ANCA vasculitis and IgA nephropathy linked to silica exposure

Abstract

There is a recognized association between silica exposure and Antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV); however, no clear association between silica exposure and Immunoglobulin A (IgA) nephropathy. We describe the case of a 26-year-old male stonemason who presents with hilar lymphadenopathy, haematuria and acute kidney injury related to silica exposure, AAV and IgA nephropathy. He was asymptomatic on presentation; urinalysis revealed glomerular haematuria (>1000 red blood cells/L) and proteinuria (protein-to-creatinine ratio 84 mg/mmol). ANCA anti-myeloperoxidase serology was strongly positive. Mediastinal lymph node biopsy revealed multiple necrotizing granulomas with silica inclusions, and renal biopsy demonstrated crescentic glomerulonephritis and mesangial IgA staining. The patient was treated with cyclophosphamide and high-dose prednisolone with subsequent improvement in renal function. To our knowledge, this is the first report of both ANCA vasculitis and IgA nephropathy in the setting of silica exposure. This case highlights the relevance of occupational exposures in renal disease, and the immune-stimulatory effect of silica.