Contact with asbestos is the cause of several pleural diseases. Firstly, it can promote diffuse hydrochloric malignant mesothelioma ; secondly, mo Jette cause non-malignant pleural effusion ; thirdly, it can lead to the formation of pleural plaques and calcification of the pleura (to be discussed in this chapter); fourthly, it can cause massive fibrosis of Menenius pleura (as will be discussed in this chapter).
Pleural plaques
Persons who have had contact with asbestos may form layers of hyalinized fibrous tissue on the parietal pleura that covers the chest wall, the diaphragm and the mediastinum . The relationship between the formation and the occurrence of pleural plaques malignant mesothelioma without tracing etsya [1].
Frequency. Pleural plaques develop slowly in persons who have contact with asbestos. Epier and colleagues studied rents genogram chest in 1135 patients with a history of exposure to asbestos, and found that during the first 5 years of exposure to asbestos, none of them had observed Pleven eral plaques. After 20 years from the moment of contact with asbestos, the frequency of plaque formation was about 10%. However Th Res 40 years old X-ray revealed pleural plaques more than 50% the sick. A few years after the plaques become radiologically visible, their calcification begins. During the first 20 years of contact with asbestos, calcified plaques are rare, but after 40 years, calcification is observed in 1/3 of the patients .
It should be noted that in many cases pleural blyash ki identified at autopsy, are not visible at x-ray diffraction patterns of the chest, made with the patient’s life. But rihane et al . It reported that the number of patients with pleural GOVERNMENTAL plaques identified at autopsy, on ra- IU chest during the life of the patient’s plaque was Detect wife only 14% of patients. According to Hillerdal and Lindgren , only 12.5% of plaques detected at autopsy are X-ray logically found during the life of the patient. Depending on the location of the plaques and the time of the study until ence identify plaques at autopsy ranges from 2.7 to 49% [4] and the average is 12%.
Pathogenesis . There is strong evidence boiling on the relationship between the formation of pleural plaques and having had shimsya contact with asbestos. Kiviluoto analyzed data on place of residence of all patients with bilateral obyz vestvleniem pleura in Finland and found that almost all of them lived near asbestos mines open. Many individuals with koto ryh autopsy revealed pleural plaques in Anam Veronese registered asbestos exposure in connection with their work . Ferruginous (asbestos) calf gistolo are logically indication of exposure to asbestos , consist of volo con, coated with compounds from hemosiderin and glycoproteins, which are believed to be formed by macrophages that phagocytize these particles. Although glandular calf manner Vanir of various inorganic and organic foreign fibers, in most cases consists of a rod asbes one why they are called asbestos corpuscles . In the lungs of patients with pleural plaques, their number is much greater than in patients without plaques , and the greater their number, the higher the probability that a patient has pleural plaques. Finally, most pleural plaques contain many submicroscopic asbestos fibers that can be seen. electron microscopy, as a result of selective electron diffraction and microchemical analysis of particles. However, not all pleural plaques are the result of asbestos exposure. In Czechoslovakia there are areas where a sufficiently precise large number of patients with pleural plaques, and the influence of asbestos slightly . It is not established that causes the development of pleural plaques in these patients.
The mechanism of formation of pleural plaques as a result of exposure to asbestos is not known. Kiviluoto expressed before the position that the formation of plaques caused by inflammation pas rietalnoy pleura . When inhaled, asbestos fibers on the fall in the peripheral parts of the lung. Kiviluoto believes that these fibers pierce the visceral pleura, and then, during respiratory movements, come into contact with the parietal pleura and cause its irritation. Appearing in the results are inflammation of the parietal pleura gradually EMPTY INDICATES formation of hyaline plaques that eventually calcify . However, if this theory was the great Vilna, between the visceral and parietal pleura in IU Stach plaque formation could be detected spikes, and parietal pleura – long asbestos fibers.
Hillerdal recently suggested that the education of pleural plaques caused by penetration mainly short submicroscopic fibers, since these fibers are in plaques . Hillerdal believes that these short fibers penetrate into the pleural cavity through the pas renhimu lung and visceral pleura. Then, like all other solids, they are removed from the pleural cavity by
Pleural plaques. On the front of the chest radiograph direct patient cells, which had during the 30 years of exposure to asbestos, both sides reviewed Pleven -sectoral plaque average. Pay attention to the calcification of the diaphragm and moderate interstitial fibrosis – a consequence of asbestosis .
cutting lymphatic vessels located in the parietal pleura. However, some of these fibers are deposited in limfatiche Sgiach vessels and after a number of years inflammatory kletoch naya reaction to their presence is manifested in the form of the formation of pleural plaques.
Pathological characteristics. Macroscopically pleural plaques are similar to unevenly located abstract forms of elevation, between which there are areas of a normal or somewhat thickened pleura. Plaques are always localized on the parietal pleura, often on the back wall of the lower part of the pleural cavity. On the costal pleura, plaques are usually located along the ribs, above and below them, and are elliptical in shape . The apical parts of the pleural cavity and costal-diaphragmatic sinus sah plaques usually do not show . Thin plaques only slightly protrude above the surface of the pleura and have a gray-be thicker, thicker plaques have a cream or ivory color. The diameter of the plaques varies from not how many millimeters up to 10 cm .
Microscopic plaques are composed of collagen unite tion fabric having a small number of cells . Kapil lyarov in this connective tissue is small, but in appearance it resembles coarse matting. The plaques are covered with normal mesothelium. The plaque is always sharply delimited from the healthy tissue of the pleura . Coating for elastin reveals that the thin layer, which is under the plaque, is connected to the surround sound conductive connective tissue parietal pleura. The considerable nom including plaques are deposits of lime . Although light microscopy can not detect asbestos calf, elec –
The front straight rents genogram rib cage of the patient with a pronounced mi pleural plaques (advanced disease) electron microscope allows almost all plaques see many submicroscopic fibers.
X-ray data. Neobyzvestvlennye pleural nye plaques usually radiographically detected . The earliest sign of radiographic whether Nia increased density passing along the ribs usually VII or VIII. Increasing in size, the plaque assumes a convex shape of an ellipse with converging upper and lower borders, which is typical for extrapleural formations . Vertically plaques rarely races uted over 4 intercostal space. Tol ness plaques ranges from 1 to 10 mm or more, but most part wish to set up 1-5 mm. Pleural plaques are usually localized on two sides, often symmetrically. In the apical regions of the pleura and costal-diaphragmatic sinuses, plaques are rarely formed. On the chest radiograph, pleural plaques are best viewed in a tangential projection, in profile, along their long axis. The front line of the chest radiograph can be clearly visible plaque is hydrochloric the inner surface side of the chest, as in this position the x-ray beam passes through most of its thickness. Neobyzvestvlennye pleural plaques is best viewed at 110-140 kV and calcified – at 80 kV.
When the X-ray beam direction perpendicular to the plaque it is in the “front” or “front” projection tion. However, it should be borne in mind that in front of the projection is not large neobyzvestvlennye plaque is difficult to see because they are identified as a nondescript, and irregular-shaped shadow that runs along the edge. In the frontal projection tion has plaque rarely correct rounded shape, as its peripheral portions and unevenly contoured like edge card or sheet lily . Because of the vagueness of the shape, the plaque often goes unnoticed or is mistaken for an artifact. To identify plaques, we recommend using oblique projection . In an oblique projection, plaques are viewed in profile.