Symptoms of bronchitis in children

Acute bronchitis (simple) develops in the first days of ARVI (1-3 days of illness). The main general symptoms of a viral infection are characteristic (subfebrile temperature, moderate toxicosis, etc.), clinical signs of obstruction are absent. The features of the course of bronchitis depend on the etiology: with most respiratory viral infections, the condition normalizes starting from the 2nd day, with adenovirus infection, high temperatures persist for up to 5-8 days.

Acute obstructive bronchitis is accompanied by bronchial obstruction syndrome, more often in young children on the 2nd-3rd day of ARVI, in case of a repeated episode - from the first day of ARVI and develops gradually. Acute obstructive bronchitis occurs against the background of RS viral and parainfluenza type 3 infection, in 20% of cases - with ARVI of other viral etiology. In older children, the obstructive nature of bronchitis is noted with mycoplasma and chlamydial etiology.

Acute obliterating bronchiolitis (postinfectious obliterating bronchiolitis) is a rare form of bronchiolitis, which affects small-caliber bronchi (less than 1 mm in diameter) and arterioles with subsequent obliteration of their lumen and narrowing of the branches of the pulmonary, and sometimes bronchial arteries. It usually develops in children of the first 2 years of life, at school age; it rarely develops in adults. Adenoviruses (types 3, 7, 21) most often play an unfavorable role, but its development is also noted after influenza, measles, whooping cough, legionella and mycoplasma infections.

Obliterating bronchiolitis of another (non-infectious) etiology, for example in a transplanted lung, has an immunopathological genesis.

In early childhood, postinfectious obliterating bronchiolitis develops at the stage of maximum development of new alveoli from embryonic terminal and respiratory bronchioles. As a result of obliteration of the bronchioles, the distal parts of the bronchial tree are permanently damaged, the number of forming alveoli decreases. The lung volume decreases, but its airiness is preserved due to collateral ventilation. Air enters through intact airways through the pores of Kohn from nearby alveoli. This is the basis for the mechanism of formation of the "air trap" in this disease.

The basis of the morphological picture is damage to the membranous and respiratory bronchioles, which causes partial or complete concentric narrowing of the bronchiole lumen, i.e. its obliteration. As a rule, the alveolar walls and alveolar ducts are not damaged. Most patients do not have deep destructive changes in the bronchial walls, but some have bronchiectasis. Areas of emphysematously inflated alveoli alternate with focal dystelectasis and small focal atelectasis. Rupture of the thinned interalveolar septa and desolation of the capillary network are revealed. Thickening of the middle shell of the segmental, subsegmental and smaller branches of the pulmonary artery occurs. Plethora is observed in the venous network.

The outcome of the process is the development of areas of sclerosis against the background of preserved airiness of the lung tissue with hypoperfusion phenomena - the picture of a “super-transparent lung”.

The course of the disease depends on the different extent of lung damage. It is possible to develop unilateral damage, sometimes of almost the entire lung, for example, in the Swier-James (McLeod) syndrome, as well as isolated damage to one lobe or individual segments of both lungs.

Recurrent bronchitis is defined by the recurrence of episodes of bronchitis without obstruction 2-3 times over 1-2 years against the background of ARVI. It is known that children who often suffer from ARVI are at risk for developing recurrent bronchitis, which is characterized by a longer course due to the peculiarities of etiopathogenesis and the possible complication of the addition of a bacterial infection.

The frequency of detection of microorganisms in recurrent bronchitis (from sputum and tracheal aspirate) is about 50%: Str. pneumoniae - 51%, No. Influenzae - 31%, Moraxella cat. - 2% and other microflora - 16%. In monoculture, bacteria are detected in 85% of children, in associations - in 15%.

The prevalence of recurrent bronchitis is 16.4% per 1000 children. Among frequently ill children, the number is 44.6%, of which 70-80% have obstructive syndrome.

The high frequency of bronchitis in children against the background of ARVI indicates the possible involvement of bronchial hyperreactivity and an allergic component. 80% of children have positive skin tests and elevated IgE. However, sensitization to air allergens is detected only in 15% of children with recurrent bronchitis and in 30% with recurrent obstructive bronchitis (compared to bronchial asthma - in 80%). The sensitivity of bronchial receptors increases with a viral infection accompanied by damage to the epithelium of the mucous membrane of the respiratory tract.

Repeated acute respiratory infections can contribute to the sensitization of the body and create the preconditions for the development of generalized hypersensitivity reactions with the subsequent formation of obstructive bronchitis and bronchial asthma.

In recurrent bronchitis, no disturbances of humoral immunity are observed; selective reduction of IgA is rarely observed. The direct role of chronic foci of infection has not been proven.

The role of connective tissue dysplasia cannot be ruled out, since 90% of children have not only clinical signs (increased elasticity of the skin and high joint mobility), but also mitral valve prolapse.

Recurrent obstructive bronchitis is bronchitis with recurring episodes of broncho-obstruction against the background of acute respiratory viral infections in young children (usually under 4 years of age), but unlike bronchial asthma, it is not paroxysmal in nature and does not develop in response to non-infectious allergens. In most children with allergic reactions, episodes of bronchitis recur more frequently. If such episodes persist for a long time (from 2 to 5 years), the diagnosis of bronchial asthma is more justified.

The risk group for developing recurrent obstructive bronchitis includes children with skin manifestations in the first year of life, with a high level of IgE or positive skin tests, with parents with allergic diseases, who have suffered three or more paroxysmal obstructive episodes that occur without fever. It should be emphasized that recurrent bronchitis is more often observed in young children and in most of them, episodes of obstruction cease with age and the children recover.

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