Diagnosis of bronchial asthma in children

For typical patient complaints, a specific algorithm for diagnosing bronchial asthma is used.

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History and physical examination

The likelihood of bronchial asthma increases if the medical history includes:

• atopic dermatitis;
• allergic rhinoconjunctivitis;
• a burdened family history of bronchial asthma or other atopic diseases.

The diagnosis of bronchial asthma can often be assumed if the patient has the following symptoms:

• episodes of shortness of breath;
• wheezing;
• cough that intensifies mainly at night or in the early morning hours;
• chest congestion.

The appearance or increase of symptoms of bronchial asthma:

• after episodes of contact with allergens (contact with animals, house dust mites, pollen allergens);
• at night and in the early morning hours;
• upon contact with triggers (chemical aerosols, tobacco smoke, strong odors);
• when the ambient temperature changes;
• for any acute infectious diseases of the respiratory tract;
• under strong emotional stress;
• during physical exertion (patients note typical symptoms of bronchial asthma or sometimes a prolonged cough, usually occurring 5-10 minutes after stopping the exercise, rarely during the exercise, which goes away on its own within 30-45 minutes).

During examination, it is necessary to pay attention to the following signs characteristic of bronchial asthma:

• dyspnea;
• emphysematous form of the chest;
• forced pose;
• distant wheezing.

On percussion, a box-like percussion sound is possible.

During auscultation, prolonged exhalation or wheezing are detected, which may be absent during normal breathing and only detected during forced exhalation.

It is necessary to take into account that due to the variability of asthma, manifestations of the disease may be absent, which does not exclude bronchial asthma. In children under 5 years of age, the diagnosis of bronchial asthma is based mainly on anamnesis data and the results of a clinical (but not functional) examination (most pediatric clinics do not have such precise equipment). In infants who have had three or more episodes of wheezing associated with the action of triggers, in the presence of atopic dermatitis and / or allergic rhinitis, eosinophilia in the blood, bronchial asthma should be suspected, examination and differential diagnosis should be carried out.

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Laboratory and instrumental diagnostics of bronchial asthma

Spirometry

In children over 5 years of age, it is necessary to evaluate the function of external respiration. Spirometry allows to evaluate the degree of obstruction, its reversibility and variability, as well as the severity of the disease. However, spirometry allows to evaluate the child's condition only at the time of examination. When evaluating the FEV ₁ and forced vital capacity (FVC), it is important to focus on the appropriate indicators obtained in the course of population studies that take into account ethnic characteristics, gender, age, height.

Thus, the following indicators are assessed:

• OFV;
• FVC;
• FEV/FVC ratio;
• reversibility of bronchial obstruction - an increase in FEV by at least 12% (or 200 ml) after inhalation of salbutamol or in response to a trial of glucocorticosteroids.

Peak flowmetry

Peak flowmetry (determination of PEF) is an important method for diagnosing and subsequently monitoring the treatment of bronchial asthma. The latest models of peak flow meters are relatively inexpensive, portable, made of plastic and are ideal for use by patients over 5 years of age at home for the purpose of daily assessment of the course of bronchial asthma. When analyzing PEF indicators in children, special nomograms are used, but daily monitoring of PEF for 2-3 weeks is more informative to determine the individual best indicator. PEF is measured in the morning (usually the lowest indicator) before inhalation of bronchodilators, if the child receives them, and in the evening before bedtime (usually the highest indicator). Filling out self-monitoring diaries by the patient with daily registration of symptoms and PEF results plays an important role in the strategy of treating bronchial asthma. Monitoring PEF can be informative for determining early symptoms of exacerbation of the disease. A daily variation in PEF values of more than 20% is considered a diagnostic sign of bronchial asthma, and the magnitude of deviations is directly proportional to the severity of the disease. Peak flowmetry results support the diagnosis of bronchial asthma if PEF increases by at least 15% after inhalation of a bronchodilator or with a trial administration of glucocorticoids.

Therefore, it is important to evaluate:

• daily variability of PSV (the difference between the maximum and minimum values during the day, expressed as a percentage of the average daily PSV and averaged over 1-2 weeks);
• the minimum value of PSV for 1 week (measured in the morning before taking the bronchodilator) as a percentage of the best value for the same period (Min/Max).

Detection of airway hyperreactivity

In patients with symptoms typical of asthma but with normal lung function tests, airway exercise testing may help in making the diagnosis of asthma.

In some children, asthma symptoms are triggered only by physical activity. In this group, exercise testing (6-minute running protocol) is useful. Using this test method together with FEV or PSV determination can be useful for making an accurate diagnosis of asthma.

To detect bronchial hyperreactivity, a test with methacholine or histamine can be used. In pediatrics, they are prescribed extremely rarely (mainly in adolescents), with great caution, according to special indications. In diagnosing bronchial asthma, these tests have high sensitivity, but low specificity.

Specific allergological diagnostics are carried out by allergists/immunologists in specialized institutions (departments/offices).

Allergological examination is mandatory for all patients with bronchial asthma, it includes: collecting an allergological anamnesis, skin testing, determining the level of total IgE (and specific IgE in cases where skin testing is not possible).

Skin tests with allergens and determination of serum specific IgE levels help to identify the allergic nature of the disease, identify causative allergens, on the basis of which appropriate control of environmental factors (elimination regimen) is recommended and specific immunotherapy regimens are developed.

Non-invasive determination of markers of airway inflammation (additional diagnostic methods):

• examination of sputum, spontaneously produced or induced by inhalation of hypertonic sodium chloride solution, for inflammatory cells (eosinophils or neutrophils);
• determination of the level of nitric oxide (NO) and carbon monoxide (FeCO) in exhaled air.

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Determining the severity of exacerbations of bronchial asthma and indications for hospitalization during exacerbations

Determining the severity of exacerbations of bronchial asthma

Indicator	Mild exacerbation	Moderate to severe exacerbation	Severe exacerbation	Respiratory arrest is inevitable
Dyspnea	When walking; can lie down	When talking; crying is quieter and shorter, difficulty feeding; prefers to sit	At rest; stops eating; sits leaning forward
Speech	Offers	Individual phrases	Single words
Level of wakefulness	May be excited	Usually excited	Usually excited	In a lethargic or confused state
NPV	Increased	Increased	High (>30 per minute)	Paradoxical breathing
Wheezing sounds	Moderate	Loud	Usually loud	None
Heart rate	<100/min	100-120 per minute	>120 per minute	Bradycardia
PSV	>80%	60-80%	<60%
PaCO2	There is usually no need to measure	>60 mmHg	<60 mmHg
PaCO2	<45 mmHg	<45 mmHg	>45 mmHg
SaO2	>95%	91-95%	<90%
Paradoxical pulse	Absent, <10 mmHg	Possible, 10-25 mm Hg.	Often, 20-40 mmHg.	Absence indicates fatigue of the respiratory muscles
Participation of accessory muscles in the act of breathing, retraction of the supraclavicular fossae	Usually no	Usually there is	Usually there is	Paradoxical movements of the chest and abdominal wall

Normal respiratory rate in children:

• more than 2 months - <60 per minute;
• 2-12 months - <50 per minute;
• 1-5 years - <40 per minute;
• 6-8 years - <30 per minute.

Normal pulse in children:

• 2-12 months - <160 per minute;
• 1-2 years - <120 per minute:
• 2-8 years - <110 per minute.

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Differential diagnosis of bronchial asthma

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Young children

Diagnosis of bronchial asthma in young children is difficult due to age restrictions on the use of a set of diagnostic measures. It is based primarily on clinical signs, assessment of symptoms and physical examination data.

There are three types of wheezing in the anamnesis of young children:

• Transient early wheezing occurs in the first 3 years of life and is associated with prematurity and parental smoking (although there is some evidence that bronchopulmonary dysplasia of prematurity is a predictor of childhood asthma; Eliezer Seguerra et al., 2006).
• Persistent wheezing with early onset is associated with acute respiratory viral infections (in children under 2 years of age - respiratory syncytial virus infection) in the absence of signs of atopy in children.
• Wheezing with late-onset asthma is present throughout childhood and continues into adulthood in patients with a history of atopy.

Clinical criteria for differential diagnosis of bronchial asthma and obstructive symptoms against the background of acute respiratory infection in young children

Signs	Bronchial asthma	Symptoms of obstruction in ARI
Age	Over 1.5 years old	Under 1 year old
The appearance of broncho-obstructive syndrome	Upon contact with an allergen and/or in the first day of ARI	No connection with contact with allergens, symptoms appear on the 3rd day of ARI and later
Duration of episodes of broncho-obstructive syndrome against the background of ARI	1-2 days	3-4 days or more
Recurrence of broncho-obstructive syndrome	2 times or more	For the first time
Hereditary burden of allergic diseases	Eat	No
Including bronchial asthma on the maternal side	Eat	No
History of immediate allergic reactions to food, medications, or vaccinations	Eat	No
Excessive household antigen load, presence of dampness, mold in living quarters	Eat	No

If wheezing episodes occur repeatedly, the following diseases should be ruled out:

• foreign body aspiration;
• cystic fibrosis;
• bronchopulmonary dysplasia;
• developmental defects that cause narrowing of the intrathoracic airways;
• primary ciliary dyskinesia syndrome;
• congenital heart defect;
• gastroesophageal reflux;
• chronic rhinosinusitis;
• tuberculosis;
• immunodeficiencies.

Older children

In older patients, differential diagnosis of bronchial asthma with the following diseases is necessary:

• upper respiratory tract obstruction (respiratory papillomatosis);
• aspiration of foreign bodies;
• tuberculosis;
• hyperventilation syndrome and panic attacks;
• other obstructive pulmonary diseases;
• vocal cord dysfunction;
• non-obstructive lung diseases (eg, diffuse lesions of the lung parenchyma);
• severe deformation of the chest with compression of the bronchi;
• congestive heart defects;
• tracheo- or bronchomalacia.

If the following symptoms occur, it is necessary to suspect a disease other than bronchial asthma.

• Anamnesis data:
  • neurological dysfunction in the neonatal period;
  • lack of effect from the use of bronchodilators;
  • wheezing associated with feeding or vomiting;
  • difficulty swallowing and/or recurrent vomiting;
  • diarrhea;
  • poor weight gain;
  • persistence of the need for oxygen therapy for more than 1 week after an exacerbation of the disease.
• Physical data:
  • deformation of the fingers in the form of "drumsticks";
  • heart murmurs;
  • stridor:
  • focal changes in the lungs:
  • crepitus on auscultation:
  • cyanosis.
• Results of laboratory and instrumental studies:
  • focal or infiltrative changes on chest X-ray:
  • anemia:
  • irreversible airway obstruction;
  • hypoxemia.