Nutcracker syndrome with urolithiasis.

The nutcracker syndrome, caused by compression of the left renal vein between the superior mesenteric artery and the aorta, usually manifests with hematuria, flank pain and proteinuria. We report on a 9-year-old boy who was previously diagnosed with urolithiasis but had significant proteinuria, not explained by this diagnosis. On further investigation by renal Doppler ultrasonography it was found that he had nutcracker syndrome. We would like to emphasize that this syndrome should be considered where there is no obvious cause of proteinuria and hematuria.