Double-positive Anti-glomerular Basement Membrane Disease in a Child with Crescentic Glomerulonephritis: A Case Report and Review of Literature

‘Double-positive’ with anti-glomerular basement membrane (anti-GBM) antibody and anti-neutrophil cytoplasmic antibody (ANCA) is an extremely rare cause of small vessel vasculitis in children. Studies have reported a distinct hybrid phenotype in double-positive patients which requires an aggressive treatment approach. The data on double positive children are scarce with few case reports available with varied outcomes. A case of 9-year-old girl from India who had double-positive anti-GBM disease is reported here. The patient presented with complaints of edema, oliguria, gross hematuria with rising creatine and was diagnosed as rapidly progressive glomerulonephritis (RPGN). Histological examinations of linear immunoglobulin G deposits along with glomerular capillaries were suggestive of anti-GBM disease. The anti-GBM and p-ANCA antibody titers were also high, and the aforementioned findings led to a diagnosis of ‘double-positive’ anti-GBM with RPGN. She was treated with standard plasma exchange therapy along with pulse methyl prednisolone (3 doses of 30 mg/kg/day on Days 1 to 3), oral prednisolone (1.5 mg/kg on Day 4), single intravenous injection of cyclophosphamide (500 mg/m2 on Day 5) and mycophenolate mofetil (MMF; 1000 mg/m2 on Day 6) followed by maintenance treatment with oral prednisolone (1 mg/kg/day) and MMF (800 mg/m2/day) from Day 7 onwards. Overall, the anti-GBM and p-ANCA levels declined throughout the treatment period but the patient progressed towards end stage renal disease.