Active and chronic phases of Berger's disease (IgA nephropathy).

Berger's disease, or IgA nephropathy, is generally considered as pursuing a chronic course, often with recurrent attacks of gross hematuria or persistent microscopic hematuria. However, little attention has been paid to the acute changes that may accompany this nephropathy, and there are few reports of follow-up renal biopsy studies in these patients. We have had the opportunity to study two patients with Berger's disease (IgA nephropathy) in whom initial and follow-up renal biopsy studies were available. Both of these patients presented clinically with gross hematuria and moderately heavy proteinuria. In both cases, the initial renal biopsy disclosed diffuse mesangial proliferation associated with crescent formation, while follow-up biopsy disclosed only mild mesangial proliferation and no crescents. In one case electron microscopy revealed prominent subendothelial and small mesangial deposits in the initial biopsy, which became almost solely large mesangial in the second biopsy. The other case demonstrated only mesangial deposits in both biopsies.