Bronchial asthma (BA) is one of the most common chronic diseases that a person has to deal with. At the same time, it is characterized by a different frequency of exacerbations and the degree of manifestation of symptoms, a different reaction to the drugs used.
In modern conditions, an in-depth study of the factors affecting the progression of asthma and the frequency of exacerbations is being carried out, targeted therapeutic techniques are being developed that take into account the phenotypes of a clinical nature, as well as a biological one. BA treatment involves the use of a fairly limited range of drugs that have proven their effectiveness in practice.
One of the most important tasks of the attending doctor is to determine what is the phenotype of bronchial asthma in each particular case. This allows you to significantly increase the effectiveness of the therapeutic effect.
Bronchial asthma and its classification
Ado and Bulatov, who presented their vision of the issue in 1968, were the pioneers of compiling the BA classification in Soviet medicine . Their main classification was the etiological theory, according to which two basic types of the disease are distinguished: infectious-allergic and non -infectious-allergic , also called atopic.
In 1982, Fedoseyev presented a radically different classification system, much similar to the modern one, which provided for grouping by phenotypes, taking into account the pathogenetic causes of the development of the disease, its etiological signs. In accordance with this classification, the following forms of the disease are distinguished:
- allergic and non-allergic;
- with a pronounced violation of the adrenergic balance;
- dyshormonal ;
- aspirin ;
- glucocorticosteroid ;
- with initially atypical bronchial reactivity;
In modern realities, two main approaches to the classification of BA are practiced: grouping taking into account the clinical and biological indications of the disease and cluster analysis.
The clinical and biological approach is somewhat limited, as it involves focusing only on one aspect of the disease. The most successful example of such a classification is the system proposed by the American professor Wenzel . He identified three main groups of AD phenotypes:
- Clinical / physiological, in determining which they are based on how asthma proceeds, what is the frequency of exacerbations, how the body responds to treatment.
- Trigger phenotypes (allergens, aspirin, physical activity , etc.).
- Phenotypes, in the definition of which, are repelled by the type of the ongoing inflammatory process ( neutro – or eosinophilic, low granulocytic ).
In cluster analysis, it is mandatory to maintain multifaceted statistics, which allows you to divide a complex of objects into similar groups.
General concept of phenotype
The asthma phenotype is understood as a stable clinical variation of asthma that requires an individual approach to treatment.
The phenotype of the disease is determined in the presence of a stable biological marker, which makes it possible to isolate a specific clinical form with characteristics specific for a particular variant of asthma. Modern scientists distinguish phenotypes taking into account the nature of inflammation, the functional state of the respiratory system, and the nuances of clinical manifestations.
Principles of dividing asthma by phenotype
When determining the phenotypes of bronchial asthma, they are guided by a number of characteristics, including:
- clinical features (having an earlier or later onset caused by smoking, menstruation, obesity, hypersensitivity to aspirin, etc.);
- demographic (belonging to a certain age category, gender, race);
- functional parameters (obstruction of the respiratory system, sensitivity to a certain type of drug, low FEV1);
- outcome (development of chronic OBL, frequency of exacerbations, worsening or improvement of asthma);
- pathogenetic pathways (with remodeling of the airways, with a predominance of inflammation, etc.);
- the presence of a risk to life.
With the traditional approach to determining the AD phenotype using a classification based on clinical, functional, etiological and inflammatory indicators, it is possible to take into account only one specific parameter, as a result of which the characteristic is one-sided and a whole set of phenotypes is formed, the connection between which is difficult to establish.
Since the second half of the 90s of the last century, European scientists have carried out large-scale studies related to the problems of BA classification. As a result, a completely new approach to determining the phenotypes of this disease was proposed. Scientists came to the conclusion that one should rely primarily on the response of the patient’s body to therapy, the type of inflammatory process in the respiratory tract, as well as the features of a clinical and physiological nature.
The modern grouping of phenotypes of bronchial asthma implies the allocation of four groups:
- Allergic treatment of active type in children.
- Treated active type, detected in adults and has a pronounced character.
- Allergic untreated, not highly active.
- Non-allergic untreated inactive type.
In severe bronchial asthma, the phenotypes of this disease can be as follows:
- with a severe form;
- with a severe form of chronic course;
- BA in the second half of life;
Significant attention is paid to severe asthma due to the fact that patients with bronchial asthma of this phenotype, whose number is about 1/5 of the total number of sufferers, spend 4/5 of all funds spent on fighting asthma. The severe form of the disease is characterized by the presence of a threat to the life of patients, sharp exacerbations, sudden and prolonged attacks of suffocation, instability of the course, even with the right treatment.
Among the most typical phenotypes of severe asthma is aspirin , which develops while taking non-steroidal drugs with an anti – inflammatory effect.
The severe form of chronic asthma is characterized by poor control by inhalation with glucocorticosteroids . When such a problem occurs, the doctor usually switches to treatment with systemic steroid drugs. The group of patients with chronic severe BA is usually united by the presence of:
- permanent symptoms;
- frequent attacks at night;
- poor functional performance;
- reduced and limited physical activity and sleep disturbances.
BA in the second half of life, typical for people of age, is a fairly common phenomenon and was previously associated with chronic obstructive pulmonary disease. It is the disease of this phenotype that often ends in death.
Fatal asthma is a type of illness in which a patient suddenly dies for no apparent reason and changes in symptoms. The development of this phenotype of the disease is extremely difficult to predict, since the condition deteriorates sharply with normal breathing.
Treatment of bronchial asthma depending on the phenotype
In the past, doctors have used roughly the same approaches to treating patients of all age groups. The peculiarities of the development of the disease, its course, the body’s response to certain drugs at different ages did not attach much importance, and they tried to find universal options for therapy. The development of treatment methods was carried out on the assumption that the causes of the development of the disease are the same for everyone, and it makes no sense to separate patients based on their age.
However, a deeper study of BA made it possible to establish that each age group has its own characteristics of the course of the disease, its diagnosis, course, and response to medications. In addition, at different ages, patients have a different reaction to the very fact of the disease, they have different psychoemotional mood, which also has a significant effect on the course of the disease.
Therefore, in modern conditions, the diagnosis and therapy of bronchial asthma is necessarily carried out taking into account the age of the patients. Also, a scrupulous study of the problem of the effectiveness of the method of anti- IgE therapy in AD and targeted treatment focused on the phenotype of the disease is being carried out .
For a long time, the therapy of atopic asthma has been successfully used in practice with the use of elimination measures aimed at eliminating the effects of allergens, and allergen- specific immunotherapy (ASIT). As practice shows, this approach serves as an excellent alternative to long-term maintenance treatment with the use of inhaled glucocorticosteroids (ICS) for patients diagnosed with mild atopic asthma.
Selected areas of treatment
Another example of effective treatment in accordance with the phenotype is therapy aimed at reducing the activity of immunoglobulin E. It is especially effective for patients with atopic asthma, whose number is up to half of all patients with severe asthma.
People with this AD phenotype have an increased susceptibility to allergens, a high level of immunoglobulin E in the blood, as well as a predisposition to the disease, that is, a burdened family analysis. It is the phenotype of severe AD that is currently the target for anti- IgE therapy.
The American Lung Society and the European Respiratory Society recommend that each patient should undergo detailed questioning and keep a symptom diary. This simplifies the assessment of the severity of the disease, the determination of its phenotype, as well as the selection of the most effective treatment method.
Prescribing drugs for therapy should be carried out individually for each patient. It often happens that a seemingly effective treatment is prescribed to a person, the optimal dosages of drugs are determined, but at the same time it is not possible to properly control the disease, and the likelihood of developing its exacerbations remains at a high level.
In such cases, it is especially important to carry out the correct phenotyping of AD, taking into account the nature of inflammation and atopic status, which will provide additional information that can be used as a basis for correcting the treatment.
Of the wide range of medications used to treat AD, inhaled glucocorticosteroids are the most popular . With their help, it is possible to achieve an effective decrease in the severity and frequency of manifestation of BA symptoms, to normalize lung function due to a decrease in bronchial hyperreactivity and the intensity of inflammatory processes occurring in them, to reduce the frequency of exacerbations and, in general, to improve the quality of life of patients.
Bronchial asthma is a heterogeneous disease characterized by a large number of causes leading to its occurrence, as well as an initially difficult to predict course.
In this regard, the recognition and classification of different phenotypes of the disease is of paramount importance, thanks to which doctors are able to carry out individual treatment of bronchial asthma in each case.
It is with this approach that therapy turns out to be most effective, it allows you to eliminate symptoms and control the course of the disease.