The causative agents of the disease are influenza virus, parainfluenza, respiratory syncytial virus, adenovirus, pneumonia mycoplasma, streptococcus, pathogenic staphylococcus, pneumococcus, Afanasyev-Pfeiffer coli or a combination of virus and microbes. It is important to consider the role of endogenous microbial invasion, especially staphylococcal, which occurs most often against the background of influenza or adenovirus infection.
Bronchitis or tracheobronchitis may be the initial manifestation of measles, less commonly whooping cough and other childhood infections.
The predisposing factors for the occurrence of bronchitis are the following: hypothermia, defects in care (inadequate stay of the child in fresh air, clothing not suitable for the weather, etc.), air pollution with industrial dust and rooms in which children are located, with tobacco smoke.
Depending on the etiological factors, more or less pronounced pathomorphological changes occur. So, tracheobronchitis in influenza is characterized by hemorrhages in the mucous membrane of the bronchi and the presence of fibrinous effusion. With parainfluenza, pillow-like growths of the epithelium are found, mainly in the small bronchi, narrowing their lumen. With adenovirus infection, mucus on the mucous membrane is noted. In the wall of the bronchus, round-cell infiltrates are formed. With respiratory syncytial infection, changes in the small, medium bronchi and bronchioles are most pronounced. Characterized by an abundance of foamy semi sputum. Microscopically determined a certain increase in epithelial cells, their reproduction with the formation of multinuclear papillary growths, occupying a significant part of the lumen of the bronchus. In bacterial bronchitis, infiltration of the mucous membrane by polynuclear cells and lymphocytes is microscopically detected; in severe cases, the formation of a fibrinous film.
The onset is acute. The temperature rises to subfebrile, but often its short (1 – 2 days) increase to 38 – 39 ° С is observed. The main symptom is a cough, worse at night. At the beginning of the disease, a cough is dry, sometimes paroxysmal in nature, may be accompanied by vomiting. On the 3rd – 4th day of the disease, sputum mucus begins to discharge, later replacing purulent. Older children complain of chest pain and tightness, headache, sleep disturbance.
In acute (non-spastic) bronchitis in the first days of the disease, scattered dry rales are heard, on the 3rd – 5th day the rales become wet. Sometimes wet rales are heard at a distance both on inhalation and on exhalation, you can also hear small bubbling rales, which differ from the rales in diffuse pneumonia. Localization of changes in bronchitis is mainly bilateral. With unilateral auscultatory changes, pneumonia should be excluded, although unilateral bronchitis is observed even in young children (S.V. Rachinsky et al., 1978). Percussion changes are usually not.
On the 6th – 8th day of the disease, cough decreases, body temperature normalizes, wheezing disappears in the lungs; recovery comes.
Bronchitis can occur not only from the first days of an acute respiratory viral infection, but at a later date in connection with the addition of a secondary bacterial infection. The clinical picture of the disease in such cases changes: the general condition worsens, body temperature rises, cough intensifies, moist large and medium bubbling rales appear in the lungs. In infants and young children, the disease can be complicated by pneumonia. In uncomplicated bronchitis, there is no marked respiratory failure. In infants, breathing can increase up to 60 in 1 min, accompanied by a slight participation in the act of breathing of the supple parts of the chest in the absence of cyanosis.
Radiologically in acute bronchitis, a symmetrical increase in the pattern of the lungs is detected mainly in the basal and lower medial zones. The enhancement of the pattern is also determined along the bronchovascular structures, which is a consequence of vascular hyperemia and increased lymph production mainly in the peribronchial spaces. These reactive changes in the lungs last longer than the clinical manifestations of bronchitis.
A separate clinical variety of acute bronchitis is spastic bronchitis (bronchitis spastica).
The main pathogenetic essence of spastic bronchitis is a narrowing of the lumen of the bronchi, a violation of their patency, due to vaso-secretory changes that occur under the influence of acute respiratory viral infections. Due to inflammatory changes, the mucous membrane of the bronchi thickens, becomes swollen and swollen, in the lumen of the bronchi there is an abundant accumulation of mucus, sometimes viscous. These changes are the cause of the development of obstructive syndrome. It is possible that viral bacterial allergy is important in the mechanism of the occurrence of spastic bronchitis, as 5-30% of such patients subsequently develop bronchial asthma.
In connection with obstructive disorders, tracheobronchial resistance to air flow increases, especially on exhalation, with its subsequent delay in the lungs and the development of functional emphysema, determined radiologically as bloating of the lungs.
Spastic bronchitis is most common in children of the second half of life and differs from bronchiolitis in a lower degree of respiratory failure due to damage to the bronchi of a larger caliber. Breathing becomes moderately rapid. The clinical picture of the disease is dominated by signs of expiratory difficulty breathing, although in infants there is an involvement in the act of breathing of the supple parts of the chest, which may also indicate difficulty in breathing.
In addition to expiratory difficulty breathing, coughing and wheezing noisy breathing are observed. Auscultation of dry wheezing is determined. Percussion in connection with the phenomena of emphysema is a boxed shade of sound.
Spastic bronchitis in most cases ends in recovery within 5 to 10 days, simultaneously with acute respiratory viral infections, sometimes delayed up to 2 to 3 weeks. More severe forms of spastic bronchitis can be complicated by bronchiolitis.
Significant differential diagnostic difficulties, especially in infants and young children, arise between spastic bronchitis due to airway obstruction as a result of a response to infection and an asthmatic component that complicates pneumonia. For this purpose, it is important to take into account anamnestic data indicating the manifestation of allergy during acute respiratory viral infections in the past, the presence of drug allergy, exudative diathesis, hereditary allergy, etc.
The diagnosis of acute bronchitis is established on the basis of diffuse lesion (physical changes on both sides). Pneumonia is characterized by the presence of physical changes over a limited area of the lung. If pneumonia occurs against the background of diffuse bronchitis or simultaneously with it, the deterioration of the general condition of the child, the identification of limited areas of shortening of percussion sound and changes in auscultation data are taken into account. X-ray with pneumonia revealed infiltrative changes in the lung tissue.