Primary Membranous Nephropathy with Concomitant IgA Nephropathy

Membranous nephropathy (MN), an autoimmune glomerulonephritis which can occur in primary and secondary forms, is one of the most common inflammatory glomerulopathies in elderly patients. The pathophysiology of the primary form is generally due to circulating immunoglobulin (IgG4) antibodies which often target phospholipase A2 receptors (anti-PLA2R) and Thrombospondin Type 1 Domain containing 7A (anti THSD7A). IgA nephropathy is one of the most common autoimmune glomerular diseases in the world and presents with a spectrum of disease ranging from asymptomatic mild hematuria and proteinuria to rapidly progressive crescentic glomerulonephritis. We present a rare case of concomitant IgA and primary MN in a single patient treated successfully with renin-angiotensin-aldosterone blockade, corticosteroids, and calcineurin inhibitors. The peak proteinuria was near 7.5-8 g protein/g creatinine by various measures. Serum creatinine remained normal, and anti-PLA2R was detectable and decreased with successful treatment. Clinicians should be aware of the possibility of two glomerular disorders in patients with glomerulonephritis and atypical presentations for any single disorder.