Diagnosis: IgA Nephropathy
• IgA nephropathy is the most common glomerular disease worldwide and is particularly common in Asian patients.
• IgA nephropathy typically manifests with microscopic hematuria, low-grade proteinuria, and normal renal function. Transient gross hematuria may occur simultaneously with an upper respiratory tract infection (“synpharyngitic gross hematuria”). Serum antinuclear antibody (ANA) and complement levels are normal.
• End-stage renal disease occurs in approximately 30% of patients with IgA nephropathy.
• Most cases of IgA nephropathy are idiopathic in origin (i.e., primary). The pathogenesis is thought to involve defective galactosylation of IgA molecules, making the IgA molecules prone to deposition in the mesangium where they trigger inflammatory and fibrogenic pathways.
• Secondary causes of IgA nephropathy include chronic liver disease (in which there is decreased hepatic clearance of IgA), chronic inflammatory gastrointestinal and skin diseases (which are associated with increased mucosal IgA secretion), and HIV infection.