S TAN 1,2, T POTEZNY 1, J LI 1,2
1Department of Renal Medicine, Adelaide, Australia, 2College of Medicine & Public Health, Flinders University, Adelaide, Australia
Background: IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis. Crescentic IgAN with concurrent circulating antineutrophil cytoplasmic antibody (ANCA) is rare but may have a better response to aggressive immunosuppressive treatment. We report a case of acute kidney injury (AKI) due to crescentic IgAN and concurrent positive myeloperoxidase (MPO)-ANCA.
Case Report: A 26-year-old man with no past medical history presented with macroscopic haematuria, sub-nephrotic proteinuria with urinary albumin/creatinine ratio (ACR) 80.9 mg/mmol and an AKI (serum creatinine 333 μmol/L). MPO-ANCA titre was 11 IU/mL (reference range ≤5). Renal biopsy showed crescentic IgAN (57% crescents and 21% necrotising lesions). Due to concerns of cyclophosphamide-induced gonadal toxicity, it was decided to trial three days of 500mg intravenous methylprednisolone and rituximab followed by an oral prednisolone taper. He received two doses of intravenous rituximab a fortnight apart but his renal function continued to decline (creatinine 613μmol/L, urea 41mmol/L) and a Tenckhoff catheter was inserted in preparation for dialysis. However, 5 weeks post-rituximab infusion his renal function was starting to improve and his MPO-ANCA had become negative. The Tenckhoff catheter was removed. At over 1 year following his initial presentation, he has remained steroid-free with a creatinine of 122μmol/L and urine ACR 102.7mg/mmol.
Conclusion:Rituximab can be an alternative treatment if cyclophosphamide is contraindicated in patients with crescentic IgAN with ANCA positivity. This case highlights an excellent renal response following rituximab as part of aggressive immunosuppressive treatment in a patient with crescentic IgAN and concurrent positive MPO-ANCA.
Sarah is a final year nephrology advanced trainee currently based in Adelaide.