Pericardial plaque: a unique complication of silicosis

Unveiling the threat of crystalline silica on the cardiovascular system. A comprehensive review of the current knowledge

Introduction

This paper aims to expose the link between occupational exposure to respirable crystalline silica (SiO2) and cardiovascular diseases (CVDs).

Methods

A comprehensive review of the literature was conducted, focusing on epidemiological studies that assessed the association between silicosis or SiO2 exposure and CVDs. Specific cardiovascular diseases, such as acute myocardial infarction, arrhythmias, pulmonary hypertension and pericarditis, were also pointed. Biomarkers commonly used in both silicosis and cardiovascular diseases were reviewed to underline the common pathological pathways.

Results

Published epidemiological data revealed a higher risk of ischemic heart disease, stroke, and hypertension in silica-exposed workers, even at low exposure levels. SiO2 exposure was linked to an increased risk of myocardial infarction, with potential mechanisms involving inflammation and platelet activation. Elevated risk of arrhythmias, particularly atrial fibrillation, correlated with occupational silica exposure. Consistent with the pathological mechanisms supporting the SiO2 exposure-CVDs relationship, biomarkers related to NLP3 inflammasome activation, reflecting oxidative stress, and revealing fibrosis have been presented.

Conclusion

Actual data support the relationship between occupational SiO2 exposure and various CVDs promoting cardiovascular monitoring in silica-exposed workers. Further studies are needed to identify specific/distinctive biomarkers to improve early detection of CVDs in silica exposed workers.

A Rare Case of Pericardial Effusion in a Patient with Silicosis

Silicosis is an occupational lung disorder caused by inhalation of silica dust. It not only causes respiratory disorders but also affects other organs. We report an extremely rare case of silicosis complicated by pericarditis in an 83-year-old male. He had been working as a coal miner and was diagnosed with silicosis at the age of 63. Because he had experienced repeated pericardial effusions, he was referred for a surgical pericardial biopsy to elucidate the cause of his repeated pericardial effusion and to perform pericardial fenestration. Thoracoscopic surgery was performed. The pericardium was resected, and a drain was placed in the left thoracic cavity. Histopathological examination revealed the pericardial degeneration due to silicosis, suggesting that pericarditis and pericardial effusion are related to silicosis. The operation was successful, and he experienced no recurrence of pericardial effusion at the 7-month follow-up.

A stone miner with both silicosis and constrictive pericarditis: case report and review of the literature

Background

The working environment of stone miners has been believed to cause their susceptibility to respiratory diseases. Silicosis is an occupational disease caused by exposure to crystalline silica dust which is marked by inflammation and scarring in the lung. The immune system boosted after the silica invasion led to self-damage and lay the foundation of silicosis pathogenesis. Silicosis coexisting with other diseases in one patient has been reported, however, was not reported to coexist with constrictive pericarditis. We, for the first time, reported a patient with silicosis and constrictive pericarditis and thought the immune response was probably the link between the two.

Case presentation

A 59-year-old Chinese stone miner complained of chest distress was found to have lung nodules which were found to be silica deposits by biopsy. This patient was also found to have constrictive pericarditis at the same time. Later surgical decortication cured his symptoms.

Conclusion

We provided the first case having constrictive pericarditis concomitant with silicosis. A probable link between the two diseases was the immune response boosted by the silica deposits.

Interleukin-18, interleukin-8, and CXCR2 and the risk of silicosis

Molecular mechanisms in the pathogenesis of silicosis are not fully understood. Exposure to crystalline silica leads to the activation of signaling pathways controlling the production and secretion of inflammatory mediators. Inflammatory cytokines are noted as important candidate genes for fibrotic lung diseases. Cytokines, chemokines, and variations of their genes have been associated with upregulation or downregulation of chronic inflammatory mediators. Variations in the interleukin (IL)-18, IL-8 and chemokine receptor CXCR2 genes are believed to influence the risk of silicosis in stone-grinding factory workers in Iran. Allele-specific oligonucleotide polymerase chain reaction (PCR) procedure was carried out for IL-18 -137 and IL-18 -607, meanwhile touchdown PCR was performed for IL-8 -251 and CXCR2 +1208 genotyping. Variation in genotypic and allelic frequencies was not statistically different among cases versus controls (p > 0.05). These findings indicated for the first time that IL-18 -137, IL-18 -607, IL-8 -251, and CXCR2 +1208 are suggested not to influence the risk of silicosis in tested occupational group.