Idiopathic Membranous Glomerulonephritis in Patients with Type 2 Diabetes Mellitus

The occurrence of membranous glomerulonephritis (MGN) in patients with type 2 diabetes mellitus (DM) is a rare event and of pathogenetic interest. We report two males (52 and 64 years old) with type 2 DM and nephrotic syndrome of recent onset. Renal biopsy was performed because of the unusual clinical pictures: microscopic hematuria; heavy proteinuria without evidence of diabetic retinopathy; and, in one case, a sudden onset of renal failure. Renal biopsy disclosed pure MGN without glomerulosclerosis. In both cases, clinical history, physical examination and biologic assessment failed to reveal the cause; MGN was thus considered idiopathic. Treatment, including glycemic control and angiotensin-II receptor blockers, led to resolution of proteinuria in one case. We suggest that renal biopsies should be performed in diabetic patients with a sudden onset of renal failure, proteinuria without retinopathy, or other evidence of microvascular disease.