Diagnosis of chronic bronchitis is based on clinical, radiological, laboratory, bronchoscopic and functional data.
Radiological chronic bronchitis is characterized by increased transparency and reticular deformity of the pulmonary pattern, most pronounced in the middle and lower sections and due to sclerosis of interacinar, interlobular, intersegmental septa. Differentiation of the roots of the lungs may also be lost, and the basal pattern may change. A third of patients show signs of emphysema. In the later stages, a quarter of patients develop anatomical defects of the bronchi, detected by bronchography.
The function of external respiration in the early stages of chronic bronchitis is not changed. Obstructive syndrome is characterized by a decrease in FEV1 from 74 to 35% of the proper value, Tiffno test indices from 59 to 40%, a decrease in MVL, VC and dynamic extensibility, an increase in OOL and respiratory rate. When studying the dynamics of ventilation disorders, preference is given to speed indicators (FEV1). In the first stages of chronic bronchitis, the minimum dynamics of FEV is determined no earlier than 8 years later. The average annual decrease in FEV1 in patients with chronic bronchitis is 46-88 ml (this value determines the prognosis of the disease). Often FEV falls abruptly. The predominance of proximal obstruction is characterized by an increase in OOL without an increase in OEL, a peripheral significant increase in OOL and OEL; generalized obstruction is characterized by a decrease in FEV], an increase in bronchial resistance, the formation of emphysema. The functional component of obstruction is detected by pneumotachometry before and after the administration of bronchodilators. The data of analyzes of peripheral blood and ESR do not change much: moderate leukocytosis, an increase in the level of histamine and acetylcholine (more with obstructive chronic bronchitis) in the blood serum can be observed. In a third of patients with obstructive chronic bronchitis, a decrease in blood antitryptic activity is noted; with asthmatic chronic bronchitis, the level of acid phosphatase in the blood serum is increased. In the case of the development of chronic pulmonary heart, the content of androgens, fibrinolytic activity of the blood, and the concentration of heparin are reduced. For the purpose of timely diagnosis of an active inflammatory process, a complex of laboratory studies is used: biochem. analyzes, a study of sputum and bronchial contents. From biochem. indicators of inflammation activity are considered the most informative level of sialic acids, haptoglobin and protein fractions in serum, plasma fibrinogen content. The increase in the concentration of sialic acids above 100 srvc. units and protein in the range of 9-11 mg / l in sputum corresponds to the activity of inflammation and the level of sialic acids in serum. In chronic bronchitis, the concentration of pathogenic microorganisms increases, is 102-109 in 1 ml; pneumococcus predominantly stands out at the exacerbation stage (and in 50% of patients it is also detected at the remission stage – a hidden course of inflammation); pH, viscosity of sputum and the content of acid mucopolysaccharides in it increase; the level of lactoferin, lysozyme, secretory YG A and protease activity are reduced; the activity of ai-antitrypsin increases. Cytological analysis of sputum in patients with chronic bronchitis reveals: accumulations of neutrophils, single macrophages at the stage of severe exacerbation; neutrophils, macrophages, cells of the bronchial epithelium – at the moderate stage; the predominance of cells of the bronchial epithelium, single leukocytes, macrophages at the stage of mild exacerbation. In the bronchial contents (lavage fluid obtained by fibrobronchoscopy) of patients with chronic bronchitis, the level of phosphatidylcholine and lysophosphatides is reduced, and the free fraction of cholesterol is increased, the ratio of serum and secretory immunoglobulin A is shifted to the predominance of serum, the concentration of lysozyme is reduced. Neutrophils predominate in the lavage fluid of patients with purulent chronic bronchitis (75-90%), the number of eosinophils and lymphocytes is insignificant and does not change significantly during treatment, whereas in healthy individuals this fluid contains only alveolar macrophages (80-85% In non-smokers, 90- 95 – in smokers) and lymphocytes. In allergic chronic bronchitis, eosinophils (up to 40%) and macrophages predominate in the lavage fluid . With the catarrhal form of chronic bronchitis, the cytology of lavage fluid depends on the nature of the secret.