Pneumoconiose reumatoide (síndrome de Caplan) com apresentação clássica

Abstract

Although rare, rheumatoid pneumoconiosis, also known as Caplan's syndrome, can occur in workers exposed to silica, as well as in patients with silicosis, coal workers' pneumoconiosis or asbestosis. Prevalence is higher among patients with silicosis, despite the fact that it was originally described in coal workers with pneumoconiosis. The classical finding that defines this syndrome is that of rheumatoid nodules in the lungs, regardless of whether there are small rounded opacities suggestive of pneumoconiosis or large opacities consistent with massive pulmonary fibrosis, with or without clinical rheumatoid arthritis. We describe the case of a female patient with rheumatoid arthritis, diagnosed 34 years after 7 years of occupational exposure to silica at a porcelain plant. A chest X-ray showed circular opacities of 1-5 cm in diameter, bilaterally distributed at the periphery of the lungs. A CT-guided thoracic punch biopsy of one of those nodules revealed that it was rheumatoid nodule surrounded by a palisade of macrophages, which is typical of Caplan's syndrome. Aspects of diagnosis, classification and occurrence of this syndrome are discussed, emphasizing the importance of the occupational anamnesis of patients with rheumatoid arthritis and lung opacities on chest X-rays.Keywords: Pneumoconiosis; Arthritis, rheumatoid; Caplan's syndrome; Silicosis. ResumoApesar de rara, a pneumoconiose reumatoide, também chamada de síndrome de Caplan, pode ser diagnosticada entre trabalhadores expostos à sílica e entre pacientes com silicose, pneumoconiose dos mineiros de carvão e asbestose. A maior prevalência ocorre entre os silicóticos, apesar de ter sido descrita inicialmente em mineiros de carvão com pneumoconiose. O achado que define o tipo clássico da síndrome é a presença de nódulos reumatoides nos pulmões, independente da presença ou não de pequenas opacidades pneumoconióticas, ou de grandes opacidades de fibrose pulmonar maciça, associada ou não a um quadro de artrite reumatoide em atividade. Relatamos o caso de uma mulher com quadro de artrite reumatoide, diagnosticada 34 anos após exposição à sílica livre em uma indústria de porcelana por 7 anos, apresentando radiograma de tórax com opacidades arredondadas de 1 a 5 cm de diâmetro, distribuídas na periferia de ambos os pulmões. A biópsia transtorácica guiada por TC de um dos nódulos revelou tratar-se de nódulo reumatoide com macrófagos em paliçada, típico da síndrome de Caplan. São discutidos aspectos de diagnóstico da síndrome, classificação e ocorrência, ressaltando a importância da anamnese ocupacional em casos de artrite reumatoide com opacidades radiológicas pulmonares.

Is Male Rheumatoid Arthritis an Occupational Disease? A Review

“…Given that the lung is an important site of RA initiation [ 5 ], this is of contemporary interest in RA aetiology. Radiological changes of Caplan’s syndrome can precede RA development, and regional differences in the incidence of Caplan’s syndrome in coal miners have been noted [ 28 ]. Underground coal miners in Staffordshire, UK, demonstrated a significantly increased risk of RA development (OR 8.47, 95% CI 2.59 to 27.66) [ 29 ].…”

A case of Caplan syndrome in a recently diagnosed patient with silicosis: A case report

“…Also positive anticyclic citrullinated peptides were frequently found in Caplan syndrome, and there is a link between exposure to silica and antibodies against citrullinated proteins-positive RA [14] . Radiological abnormalities and exposure history to silica allowed us to retain the diagnosis of Caplan syndrome in the clinical case we present by meeting the criteria established for the diagnosis of Caplan syndrome [13] . The occupational anamnesis in RA cases associated with radiological opacities allows differentiation of Caplan syndrome from pulmonary alterations due to RA [13] .…”

“…Radiological abnormalities and exposure history to silica allowed us to retain the diagnosis of Caplan syndrome in the clinical case we present by meeting the criteria established for the diagnosis of Caplan syndrome [13] . The occupational anamnesis in RA cases associated with radiological opacities allows differentiation of Caplan syndrome from pulmonary alterations due to RA [13] . This case also illustrates the potential of free silica and other mineral dusts to trigger autoimmune diseases.…”

“…The hypothesis is that silica particles are ingested by alveolar macrophages leading to inflammation and activation of fibroblasts. The macrophages destroyed the silica, which is again digested by new macrophages [13] . Activated macrophages by silica via the pathogen-associated molecular pattern will cause the production of several cytokines, including interleukin-1 and tumor necrosis factor-alpha.…”

“…Activated macrophages by silica via the pathogen-associated molecular pattern will cause the production of several cytokines, including interleukin-1 and tumor necrosis factor-alpha. Following the activation of the innate immune system, dendritic cells will present antigens to CD4 T lymphocytes [13] . This repeated process causes chronic immune activity and fibrosis, and so facilitates the formation of autoantigens [12] .…”