IgA-Dominant Postinfectious Crescentic Glomerulonephritis after a Cervical Smear

Introduction: IgA-dominant infection-associated glomerulonephritis(IRGN) usually presents diffuse endocapillary and/or mesangial proliferation with a few crescents. Here we report a rare case of IgA-dominant IRGN with diffuse necrotizing cellular crescents, which benefited from corticosteroid and cyclophosphamide treatment. Case Description: A 29-year-old woman developed rapidly progressive edema and anuria with fever and persistent vaginal discharge of pus after a cervical smear for health checkup. Laboratory analyses revealed serum creatinine of 723μmol/l, serum albumin of 17.4g/l, C-reactive protein of 172mg/l, hypocomplementemia and prominent proteinuria and hematuria. Anti-GBM and ANCA were negative. Enterococcus faecium were isolated from culture of vaginal discharge. Kidney biopsy (Figure 1) showed starry sky patten of IgA and C3 deposition along GBM by immunofluorescence. Light microscope showed 90% of glomeruli with necrotizing cellular crescents, endocapillary infiltration and Bowman's capsule rupture. Electronic microscope showed major subepithelial and subendothelial electron-dense deposits with mild mesangial deposits. Therefore, IgA-dominant IRGN was diagnosed. Pulse therapy of methylprednisolone and intravenous cyclophosphamide (CTX) were given after infection controlled. Her urine output began to increase after 3 days and reached dialysis independence after two weeks. She was treated with i.v. CTX 0.4g every 2 weeks with tapering oral methylprednisolone, and maintained stable renal function for ten months(Figure 2). Discussion: IgA-dominant IRGN can mimic ANCA glomerulonephritis with diffuse necrotizing lesions and crescents. Prompt immunosuppression besides infection control is crucial for kidney function restoration and preservation.Histopathologic findings of kidney biopsyClinical course after presentation