Diagnosis of bronchial asthma

A study of the external respiratory function in patients with bronchial asthma is mandatory and allows one to objectively determine the degree of bronchial obstruction, its reversibility and variability (daily and weekly fluctuations), as well as the effectiveness of the treatment.

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Spirography

Spirometry is a graphical recording of lung volume during breathing. The following are characteristic spirographic signs of impaired bronchial patency in patients with bronchial asthma:

• a decrease in forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1), with FEV1 being the most sensitive indicator reflecting the degree of bronchial obstruction;
• decrease in the Tiffno index (FEV1/VC ratio), usually less than 75%. In case of bronchial obstruction, the decrease in FEV is more pronounced than FVC1, therefore the Tiffno index always decreases.

The measurement of the above mentioned parameters should be made 2-3 times and the best indicator should be taken as the true value. The obtained absolute values are compared with the expected ones, which are calculated using special nomograms taking into account the patient's height, sex, and age. In addition to the above-mentioned changes in the spirogram, during an exacerbation of bronchial asthma, the residual volume of the lungs and the functional residual capacity increase significantly.

With frequent exacerbations of the disease and the development of pulmonary emphysema, a decrease in the vital capacity of the lungs (VC) is detected.

Pneumotachography

Pneumotachography is a two-coordinate system recording of the "flow-volume" loop - the expiratory air flow rate in the section 25-75% FVC, i.e. at the middle of the exhalation. Using this method, the peak volume rate (PVR), maximum volume rates at the level of 25%, 50%, 75% FVC (MVVR25, MVVR50, MVVR75) and average volume rates SVR25, 75 are calculated.

According to pneumotachography (flow-volume loop analysis), it is possible to diagnose impaired bronchial patency at the level of large, medium or small bronchi. Obstruction mainly at the level of the central airways and large bronchi is characterized by a marked decrease in the volumetric flow rate of forced expiration in the initial part of the descending branch of the flow/volume curve (FEV and MEF25 in % of the expected values are reduced more significantly than MEF50 and MEF75). In peripheral bronchial obstruction observed in bronchial asthma, a concave expiratory curve and a significant decrease in the maximum volumetric flow rate at the level of 50-75% of FVC (MEF50, MEF75) are characteristic.

It is advisable to determine the FEV1 Tiffeneau index and pneumotachography with the construction of the flow-volume curve before and after the use of bronchodilators, as well as to assess the severity of the disease and monitor the course of bronchial asthma (2 times a year).

Peak flowmetry

Peak flowmetry is a method of measuring the maximum (peak) volumetric air velocity during forced exhalation (peak expiratory flow rate) after a full inhalation.

Peak expiratory flow rate (PEF) closely correlates with FEV1. Portable individual peak flow meters have been designed and are widely used. Peak flowmetry is performed several times during the day, before and after taking bronchodilators. It is mandatory to measure PEF in the morning (immediately after the patient gets up), then after 10-12 hours (in the evening). Peak flowmetry should be performed by a doctor during a patient's appointment, as well as daily by the patient. This allows us to determine the stability and severity of bronchial asthma, identify factors that cause an exacerbation of the disease, and the effectiveness of the treatment measures.

Normal values of PSV in adults can be determined using a nomogram.

The following changes in PSV are characteristic of reliable bronchial asthma:

• an increase in PEF by more than 15% 15-20 minutes after inhalation of short-acting beta2-stimulants;
• daily fluctuations in PEF are 20% or more in patients receiving bronchodilators and 10% or more in patients without bronchodilator therapy;

Daily fluctuations in PSV are determined by the following formula:

Daily fluctuations of PSV in % (PSV daily in %) = PSV max - PSV min / PSV average x 100%

• a decrease in PEF by 15% or more after physical exertion or after exposure to other triggers.

Tests using bronchodilators

Bronchodilator tests are used to determine the degree of reversibility of bronchial obstruction. FEV1, Tiffeneau index, flow-volume curve (pneumotachography) and peak flowmetry are determined before and after the use of a bronchodilator. The state of bronchial obstruction is judged based on the absolute increase in FEV1 (Δ FEV1isch%)"

ΔFEV1ref% = FEV1dilate (ml)-FEV1ref(ml) / FEV1ref(ml) x 100%

Notes: FEV1dilat (ml) is the forced expiratory volume in the first second after the use of bronchodilators; FEV1init (ml) is the forced expiratory volume in the first second, initially, before the use of bronchodilators.

X-ray examination of the lungs

No specific changes are detected during X-ray examination of the lungs. During an attack of bronchial asthma, as well as during frequent exacerbations, signs of pulmonary emphysema, increased transparency of the lungs, horizontal position of the ribs, widening of the intercostal spaces, and a low position of the diaphragm are detected.

In case of infection-dependent bronchial asthma, X-ray examination can reveal signs characteristic of chronic bronchitis (see the corresponding chapter) and pneumosclerosis.

Electrocardiographic examination

During an attack of bronchial asthma, signs of increased load on the myocardium of the right atrium are detected: high pointed P waves in leads II, III, aVF, V„ V„, the heart may rotate around the longitudinal axis clockwise (with the right ventricle forward), which is manifested by the appearance of deep S waves in the chest leads, including the left ones. After the attack is stopped, these ECG changes disappear. In severe cases of bronchial asthma, its frequent exacerbations, chronic pulmonary heart disease gradually develops, which is manifested by ECG signs of myocardial hypertrophy of the right atrium and right ventricle.

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Evaluation of arterial blood gas composition

Determination of the gas composition of arterial blood allows for a more objective assessment of the severity of an exacerbation of the disease, and is also necessary in asthmatic status. Severe bronchial obstruction (FEV1 - 30-40% of the expected, PSV < 100 l/min) is accompanied by hypercapnia, with less severe obstruction, hypoxemia and hypocapnia are determined.

During severe exacerbation of bronchial asthma, arterial hypoxemia is observed due to ventilation-perfusion disorders.

It is advisable to use the pulse oximetry method, which allows determining the saturation of arterial blood with oxygen and making a conclusion about the effectiveness of the administration of bronchodilators.

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Bronchoscopy

Bronchoscopy is not a routine method of examination in bronchial asthma. It is used only when differential diagnostics are necessary, usually with neoplasms of the bronchopulmonary system.

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Assessment of allergological status

An assessment of the allergological status is carried out for the purpose of diagnosing the atopic (allergic) form of bronchial asthma and identifying the so-called causative allergen (the “culprit” allergen) that causes the development and exacerbation of bronchial asthma.

Allergological diagnostics is carried out only in the remission phase of bronchial asthma, using sets of various allergens. Skin tests are most often used (application, scarification and intradermal methods of using allergens). The size and nature of the swelling or inflammatory reaction that develops are assessed. The introduction of the "allergen-culprit" is accompanied by the most pronounced swelling, hyperemia, itching. The most sensitive, but less specific test is the intradermal introduction of the allergen. These tests do not have an independent diagnostic value, but taking into account the allergological anamnesis and clinical data, they are a great help in the diagnosis of bronchial asthma.

In the allergic form of bronchial asthma, provocative tests based on reproducing allergic reactions by introducing an allergen into the shock organ are also positive. An inhalation provocative test is used, the essence of which is that the patient inhales through an inhaler first a control indifferent solution, and if there is no reaction to it, then allergen solutions in a sequentially increasing concentration (starting with the minimum to the one that gives a noticeable reaction in the form of difficulty breathing). Before and after each inhalation of the allergen, a spirogram is recorded, FEV1 and the Tiffno index are determined. The provocative test is considered positive if FEV1 and the Tiffno index decrease by more than 20% compared to the initial values. A provocative inhalation test can only be carried out in the remission phase in a hospital setting; any bronchospasm that develops should be immediately stopped with bronchodilators.

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Laboratory diagnostics of bronchial asthma

Laboratory test data are of great importance in confirming the diagnosis of bronchial asthma (primarily the allergic form), assessing its severity and the effectiveness of treatment. The most characteristic changes in laboratory parameters are the following:

• Complete blood count - eosinophilia, moderate increase in ESR during exacerbation of bronchial asthma;
• General sputum analysis - many eosinophils, Charcot-Leyden crystals are determined (shiny transparent crystals in the form of rhombuses or octahedrons; formed during the destruction of eosinophils); Curschmann spirals (casts of transparent mucus in the form of spirals, are casts of small spasmodically contracted bronchi); in patients with infection-dependent bronchial asthma with pronounced activity of the inflammatory process, neutral leukocytes are found in large quantities. In some patients, during an attack of bronchial asthma, "Creola bodies" are detected - round formations consisting of epithelial cells;
• Biochemical blood test - possible increase in the level of alpha2- and gamma-globulins, sialic acids, seromucoid, fibrin, haptoglobulin (especially in infection-dependent bronchial asthma);
• Immunological studies - an increase in the amount of immunoglobulins in the blood, a decrease in the amount and activity of T-suppressors (more typical for atopic asthma). With the help of a radioimmunosorbent test in atopic bronchial asthma, an increase in the amount of IgE is determined. The use of this test is especially important when it is impossible to conduct allergy testing (skin and provocative tests).

Clinical diagnosis of asthma

Diagnosis of bronchial asthma is facilitated by using the following diagnostic criteria:

• attacks of suffocation with difficulty exhaling, accompanied by dry wheezing over the entire surface of the lungs, which can be heard even at a distance (distant dry wheezing);
• equivalents of a typical asthma attack: paroxysmal coughing at night that disrupts sleep; recurring wheezing; difficulty breathing or a feeling of tightness in the chest; the appearance of coughing, shortness of breath or wheezing at a certain time of year, upon contact with certain agents (animals, tobacco smoke, perfumes, exhaust fumes, etc.) or after physical exertion;
• identification of the obstructive type of respiratory failure during the study of the parameters of the external respiratory function (decrease in FEV1, Tiffeneau index, peak expiratory flow rate, maximum expiratory volume flow rate at the level of 50-75% FVC - MEF50, MEF75 during the analysis of the flow-volume loop;
• daily variability of peak expiratory flow rate (20% or more in individuals receiving bronchodilators; 10% or more without the use of bronchodilators);
• disappearance or significant relief of breathing and an increase in FEV1 by 20% or more after the use of bronchodilators;
• the presence of a biological marker of bronchial asthma - a high level of nitrogen oxide (NO) in exhaled air.

The diagnosis of clinical and pathogenetic variants of bronchial asthma according to G. B. Fedoseyev (1996) is presented below.

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Diagnostic criteria for atopic bronchial asthma

1. Allergic history. Hereditary predisposition: bronchial asthma or other allergic diseases have been detected in close relatives. Allergic constitution: development of other allergic diseases (except asthma) in the patient at different periods of life - exudative diathesis in childhood, allergic rhinitis, urticaria, Quincke's edema, neurodermatitis. Pollen allergy: the connection between exacerbations of bronchial asthma and the flowering season of grasses, shrubs, trees, the occurrence of asthma attacks in the forest, field. Dust allergy: to house dust (allergens of fluff, feathers, pet hair, human epidermis, Dermatophagoides mite); worsening of breathing when cleaning the apartment, working with books, papers; improvement of well-being at work or with a change of environment. Food allergy is associated with certain food products (strawberries, honey, crabs, chocolate, potatoes, milk, eggs, fish, citrus fruits, etc.), exacerbations are often accompanied by recurrent urticaria, migraines, constipation; a history of asthma attacks associated with eating the above products. Drug allergy: intolerance to certain drugs (penicillin and other antibiotics, sulfonamides, novocaine, vitamins, iodine preparations, vaccines, serums, etc.), manifested by asthma attacks, skin rashes, and sometimes anaphylactic shock. Professional allergy: asthma attacks at work upon contact with a professional allergen, improvement of well-being at home, on vacation.
2. Predominantly young age (75-80% of patients are under 30 years of age).
3. Positive skin tests with certain allergens.
4. Positive provocative tests (nasal, conjunctival, inhalation) for certain allergens (carried out according to strict indications).
5. Identifying a specific food allergen by keeping a food diary, following an elimination diet, and then challenging it.
6. Laboratory criteria: elevated IgE levels in the blood; elevated eosinophil levels in the blood and sputum; Shelley basophil test (study of morphological changes in basophils as a result of the interaction of the patient's blood serum and a specific allergen); positive alteration reaction of the patient's neutrophils with the allergen; increased glycogenolysis in lymphocytes under the influence of adrenaline in the presence of an allergen; increased sputum viscosity under the influence of an allergen; identification of erythrocyte characteristics (more than 11% microcytes, an increase in the number of hemolyzed erythrocytes in a hypotonic solution with obzidan).

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Diagnostic criteria for infection-dependent bronchial asthma

1. Clinical examination: complaints, anamnesis, objective data indicating a connection between bronchial asthma and a previous respiratory infection, acute bronchitis, flu, pneumonia, exacerbation of chronic bronchitis or chronic pneumonia.
2. Complete blood count: leukocytosis, increased ESR.
3. Biochemical blood test: appearance of CRP, increase in sialic acids, alpha2- and gamma-globulins, seromucoid, haptoglobin, sialic acid activity.
4. General sputum analysis: mucopurulent, neutrophilic leukocytes predominate in the smear, detection of pathogenic bacteria in the diagnostic titer.
5. X-ray of the lungs in 3 projections, according to indications bronchography, tomography, X-ray of the paranasal sinuses: detection of infiltrative shadows in pneumonia, signs of local or diffuse pneumosclerosis, darkening of the paranasal sinuses.
6. Fiberoptic bronchoscopy with examination of bronchial contents: signs of inflammation of the mucous membrane, thick mucopurulent secretion, predominance of non-schrophilic leukocytes in bronchial washings, detection of pathogenic bacteria pneumococcus, staphylococcus, etc. with their quantitative counting and determination of sensitivity to antibiotics.
7. Determination of bacterial sensitization (intradermal tests with bacterial allergens, cellular diagnostic methods, provocative tests): positive tests with the corresponding bacterial allergens (local and general reactions).
8. Mycological examination of sputum: culture of Candida fungi and yeast from sputum, urine, feces.
9. Virological examination: detection of viral antigens in the epithelium of the nasal mucosa using immunofluorescence, serodiagnostics, high titers of antibacterial and antiviral antibodies in the blood.
10. . Consultation with an otolaryngologist, dentist: identification of foci of infection in the upper respiratory tract, nasopharynx and oral cavity.

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Diagnostic criteria for glucocorticoid deficiency

1. Clinical observation and detection of glucocorticoid insufficiency: lack of effect with long-term treatment with glucocorticoids, corticosteroid dependence, occurrence of skin pigmentation, tendency to arterial hypotension, deterioration of the condition (sometimes development of an asthmatic condition) upon discontinuation of prednisolone or reduction of the dose.
2. Decreased blood levels of cortisol, 11-OCS, decreased urinary excretion of 17-OCS, insufficient increase in urinary excretion of 17-OCS after administration of adrenocorticotropic hormone, decreased number of glucocorticoid receptors on lymphocytes.

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Diagnostic criteria for dysovarian variant of bronchial asthma

1. Deterioration of the patient's condition before or during the menstrual cycle, in connection with pregnancy and during menopause.
2. Cytological examination of a vaginal smear: signs of decreased progesterone levels (inadequacy of the second phase of the cycle or anovulation).
3. Basal (rectal) temperature measurement: decreases in the second phase of the menstrual cycle.
4. Radioimmunological determination of estrogen and progesterone levels in blood plasma: increased estrogen levels in the second phase of the menstrual cycle, disturbance of the estrogen/progesterone ratio.

Diagnostic criteria for autoimmune bronchial asthma

1. Severe, continuously recurring course of the disease (with the exclusion of other causes of the severity of the disease).
2. Positive intradermal test with autolymphocytes.
3. High levels of acid phosphatase in the blood.
4. Positive RBTL with phytohemagglutinin.
5. Decreased complement levels in the blood and detection of circulating immune complexes and anti-pulmonary antibodies.
6. The presence of severe, often disabling complications of glucocorticoid therapy.

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Diagnostic criteria for adrenergic imbalance

1. Clinical observation - identification of factors contributing to the formation of adrenergic imbalance: excessive use of sympathomimetics, viral infection, hypoxemia, acidosis, endogenous hypercatecholaminemia due to a stressful situation, transformation of an attack of bronchial asthma into asthmatic status.
2. The paradoxical effect of sympathomimetics is an increase in bronchospasm when they are used.
3. Laboratory and instrumental diagnostics:
   • functional study of bronchial patency before and after inhalation of selective beta2-adrenergic agonists: no increase or decrease in FVC, expiratory flow rate after inhalation of a sympathomimetic;
   • a decrease in the degree of hyperglycemic response to adrenaline, the appearance of paradoxical reactions (a decrease in glucose levels in response to the administration of adrenaline);
   • eosinopenic test with adrenaline: a decrease in the eosinopenic response to the administration of adrenaline (the absolute number of eosinophils in 1 mm3 ^of blood decreases in response to the administration of adrenaline by less than 50%);
   • glycogenolysis of lymphocytes: a decrease in the degree of glycogenolysis in lymphocytes after incubation with adrenaline.

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Diagnostic criteria for the neuropsychic variant of bronchial asthma

1. Identification of disorders of the neuropsychiatric sphere in the premorbid period, during the development of the disease, according to the anamnesis data - psychological characteristics of the individual; the presence in the anamnesis of mental and craniocerebral trauma, conflict situations in the family, at work, disorders in the sexual sphere, iatrogenic effects, diencephalic disorders.
2. Clarification of neuropsychic pathogenetic mechanisms (carried out by a psychotherapist) - hysterical-like, neurasthenic-like, psychasthenic-like mechanisms are determined, which contribute to the occurrence of attacks of suffocation.

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Diagnostic criteria for vagotonic (cholinergic) variant of bronchial asthma

1. Violation of bronchial patency mainly at the level of large and medium bronchi.
2. Bronchorrhea.
3. High efficiency of inhaled anticholinergics.
4. Systemic manifestations of vagotonia - frequent combination with duodenal ulcer, hemodynamic disorders (bradycardia, hypotension), mottled skin, sweaty palms.
5. Laboratory signs: high blood acetylcholine levels, significant decrease in serum cholinesterase activity, increased blood and urine cyclic guanosine monophosphate levels.
6. Identification of the predominance of the tone of the parasympathetic nervous system using the method of variation pulsometry.

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Diagnostic criteria for primary altered bronchial reactivity

1. Clinical observations - the occurrence of asthma attacks after physical exertion, when inhaling cold or hot air, changes in weather, from strong odors, tobacco smoke in the absence of evidence of the leading role of other pathogenetic mechanisms that form altered reactivity.
2. Decreased bronchial patency indicators, according to spirography and peak flowmetry, cold air inhalation tests, acetylcholine, PgF2a, obzidan.
3. Positive acetylcholine test. Immediately before the test, acetylcholine solutions are prepared in concentrations of 0.001%; 0.01%; 0.1%; 0.5% and 1% and FEV1 and Tiffeneau index are determined. Then, using an aerosol inhaler, the patient inhales an aerosol of acetylcholine in the highest dilution (0.001%) for 3 minutes (if the patient begins to cough earlier than 3 minutes, the inhalation is stopped earlier).

After 15 minutes, the patient's condition is assessed, the lungs are auscultated, and FEV1 and the Tiffno index are determined. If clinical and instrumental data do not reveal any bronchial patency disorders, the test is repeated with the next dilution. The test is considered positive if the Tiffno index drops by 20% or more. Even a reaction to a 1% solution is considered positive. A positive acetylcholine test is pathognomonic for all forms of bronchial asthma.

In some cases, an inhalation histamine test is used to determine bronchial hyperreactivity. In this case, a histamine concentration of < 8 mg/ml, leading to a decrease in FEV1 < 20%, indicates the presence of bronchial hyperreactivity.

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Diagnostic criteria for "aspirin" asthma

A clear connection between an asthma attack and the use of aspirin or other non-steroidal anti-inflammatory drugs, as well as patented prescriptions containing acetylsalicylic acid (theophedrine, citramon, askofen, etc.), products containing salicylates, as well as the yellow food dye tartrazine, and any yellow tablets (they contain tartrazine).

Analysis of the features of an attack of "aspirin" asthma. An attack of suffocation occurs within an hour after taking aspirin and is accompanied by abundant mucus discharge from the nose, lacrimation, hyperemia of the upper half of the body. During an attack of suffocation, nausea, vomiting, hypersalivation, pain in the epigastric region, a decrease in blood pressure (sometimes to very low numbers) can be observed. Over time, bronchial asthma acquires specific features: seasonality disappears, asthma symptoms bother the patient constantly, the inter-attack period is accompanied by a feeling of "stuffiness" in the chest, bronchodilator therapy is less effective than before, bronchial asthma gradually takes a progressive course.

The presence of the asthmatic triad, including:

1. "aspirin" asthma (usually with a severe progressive course);
2. intolerance to aspirin and other non-steroidal anti-inflammatory drugs (headache, pressure in the temples, increased rhinorrhea, sneezing, lacrimation, scleral injection);
3. rhinosinusitis and recurrent nasal polyposis (X-ray of the paranasal sinuses reveals rhinosinusopapaya).

A. G. Chuchalin's positive diagnostic test - determination of the blood content of various groups of prostaglandins against the background of taking a provocative dose of indomethacin. In this case, in patients with "aspirin" asthma and asthmatic triad, the content of PgR increases against the background of a decrease in PgE, while in other forms of bronchial asthma, the level of prostaglandins of both groups decreases.

Positive provocation test with acetylsalicylic acid. The test is started after a negative reaction to "aspirin placebo" (0.64 g of white clay) is obtained. The patient then takes acetylsalicylic acid in the following doses:

Day 1 - 10 mg; Day 2 - 20 mg; Day 3 - 40 mg; Day 4 - 80 mg; Day 5 - 160 mg; Day 6 - 320 mg; Day 7 - 640 mg. After 30, 60 and 120 minutes after taking acetylsalicylic acid, the patient's objective sensations and lung auscultation data are analyzed and FEV1 is determined.

The provocative test is considered positive if the following signs appear:

• feeling of suffocation;
• difficulty breathing through the nose;
• rhinorrhea;
• lacrimation;
• decrease in FEV1 by 15% or more from baseline.

Dahlen and Zetteistorm (1990) proposed an inhalation provocation test with lysine-acetylsalicylic acid for the diagnosis of aspirin asthma. In this case, the dose of the drug is increased every 30 minutes, the entire test lasts several hours.

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Diagnostic criteria for exercise-induced asthma

Exercise-induced asthma (post-exertional bronchospasm) is rarely found in isolation, but mostly against the background of other pathogenetic variants of bronchial asthma. Exercise-induced asthma is observed more often in children than in adults. The main diagnostic criteria for exercise-induced asthma are:

• indications in the anamnesis of a clear connection between an attack of suffocation and physical exertion, and, unlike ordinary bronchial asthma or obstructive bronchitis, an attack of suffocation occurs not during physical exertion, but within the next 10 minutes after its completion (“post-exertional bronchospasm”);
• asthma attacks are more often associated with certain types of physical exercise - running, playing football, basketball; lifting weights is less dangerous, swimming is well tolerated;
• positive exercise challenge test.

The test is performed in the absence of contraindications - heart failure, ischemic heart disease, arterial hypertension (above 150/90 mm Hg), heart rhythm and conduction disorders, cerebral circulation disorders, thrombophlebitis of the veins of the legs, high degree of myopathy. Within 12 hours before the test, the patient should not take bronchodilators and Intal (or Tayled). Before and after the test, bronchial patency indicators are measured.

When conducting a physical exercise test, it is necessary to comply with the following requirements for its standardization:

• the intensity of physical activity should be such as to cause an increase in heart rate to 85% of the maximum heart rate, calculated using the formula: HRmax = 209 - 0.74 x age in years;
• load duration b-10 minutes;
• physical exercise is carried out using bicycle ergometry or a treadmill, the form of exercise is gradually increasing;
• bronchial patency indicators are determined before and 5, 30, 60 minutes after its completion.

The most informative method for diagnosing exercise-induced asthma is to determine the flow-volume curve. Mild exercise-induced asthma is characterized by a 15-30% worsening of the flow-volume curve, and severe asthma is characterized by a 40% or more worsening of the flow-volume curve.

If it is impossible to strictly standardize the test, a simpler test can be performed, which is recommended by V. I. Pytskiy et al. (1999). It is performed as follows. The initial pulse rate and expiratory power are recorded using pneumotachometry or spirography. Then physical exercise is given - free running or squats until the pulse rate reaches 140-150 beats/min. Immediately after the end of the exercise and after 5, 10, 15 and 20 minutes, a physical examination is again performed and the power (speed) of expiration is determined. If the expiratory power decreases by 20% or more, the test is considered positive, i.e. indicates asthma of physical effort.

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Differential diagnosis of bronchial asthma

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Chronic obstructive bronchitis

Most often, bronchial asthma must be differentiated from chronic obstructive bronchitis. In this regard, the list of supporting diagnostic signs of chronic bronchitis according to Vermeire (cited by A. L. Rusakov, 1999) can be of significant help:

• bronchial obstruction proper - decrease in FEV1 < 84% and/or decrease in Tiffeneau index < 88% of the predicted values;
• irreversibility/partial reversibility of bronchial obstruction, variability (spontaneous variability) of FEV1 values during the day < 12%;
• consistently confirmed bronchial obstruction - at least 3 times during the one-year observation period;
• age, usually over 50 years;
• frequently detected functional or radiographic signs of pulmonary emphysema;
• smoking or exposure to industrial air pollutants;
• progression of the disease, which is expressed in increasing shortness of breath and a steady decrease in FEV1 (an annual decrease of more than 50 ml).

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Tracheobronchial dyskinesia

Tracheobronchial dyskinesia syndrome is an expiratory collapse of the trachea and large bronchi due to prolapse of the thinned and stretched membranous wall, partially or completely blocking the lumen of the trachea and large bronchi during the exhalation phase or during coughing. The clinical picture of tracheobronchial dyskinesia is characterized by paroxysmal coughing and expiratory dyspnea. Coughing attacks are caused by physical exertion, laughter, sneezing, acute respiratory viral infection, and sometimes by a sharp transition from a horizontal to a vertical position. The cough is bitonal in nature, sometimes rattling, nasal. Coughing attacks cause short-term dizziness, darkening of the eyes, and short-term loss of consciousness. During a coughing attack, severe expiratory dyspnea is observed, up to suffocation.

Diseases causing obstruction and compression of the bronchi and trachea

Significant breathing difficulties, especially exhalation, may occur when the trachea and large bronchi are compressed by benign and malignant tumors, greatly enlarged lymph nodes, and aortic aneurysm. Tumors may cause bronchial obstruction when growing into the lumen of the bronchus.

In differential diagnostics of bronchial asthma, it should be taken into account that in the above situations, auscultatory symptoms (wheezing dry rales, sharply prolonged exhalation) are observed on one side, and not over the entire surface of the lungs, as in bronchial asthma. It is also necessary to analyze the clinical symptoms characteristic of diseases causing occlusion or compression of the trachea and bronchi (bronchial cancer, lymphogranulomatosis, lymphocytic leukemia, mediastinal tumor, aortic aneurysm). In case of mediastinal tumor, superior vena cava syndrome is characteristic (cyanosis and swelling of the neck and face, swelling of the jugular veins). To clarify the diagnosis, bronchoscopy, X-ray tomography of the mediastinum, and computed tomography of the lungs are performed.

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Carcinoid

Carcinoid is a tumor of the APUD system, consisting of cells producing serotonin, bradykinin, histamine, and prostaglandins. Usually, the tumor is localized in the gastrointestinal tract, and in 7% of cases, in the bronchi. With bronchial localization of carcinoid, the clinical picture of bronchospasm appears. Unlike bronchial asthma, with carcinoid syndrome, along with bronchospasm, there are flushes with pronounced redness of the face, venous telangiectasias, profuse diarrhea, endocardial fibrosis of the right heart with the formation of tricuspid valve insufficiency (diagnosed using echocardiography), and the excretion of a large amount of 5-hydroxyindoleacetic acid, a product of serotonin metabolism, in the urine.

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Cardiac asthma

Cardiac asthma is a manifestation of severe left ventricular failure.

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Pulmonary embolism

In pulmonary embolism (PE), a sudden feeling of shortness of breath and severe dyspnea appear; dry wheezing is detected during auscultation, which makes it necessary to differentiate PE from bronchial asthma.

Disorders of nervous regulation of breathing

Patients suffering from neuroses, hysteria, especially women, often have attacks of shortness of breath, which makes it necessary to differentiate this condition from bronchial asthma. As a rule, patients suffering from neurogenic breathing disorders associate the feeling of lack of air and shortness of breath with an acute psycho-emotional stress situation, and are often very neurotic. The main diagnostic sign that distinguishes neurotic or hysterical asthma from bronchial asthma is the absence of wheezing during auscultation of the lungs.

Foreign body of the trachea or bronchi

When a foreign body gets into the trachea or bronchi, an attack of suffocation occurs, which may resemble an attack of bronchial asthma. However, if there is a foreign body in the respiratory tract, a strong cough and cyanosis appear; at the same time, wheezing is not heard during auscultation of the lungs. Anamnestic data and bronchoscopic examination help in establishing the correct diagnosis.

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Bronchial obstruction syndrome in parasitic infestations

Bronchial obstruction may be accompanied by invasions by roundworms, hookworms, schistosomes, filariae and other parasites. Characteristic signs of broncho-obstructive syndrome of parasitic etiology are pronounced eosinophilia of blood and sputum, pulmonary infiltrates, detection of helminth eggs during coprological examination. It is also necessary to take into account the corresponding clinical symptoms of parasitic invasion and quite often the disappearance of bronchial obstruction syndrome after successful deworming.

Reflux-induced bronchial asthma

Reflux-induced asthma is an asthma attack caused by aspiration of gastric contents due to gastroesophageal reflux. An asthma attack associated with aspiration of gastric contents was first described by Oder in 1892.

The prevalence of gastroesophageal reflux disease (GERD) among the population of the USA and in some European countries is 20-40%, and among patients with bronchial asthma this figure reaches 70-80% (Stanley, 1989). The main factors in the pathogenesis of GERD are decreased tone of the lower esophageal sphincter, increased intragastric pressure, weakened esophageal peristalsis, and slowed esophageal clearance.

The pathogenesis of bronchial asthma arising against the background of GERD is associated with the following factors (Goodall, 1981):

• development of bronchospasm due to the reflux (microaspiration) of gastric contents into the lumen of the bronchial tree;
• stimulation of vagal receptors of the distal esophagus and induction of the bronchoconstrictor reflex.

The clinical features of bronchial asthma that occurs with GERD are:

• the occurrence of an attack of suffocation, mainly at night;
• the presence of concomitant clinical manifestations of GERD: heartburn, belching, regurgitation, pain in the epigastrium or behind the breastbone, when food passes through the esophagus;
• the appearance or intensification of attacks of suffocation, as symptoms of GERD, under the influence of a large meal, a horizontal position after eating, taking medications that damage the mucous membrane of the stomach and esophagus, physical activity, flatulence, etc.;
• predominance of bronchial asthma symptoms over other manifestations of GERD.

Nocturnal bronchial asthma

Nocturnal bronchial asthma is the occurrence of asthma attacks in patients with bronchial asthma at night or early morning hours.

According to Turner-Warwick (1987), one third of patients with bronchial asthma suffer from nocturnal attacks of suffocation.

The main pathogenetic factors of nocturnal bronchial asthma are:

• increased contact of a patient with bronchial asthma with aggressive allergens at night (high concentration of spore fungi in the air on warm summer nights; contact with bedding containing allergens - feather pillows, mites - dermatophagoides in mattresses, blankets, etc.);
• maximum synthesis of IgE antibodies (reagins) in the period from 5 to 6 am;
• the effect of gastroesophageal reflux at night;
• the influence of the horizontal position (in the horizontal position and during sleep, mucociliary clearance worsens, the tone of the vagus nerve increases and, consequently, its bronchoconstrictor effect);
• the presence of circadian rhythms of changes in bronchial patency (maximum bronchial patency is observed from 13:00 to 17:00, minimum - from 3:00 to 5:00 in the morning;
• daily fluctuations in barometric pressure, relative humidity and air temperature. The respiratory tract of patients with bronchial asthma is hypersensitive to a decrease in ambient temperature at night;
• circadian rhythm of cortisol secretion with a decrease in its level in the blood at night;
• a decrease in the blood concentration of catecholamines, cAMP and beta 2-adrenergic receptor activity at night and in the early morning hours;
• The presence of sleep apnea syndrome, especially the obstructive form, contributes to the development of attacks of nocturnal bronchial asthma.

Survey program

1. General analysis of blood, urine, feces (including for helminth eggs).
2. Biochemical blood test: determination of total protein, protein fractions, serum protein, haptoglobin, fibrin, C-reactive protein.
3. Immunological blood test: content of B- and T-lymphocytes, subpopulations of T-lymphocytes, immunoglobulins, circulating immune complexes, complement, determination of the functional activity of T-lymphocytes.
4. Sputum analysis: cellular composition, Charcot-Leyden crystals, Curschmann spirals, atypical cells, Koch's bacilli.
5. X-ray examination of the lungs (if indicated - X-ray examination of the paranasal sinuses).
6. Spirometry, determination of volume-flow curve parameters (pneumotachography), peak flowmetry.
7. Consultations with an allergist, otolaryngologist, dentist.
8. FGDS (in the remission phase, according to indications - if there are clinical signs that allow one to suspect gastroesophageal reflux disease).
9. ECG.
10. During the non-attack period, conducting tests with allergens, and, if indicated, provocative tests and conducting research.

Formulation of diagnosis

When formulating a diagnosis of bronchial asthma, it is advisable to take into account the following provisions:

• name the form of bronchial asthma according to ICD-X (allergic, non-allergic, mixed, unspecified genesis). It should be noted that the classification of bronchial asthma by Professor G. B. Fedoseyev can also be used when diagnosing bronchial asthma, since it successfully classifies clinical and pathogenetic variants and actually clearly defines which forms of bronchial asthma should be classified as non-allergic bronchial asthma;
• indicate to which allergen there is sensitization in the allergic form of bronchial asthma;
• reflect the severity and phase of bronchial asthma (exacerbation, remission);
• indicate concomitant diseases and complications of bronchial asthma.

Examples of asthma diagnosis formulation

1. Bronchial asthma, allergic form (sensitization to house dust), mild episodic course, DN0, remission phase. Allergic rhinitis.
2. Bronchial asthma, non-allergic form (infection-dependent), severe course, exacerbation phase. Chronic purulent-catarrhal obstructive bronchitis. Pulmonary emphysema. DNIIst.

From the examples given it is clear that for clinical and practical purposes it is advisable to use the classification of G. B. Fedoseyev, and for statistical reporting – the classification according to ICD-X.

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