Membranous nephropathy in a patient with coronavirus disease 2019 (COVID-19): A case report

Abstract

Introduction: Though respiratory, immune, and coagulation systems are major targets of coronavirus disease 2019 (COVID-19), kidney dysfunction, presenting with acute kidney injury (AKI), is also common. Most AKI cases in COVID-19 manifest as acute tubular injury (ATI) in conjunction with multiorgan failure. While initial renal pathological findings were limited to acute tubular necrosis and collapsing glomerulopathy, a recent case series reported a larger spectrum of findings.

Case report: Here, we report a case of membranous nephropathy (MN) in an 81-year-old Hispanic man with underlying chronic kidney disease (CKD) stage 3 who developed ATI in the setting of COVID-19. The patient was hospitalized for hypoxic respiratory failure in the setting of AKI stage 3 with serum creatinine 7.1 mg/dL 6 days after a positive-SARS-CoV-2 screening. He was found to have nephrotic range proteinuria, glycosuria (with normal serum glucose), anemia, and hypoalbuminemia. Kidney biopsy showed ATI and early MN. Workup for primary and secondary MN was unrevealing, and serum PLA2R antibody was negative. No viral particles were observed in podocytes.

Conclusion: Although the MN could be incidental, this observation raises the question of whether SARS-CoV-2 infection can trigger or worsen an underlying MN from an exaggerated immune response associated with COVID-19.

Keywords: SRAS-CoV-2; acute kidney injury (AKI); coronavirus disease 2019 (COVID-19); membranous nephropathy (MN); renal pathology.

Figure 1.. Renal pathologic findings in this COVID-19 patient. A: Glomerulus showing thickening of the glomerular basement membrane with mild mesangial sclerosis and hypercellularity (silver stain, × 400). B: Glomerular capillary loop showing abundant small sub-epithelial electron-dense deposits. The overlying podocytes show extensive foot process effacement (electron microscopy, × 11,000). C: Large glomerular endothelial tubuloreticular inclusion is shown. Tiny sub-epithelial electron-dense deposits are also evident (electron microscopy, × 30,000).