Flow Velocity of Left Renal Vein in Children with Asymptomatic Hematuria or Proteinuria

ABSTRACT

PURPOSE: Nutcracker syndrome must be considered when hematuria or proteinuria occurs in a healthy child. The purpose of this study is to investigate the prevalence of nutcracker syndrome among children with asymptomatic hematuria or proteinuria, and to obtain the ratios of the peak velocity of the left renal vein between the aortomesenteric portion and the hilar portion in children with asymptomatic hematuria or proteinuria in which nutcracker syndrome was excluded and to observe whether the ratios are affected by sex, age or urinalysis findings. METHODS: Using Doppler ultrasonography, we measured the flow velocity and obtained the peak velocity ratios of the left renal vein at the aortomesenteric portion and at the hilar portion of the left kidney in children with asymptomatic hematuria or proteinuria who visited the Division of Pediatric Nephrology, Severance Hospital from May 2001 to March 2004. RESULTS: Of 304 children with asymptomatic hematuria or proteinuria, 107 children(35.2%) were diagnosed with nutcracker syndrome. For 197 children with asymptomatic hematuria or proteinuria excluding nutcracker syndrome, the mean ratio of the peak velocity was 2.54+/-0.73, which was not affected by sex, age or urinalysis findings. CONCLUSION: Nutcracker syndrome was the major cause of asymptomatic hematuria or proteinuria in children, comprising 35% of all cases. Doppler ultrasonography was helpful in the screening of nutcracker syndrome and prevention of its complications. For children with asymptomatic hematuria or proteinuria excluding nutcracker syndrome, the peak velocity ratio of the left renal vein did not differ from that of normal children and was not affected by sex, age or urinalysis findings.