Antineutrophil cytoplasmic antibody-negative pauci-immune crescentic glomerulonephritis associated with rheumatoid arthritis: An unusual case report.

Clinically relevant renal lesions in rheumatoid arthritis (RA) are not common. More often renal involvement is related to complications of therapy than the disease itself. The most common forms of primary renal disease in RA are membranous glomerulonephropathy and a pure mesangial proliferative glomerulonephritis. Some studies have described the association between crescentic glomerulonephritis (crescentic GN) and RA, but they were all found to be perinuclear antineutrophil cytoplasmic antibody (p-ANCA) positive. However, RA associated with ANCA negative pauci-immue crescentic GN has not been reported. This is a case report of a 37-year-old female with RA who initially presented with general oedema and acute deterioration of renal function. The renal biopsy revealed ANCA negative pauci-immune crescentic GN. The patient was treated with steroid pulse and plasmapheresis, but not cyclophosphamide because of severe urosepsis. Despite the use of aggressive therapy, her renal function was not improved and she underwent maintenance haemodialysis thereafter. Because ANCA negative crescentic GN may occur in RA patients without frank systemic vasculitis, but with severe clinical manifestation, a heightened suspicion for a relatively 'silent' crescentic GN would have led to the correct diagnosis and appropriate treatment.