Glomerular haematuria, renal interstitial haemorrhage and acute kidney injury.

Macroscopic haematuria of glomerular origin has been associated with acute kidney injury. We report a patient with IgA nephropathy, macroscopic haematuria and acute kidney injury. Systemic anticoagulation may have aggravated haematuria. There was extensive interstitial and intratubular red blood cell extravasation, and interstitial haemosiderin deposits. The abundant presence of macrophages expressing the haemoglobin scavenger receptor CD163 and of cells stained for oxidative stress markers (NADPH-p22 phox and heme-oxigenase-1) in areas of interstitial haemorrhage and red blood cell cast-containing tubules provided evidence for a role for free haemoglobin in tubulointerstitial renal injury in human glomerular disease.