other hand, on changing class relationships and prevailing religious and philosophical views (see Medicine). Through the thickness of religious, mystical and vitalistic views until the middle of the 19th century, only with great difficulty do the shoots of materialist understanding of etiology break through their way, partly in the form of various speculative theories of antiquity and later epochs (mechanists, atomists, pneumatics, humorists), partly in the form of empirical generalizations of everyday experience (miasmic and contagious theories of infectious diseases, food poisonings, injuries, colds, etc.). It is characteristic that in those cases where the etiology of diseases did not yield to a more or less rational solution, materialistically-minded physicians of that time did not resort to the help of mystical forces, but considered it possible to be content with recognizing the accidental origin of diseases [thus, for example, Laennec defined the tubercle he discovered as an 'accidental formation' (production accidentelle)] or left the question open. A turning point in the direction of materialist understanding of etiology occurs in the second half of the 19th century simultaneously with the defeat of vitalism across the entire front of biological sciences, on the basis of the enormous successes of physics and chemistry, Darwin's theory, etc. But scientific etiology begins to develop especially rapidly from the 1880s: the discovery of pathogenic microorganisms, the development of experimental pathology, endocrinology, the doctrine of vitamins, the doctrine of heredity, experimental and social hygiene, medical statistics have completely changed all previous ideas about the etiology of diseases, provided it with an inviolable materialist base and dealt a decisive blow to all sorts of mystical and vitalistic teachings and concepts. Nevertheless, even at the present time the struggle is not only not yet finished, but is even intensifying; this is evidenced not only by the growth of all sorts of charlatanism and mystical 'medical' teachings in all capitalist countries, but also by the statements of such medical authorities as Krehl, Bier, Sauerbruch and many others, persistently advancing the position on the decisive role of the 'irrational' in pathology. Such pollution of etiological teachings with all sorts of mysticism and the vitality of the latter in no way can be attributed to a lack of knowledge in this area, since in this respect questions of etiology do not essentially differ from questions of pathogenesis. The real reason for this situation is that in the conditions of class society, the scientific formulation of questions of etiology inevitably comes into conflict with the interests of the ruling classes—mainly because the true causes of the most common diseases are rooted in the class structure of society and in the exploitation of the vast majority of the population by the ruling minority. Hence—opposition to the deep materialist study of etiology, more or less obvious patronage of all sorts of religious-mystical prejudices in this area, the double class orientation of ruling etiological theories. Even during the period of the greatest flourishing of capitalism and materialist approaches to the study of etiology, bourgeois medicine very strictly guarded the interests of its class and did not go beyond the framework of these interests. In those cases where individual researchers allowed themselves to cross these boundaries and expressed undesirable views, the latter were either immediately and unanimously 'refuted' by a host of well-meaning scientists, or were diligently suppressed, not allowed into widely circulated manuals for physicians and students, and remained known only to readers of specialized journals. A bright example of this kind is the history of the question of the etiology of anemias. When at the end of the 1870s the extraordinary prevalence of anemia among the working population attracted attention, there were conscientious physicians who saw the cause of this in the exceptionally unfavorable conditions of labor, living and nutrition of workers and even called anemia the 'proletarian disease.' To 'refute' such heresy, the entire apparatus of bourgeois science was immediately mobilized. The famous French hematologist Hayem considered it possible to refer to the fact that, they say, anemia 'also occurs among the wealthy classes,' and therefore cannot be connected with material well-being. Other scientists brought in horses that spend their entire lives in mines, polar travelers, specialists in prolonged fasting, rabbits placed in a dusty atmosphere, and 'proved' that neither sunlight nor clean air nor the quality of nutrition has any effect on blood composition. Since then, in all textbooks and manuals, as etiological factors for anemia appear chronic tuberculosis of the lungs (although it is known that anemia accompanies it only in rare cases), and chronic minimal blood loss (although in no experiment did they cause anemia), and intoxications, and the rarest avitaminoses, and constitution, but nowhere can one find references to socio-domestic conditions or to the composition of food. Mutatis mutandis, the same can be said about the widely spread chronic diseases of the stomach and intestines, diseases of the liver, blood vessels, and many others. Even with respect to such infections as tuberculosis or syphilis, and various epidemic diseases, where considerations of personal safety prompt the bourgeoisie to more energetic measures and greater liberalism in regard to revealing etiology, questions are not carried through to the end, since this would point to the social roots of these diseases. Only after the victory of the proletarian revolution does Soviet medical science receive the opportunity to fearlessly uncover the true etiological factors of diseases and assign to each its proper place, and thereby provide a rational basis for prevention. However, the implementation of this possibility does not come by itself, but requires great and complex work. | The first and necessary condition for a truly scientific formulation of questions of etiology is the thorough development of the methodology of etiological research on a solid basis of dialectical materialism. In this, it is of course necessary to take into account the forms of causal connection already revealed by various sciences about nature and society, but at the same time it is necessary to firmly remember that pathology represents a qualitatively unique sphere of phenomena with its own specific regularities, and therefore forms of causality from other sciences cannot be mechanically transferred into it.

As an example, let us take the disease tuberculosis with its causal regularities (of course, in schematic form). The starting point of all tuberculous diseases is the susceptibility inherent in humans to the Koch bacillus. This biological fact in itself does not yet determine the possibility of infection. The latter occurs only when the tubercle bacillus appears in the human environment. It is this combination—a susceptible person and the presence of the tubercle bacillus in their environment—that creates the real possibility (probability) of infection, and this constitutes the basis of infection. The cause of the latter in each specific case, which transforms the possibility of infection into reality, should be considered direct contact with a tuberculosis patient, staying in an infected atmosphere, consuming infected food, etc. Sometimes infection is immediately followed by disease, in the vast majority of cases the disease does not occur at all, and in the remaining cases it occurs after a shorter or longer period of time. Therefore, although infection is a necessary condition for the disease, in these cases it cannot yet be considered the cause of the disease, but only its basis, containing within it the possibility of the disease. The realization of this possibility depends on a number of conditions, such as intercurrent diseases, colds, injuries, reinfection, endocrine disorders, etc., and all these influences pass through the prism of the influences of working, living, and nutritional conditions. In each individual case, one or another of these conditions, and often one or another of their combinations, plays a decisive role, and these are the true cause of this individual disease. All the others play the role of accompanying conditions, which can facilitate or hinder, accelerate or delay the onset of the disease, but cannot prevent the inevitable result. At the same time, depending on the properties of the basis, a number of factors that in one case play the role of cause may in another play the role of accompanying conditions and vice versa, due to which it is impossible to draw any general distinction between these conditions for all individual tuberculosis diseases. The distinguishing features of tuberculosis as a social disease under the conditions of the capitalist system are the continuous infection of the population and mass morbidity, especially among the working class and the less well-off strata of the city and countryside. Both in comparison with other social formations and historical data and morbidity statistics show that the issue here is not in the biopathological properties of humans and the tuberculosis virus themselves, but in such factors as poor working and living conditions and quantitatively insufficient and qualitatively poor nutrition of the broad working masses. These factors are the cause of the widest spread of tuberculosis in capitalist countries. But these factors themselves are in turn a necessary manifestation of the basic contradictions of the capitalist system. Thus, the simple possibility of the mass spread of tuberculosis inherent in human society under capitalism turns into a necessity; capitalism represents the basis of this spread, and the associated working, living, and nutritional conditions are its causes. Here, factors little related to the basis, such as climate, changes in meteorological conditions, accidental epidemics, good or bad harvests, or changes in the cultural level related to the basis, upswings in the business cycle, crises, wars play the role of accompanying conditions: affecting people either directly or through changes in their working and living conditions, they lead to an increase or decrease in tuberculosis morbidity, but cannot eliminate its mass spread, which is necessarily linked to the basic contradictions of the basis. Finally, the role of the trigger apparently comes down here to the sudden external manifestation of processes that have already been maturing. From the analysis of causality in the field of tuberculosis, the most important conclusion follows that under the conditions of capitalism, any, even successful, struggle against tuberculosis can only yield secondary, temporary, insignificant results, and the elimination of tuberculosis as a mass social disease is possible only after the destruction of capitalism, in a socialist society. Approaching the problem of anemia in a similar way, we see that in individual cases the basis of the disease, which determines the possibility of its occurrence, consists of genotypically or paratypically caused dysfunctions of the hematopoietic and hemolytic apparatuses or the endocrine system, insufficiency of digestive enzymes, metabolic disorders, etc. The causes that necessarily lead to the transformation of this possibility into reality, i.e., the disease anemia, are the lack in food of full-fledged proteins and vitamins, one or another acute or chronic infection, acute or chronic blood loss, a certain professional harmfulness or intoxication, etc. But if we ask ourselves not why certain individuals get anemia, but why in capitalist countries anemia is the lot of the majority of workers, while among the ruling classes it occurs incomparably less frequently, then here too we will see that the basis of this are the basic contradictions of capitalism, and the cause is the nutrition, work, and living conditions of the working population necessarily associated with this basis, and that no other position is possible under capitalism. The second condition for the strictly scientific development of questions of etiology is the most precise establishment of the concept of 'disease' and its clear distinction from various pathological states, even if they lie at the basis of the disease but are not the disease itself. This of course does not mean establishing any absolute, metaphysical boundaries between health and disease, between nosos and pathos (see Disease, Nosology), but it is still necessary to avoid the incorrectness that has been observed in this question to this day. The main cause of this is undoubtedly the biologism that has dominated this field up to now, while in reality processes are taking place here that are social to the same extent as they are biological. Only when, in the concept of disease, along with moments of norm and viability, to which the old definitions are reduced, their due place is also found for work capacity and other social characteristics, will this concept acquire the necessary fullness and clarity. From the point of view of etiology, this has, for example, significance in the study of infections with their often very long stages of latency, in the study of genotypic diseases, the first signs of which sometimes appear only in old age or even senile age, in all those lesions of various organs where the appearance of the first symptoms depends on the degree of functional load or on the degree of destruction of the organ. Finally, the third indispensable condition on which the success of etiological research depends is the scientific nature of its methodology. In this field, the most primitive empiricism is still widely in circulation, due to which a simple sequence of phenomena in time is uncritically identified with a causal connection (post hoc-propter hoc); conditions favorable to the occurrence of the disease are taken as its causes, and sometimes even triggers that accidentally contributed to the manifestation of the disease appear as such. One of the best ways to identify the true causes of the disease is undoubtedly a properly conducted experiment (see). However, in this case, it must be taken into account that the results of experiments on animals cannot always and in full measure be transferred to humans, and the setting up of an experiment on a human is naturally possible only comparatively rarely, and in relation to many diseases it is altogether impossible. Therefore, along with the experiment, the statistical method (see Statistics, Variational Statistics, Correlation) rightfully plays a very important role in the study of etiology. As Engels taught, the cause is proved and verified only by social practice. However, to obtain results corresponding to the truth, it is not enough here merely to observe the 'simple rules of statistics', but one should keep in mind that the manifestation of the disease always depends on many conditions. In order to single out from these the one that is essential, i.e., the cause of the disease, it is therefore necessary to correlate with it (correlate) as many conditions as possible, and first of all those conditions regarding which it is known or can be assumed that they exert this or that influence on the pathological processes underlying this disease. Failure to meet these requirements can lead to completely incorrect conclusions. Thus, for example, old statistical data showed that among textile workers the morbidity from anemia was significantly higher than among workers of other professions; from this some authors concluded about the anemia-inducing effect of one or another textile 'professional harmfulnesses.'

However, if they had not limited themselves to comparing statistics of anemia with data on profession and length of service in it, but had also included in the scope of their research the size of wages and the living conditions associated with them, and especially nutrition, they could have without particular difficulty convinced themselves that the etiology of anemia in textile workers, and indeed in other professional groups, lies primarily in the latter, and not in the factors which they had established. Needless to say, the results obtained in this way must, whenever possible, be verified with the help of appropriate experiments. On the other hand, the statistical method in a number of cases can introduce the most important corrections into those conclusions which are drawn from experiment. For example, everyday observation and experiment with certainty establish that under the influence of alcohol chronic gastritis develops. Based on this, bourgeois medicine concludes that alcoholism is the main cause of the widespread chronic gastritis among the working class and peasantry. Statistical examination of a sufficiently large and varied material, however, helps to clarify that along with alcoholism and to a much greater degree than it, such class-conditioned factors as prolonged poor-quality or irregular nutrition or the condition of the dental apparatus play a role. Where the uncertainty of the experiment, the abundance of extraneous conditions, and the insufficiency of statistical material do not make it possible to arrive at a conclusion about the etiological significance of any factor, as well as for the purpose of reinforcing already obtained results, one can resort to the help of various indirect proofs. For example, in the uncertainty of the question about the etiology of anemia in a group of workers in any particular production, the detection of signs of increased hemolysis in workers in the same workplace with normal blood composition allows one to conclude about the anemizing effect of the corresponding substance or work process, on the one hand, and about the increased predisposition to anemia in workers of this particular group - on the other (of course, if other influences are excluded). Finally, in recent years, genetic research (see Genetics, Genetic Analysis, Man) has been acquiring ever greater importance in the study of etiology, which essentially helps to clarify such still rather vague etiological factors as constitution, predisposition, etc., and to distinguish between genotypic and paratypic elements in them. Here one should warn against too hasty application of these research methods and incorrect genetic conclusions about those mass diseases whose foundations and causes are rooted in the conditions of the capitalist system. The statements of this kind found in bourgeois medical literature are caused by a desire to obscure the true social causes of these diseases and to create a basis for various fascist 'theories' about the biological inferiority of oppressed classes, other nations, 'lower races,' etc. The correct resolution of questions of etiology and the distinction of etiological factors are called upon to play the greatest role in the fight against diseases. In regard to the prevention of social diseases, this is already clearly proven by the practice of Soviet public health. Thanks to the fact that the Party and the Soviet power correctly identified the true causes of the mass character of these diseases not in microbiological, climatic, and other factors, but in the conditions of labor, living, and nutrition inherited from capitalism by the broadest masses of working people, and concentrated the focus of health measures in this direction, we already now have a sharp decrease in morbidity. The same applies to epidemic diseases, gastro-intestinal diseases, anemia, etc. In the field of individual prevention, the correct distinction of etiological factors makes it possible to concentrate our efforts on the decisive points. In particular this applies, for example, to those diseases whose basis is one or another allergic condition, and whose cause is the most diverse, associated with chance or difficult to eliminate effects of the external environment or endogenous processes, and which (diseases) can be prevented only by changing the basis (desensitization). Finally, in the field of treatment, the clear distinction between the bases and causes of diseases will allow us to substantially clarify our concepts of symptomatic and causal treatment and to rationally direct the latter. In this connection, the doctrine of Speransky on changes in nervous trophicity as the basis of many diseases and the development of lysate therapy as a method of acting again on the basis of pathological STATES must undoubtedly play a major role.

"Worm."