Etiology is ... Viral etiology. Etiology of the disease

Sections of medicine investigate various problems. One, for example, studies a clinical picture, that is, a manifestation of pathology. Other sections of medicine investigate the consequences or reactions of the body to these or other effects. Particular importance both in diagnosis, and in the subsequent choice of therapy, have pathologic factors. Etiology is an area that explores the causes. Further in the article we will discuss this term in more detail.

General information

Etiology is the cause of diseases, for the emergence of which requires the combination of the influence of the main factor and the set of conditions suitable for the manifestation of its action of the internal and external environment. Poisons, pathogenic microorganisms, radiation, injuries, as well as many other chemical, biological and physical effects may act as triggers. The disease can occur in conditions of hypothermia, fatigue, eating disorders, inappropriate social and geographical environment. An important role played by the characteristics of the body. They include, in particular, gender, age, genotype, and others.

Factors

The concept of etiology is not limited to specific causes. In general, for the emergence of the disease, in addition to a provoking phenomenon, certain favorable conditions are necessary for it. For example, streptococcus, present in the oral cavity in the form of saprophyte, due to the prolonged influence of low temperatures causes angina. This is due to the weakening of the protective mechanisms of the body. And sticks of typhoid and diphtheria without conditioning factors (fatigue, starvation) may not manifest themselves. Often there are situations in which the same factor may act as etiological in some cases, and in others it may be conditional. An example is hypothermia. It, on the one hand, causes frostbite, and on the other hand it provides optimal conditions for the appearance of many infectious diseases of the catarrhal character.

Classification of pathologies

In some cases, the etiology of the disease may be limited to one factor. In other cases, several provoking factors can be detected at once. In the first case, the disease is called mono-, and in the second - poly-physiological. The first type includes, for example, influenza, angina. But the heart defect is formed as a result of syphilis, rheumatism and many other factors. The etiology of the disease makes it possible to determine its specificity and pathogenetic therapy. For example, the course, severity and prognosis of staphylococcal and anthrax carbuncle have significant differences. Also, certain types of hypertension are specific , which can be caused by both neurogenic and renal factors. The cause of intestinal obstruction is external compression of the intestine or its internal blockage.

Effect factor

Distinguish one-stage (trauma, burn) and prolonged (starvation, infection) the effect of provoking the phenomenon. These phenomena also include etiology. This influence can cause the development of acute or chronic stage of pathology. As a result of the influence of the factor - long or short-term - in the human body there is a failure in various systems. This is what causes the disease, which is mainly a consequence of these disorders.

Treatment and prevention

Etiology is one of the main factors determining this or that method of therapy. Having identified the causes and conditions for the development of pathology, you can choose the way that eliminates provoking factors. Only in this case it is realistic 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, detection of bacilli carriers, disposal of mosquitoes in places of possible malaria, 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 passes under the supervision of a doctor. Together with this, differential diagnostics and monitoring of his condition are carried out. Often, treatment doctors in such cases are appointed "blindly."

Etiology of diabetes mellitus

To date, there is undeniable evidence that the main cause of development of diabetes is the genetic factor. This disease belongs to the polygenic species. It is based on at least two mutant diabetic genes in the b-chromosome, which are associated with the HLA system. The latter, in turn, determines the specific reaction of the organism and its cells to the effect of antigens. Based on the theory of polygenic inheritance of diabetes mellitus, two mutant genes or two of their groups are present in the disease, which are inherited by recessive means. In some people, there is a predisposition to damage the autoimmune system, or the sensitivity of certain cells to viral antibodies is increased, immunity is reduced to combat viruses. The genes of the HLA system are the 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. At the same time, there is a connection between diabetes mellitus and certain antibodies of leukocytes in the human body. They are encoded by genes of the main histocompatibility complex. They, in turn, are located on a given chromosome.

Classification of the main histocompatibility complex genes

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, and C. They are able to encode antigens that are found on all cells that contain the nucleus. These elements perform the function of protection against infections (mainly viral). Genes 2 classes, located on the D-area, contain loci DP, DQ, DR. They encode antigens that can be expressed exclusively on immunocompetent cells. These include monocytes, T-lymphocytes and others. With the help of class 3 genes, complement, tumor necrosis factor and transporter components are encoded, which are associated with antibody processing.

Recently, it has been suggested that not only the elements of the HLA system are associated with the inheritance of insulin-dependent diabetes mellitus, but also the gene coding for the synthesis of insulin, the immunoglobulin heavy chain, the T-cell receptor linkage, and others. People who have a congenital predisposition to IDDM, change under the influence of the environment. Their antiviral immunity is weakened, cells can undergo cytotoxic damage under the influence of pathogenic microorganisms and chemical components.

Other reasons

VIZD can have a viral etiology. Most often, rubella contributes to the onset of the pathology (the pathogen gets to the islets of the pancreas, then accumulates and replicates there), epidemic parotitis (most often the disease in children after the epidemic, after 1-2 years), hepatitis B virus and Coxsackie B (replicated in Insular apparatus), mononucleosis, influenza and others. The fact that the factor in question has to do with the development of diabetes mellitus is confirmed by the seasonality of the pathology. Usually IDDM is diagnosed in children in autumn and winter, reaching its peak in October and January. Also, high titers of antibodies to pathogens can be detected in the blood of patients. In people who died from diabetes, as a result of immunofluorescence methods of research, viral particles are observed in the islets of Langerhans.

Principle of the pathogen

Experimental studies conducted by M. Balabolkin, confirm the involvement of this infection in the development of the disease. According to his observations, the virus in people who are addicted to diabetes mellitus acts in this way:

- acute damage to cells (eg, 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 of the onset, this pathology is divided into three groups. These include, in particular:

1. With certain etiological causes.
2. With controversial provoking factors.
3. Unclear etiology.

Study of the causes of damage

To identify factors that cause cirrhosis, conduct clinical, epidemiological and laboratory studies. At the same time, they establish a connection with the excessive use of alcohol. For a long time it was believed that cirrhosis of the liver occurs in conditions of malnutrition of the alcoholic. In this regard, this pathology was called nutritional or nutritional. In 1961, Beckett created a work in which he described alcoholic acute hepatitis. He suggested that this disease increases the risk of liver cirrhosis associated with taking alcohol. In the future, the effect of ethanol on the development of toxic hepatitis, which can go into damage to the tissues of the hematopoietic organ, was established. Especially this refers to the re-transfer of the disease.

Dangerous dosages of ethanol

Cirrhosis of the liver, caused by alcohol, does not necessarily develop with the stages of acute or chronic hepatitis. The disease can be transformed in a different way. There are three main stages:

- fatty degeneration of the organ;

- fibrosis with mesenchymal reaction;

Cirrhosis.

The risk of the disease as a result of 15 years of excessive consumption of alcohol exceeds 8 times that which occurs with a five-year intake of alcohol. Pekvigno identified a dangerous dosage of ethanol for the development of liver cirrhosis. It is 80 grams per day (200 grams of vodka). A very dangerous daily dose is the intake of 160 g of alcohol and more. In the future, the "Pekvigno formula" was changed somewhat. In women, alcohol sensitivity is more than twice that of men. In some representatives of the stronger sex, the cirrhozogenic border is reduced to 40 g of ethanol per day, in others, the disease develops with the intake of 60 ml of alcohol. Women are enough and 20 ml of alcohol a day. In the development of alcoholic cirrhosis of the liver, the main role is played by a specific lipopolysaccharide of intestinal origin - endotoxin.

Other reasons

Cirrhosis can occur due to genetically caused metabolic disorders. Both in children and adults, a link between the development of pathology and a1-antitrypsin deficiency was found. A1-antitrypsin is a glycoprotein that is synthesized in the hepatocyte and is an inhibitor of the immediate effect of serine proteinases (elastase, trypsin, plasmin, chymotrypsin). Against the backdrop of deficiency occurs cholestasis in 5-30% of children, and 10-15% there is cirrhosis of the liver at a very young age. In this case, even in cases of biochemical abnormalities, usually a favorable prognosis. In the elderly, the likelihood of developing cirrhosis and liver cancer increases. This is especially true for people with emphysema. The functioning of the liver can also be disturbed by ingestion of chemicals and pharmacological agents. As a result, acute stages of involvement of this organ and chronic hepatitis occur. In rare cases, cirrhosis develops. For example, carbon tetrachloride can cause acute and sometimes toxic hepatitis of a chronic type. This pathology may in some cases accompany massive necrosis and the development of cirrhosis.