SIGNIFICANCE OF THE CONSTITUTION IN PATHOLOGY Concept of Constitution Constitution implies the aggregate of all sufficiently stable functional and morphological characteristics of an organism, which determine the specificity of its reactions to external agents and are formed on the basis of heredity and acquired properties in interaction with the external environment, primarily the social environment in the case of man, Great importance was attached to constitutional properties even in antiquity, Hippocrates held that the constitution was determined by a mixture of body fluids (humoral) and that disease resulted from their improper mixture. He distinguished good, bad, strong, weak, dry and moist constitutions according to the state of the humoral environment and divided people Into sanguine (energetic and lively), choleric (impetuous), melancholic (reticent and unsociable) and phlegmatic (inert) according to temperament, Cellular pathology with its anatomic localistic principle tended to ignore the significance of the organism as a whole in origination of disease and the very concept of constitution. Another factor indirectly conductive to this was the development of bacteriology and the understimulation - characteristic of the time - of the significance of the host in the etiology and pathogenesis of diseases. The problem of constitution was only later subjected to deeper study. Today there is no agreement on the essence of constitution as yet, There are two diametrically opposed trends in understanding constitution. Representatives of one trend understand constitution as an aggregate of stable and only inherited properties. They hold that constitution remains unchanged all through a person's life and is the cause of most of the diseases. This view is a result of their concept of heredity, according to which nature is invariable, The adherents of this trend disregard the role of the environment in changing heredity, The definition that "constitution is the somatic fate of the organism", which always predetermines the origination of disease, ignores the significance of the external environment in the formation of man's constitution. The representatives of the other tend understand constitution as the complex of the organism's properties formed in the process of its development in interaction with the conditions of its existence. They believe that the organism's constitution is not something invariable and fixed either in the organism’s individual (ontogenetic) or historical (phylogenetic) development, Prolonged influence of external factors leads to the appearance of qualitatively new and stable properties which in some cases are fixed, in the progeny and determine man's reactions to physiologic and pathologic factors. For a correct evaluation of the significance of constitution the organism must be viewed not as a sum of the properties of its organs, tissues or cells, but as a single whole in its inseparable unity with its environment, in all its individuality at the moment of its affection. Classification of Constitutions Many attempts have been made to establish definite types of constitutions according to similarities of the various properties of t he or gan i sm. Me asu re me nts of th e b ody an d i ts par ts (somatometry) were most frequently used as criteria. Some observations showed certain types of body build to correspond to certain functional properties. Thus one of the widespread classifications of constitutions (Sigaud) establishes the following four principal types according to characteristics of body build: 1) respiratory type - long thorax, acute epigastric angle, long neck, relatively small abdomen, developed maxillary and frontal sinuses, and hexagonally-shaped face; 2) muscular type - broad and high shoulder girdle, developed chest, developed muscles, medium epigastric angle, and square face; 3) digestive type well developed lower third of the face, protruding jaw, short neck, broad chest, and. well developed abdomen and obtuse epigastric angle; 4) cerebral type - delicate slim physique, large skull, well developed frontal part of the face, and short limbs. In addition to classifications according to body build, there have been several more attempts to distinguish constitutions in accordance with the organism's functional properties, the peculiarities of muscle tone, metabolism, nutrition or vegetative functions. The constitutions established by various researchers according to these characteristics usually- fit into the three following principal types with certain variations in the different classifications: 1) hyposthenic, hypotonic and asthenic types (correspond to Sigaud respiratory and. cerebral types); 2) normosthenic, normotonic and athletic- types (correspond to the muscular type); 3) hypersthenic, hyper-tonic and pyknic types (correspond to the digestive type). A predisposition to particular diseases was frequently ascribed without sufficient reason to each of the foregoing types, for example, a predisposition to respiratory diseases was ascribed, to people of the respiratory and asthenic types, metabolic diseases - to people of the digestive or pyknic type. Some investigators (Kretschmer) ascribed to the types they distinguished (asthenic, pyknic and athletic) predispositions to various mental diseases, But this view is erroneous because it is based on observations of mental patients, The basic flaw of these classifications is that they are all schematic and one-sided. In most cases they are predominantly of a descriptive character and fail to take into account the continous interaction of the organism with the external environment. They do not always permit of determining with centainty the character of man's possible reaction to a particular pathogenic agent. Moreover, the constitution of most people is mixed and does not fit into any definite types; this is particularly true of women and children. It is very important to note that an individual's constitution may vary with the conditions of this life. Observations have shown, for example, that the physique of a. person, who as a child belonged to the hyposthenic or asthenic type but for a long time did. physical work or systematically wet in for sports, gradually changes and manifests features characteristic of a normosthenic or athletic type. This shows the certain external factors acting over a long period of time may alter the manifestations of a constitution, its functional and even morphological characteristics. Attempts have also been made to classify constitutions according to properties of certain systems, for example, the endocrine glands or vegetative nervous system. Types of people were at different times distinguished according to the properties of endocrine glands, i.e., by an increase or decrease in certain incretory functions, for example, hypo- or hyperthyroid constitutions, hypo- and hyperpituitary, etc. However. there are no reasons to consider the constitution of an organism exclusively from the standpoint of the functional characteristics of the endocrine glands because the latter closely interact with the nervous system. Human constitutions were also distinguished according to peculiarities of the vegetative functions, i.e., with the tone of either the sympathetic or parasympathetic nervous systems predominating (sympathicotonic and vagotonic types). But this classification was likewise based, on a one-sided and erroneous concept of the self-sufficiency of each division of the vegetative nervous system and the direct antagonism between them. Significance of Types of Higher Nervous Activity in the Theory of Constitution. The teaching on higher nervous activity and the role of the cerebral hemispheres in the regulation of all functions of the organism has made it possible to overcome to one-sided views of constitution and its significance for pathology and the clinic and to elaborate a classification of types of nervous system. A type of higher nervous activity is a complex of inborn traits and. characteristics acquired by the organism in the course of its individual development under the continuous influences of the external environment. Each type is characterized, by certain features of higher .nervous activity such as: 1) strength of the basic nervous processes - excitation, and inhibition - which determines the efficiency of the nervous system, 2) balance between the two processes, and 3) mobility of these processes, i.e. ready reaction to stimulation and rapid transition from inhibition to excitation and vice versa. These features ensure the organism's adjustment to the conditions of its existence, Pavlov distinguished weak and strong types of nervous system in accordance with the strength of the nervous processes excitation and inhibition. Strong animals are divide into equilibrated and unequilibrated according to the balance between the basic nervous processes in the cerebral cortex. The equilibrated animals are in their turn divided into lively (mobile) and calm (inert), according to the mobility of the cortical processes. Thus the following principal types of nervous system may be distinguished according to the manifestations of nervous activity: 1) weak type characterized by weakness of the stimulatory and inhibitory process with relative predominance of inhibition over excitation; 2) strong, equilibrated, mobile type with equally strongly developed, processes of excitation and inhibtion, and capable of resisting pathogenic stimuli: 3) strong, unequilibrated, excitable ("impetuous") type with excitatory and inhibitory reactions out of proportion to the stimulation, a type in which both processes are strong but the process of excitation predominates: 4) calm, phlegmatic type with a well balanced and somewhat inert nervous system, capable of great endurance and easily adjusting itself to its environment. The aforesaid, types correspond to the melancholic, sanguine, choleric and phlegmatic temperaments. There are also a number of intermediate typological variants. For the clinic the problem of types of nervous system is of paramount importance because its solution would allow a correct evaluation of the role of constitution in the pathogenesis of — 4 ~ disease and would offer a possibility of exerting purposeful influences on the affected organism. Attempts at elaborating a working scheme for classifying types of nervous system in man in accordance with Pavlov"s classification principles based on experimental studies of higher- nervous activity in animals have been repeatedly made. The problem is extremely complex, however, and these attempts have not as yet succeeded, Concept of Diathesis The concept of constitution is tied in with that of diathesis, Diathesis usually a morbid state of the organism characterized by its abnormal reactions to the action of usual stimuli. The clinic often endeavours to distinguish different forms of diatheses according to the organism's susceptibility to certain groups of diseases. The following diatheses are thus distinguished: exudative diathesis with frequent inflammatory reactions and eczematous eruptions on the skin; neuroarthritic diathesis with sluggish metabolism, endocrine disturbances and joint affections; spasmophilic diathesis with increased nervous excitability and tendency to convulsions; asthenic diathesis with adynamia and diminished vascular tone; hemorrhagic diathesis with a tendency to hemorrhages. There are also other forms. Certain scientists identify diatheses with hereditary predispositions for certain diseases. However, such concepts are ungrounded since various external factors influencing the organism during intra- and extrauterine life may play a certain part in the origination of diatheses. The prolonged influences exerted-on the mother and fetus by infections, intoxications, altered nutrition, and climatic conditions are particularly important. It is sometimes possible to diminish or entirely eliminate the manifestations of diatheses by prophylactic and therapeutic measures.