Hereditary lung diseases
In the development of hereditary diseases, the gene mutation causes the onset of the disease practically regardless of the effect of environmental factors. In contrast, a genetic defect in multifactorial pulmonary diseases is realized under the influence of a whole complex of environmental factors.
The classic model of polygenically inherited diseases is bronchial asthma. Family burden of allergic diseases is revealed in 50-86% of children suffering from bronchial asthma. It is established that the risk of a child suffering from bronchial asthma in the presence of this suffering in both parents is higher than that of one of them.
In the presence of bronchial asthma in one of the parents, the risk of the appearance in the family of the first sick child is increased by 12 times in comparison with general population indicators;if there are children with bronchial asthma in the same family, the risk of further children's illness increases by 20-25 times. In monozygotic twins, the risk of developing bronchial asthma is many times greater than that of dizygotic twins.
At the heart of bronchial asthma, as we know, are the immune mechanisms. Most people with bronchial asthma have specific antibodies to various allergens. A high level of specific antibodies is usually accompanied by an increased content of total immunoglobulin E. A significant increase in serum levels of immunoglobulin E is a characteristic feature of atopic bronchial asthma. The content of immunoglobulin E in the blood with atopic asthma usually sharply exceeds the norm. This confirms the opinion that at the atopic form of bronchial asthma the key role belongs to the antibody-dependent type of allergic reaction. It is suggested that the ability to produce antibodies( as well as the factors regulating their production) is genetically programmed.
Hereditary predisposition is of undoubted importance in the formation of chronic inflammatory lung diseases. It is known that relatives of patients with chronic bronchitis are three times more likely to suffer from pulmonary pathology compared to members of healthy families. A high coefficient of heritability for chronic non-obstructive bronchitis was established.
The role of hereditary factors in the occurrence of chronic lung diseases is ambiguous. They are clearly traced under inherently inherited diseases, less - in diseases with hereditary predisposition. The latter group of diseases is the most common and has a significant impact on morbidity indicators, limits the working capacity of persons of working age, leading them to disability, and sometimes to dramatic outcomes. Ways of preventing these diseases are known.
The main principles of clinical examination of patients with chronic bronchopulmonary pathology are early and active detection, recording, dynamic observation and treatment at the stages of a polyclinic, a hospital, a sanatorium. This applies primarily to children, as in childhood, as a rule, and are diagnosed with congenital and hereditary diseases.
The spectrum of congenital and hereditary pathology of the lungs is quite wide. These diseases are characterized by clinical diversity, the nature of the current, the nature of inheritance. However, at the same time, the basic principle of clinical examination of patients with chronic bronchopulmonary pathology remains. The main role in the prophylactic medical examination of sick children belongs to the district pediatrician. The doctor of the children's polyclinic identifies patients with chronic lung pathology, including hereditary and congenital lesions, and directs them for examination to specialized pulmonology departments and hospitals. The modern complex of instrumental, immunological, biochemical and other methods used in conditions of well-equipped hospitals allows one to decipher individual forms of this pathology.
After the initial examination and detection of the disease, a person with a congenital and hereditary pathology of the lungs should be under constant supervision of both the pediatrician and the pulmonology center. The frequency of examination by the district pediatrician should be at least 1 time in 1-2 months, and pulmonary specialists - once every 3-4 months. At the same time, dynamic control of the function of external respiration and cardiovascular system is carried out. In the course of dispensary observation, not only in the hospital, but also at home, antibiotic treatment is carried out, especially in diseases such as cystic fibrosis, polycystosis, immunodeficiency, which often have a continuously recurring( with periodic exacerbations) during the inflammatory process in the lungs. Rehabilitation of other foci of infection is being carried out. Special attention is paid to maintaining and restoring the drainage function of the lungs( therapeutic exercises, postural drainage, chest massage, repeated inhalation courses with mucolytic drugs are needed).
In the implementation of prophylactic medical examination of patients with bronchial asthma, the district doctor also has a paramount role. Consultation in allergological rooms, pulmonology centers allows the doctor in charge to decipher the form of the disease and give recommendations on the management of the patient. Children suffering from mild and moderate bronchial asthma are examined by a pediatrician at least once a quarter, and a specialist in an allergic room 1-2 times a year. In severe asthma, it should be observed monthly by the district pediatrician and once a quarter - from an allergist.
One of the stages of treatment of patients with chronic pulmonary pathology is a specialized pulmonological sanatorium. At the same time, it can not be stressed that selection of patients for referral to sanatorium treatment is a serious task. For treatment in specialized sanatoriums, patients with severe respiratory failure( DN II-III), hemoptysis, purulent intoxication should not be referred. These people quite often need urgent qualified help, sending them to a sanatorium can lead to dramatic consequences. At all stages of dispensary follow-up, social rehabilitation is essential. In this regard, the professional orientation of students is extremely important.
Continuous dispensary observation and periodic treatment courses allow in many cases to achieve stabilization of the process, reduce the activity of bronchopulmonary infection in diseases such as Kartagener's syndrome, malformations, cystic fibrosis.
Children with congenital and hereditary pathology of the lungs are not taken off the register. Until the age of 15 they are observed by the district pediatrician and specialists of the pediatric pulmonology center, then they are supervised by therapists. The most severe patients with congenital and hereditary pathology are transferred to disability already in childhood.
A special place in the system of observation of persons with congenital and hereditary pathology of the lungs is medico-genetic counseling. Medico-genetic counseling is aimed at the prevention of hereditary pathology, preventing the birth of children with genetic defects. Currently, the most appropriate is a multi-level system of genetic counseling - from the general network of medical and preventive institutions to a specialized genetic center. The main principle of genetic counseling is to determine the degree of genetic risk for subsequent offspring and clarify this to parents. However, it must be emphasized that the issues of procreation are decided only by the family.
Genetic counseling primarily determines the risk of having a sick child, which depends on the nature of the inheritance. Monogeneously inherited pathology of the lungs, like all monogenic diseases, belongs to high-risk diseases( 1: 10).It should be noted that in the list of diseases with autosomal dominant type of inheritance, the number of pulmonary diseases is small( primary pulmonary hypertension, alveolar microlithiasis, idiopathic diffuse fibrosis).In this type of inheritance, the patient is usually one of the parents. The probability of inheritance of a mutant gene is 50% in these cases.
Most of the hereditary lung diseases are transmitted by an autosomal recessive type. This group includes the most common hereditary pathology, which occurs with the defeat of the bronchopulmonary system: cystic fibrosis, primary ciliary dyskinesia and Kartagener's syndrome. Parents of children with these suffering can be healthy and are only carriers of the mutant gene. The risk of the birth of a sick child is 25%.
It is extremely difficult to determine the risk of inheritance in the developmental defects of the bronchopulmonary system, because in some cases they can be a manifestation of monogeneously inherited diseases, and sometimes - the result of adverse environmental influences.
The risk assessment for polygenically inherited diseases, in particular for bronchial asthma, presents considerable difficulties, since both hereditary predisposition and the influence of unfavorable environmental factors are important in the development of the disease. It is believed that the risk of the disease of the child born after the patient is 14%, with a disease of one of the parents - 31%, with the disease of both parents - 70%.
The further development of genetic counseling is inextricably linked with the development of prenatal diagnostic methods. With regard to lung diseases, great attention is paid to the possibility of prenatal diagnosis of cystic fibrosis, a deficiency of a-antitrypsin. Success in this regard is associated with the development of DNA diagnostics methods.