Bronchial asthma in children

Bronchial asthma is a chronic allergic inflammatory disease of the respiratory tract, in which many cells and cellular elements participate. Chronic inflammation causes the development of bronchial hyperreactivity, which leads to repeated episodes of wheezing, dyspnea, a feeling of stuffiness in the chest and cough, especially at night or in the early morning. During these episodes, usually a diffuse, variable bronchial obstruction, reversible spontaneously or under treatment, is noted.

ICD-10 codes

• J45.0 Asthma with predominance of the allergic component.
• J45.1 Non-allergic asthma.
• J45.9 Asthma, unspecified.
• J46 Asthmatic status [status asthmaticus].

The episodes of severe exacerbation of bronchial asthma that last for more than 24 hours, traditionally defined as asthmaticus , in modern guidelines for respiratory medicine are termed acute asthma , life threatening asthma , asthma, a close to fatal (near-fatal asthma). All definitions have a single meaning - unusual severity and resistance to conventional bronchodilator treatment, and not just the duration of the attack.

Epidemiology of bronchial asthma

The prevalence of bronchial asthma in children varies in different countries and populations, but it occupies a leading place among the chronic pathology of the respiratory system. The results of large epidemiological studies indicate that timely diagnosis of bronchial asthma is delayed, for example, the duration of the period between the first symptoms of the disease and the establishment of the diagnosis on average exceeds 4 years. Such a situation can be caused, first of all, by the ignorance of practical doctors of clear criteria for diagnosing bronchial asthma, unwillingness to register a disease due to fear of worsening reporting indicators, negative attitude of the parents of the child to this diagnosis,

According to DB Coultas and JM Saniet (1993), the prevalence of asthma varies in the population, depending on the age and sex characteristics. It was found that boys are more often sick at an early age than girls (6% compared to 3.7%), but in the pubertal period the frequency of the disease is the same for both sexes.

The higher prevalence of bronchial asthma in children is characteristic of environmentally unfriendly industrial areas of cities. The inhabitants of the city register bronchial asthma more often than in the village (7.1 and 5.7% respectively). Studies carried out in different countries show a high prevalence of bronchial asthma in regions with a humid and warm climate and a smaller one in high-altitude regions, which is associated with different levels of air saturation with air-allergens. Despite the many existing hypotheses, none of them explain in full the growth of the frequency of bronchial asthma and other allergic diseases.

[1], [2], [3], [4], [5], [6], [7], [8]

The causes of bronchial asthma in children

Bronchial asthma can be infectious-allergic and allergic in nature. Children are more likely to have an infectious-allergic form. Among antigenic factors, the main role is played by food allergens, animal hair, house dust, plant pollen, medicines, serums. Allergens realize bronhoobstructive effect on immune mechanisms. Allergen, connecting with fixed on the membrane of the mast cell with antibodies (mainly IgE), forms an immune complex. Immune complexes activate membrane enzymes of mast cells, their permeability increases, the mediators of anaphylaxis (histamine, serotonin, etc.) are released, which realize the triad of bronchial obstruction syndrome, edema, hypercapnia, and bronchospasm.

Causes of bronchial asthma

Symptoms of bronchial asthma in children

For bronchial asthma, irritability, decreased appetite, sweating, hyperemia sclera, thirst and polyuria, a shallow sleep are characteristic. The main symptoms are cough, asthma attacks (more often at night), difficulty exhaling. In the act of breathing, all the auxiliary musculature is involved, the excursion of the thorax is sharply reduced, wheezing is audible from a distance. The face turns blue, lips swell, eyelids swell, the baby sits, resting on elbows. With the development of the attack, hypercapnia increases. The most dangerous development of asthmatic status.

Asthmatic status is a protracted attack of bronchial asthma that is not stopped by a single injection of bronchodilators. At the base of the AS lies the refractoriness of beta2-adrenergic receptors.

Symptoms of bronchial asthma

Classification of bronchial asthma

By origin:

• infectious-allergic,
• allergic.

Type:

• typical,
• atypical.

By gravity:

• light,
• middle-aged,
• heavy.

[9], [10], [11], [12], [13], [14], [15], [16], [17]

Diagnosis of bronchial asthma

In the analysis of blood during an attack, leukopenia, thrombocytopenia and increased ESR are revealed. More often the diagnosis is based on a clinical picture. Sometimes the presence of wet wheezes on inhaling and exhaling allows you to erroneously suspect small-focal pneumonia. Differential diagnosis is performed with the following diseases:

• dysfunction of the vocal cords,
• bronchiolitis,
• Aspiration of foreign bodies,
• cystic fibrosis,
• tracheo-or bronchomalacia,
• bronchopulmonary dysplasia,
• bronchiolitis obliterans,
• stenosis of the respiratory tract due to hemangiomas or other tumors.

Diagnosis of bronchial asthma

[18], [19], [20], [21], [22], [23]

Treatment of bronchial asthma

Indications for admission to the intensive care unit:

• Difficulty breathing at rest, forced position, agitation, drowsiness or confused consciousness, bradycardia and shortness of breath.
• The presence of loud wheezing.
• The heart rate is more than 120-160 per minute.
• Absence of fast and obvious reaction to bronchodilator.
• Lack of improvement after starting treatment with glucocorticoids for 2-6 hours.
• Further deterioration of the condition.

Medical treatment of bronchial asthma in children

Preparations for the treatment of bronchial asthma are administered by mouth, parenterally and by inhalation.

Membrane stabilizing preparations

Cromones

• cromoglycic acid,
• undershot

Cromoglycic acid and nedocromil are used for the treatment of mild, intermittent and persistent bronchial asthma. Nedocromil can reduce the severity and duration of bronchoconstriction.

The therapeutic effect of cromoglycic acid is associated with the ability to prevent the development of an early phase of an allergic response by blocking the release of allergic mediators from mast cells and basophils. Cromoglycic acid reduces the permeability of the mucous membranes and reduces bronchial hyperreactivity. The drug is prescribed for mild and moderate forms of bronchial asthma for 1-2 inhalations per day for at least 1.5-2 months. Long-term use of cromoglycic acid provides a stable remission.

Nedocromilus suppresses both the early and the late phase of allergic inflammation by inhibiting the release of respiratory tract histamine, leukotriene C4, prostaglandin B, chemotactic factors from the mucous membrane cells. Has 6-8 times more pronounced, in comparison with cromoglicic acid, anti-inflammatory activity. Assign 2 inhalations 2 times a day, treatment course at least 2 months.

Among drugs that can suppress the release of mediators of allergic inflammation and cause blockade of H1 receptors of histamine, it should be noted ketotifen, which is used primarily in young children. Currently, a new class of anti-asthmatic agents is being studied-antileukotriene preparations of montelukost and zafirlukast.

Inhaled glucocorticoids

The most effective drugs currently available for the control of bronchial asthma. In school-age children, maintenance therapy with inhaled glucocorticoids can reduce the frequency of exacerbations and the number of hospitalizations, improve the quality of life, improve the function of external respiration, reduce the hyperreactivity of the bronchi and reduce bronchoconstriction with physical exertion. Inhaled glucocorticoids have a good effect in preschool children. Inhaled glucocorticoids are the only drugs of basic therapy for children under 3 years of age. In pediatric practice, the following inhaled glucocorticoids beclomethasone, fluticasone, budesonide. The use of inhaled glucocorticoids at a dose of 100-200 μg / day has no clinically significant side effects, but the use of high doses (800 μg / day) leads to inhibition of bone formation and degradation. Treatment with inhaled glucocorticoids in a dose of less than 400 μg / day is usually not accompanied by significant inhibition of the hypothalamic-pituitary-adrenal system and does not increase the frequency of cataract development.

Preference is given to the inhalation route of administration. Its main advantages are:

• direct admission of drugs into the respiratory tract,
• quick start of action,
• reduction of systemic bioavailability, which minimizes side effects.

In the case of insufficient effectiveness of inhaled glucocorticoids, glucocorticoids are administered orally or parenterally. By the duration of action, glucocorticoids are divided into short (hydrocortisone, prednisolone, methylprednisolone), medium (triamcinolone) and long-acting (betamethasone, dexamethasone) actions. The effect of short-acting drugs lasts 24-36 hours, medium-36-48 hours, long-term - more than 48 hours. Bronchodilators.

Beta2-Adrenomimetics

According to the duration of the action, sympathomimetics are sub-divided into preparations of short and prolonged action. Short-acting beta2-adrenomimetics (salbutamol, terbutaline, fenoterol, clenbuterol) are used for emergency care. Among beta2-adrenomimetics of prolonged action, two types of drugs are distinguished:

1. 12-hour forms based on the salt of salmeterol hydroxy-naphthoic acid (sertide),
2. preparations with controlled release of a medicinal substance based on salbutamol sulfate (salto).

[24], [25], [26], [27], [28], [29]

Methylxanthines

Theophylline improves lung function even at doses below the usually recommended therapeutic range. The pharmacological action of theophyllines is based on the inhibition of phosphodiesterase and the increase in the content of cyclic adenosine monophosphate, which has the ability to reduce the contractile activity of the smooth muscles of the bronchi, brain vessels, skin and kidneys. Drugs of short and prolonged action are allocated. The short-acting theophylline (aminophylline) is used to stop acute attacks of bronchospasm. In severe attacks aminophylline is used intravenously in a daily dose of 5-10 mg / kg in children under 3 years and 10-15 mg / kg in children from 3 to 15 years.

Aminofillin - a drug of prolonged action, is administered at a rate of 5-6 mg / kg for 20 minutes (if necessary, the administration can be repeated after 6 hours). The maximum daily dose is 20 mg / kg.

Emergency treatment for bronchial asthma

Drugs of choice for the treatment of acute bronchospasm are beta2-adrenomimetics of fast action (salbutomol, fenoterol), aminophylline.

An important place in the treatment of an attack of bronchial obstruction is intravenous use of glucocorticoids (1-2 mg / kg by prednisolone), which restore the sensitivity of beta2-adrenoreceptors to adrenomimetics.

If there is no effect, 0.1% solution of epinephrine is administered (not more than 0.015 mg / kg). The use of small doses of epinephrine is justified by the selective sensitivity of bronchial beta2-adrenergic receptors to it and allows one to count on the therapeutic effect with a minimal risk of complications from the cardiovascular system. After stopping the attack, continue intravenous drip epinephrine at a rate of 0.5-1 μg / (kghh).

Patients enter the intensive care unit with severe signs of respiratory failure. Clinical experience shows that patients are more likely to suffer hypercapnia than hypoxemia.

In recent years, the attitude toward the early transfer of patients to mechanical ventilation has changed. This is due to the use of severe ventilation conditions, which lead to severe complications. Improvements in oxygenation are achieved through non-invasive lung ventilation with pressure support. A good effect in stopping asthmatic status is provided by inhalational anesthetics, there are reports of the successful use of ketamine at a dose of 1-2 mg / kg.

Treatment of bronchial asthma

[30], [31], [32], [33], [34], [35], [36], [37], [38], [39]

Prognosis for bronchial asthma in children

In children with recurring episodes of wheezing in the presence of an acute viral infection that does not show signs of atopy and atopic diseases in a family history, symptoms usually disappear at preschool age, and bronchial asthma does not appear later, although minimal changes in the function of lung and bronchial hyperreactivity are possible. When wheezing occurs at an early age (up to 2 years), in the absence of other symptoms of family atopy, the likelihood that they will persist even later is small.