Progressive Massive Fibrosis Research Articles

Radiographic and pathologic correlation of coal workers' pneumoconiosis.

The relationships between chest radiographs (CXR) and corresponding pathology were investigated in 430 autopsied coal miners from West Virginia. Whole-lung sections were reviewed and graded on four-point severity scales for the following lesions of coal workers' pneumoconiosis (CWP): macules, micro- and macronodules (small and large fibrotic nodules), and progressive massive fibrosis (PMF). Antemortem CXR were classified by three B readers using the 1971 International Labor Office (ILO) U/C classification (6). On pathologic examination, 96% of miners had macules, 70% micronodules, 45% macronodules, 15% silicosis, and 28% PMF. By CXR, 69% of the miners had small, rounded opacity profusions of category > or = 0/1. Data analysis revealed increasing odds that small opacities of category > or = 0/1 would be detected with increasing grade of nodules. Profusion category 0/0 was often reported for cases with macules of mild to moderate grade and mild levels of micronodules. Overall, q-type opacities were associated with macules and micronodules, whereas the large r-type opacities were associated with macronodules. By CXR, large opacities showed good correlation with pathologic PMF. However, about one-third of cases identified as having large opacities by CXR were not substantiated as PMF by pathology. One-fourth of these cases could be explained by lung lesions such as Caplan's nodules, tuberculosis scars, and tumors. Similarly, 22% of cases classified as PMF on pathology had no large opacities by CXR. In half of these cases, the radiologists had noted other abnormalities (cancer, tuberculosis) by CXR as large opacities. Overall, the study showed good agreement (Somer's d = 0.64) between the predicted probabilities and observed responses of a profusion category > or = 0/1 for pathologic CWP lesions. However, the study also showed that CXR were insensitive for detecting minimal CWP lesions, and were unreliable indicators in the presence of concomitant pulmonary pathology.

Tuberculosis and the Attack Rate of Progressive Massive Fibrosis

Abstract Using the data obtained by Cochrane from his prospective study of attack by progressive massive fibrosis in the populations of two mining valleys in Wales, logistic regression models have been established to investigate the complex structure of the data. The assessment of progressive massive fibrosis status made at the end of study of Cochrane was made without knowledge of the initial grade of simple pneumoconiosis. The modeling approach adopted here enables allowance to be made for the appreciable differences in the percentage attacked by progressive massive fibrosis which exist in the two valleys. The prognostic value of initial time-of-survey category of simple pneumoconiosis among those men free from progressive massive fibrosis at that time has been utilized rather than the average derived from the initial and end-of-study grades. These investigations have led to the identification of a previously unrecognized and important influence of tuberculosis infection that is both consistent and unli...

The Need for Determining the Bioavailability of Quartz in Coal Mine Dust Samples

Abstract A 3-year project focusing on the depth profiling of particles and giving their elemental characterizations at various depths has suggested that the reaction of lung tissues to coal mine dust exposures may be dependent upon coal rank-related surface coating of the particles, and ultimately upon specific quartz bioavailability. Previous research clearly indicates a coal rank relationship for the incidence of coal workers' pneumoconiosis and a hypothesized inhibitory role of clays on quartz fibrogenicity. Specifically, epidemiological studies conducted in 1961 and 1963 showed a greater disease incidence for a given cumulative dust exposure among Pennsylvania coal miners who worked in higher rank coal seams. Workers in anthracite mines had a higher incidence of coal workers' pneumoconiosis and progressive massive fibrosis than miners who worked in lower rank coal at equal cumulative exposures. This rank effect in Pennsylvania extended to all ranks of coal seams, that is, the lower the rank, the lower...

A Primate Bronchoscopy Model of Pneumoconiosis: Description of the Model and Initial Anthracite and Quartz Dust-Induced Lesions

Abstract Coal worker's pneumoconiosis and silicosis are still important respiratory diseases within the mining industry. Bronchoalveolar lavage is used to obtain samples from miners with respiratory disease to diagnose, investigate, and treat pneumoconiosis. More information is needed about the characteristics of these respirable mineral dusts and the retrieved lavage specimens to better understand and diagnose pneumoconiosis. We have used bronchoscopy to instill characterized mineral dusts into a focal area of nonhuman primate lung. Bronchoalveolar lavage was used to recover alveolar lining materials from dust-exposed and unexposed lung of the same individuals. We found that multiple doses of fibrogenic or nonfibrogenic dust could be bronchoscopically placed into a small focal area of the lung and that the dust and resulting lesions remained localized to the area of instillation. The characterized quartz dust produced marked focal fibrosis and necrosis that resembled progressive massive fibrosis, as seen...

The survival analyses of 2738 patients with simple pneumoconiosis.

To explore whether the inhalation of coal mine dust increases the risk of premature death in miners, a survival analysis was conducted in a cohort of 2738 patients with simple pneumoconiosis in the Huai-Bei coal mine, in China. Age specific mortalities were calculated by disease severity in terms of pneumoconiotic category with the life table method. The progressions from simple pneumoconiosis to death or progressive massive fibrosis (PMF) were analysed with the Cox's regression model with time as the dependent variable to identify risk factors. During a follow up period (mean 8 y) 3.2% of patients with simple pneumoconiosis developed PMF. The patients with development of PMF presented higher age specific mortalities than those remaining in a state of simple pneumoconiosis (SMR: 3.42; P < 0.01). After adjustment for tuberculosis and duration of work, the relative risk of premature death due to development of PMF was 2.4. Tuberculosis was found to be a main risk factor which not only facilitated premature death (relative risk (RR): 2.0; P < 0.01), but was also a strong facilitator for development of PMF (RR: 7.0; P < 0.01). Also, a long term of work underground and drilling as a main job were identified as risk factors for development of PMF. The results imply that patients with simple pneumoconiosis will have altered survival, and premature death among them is related to an increased risk of the development of PMF and the complication of tuberculosis.

Prevalence of pneumoconiosis and its relationship to dust exposure in a cohort of U.S. Bituminous coal miners and ex‐miners

Information on radiographic evidence of coal workers' pneumoconiosis (CWP) is presented for a group of 3,194 underground bituminous coal miners and ex-miners examined between 1985 and 1988. Prevalence of CWP was related to estimated cumulative dust exposure, age, and rank of coal. On the basis of these data, miners of medium to low rank coal, who work for 40 years at the current federal dust limit of 2 mg/m3, are predicted to have a 1.4% risk of having progressive massive fibrosis on retirement. Higher prevalences are predicted for less severe categories of CWP. Miners in high rank coal areas appear to be at greater risk than those mining medium and low rank coals. Ex-miners who said that they left mining for health-related reasons had higher levels of abnormality compared to current miners.

Panlobular pulmonary emphysema caused by i.v. injection of methylphenidate (Ritalin): findings on chest radiographs and CT scans.

Recent reports have described severe precocious pulmonary emphysema in persons who inject methylphenidate (crushed Ritalin tablets) i.v. We retrospectively evaluated the plain radiographic and CT features in 21 such patients. The chest radiographs, available CT scans, and clinical and pathologic data were reviewed in 21 cases of i.v. Ritalin use. The patients were from 35 to 54 years old. Twelve patients were men, and nine were women. Emphysema was graded on the basis of findings on chest radiographs, by consensus, on a four-point scale as absent, mild, moderate, or severe. CT scans were available for three patients, including one imaged after a single lung transplantation. Autopsy results were available for four patients. Fixed inflated lung specimens and corresponding high-resolution CT scans were available in three cases. Radiographs showed pulmonary emphysema in all cases. The distribution of disease was basilar and symmetric. Small apical bullae were suggested in only one case. Basilar emphysema was rated as mild in four patients, moderate in three patients, and severe in 14 patients. In 11 patients who had serial chest radiographs, the basilar emphysema was noted to progress over a 2- to 7-year period. No evidence of progressive massive fibrosis was seen in any patient. CT scans confirmed emphysema, most severe at the lung bases. The plain radiographic and CT findings in patients who inject Ritalin are similar to those found in patients with alpha 1-antitrypsin deficiency and different from the findings seen in other types of i.v. drug use. The finding of basilar pulmonary emphysema should alert the radiologist to the possibility of i.v. injection of Ritalin.

Recognition and progression of coal workers' pneumoconiosis in the collieries of northern France.

In France, both active and retired coal miners take part in medical surveillance programs. Those compensated for pneumoconiosis are registered and receive annual chest X-rays and regular lung function assessments. A longitudinal study was done among 2719 pneumoconiotics from the Nord-Pas de Calais region Compensation Register, who received first compensation between 1942 and 1987 to study progression of CSWP. Chest radiographs taken at time of compensation and in 1987 were examined by three independent readers. There was a change over time in the characteristics of pneumoconiosis at the time of first compensation toward a low profusion of irregular opacities. In the period from 1982 to 1987, 645 pneumoconiotics developed progressive massive fibrosis (PMF). The occurrence of PMF was related to the date of compensation and the profusion of small opacities at detection (after controlling for time to follow-up). Two profiles for changes in coal workers' simple pneumoconiosis (CWSP) were observed: the first in the group of subjects with mild pneumoconiosis at compensation, who did not reach category 2 at follow-up and had a low attack rate of PMF; and the second in the group of those compensated for category 1/2 pneumoconiosis or higher, who reached severe CWSP and had a twofold attack rate for PMF at follow-up. The changes observed in the characteristics of pneumoconiosis at first compensation between 1942 and 1987 suggest a lessening of disease severity.

Epidemiology of Pneumoconiosis in Coalminers of Nord-Pas de Calais in France

This was a longitudinal study of 3167 active or retired pneumoconiotic coalminers from Nord-Pas de Calais collieries (HBNPC, acronym in French) recognized through medico-legal decisions over three delined periods: 1942-1961, 1962-1981 and 1982-1987. Periodic medical examinations of pneumoconiotics are provided by the medical services of HBNPC for miners and exminers. Physicians involved in this follow-up programme are concerned with the high incidence of progressive massive fibrosis (PMF). The objectives of this study were to describe pneumoconiosis at time of compensation and examine factors related to the occurrence of PMF. For each subject, two radiological films were extracted from the medical files. They were reinterpreted according to the ILO classification (ILO, 1980) by three independent medical readers. Results indicated that radiological criteria for compensation had changed over time ; a marked predominice of category 212 small opacities was noted for cases compensated before 1962 and a predominice of category 1/1 among those compensated after 1981. Comparison of distribution of small opacity types in the 1942-1961 period with that in 1982-1987 confirmed the progressive fall, reported by other investigators, of proportions of predominant micronodular opacities accompanied by an increase in proportions of small irregular opacities at compensation [COCKCROFT and ANDERSON, Br. J. ind. Med. 44,484-487 (1987)]. When time interval between films was taken into account, profusion of small opacities at compensation greater than 1/1 was associated with a probability of 40% or more of developing PMF. Severity of coalworkers simple pneumoconiosis (CWSP) at compensation in HBNPC has been seen to decline since 1982 and the disease to occur mostly after retirement. The reported changes in small opacity types suggest a reduction in incidence of pure silicosis. Occurrence of PMF was correlated with profusion of small opacities at compensation.

Further Studies of Progressive Massive Fibrosis (PMF) among Miners and Ex-Miners

Further Studies of Progressive Massive Fibrosis (PMF) among Miners and Ex-Miners

Progressive Massive Fibrosis Associated With Idiopathic Pulmonary Hemosiderosis

Progressive massive fibrosis is a recognized complication of pneumoconiosis secondary to pulmonary fibrosis, with retraction forming conglomerate masses symmetrically in the upper lobes. Idiopathic pulmonary hemosiderosis is known to cause pulmonary fibrosis secondary to recurrent alveolar hemorrhage with deposition of hemosiderin in the interstitium. We present a case in which progressive massive fibrosis developed in a patient with long-standing idiopathic pulmonary hemosiderosis.

Pulmonary function parameters, arterial blood gases and flow volume curves of dental technicians.

Dental technicians working in laboratories are exposed to different doses of various dusts. Disorders of pulmonary function may occur before radiographic changes are evident. If these pulmonary function disorders are found at an early stage, the risk may be reduced by early, adequate local ventilation and by appropriate individual protective methods. Unless adequate preventive measures are taken, pulmonary disorders will increase, finally leading to obstructive or restrictive ventilatory disorders, or progressive massive fibrosis. Results of pulmonary function tests provide objective criteria for prognosis, and are a measure of disease disability. In this situation, abnormal pulmonary function results should be considered as alarm signs.

STANDARD IMAGING IN SILICOSIS AND COAL WORKER'S PNEUMOCONIOSIS

Silicosis and coal worker's pneumoconiosis (CWP) are two relatively common occupational diseases. Silicosis is the most common pneumoconiosis in the United States. It results from inhalation of the particulate form of quartz or other crystalline forms of silicon dioxide with a diameter of less than 5 micrograms. CWP is the result of inhalation of carbon particles. Pathologic features of the two diseases differ, yet their radiologic features are identical. Simple pneumoconiosis is characterized by multiple small rounded opacities of 1 to 5 mm in diameter and with a bias for the upper lung zones. Complicated pneumoconiosis results from confluence of small opacities into large opacities that form conglomerate masses or progressive massive fibrosis.

British data on coal miners' pneumoconiosis and relevance to US conditions.

The current primary federal dust standard for US underground coal miners of 2 mg/m3 respirable dust is based on British epidemiological information on exposure-response derived in 1969. Since then, much new information has become available. This paper reviews and compares the available information as it relates to the US mining situation. Recent exposure-response information on pneumoconiosis and dust exposure derived by British researchers was employed to estimate working-life risks of pneumoconiosis for miners exposed to 2 mg/m3. It is estimated that close to 9% of underground coal miners who work for 40 years in a 2 mg/m3 environment would develop pneumoconiosis (category 1 or greater). Progressive massive fibrosis would develop in 0.7%. There are unresolved questions relating to the validity of extrapolating findings on British mines and miners to the US and also in predicting disease levels at the low end of the dust exposure spectrum. Given the data available, current information suggests miners who are employed for a working life-time at the current federal dust limit of 2 mg/m3 are still at risk of developing pneumoconiosis.

Dust exposure and pneumoconiosis in a South African pottery. 2. Pneumoconiosis and factors influencing reading of radiological opacities.

A cross sectional radiological survey of workers exposed to pottery dust during the manufacture of wall tiles and bathroom fittings was conducted in a South African factory. Roughly one third of workers with 15 or more years of service in high dust sections of the factory had pneumoconiosis. Previously undiagnosed advanced cases, including two with progressive massive fibrosis, were working in dusty occupations. A firm diagnosis of potters' pneumoconiosis was made in 11 of the 358 workers radiographed; all had served more than 10 years suggesting that radiography of workers with more than 10 years service would be a successful case finding strategy in South Africa. A combination of rounded and irregular opacities was the most common radiological finding in the workers with pneumoconiosis (55%). Three readers reported on the chest radiographs, and all found an association between small radiological opacities, which were usually irregular or a combination of irregular and rounded, and exposure to pottery dust. The occurrence of irregular radiological opacities in workers exposed to pottery dust deserves further study. The least experienced reader significantly associated age with small opacities when duration of service (years) was used to measure exposure to dust. Sex was not an important predictor of radiological changes consistent with pneumoconiosis. Breast shadows were not an important cause of false positive readings and participating women did not develop pneumoconiosis after less exposure than men.

Reevaluation of silicosis and lung cancer in North Carolina dusty trades workers.

We previously reported on the lung cancer mortality through 1983 of 760 males who were diagnosed with silicosis during 1930-1983 by the State of North Carolina's medical examination program for dusty trades workers. The lung cancer SMR (95% confidence interval) was 2.6 (1.8-3.6) among 655 white members of this group. In this paper, we report the results of a reanalysis of mortality among a subgroup for whom chest radiographs were currently available for rereading. Technically acceptable radiographs were available for 306 white males and were independently reclassified for pneumoconiosis by 3 "B" readers using the 1980 ILO Classification. Lung cancer SMRs were 1.7 (0.8-3.1) for the entire group of 306 white males, 2.5 (1.1-4.9) for 143 subjects reclassified as simple silicosis, and 1.0 (0.1-3.5) for 96 subjects whose radiographs were reclassified as ILO category 0. There were no lung cancer deaths among 67 subjects whose radiographs were reclassified as progressive massive fibrosis. Corresponding lung cancer SMRs for subjects who had never been employed in a job with exposure to known occupational carcinogens were 1.2 (0.2-4.4) for those reclassified as category 0, and 2.4 (1.0-5.0) for those reclassified as having simple silicosis. The age-adjusted lung cancer rate ratio among subjects with simple silicosis compared to those with category 0 was 1.5 (0.4-5.8). Our findings from this reanalysis, which effectively controls for misclassification of silicosis due to errors in radiograph interpretation by North Carolina program readers, offer additional evidence consistent with the hypothesis of an association between silicosis and lung cancer in this study group.

Hut lung: a domestically acquired pneumoconiosis of mixed aetiology in rural women.

A form of pneumoconiosis in rural African women termed "Transkei silicosis" has been thought to be due to silica particles inhaled while they are hand grinding maize between rocks. Twenty five women were studied who were considered to have this condition according to the following criteria: rural domicile, radiographic and lung biopsy evidence of pneumoconiosis, no exposure to mining or industry and no evidence of active tuberculosis. They were assessed for radiological, pathological, physiological and bronchoalveolar lavage fluid features. Potential aetiological factors were assessed by determining levels of exposure to respirable quartz and non-quartz containing dusts and smoke in rural dwellings during maize grinding and cooking. Most of the women were symptomless. Radiological findings ranged from a miliary pattern to extensive fibrosis resembling progressive massive fibrosis. Histological features included simple "anthracosis" in 12, anthracosis with macules in six, and mixed dust fibrosis in seven. Cell numbers and their proportions in lavage fluid were normal. More than 60% of macrophages were heavily laden with inorganic inclusions. Respirable quartz concentrations and calculated cumulative time weighted exposures were below those recommended for industry during grinding with sandstone (100% quartz) and they were even lower during grinding with dolerite containing no quartz despite the presence of an appreciable amount of quartz in the ground maize. Total respirable dust and smoke concentrations were greater than the recommended safe levels. Three women had no exposure to maize grinding. It is concluded that the inhalation of non-quartz containing dust and smoke from biomass fuelled fires is more important in the aetiology of this condition than exposure to quartz dust. The term "hut lung" may be more appropriate.

Silicosis in a Himalayan village population: role of environmental dust.

The Himalayan villages of Chuchot Shamma and Stok were surveyed because silicosis had been suspected from the radiographs of some of the inhabitants. The villages are agricultural, and Chuchot is exposed to frequent dust storms. Chest radiographs of villagers aged 50-62 were assessed blind by two independent observers using ILO criteria. In Chuchot five of seven men and all of the nine women examined showed varying grades of silicosis, compared with three of 13 men and seven of 11 women in Stok, which lies 300 metres higher and is exposed to fewer dust storms. The difference in prevalence of silicosis between the two villages was significant, as was the differences between men and women. Three patients from the village adjoining Chuchot were later found to have radiological evidence of progressive massive fibrosis. A necropsy on a man in a neighbouring village in the Indus valley showed classical silicosis in a hilar lymph node. Chemical analysis of the inorganic dust in the lung showed that 54.4% was elemental silicon [corrected]. This was similar to the silicon [corrected] content of dust samples collected from houses in Chuchot, which included particles of respirable size. X-ray microanalysis showed that quartz formed 16-21% of the inorganic lung dust. This study suggests that silicosis is common among the older inhabitants of these Himalayan villages. The dust exposure is clearly environmental and not industrial. Further studies are needed to define the extent and severity of silicosis in this community and to examine possible preventive measures.

Presence of acute phase response in coal workers' pneumoconiosis.

To evaluate the role of personal factors in pneumoconiosis, several acute phase proteins were studied in 62 coal miners without acute illnesses and classified as having no pneumoconiosis (n = 19), simple pneumoconiosis (n = 23), or complicated pneumoconiosis with progressive massive fibrosis (n = 20). Groups were similar for age, years of work at high risk jobs, chronic bronchitis, and forced expiratory volume in one second (FEV1). C-reactive protein concentration was significantly higher in the simple and complicated pneumoconiosis groups in comparison with the no pneumoconiosis group. The C-reactive protein concentration was above the upper normal value in 12 (27.9%) out of 43 cases with simple and complicated pneumoconiosis. On the other hand only one case of no pneumoconiosis was above the upper normal range (5.3%), a significant difference taking into account a stratified analysis for chronic bronchitis. Fibrinogen concentration was significantly increased in the simple pneumoconiosis group compared with the no pneumoconiosis group. The value of fibrinogen was above the upper normal limit in 17 out of the 43 cases with pneumoconiosis (39.5%) by contrast with two cases in the no pneumoconiosis group (10.5%). No significant differences in alpha 1-antitrypsin and ceruloplasmin concentrations were found between groups. In conclusion, an alteration in some acute phase proteins related to pneumoconiosis was found in miners. This could be used as a marker of disease activity and personal response against the pathogenic agent.

Silicosis among gemstone workers in South Africa: Tiger's‐eye pneumoconiosis

Six cases of silicosis in workers involved in the processing of semiprecious gem stones have been seen in our clinic since 1976. They had been employed as stone sculptors in lapidaries where they processed tiger's-eye, rose quartz, amethyst, quartz crystal, and a variety of other locally occurring semiprecious stones. In five of the cases, exposure was in small and poorly regulated lapidaries without specific dust control measures. The sixth was detected during the course of a health and hygiene survey (including dust sampling) that was conducted in one of two lapidaries still operating in our area. Progressive massive fibrosis (PMF) or accelerated silicosis was noted in four of the six cases, three of whom had progression of their disease after cessation of exposure. With the development of PMF, the initial restrictive pulmonary function abnormalities were followed by steadily worsening airflow obstruction. Lung biopsies confirmed silicosis in three cases. Tuberculosis was confirmed in two cases and suspected and treated in a third. Workmen's Compensation was awarded in five cases. The survey confirmed that in semiprecious gem stone processing, the risk of silicosis appears to be confined to stone sculptors. Tried and proven techniques of general and local exhaust ventilation combined with water or oil to control dust at source were capable of effectively reducing dust emission to acceptable levels.