Emphysema - a disease of the respiratory tract, characterized by the expansion of the air spaces of terminal bronchioles, accompanied by destructive changes of alveolar walls. It is one of the most common forms of chronic nonspecific pulmonary diseases.
There are two groups of causes leading to the development of emphysema.
The first group includes factors that violate the elasticity and strength of the structural elements of the lungs: pathological microcirculation, congenital deficiency of antitrypsin, gaseous substances (cadmium compounds, nitrogen oxides, etc.), as well as tobacco smoke, dust particles in the inhaled air. These reasons could lead to the development of primary, always diffuse emphysema. At the heart of its pathogenesis is pathological alteration of the respiratory department of the lung. The weakening of the elastic properties of light leads to the fact that during expiration, and hence increase in intrathoracic pressure small bronchi passively fallen down, thus increasing airway resistance by exhalation and increased pressure in the alveoli. Bronchial patency on a breath in primary emphysema is not violated.
The second group of factors contribute to the increased pressure in the respiratory department of the lungs and increase the tension of the alveoli, alveolar passages and respiratory bronchioles. Recognition of diffuse emphysema, especially in the initial phases of its development, runs into serious difficulties, primarily because of inability to distinguish emphysema from lung tissue swelling, and to establish the fact of irreversible changes in the latter. These characteristics include the development of the disease primarily of men, on average, and sometimes the young (with genetically determined emphysema), age, complaints of shortness of breath and a sharp decrease in tolerance to stress, often at a reduced body weight. The objective signs are predominantly asthenic physique, increase ("barreling") of the chest, which, as it always is in a phase of deep breaths, expanding and even bulging of intercostal spaces, the approximation of the edges to the horizontal position. With a little exertion or at rest tend to patients with emphysema breathe in dense lips, puffing out his cheeks at the same time ("puff"). This maneuver they instinctively raise the pressure in the bronchial tree during exhalation.
The primary cause of secondary or obstructive pulmonary emphysema is a chronic obstructive bronchitis, as it was when it created the conditions for the formation of the valve mechanism overdistension of the alveoli. Sometimes both of these conditions are sometimes combined the concept of "obstructive lung disease."
Secondary pulmonary emphysema causes a phenomenon called "air trap" in which the lumen of small bronchi, which has a poor conductivity at the time of inhalation, the decrease in intrathoracic pressure phase passes air into the alveoli, and during expiration, when intrathoracic pressure rises, completely blocked, resulting in Hypertension occurs in the alveoli.
In addition to the above types of diffuse emphysema, there are different types of localized or irregular emphysema which accompany the various processes in the lung tissue. Not with all the changes, which are usually attributed to localized emphysema, there is a true emphysema. Often, this occurs only swelling or overdistension of lung tissue involved in the local pathological process.
With a decrease in the volume of lung tissue, for example due to atelectasis and cicatricial shrinkage, as well as after resection of lung adjacent areas subject to hyperinflation, which is called vicarious emphysema. Next to the scar-altered portions of lung parenchyma there are pockets of the so-called okolorubtsovoy emphysema, which often creates a mosaic of alternating sections pneumosclerosis and emphysema in a number of chronic pathological processes.
Conventionally, the category of emphysema include the so-called fractional congenital emphysema, and congenital unilateral emphysema or McLeod syndrome.