Comparison of prominent glomerular injury and prominent tubular injury in immunoglobulin A nephropathy

Objectives The goal of this study was to define the differences between prominent glomerular injury and prominent tubular injury in immunoglobulin (Ig) A nephropathy patients presenting with acute renal failure. Methods In our experience of 236 patients with biopsy-proven IgA nephropathy from 2000 to 2009 at a medical center in Taiwan, 20 cases of acute renal failure were identified. The patients' records were retrospectively reviewed with respect to clinical presentation, morphology of renal biopsy, and outcomes. Results We subdivided the 20 patients into two groups: group 1 included 9 patients with prominent glomerular injury (>= 30% of glomeruli affected by crescents) and group 2 included 11 patients with prominent tubular injury (tubules filled with red blood cell casts/acute tubular necrosis/or acute interstitial nephritis). Regarding clinical parameters, the glomerular injury group had a greater urinary protein excretion (P = 0.014), a higher level of peak serum creatinine (P = 0.025), and more frequently had requirement for dialysis support (P = 0.022). Concerning histological parameters, the glomerular injury group had a higher degree of mesangial hypercellularity (P = 0.009). Regarding renal outcome, the tubular injury group had a higher remission rate than the glomerular injury group (P = 0.022). Conclusions Histological characteristics showed two distinct mechanisms of acute kidney injury associated with IgA nephropathy, including prominent glomerular injury and prominent tubular injury. The clinical presentation and prognosis largely depended on the histological presentation.