Nutcracker syndrome associated with severe anemia and mild proteinuria.

A 70-year-old man was referred to our hospital with the chief complaint of gross hematuria. Urinalysis revealed gross hematuria (3+, RBC 100/HPF or more) and mild proteinuria (3+, 1.8 g/day) with no urinary casts. Computed tomography of the abdomen showed compression of the left renal vein between the superior mesenteric artery and the aorta. Ultrasonography showed an increased flow velocity at the stenotic portion of the left renal vein. An aortography and selective left renal arteriography showed that there was no evidence of tumor vessels or arterial abnormalities in the arterial phase. However, the venous phase revealed a stenosis of the left renal vein just lateral to the aorta as well as a reflux of contrast material toward the left gonadal vein which was dilated. In addition, cystoscopy revealed left ureteral bleeding. Based on these findings, we made the diagnosis of gross hematuria caused by nutcracker syndrome (NCS). We concluded that the main cause of the anemia and proteinuria in our patient was leakage of blood and this is confirmed by the relationship of red blood cells to protein in the urine because we proved whole blood and plasma protein loss in the urine by calculation. Fourteen months after discharge, both the gross hematuria and proteinuria spontaneously disappeared. This case strongly suggested that the first therapy for hematuria and proteinuria with NCS should be observation.