Caplan's syndrome in an elderly-onset rheumatoid arthritis patient: About a new case

IntroductionThe association of silicosis and RA is rare compared to pulmonary manifestations of rheumatoid arthritis (RA). A history of lung disease or a long exposure at work to silica and typical radiographic lesions on chest X-ray suggest the diagnosis of Caplan's syndrome. We describe the case of an elderly Tunisian male RA patient with the Caplan's syndrome diagnosed after prolonged exposure to silica.Case reportA 62-year old patient was referred for exploration of a chronic symmetrical polyarthritis for 2 years involving the hands, elbows, forefeet, and knees and accompanied by prolonged morning stiffness. He had no history of lung disease but had worked in a ceramic plant for 20 years. He presented with arthritis of the wrists and knees with a rheumatoid nodule of the left elbow. Joint destruction was present in both hands and feet. Rheumatoid factor and anti-cyclic citrullinated peptide antibodies were highly positive (135 UI/L and 363 UI/L respectively). The patient was diagnosed as RA and the disease activity score (DAS-28) was up for 6.87. His breathing was normal, pulmonary auscultation and spirometry were normal. Chest X-rays revealed a multiple micro-nodules distributed throughout the lungs but predominantly in the upper and middle zones. Bronchoalveolar lavage showed a pauci-cellular liquid and chest CT scan showed bilateral, round, well-delimited small centri-lobular nodules which predominate the upper lobes. There was infra-centimetrical adenopathy with mediastinal calcification.ConclusionProlonged exposure to silica dust has a remarkable influence on the development of RA with a suggested intricacy in to its pathogenesis.