Sections of medicine research various problems. One, for example, is studying the clinical picture, that is, the manifestation of a pathology. Other sections of medicine investigate the effects or reactions of the body to certain influences. Of particular importance in the diagnosis and in the subsequent choice of therapy are factors provoking pathology. Etiology is an area that explores the causes. Further in the article we will analyze this term in more detail.
General information
Etiology is the cause of diseases, the occurrence of which requires the combination of the influence of the main factor and the totality of conditions suitable for the manifestation of its effect of internal and external environment. Poisons, pathogenic microorganisms, radiation, injuries, as well as many other chemical, biological and physical effects can act as provoking phenomena. The disease can occur in conditions of hypothermia, fatigue, malnutrition, inappropriate social and geographical environment. An important role is played by the characteristics of the body. These, in particular, include gender, age, genotype and others.
Factors
The concept of etiology is not limited to specific reasons. Basically, for the onset of the disease, in addition to the provoking phenomenon, certain favorable conditions are necessary for it. For example, streptococcus, present in the oral cavity as a saprophyte, causes a sore throat due to the prolonged influence of low temperatures. This is due to weakening of the body's defense mechanisms. And the sticks of typhoid fever and diphtheria without causing factors (fatigue, starvation) may not manifest themselves. Often there are situations when one and the same factor can act in some cases as an etiological, and in others as a determining one. An example is subcooling. On the one hand, it causes frostbite, and on the other, it provides optimal conditions for the occurrence of many colds infectious diseases.
Classification of pathologies
In some cases, the etiology of the disease may be limited to one factor. In other cases, the study may reveal several provoking factors at once. In the first case, the disease is called mono-, and in the second - polyetiological. The first type includes, for example, flu, tonsillitis. But heart disease is formed as a result of syphilis, rheumatism and many other factors. The etiology of the disease allows you to determine its specificity and pathogenetic therapy. For example, the course, severity and prediction of staphylococcal and anthrax carbuncle have significant differences. Different types of hypertension, which can be caused by both neurogenic and renal factors, also have specific characteristics. The cause of intestinal obstruction is external compression of the intestine or its internal blockage.
Factor action
There are simultaneous (trauma, burns) and prolonged (starvation, infections) effects of a provocative phenomenon. These phenomena also include etiology. This effect can cause the development of an acute or chronic stage of pathology. As a result of exposure to a factor - long or short-term - a failure occurs in the human body in various systems. This is precisely what causes the disease, which is mainly a consequence of these disorders.
Treatment and prevention
Etiology is one of the main factors determining one or another method of therapy. Having identified the causes and conditions for the development of pathology, you can choose the method that will eliminate the provoking factors. Only in this case is it possible to achieve a positive result. A significant role is played by prevention. The disease can be prevented in case of timely elimination of pathogenic causes and factors that cause it. For example, the detection of bacilli carriers, the elimination of mosquitoes in places of possible malaria, and the prevention of injuries are carried out. However, it is not always possible to identify the causes and conditions for the development of pathology. In this case, they speak of an unclear etiology. In such situations, as a rule, the patient goes under the supervision of a doctor. Along with this, differential diagnostics and monitoring of its condition are carried out. Often, doctors prescribe blind treatment in such cases.
Etiology of diabetes
To date, there is conclusive evidence that the genetic factor is the main cause of diabetes. This disease refers to a polygenic species. It is based on at least two mutant diabetic genes in the b chromosome that are associated with the HLA system. The latter, in turn, determines the specific reaction of the body and its cells to the effects of antigens. Based on the theory of polygenic inheritance of diabetes mellitus, with the disease there are two mutant genes or two groups of them, inherited by recessive means. Some people have a predisposition to damage to the autoimmune system or increased sensitivity of certain cells to viral antibodies, lowered immunity to fight viruses. HLA system genes are markers of this predisposition.
In 1987, D. Foster revealed that one of the genes that is susceptible to the disease is on the b-chromosome. In this case, there is a connection between diabetes and certain antibodies of white blood cells in the human body. They are encoded using the genes of the main histocompatibility complex. They, in turn, are located on this chromosome.
Classification of genes of the main histocompatibility complex
There are three types. Genes differ in the type of encoded proteins and their participation in the development of immune processes. Class 1 includes loci A, B, C. They are able to encode antigens that are found on all cells containing the nucleus. These elements perform the function of protecting against infections (mainly viral). Genes of class 2, located on the D-region, contain loci DP, DQ, DR. They encode antigens that can be expressed exclusively on immunocompetent cells. These include monocytes, T-lymphocytes and others. Class 3 genes are used to encode components of complement, tumor necrosis factor, and transporters that are associated with antibody processing.
Recently, there has been an assumption that not only elements of the HLA system, but also a gene encoding the synthesis of insulin, the immunoglobulin heavy chain, T-cell receptor bonds, and others are associated with the inheritance of insulin-dependent diabetes mellitus. People who have a congenital predisposition to IDDM have environmental changes. Their antiviral immunity is weakened, cells can undergo cytotoxic damage under the influence of pathogenic microorganisms and chemical components.
Other reasons
IDDM can also have a viral etiology. Most often, rubella causes the pathology (the pathogen enters the pancreatic islets, then accumulates and replicates in them), mumps (most often the disease manifests itself in children after the epidemic, after 1-2 years), hepatitis B virus and Koksaki B (replicated in insular apparatus), mononucleosis infection, flu and others. The fact that the factor under consideration is related to the development of diabetes mellitus is confirmed by the seasonality of the pathology. Typically, IDDM is diagnosed in children in the fall and winter, peaking in October and January. Also, high titers of antibodies to pathogens can be found in the blood of patients. In people who have died from diabetes, as a result of immunofluorescence research methods, viral particles are observed in the islets of Langerhans.
The principle of action of the pathogen
Experimental studies by M. Balabolkin confirm the involvement of this infection in the development of the disease. According to his observations, the virus in people with a tendency to diabetes, acts in this way:
- there is an acute damage to the cells (for example, the Coxsackie virus);
- there is a persistence (prolonged survival) of the virus (rubella) with the formation of autoimmune processes in islet tissue.
Etiology of liver cirrhosis
Depending on the causes, this pathology is divided into three groups. These include, but are not limited to:
- With certain etiological reasons.
- With controversial provoking factors.
- Unclear etiology.
Studying the causes of damage
To identify factors that provoke cirrhosis, conduct clinical, epidemiological and laboratory studies. At the same time, they establish a connection with excessive alcohol consumption. For a long time, it was believed that cirrhosis occurs in conditions of malnutrition of an alcoholic. In this regard, this pathology was called alimentary or nutritional. In 1961, Beckett created a work in which he described acute stage alcoholic hepatitis. At the same time, he suggested that it was this disease that increased the risk of liver cirrhosis associated with taking alcohol. Subsequently, the effect of ethanol on the development of toxic hepatitis, which can go into damage to the tissues of the hematopoietic organ, was established. This is especially true for repeated transmission of the disease.
Dangerous Dosages of Ethanol
Cirrhosis of the liver, caused by alcohol, does not necessarily develop with stages of acute or chronic hepatitis. The disease can transform in another way. There are three main stages:
- fatty degeneration of the organ;
- fibrosis with mesenchymal reaction;
- cirrhosis.
The risk of illness as a result of 15 years of excessive alcohol consumption is 8 times higher than that which occurs with a five-year intake of alcohol. Pekvigno determined a dangerous dosage of ethanol for the development of cirrhosis. It is 80 g per day (200 g of vodka). A very dangerous daily dose is the use of 160 g of alcohol or more. Subsequently, the "Pekvigno formula" was somewhat changed. In women, alcohol sensitivity is twice as much as in men. In some representatives of the stronger sex, the cirrhogenic boundary is reduced to 40 g of ethanol per day, in others the disease develops when taking 60 ml of alcohol. For women, 20 ml of alcohol per day is enough. In the development of alcoholic liver cirrhosis, the main role is played by a specific lipopolysaccharide of intestinal origin - endotoxin.
Other reasons
Cirrhosis can occur due to genetically determined metabolic disorders. In both children and adults, a connection was found between the development of pathology and A1-antitrypsin deficiency. A1-antitrypsin is a glycoprotein that is synthesized in hepatocyte and is an inhibitor of the immediate effects of serine proteinases (elastase, trypsin, plasmin, chymotrypsin). Against the background of insufficiency, cholestasis occurs in 5-30% of children, and in 10-15% cirrhosis occurs at a very young age. Moreover, even in cases of biochemical disturbances, a favorable prognosis is usually favorable. In old age, the likelihood of developing cirrhosis and liver cancer increases. This is especially true for people with emphysema. The functioning of the liver may also be impaired when chemicals and pharmacological agents enter the body. As a result, acute stages of damage to this organ and chronic hepatitis occur. In rare cases, cirrhosis develops. For example, carbon tetrachloride can cause acute and sometimes toxic chronic hepatitis. This pathology may in some cases accompany massive necrosis and the development of cirrhosis.