Document Ema5RyVbMOLk060xp1azn09y0

TO:16182590896 1)6 | SILICOSIS AND OTHER K1BROPIC PNEUMOCONIOSES ground-glass appearance. While there is no orderly progression of changes, the next stage is characterized by fine mottling or stippling, localized or general, and particularly conspicuous in the lower halves of the lung fields. This mottling may later become coarser, thus producing a granular pattern. Thereafter the whole picture is dominated by the sclerotic pleurisy described on page 109 Thu costo-phrcnio and cardio-phrenic angles are obscured, and the outlines of (he cupolae of the diaphragm and of the cardiac shadow appear shaggy, because of opacities, which, as so aptly described by Wycrs, resemble teused-out cotton-wool. In some cases a very characteristic appearance is presented by the horizontal fissure, which is thickened and presents a lenticular rather than a fine linear shadow, It is also often con siderably depressed in level, especially laterally, so that instead of appearing horizontal it is oblique, with the convexity directed upwards and outwards. i I Differential diagnosis it cannot be said that the condiuon requires to be differentiated from any other condition. If the investigation follows the routine which is outlined, almost complete accuracy should be achieved. It may be said, however, that, ml the early diagnosis of asbestosis, aR a supplement to the occupational history, the clinical features are a more reliable guide than radiographic changes and, indeed, often precede (hem. Incidence of asbestosis In Great Britain the risk of contracting the disease occurs in the asbestos manufacturing industries, and to a small extent in heat-insulation work, pjpc and boiler covering (lagging) and the other incidental processes, such as stripping the old composition. The risk varies, of course, with (he dustiness or the process and, in the absence of efficient dust suppressing and collecting devices, the most dusty operations are (1) preparatory processes of crushing, opening, sieving, mixing and blending, (2) sack filling and emptying and all hjandling of loose usbestos. (3) carding and card cleaning and grinding, (4) cloth weaving, (5) mattress making, and (6) cleaning dust settling or filtering chambers Jn recent years considerable advances have been made ifi controlling the dust at the source of production. Thus, whereas in 1929 cases were identified after 7 years' exposure--some even after u much shorter period--the corresponding figure now is 10 years. I