Renal involvement in a silicosis patient - case report and literature review

A 43-year-old Chinese man with a silicosis history was admitted to our hospital due to bilateral lower extremity edema for 1 year, exacerbating with hematuria for 2 months. He started working as a coal miner 30 years ago, and was diagnosed as silicosis 3 months ago. Lab tests revealed hematuria 3+, proteinuria 3+, and a serum creatinine value 2.47 mg/dl on routine check. He was diagnosed with focal proliferative IgA nephropathy (IgAN) and acute tubulo-interstitial nephritis by renal biopsy. He was treated with corticosteroids and got a remission 4 months later. Immunohistochemical staining showed the deposition of macrophage receptor with collagenous structure (MARCO), nod-like receptor pyrin domain-containing-3 (NLRP3), Caspase-1, apoptosis-associated speck (ASC), interleukin (IL)-1β, and IL-18 in both glomerular and tubulo-interstitial areas. We proposed that the silicon exposure could be related to his kidney disease in the patient and NLRP3 mediated inflammation might be involved in its pathogenesis which needs further explorations.