Журнал «Здоровье ребенка» 2 (45) 2013

Bronchial asthma – is a chronic airway pathology, what starts in childhood in mostly cases. Meanwhile first symptoms of the illness develop in 50-80 % in children under 5-year. Of course, diagnostics of asthma in this age group (under 5 year) is a difficult goal and needs deliberate decision due to lack of diagnostics instruments (only clinical and anamnestic data). And than younger child, than more intensive diagnostic search demands. When asthma diagnosed, doctor must prescribe medications with own serious side effects, and prevention of these effects is especially actual in basic antiinflammatory therapy.

According to definition, which work all over the world and in all age groups of patients, asthma – is a chronic inflammatory airway disorder, accompained by bronchial hypersensitivity and leads to repeated wheezing episods, shortness of breath, chest tightness and cough [1, 2]. But, in spite of clear interpretation of each position of this definition, diagnostics approaches in early age children can be highly variable. Asthma peculiarity in children younger than 5 years old consider variety and nonspecificity of clinical signs, which require serious differential diagnosis.  

The key event in asthma pathogenesis – development of inflammation in airway’s mucus membrane. This inflammation leads to airway’s remodelling. As per modern view, remodelling develops very early due to persistence of allergic symptoms during 1 year, this is a cause of nesessity of early start and longest antiinflammatory therapy. The evidence of this is a results of investigation of Saglani S. et al. (2005), which indicate, that in group of children with a persistent wheezing in the 1^st year of life a morphological changes are absent in mucus membrane and appears in time [3].

The most correct approach in asthma diagnostics before basic therapy prescription (minimal course of this therapy is three months) is a preliminary estimation of inflammation activity in airways. Today we know different possibilities in this: biopsy of mucus membrane (one of the most invasive diagnostics methods), analysis of bronchoalveolar fluid (not provide data for full estimation of a inflammation) and NO detection in exhaled air. The last methodics is more perspective, but, unfortunately, not available for wide sociaty of doctors and used for scientific goals. Notably in fact for the diagnostics of inflammation activity of mucus membrane we can use only nondirect methods, which adressed to bronchial hyperreactivity detection. This metodics are: clinical signs of bronchial obstruction (dry, wheezing rales detected by auscultation or distance rales, dry attack-like cough or asphyxiation paroxysm); spirometry or pickfloumeter data (decreasing of FEV1 or PEF lower than 80% from individual value), positive test with bronchodilator even in normal FEV1 or PEF. If 1 of this signs is presented (which detected in rest or after phisical effort), we can confirm the inflammatory changes in airways.

The more objective methods - is a instrumental estimation of respiratory function. But spirometry as a method give a strong evidence exclusively in correct respiratory maneurs. This aim not always achievable in adults, in children - especially. Today instrumental evaluation of respiratory function in children younger than 5 year is not used, because patients of this age group can’t perform demanding instructions correctly. But this does not means that estimation of lung function in thiese children impossible. According to official documents of American Thoracic Society, estimation of lung function is possible in patients form 2 years old [4]. This become possible with a next methodics: forsed impulsive oscillometry, airway resistence detection by interruption of air flow method, evaluation of airway resistance by the pletismography, forsed spirometry with a special child’s programm («bubble gum», «coctail», «candle», «whistle» and other), estimation of the functional residual volume by cultivation gas technic, measurement of cultivation gas indexes, maximal airflow, which characterised functional residual volume, bronchophonography [5]. Independent investigations, which dedicated to research of short-time interruption of airflow method (RINT) (Малюжинская Н.В., 2011, Фурман Е.Г., 2009), in children of 2-6 years old certified from high specificity (100%) and sensitivity (83,3%) of this methodics, which absolute equals with a classical spirometry. Moreover, this method, can be used for test with bronchodilator [6]. But using of RINT in chldren from 2 to 5 years old is available only for scientific research.

Thereby, we can confirm the changes of lung function by objective measures (even for scientific research) only in children older than 2 year. In earlier age it’s not practicable for the present. In this connection, asthma diagnostics in the early age children to take by clinical estimation and based on careful evaluation of symptoms, host and genetic factors and physical data.

Most specific symptoms in early age children are distance rales (wheezing) or dry attack-like cough. If these signs repeat periodically, than clinicians must exclude asthma. But in this case is a problem, that symptoms of bronchial obstruction so often appears as in children, who haven’t asthma (especially if these children younger than 3 year). It associate with a anatomic and physiological peculiarities of children’s airways.

International Consensusin asthma diagnostics and treatment in children PRACTALL EAACI/AAACI Consensus Report (the first document, devoted to children’s asthma and bands data of different investigations), separate two main phenotypes of wheezing, which differ each one from other by prognosis. These phenotypes are episodic (viral-induced) wheezing and multiple trigger wheeze. It consider that children with wheezing in future can develop asthma, this require from phisicians dinamic observation of patients. Not recommended to use terms “trancient”, “late onset”, “persistent” (wheezing) in practice. This possible only in epidemiologic studies [7].

The work group of European respiratory society to propose the next interpretation of phenotypes. Episodic or viral-induced wheezing – is separate episods, without symptoms of bronchial hyperreactivity with no connection with viral infection. As regards prognosis this phenotype has a favourable course, more often resolved of time, but sometimes can transforme to multiple trigger wheeze, when patients have clinical signs out of acute viral infection season. Triggers in this case are tobacco smoke, allergens, physical effort, cry, laugh. These can intensify bronchial hyperreactivity. Multiple trigger wheeze phenotype can be diagnosed if child has often non-viral episods of wheezing, family hystory of atopy, severe exacerbations (required hospitalization or systemic steroids). Multiple trigger wheeze has a worst prognosis and in our opinion in this situation can be diagnosed asthma, because require specific antiinflammatory treatment.

We don’t have absolute markers of developing asthma in children with wheezing. The study Tucson (USA) describes a attempt to calculate Asthma Predictive Index (API) [8]. It can be estimated in chidren younger than 3 years old, which has at least 4 episods of wheezing during last year, which lasts more than 1 day and provoke sleep disturbances. Phisicians must determe the presence of next symptoms:

1) Major criteria: positive asthma hystory in somebody of relatives, confirmed by clinician atopic dermatitis, prooved sensitization to aeroallergens;

1 of listed above or 2 from:

2) Minor criteria: prooved sensitisation to food allergens, more than 4% of eosinophils in periferal blood, non-viral wheezing episods.

If present positive API, the probability of asthma developing is 76% (evidence level С), and risk of asthma developing increasing to 4-10 times compared with children with negative API [1, 9].

Besides, PRACTALL to separate degrees of asthma severity. But, in contrast to GINA, interpret it not clearly: ansence of clear criteria of severity. PRACTALL to accent that severity of asthma can differ through short period of time (from week to week). Separate asthma subtupe also postulated by Consensus - unresponsive to treatment. In this case, as a GINA, PRACTALL to propose evaluate a compliance and review asthma diagnosis.

In children younger than 5 year estimation of compliance purchase especial sense due to absence of therapy effectiveness in this age group. Clinicians must ask parents carefully about inhalation technics, delivery devices. It especially important, because cut plastic bottle often is used as a spacer and it can’t provide a full receipt of inhaled medication. Even according to GINA in children under 5 year where postulated effectiveness of this measure. A big quantities of medication is missed due to absence of tight contact of patient’s skin and bottle wall. GINA destinates spacers as a main delivery devices (and his variants – babyhaler, aerochamber) and nebulizer and this devices have a preference in choice as delivery devices. Primary role take to spacers versus nebulizers.

Before verification asthma in children younger than 5 years old, clinicians must be ready to provide a differential diagnosis with a next deseases (table 1).

For differential diagnosis we need: common blood count, common IgE, 1^st and 2^nd line immunological tests, test with pylocarpinum (sweat test), α₁-antitripsynum level, phthysiatric investigations, determining of IgM и IgG to pertussis, parapertussis, cytomegalovirus, chlamidia pneumonia, mycoplasma pneumonia, helminths, chest X-Ray (frontal view, lateral view, also with a contrast for excluding of tracheobronchial defects), bronchoscopy, endoscopic investigations of gastrointestinal tract, ultrasound investigations of the heart and magistral vessels, in case of nesessity – CT of chest organs, other specialists exam – otolaryngologist, neurologist, cargiologist, gastroenterologist, infectious disease doctor [1, 11]

One of the tests for confirming asthma diagnosis is a tharapia ex juvantibus (evidence level D). Short-action в2-agonists and inhaled steroids during 8-12 weeks can be used . If clinicians see positive clinical improving for this time, than asthma diagnosis a high probable. Due to significant variability of asthma in early age children, for confirming of asthma requires a exploratory therapy not ones. If patient already received antiasthmatic therapy, but you can’t see improving – revise asthma diagnosis!

As of hypersensitivity diagnostics, skin tests not fully informative in early age children. That is why we are determining serum IgE specific for this aim .

So, at the presence of 4 and more episods of wheezing or attack-like cough in children under 5 year, it must be essential to estimate probability or risk of asthma developing. Probability of correct asthma diagnosis is above, if we are exclude all other causes of wheezing and cough, if present positive Asthma Predictive Index. In this case patients needs in therapia ex juvantibus, effectiveness of which (in case of high complaince) suggests about asthma.