1 - Paediatric Nephrology Unit, Department of Paediatrics, CHULC, Lisbon, Portugal
- 54th ESPN Annual Meeting, Ljubljana, Slovenia, 22-25/06/2022, e-poster
Introduction: Membranous Nephropathy (MN) is a morphological pattern characterized by thickening of the glomerular basement membrane. Although it is one of the most frequent causes of nephrotic syndrome in adults, it accounts for < 5% of cases among children.
Material and methods: Case 1: A 16-year-old girl treated with penicillamine for Wilson’s disease presented with nephrotic syndrome. Penicillamine was withhold. Maintenance therapy with zinc acetate was initiated and, transiently, enalapril and furosemide were added. Due to worsening oedema, prednisolone was started. Kidney histopathology was consistent with membranous nephropathy type I. Serum anti-PLA2R and tissue staining for PLA2R were both negative. Nephrotic syndrome remitted in one month, and the proteinuria resolved in six months. Case 2: A 16-year-old girl with inflammatory bowel disease, pyoderma gangrenosum and a previous history of nephritic-nephrotic syndrome presented with worsening systemic inflammation and increasing proteinuria. Amyloidosis was excluded. The kidney histopathology revealed membranous nephropathy type I. Serum anti-PLA2R antibodies and tissue staining for PLA2R were negative. Systemic inflammation was controlled under infliximab with progressive proteinuria resolution. Case 3: A 15-year-old previously healthy girl presented with nephrotic proteinuria without hypoalbuminemia. The immunological and infectious studies were unremarkable. Kidney histopathology showed membranous type II with parietal granular deposits of IgG (mostly IgG1 +++ and IgG3 +/-), IgM (++), C1q (++) and IgA (+/-). Serum anti-PLA2R and tissue staining for PLA2R were negative.
Results: MN in paediatric patients is often secondary to drug exposure or systemic illness, as seen in cases 1 and 2, respectively. In case 3, despite the absence of circulating anti-PLA2R antibodies and negative tissue staining for PLA2R, the immunohistochemical findings suggest secondary MN. However, no other criteria of systemic illness have been found.
Conclusions: These three cases illustrate that proteinuria is the clinical hallmark of MN and demonstrate the diversity of the underlying aetiology of this histological pattern, whose identification is paramount to guide treatment
Keywords: membranous nephropathy, nephrotic syndrome