Coalworker pneumoconiosis

Coal workers who work in underground mines are known to develop coal workers pneumoconiosis (CWP). CWP is the most common occupational disease in coal workers (COPD and lung cancer) . Diagnosis of the disease may have profound implications for a coal mining career as withdrawal from exposure is clinically mandated. There has been a significant  decrease in the numbers of coal miners in Western Europe and the USA in recent years, not least in the move away from coal as an energy source amid mounting concerns about greenhouse gas emission and pollution. However, the mining industry in these countries has employed large numbers in the past and these industries are still thriving in Asia, Australia, Eastern Europe, Africa, India and South America. Mechanisation and automation have developed in response to the underground risks but lapses in controls are reported as being common.  Some former and current coal workers are likely to progress CWP for the foreseeable future. Globally exposure limits for respirable coal dust are of the order of 1mgm3 with significant variance between jurisdictions. However, there are new cases are occurring even among miners who have worked exclusively under current dust exposure limits.. During the last 30 years, the prevalence of CWP has fallen consistently in many countries. In addition to coal mining per se, other occupations at risk include coal trimming (which involves loading and stowing coal in stores or ships holds) and the mining and milling of graphite. Risk and prevalence Fibrosis associated with coal dust exposure is considerably less intense and extensive than that evoked by the more bioactive dusts, such as silica and asbestos 32. The risk for CWP depends on the total dust burden in the lungs and is also related to the coal rank, which is based on its carbon content (anthracite has a higher rank than bituminous, followed by sub-bituminous and lignite) 33. In the higher ranking coal, there may be a greater relative surface area of the coal dust particles, higher surface-free radicals and higher silica content 34. Silica exposure and hence silicosis is more common in mines with a high grade of coal 35 and in workers such as roof bolters who work outside of the coal seams in quartz-containing rock 36. Both the presence and stage of CWP, and the development of progressive massive fibrosis (PMF), appear to be related to the intensity of dust exposure, age 34, proportion of inhaled silica in the dust and its surface bioactivity, individual immunological factors, and the presence of tuberculosis. It is common for miners to move to a different career in the latter part of their working life so a detailed Occupational History must be elicited for a patient complaining of worsening dyspnoea. Anthracosis (anthrac- meaning coal, carbon + -osis meaning condition) is defined as the asymptomatic, milder type of pneumoconiosis as caused by the accumulation of carbon in the lungs due to repeated exposure to air pollution or inhalation of smoke or coal dust particles Even some city workers have anthracosis due to airborne anthracite particles In some asian countries, the incidence of coal workers pneumoconiosis may be increasing whilst globally (and in China) it is decreasing. Asia consumed three fifths of the worlds coal in 2019

CWP is a pathology resulting from exposure to organic dust and silica Inhaled coal dust progressively builds up in the lungs and cannot adequately be removed by the body; this leads to fibrosis and necrosis. Smoking is synergistic with CWP in the disease process. Diagnosis of Coalworkers pneumoconiosis requires that alternative diagnoses (such as smoking related disease or asbestosis) be eliminated. The three diagnostic criteria are CXR, history of exposure and designated symptoms. Caplans syndrome includes silicosis, asbestosis or CWP accompanied by  rheumatoid arthritis. Progressive Massive Fibrosis (PMF) is  a feature of advanced silicosis characterised by the development of large masses of dense fibrosis (usually in the upper lung zones) and specific diagnostic criteria. Silicosis may be an adjunct to exposure to coal dust due to the high silica content in some ores.