Abstract
Renal ultrasonography and screening with a urine dipstick test for leucocytes and nitrite in 3-year-old children have been performed in Chiba City since 1991. We studied the efficacy of this screening for detecting congenital anomalies of the kidney and urinary tract (CAKUT). Screening with a urine dipstick test for leucocytes, nitrite, proteinuria, hematuria, and glucosuria was performed among 154,456 3-year-olds from April 1991 to March 2012 in Chiba City. In the second screening, a urine dipstick test and urinary sediments were detected, and renal ultrasonography was performed among 11,346 children. Children with a positive second screening for urine or renal abnormalities on ultrasonography were referred to hospital. Ultrasound findings included a renal pelvis anteroposterior diameter greater than 5–7 mm, a renal length less than 60 mm, and a difference in bilateral renal length of more than 1 cm. A total of 11,905 children (7.7%) at the first screening had positive urinary findings. Positive urinary findings were detected in 2,347 children (1.5%) referred to hospital. We observed vesicoureteral reflux (VUR) in 16 cases (5 with hematuria, and 11 with significant bacteriuria), Alport syndrome in 6, nephrotic syndrome in 5, focal segmental glomerulosclerosis in 5, chronic glomerulonephritis in 7, and bilateral renal hypoplasia in 1. Positive ultrasound findings were detected in 714 children (6.3%) at the second screening. CAKUT were detected in 92 children (0.8%); 17 of these cases were surgically corrected. Among 27 children with VUR, 3 had only positive urinary findings (1 hematuria and 2 bacteriuria), 13 had positive urinary (4 hematuria and 9 bacteriuria) and ultrasound findings, and 11 had only positive ultrasound findings. Reflux greater than grade III was detected in children with bacteriuria more than in children without bacteriuria (p<0.05). Ultrasound findings associated with renal size were useful for detecting multiple renal scars associated with high-grade VUR. Overall, 1 case with FSGS progressed to end-stage renal failure at 5 years after the first screening. A positive urine dipstick test for leucocytes and/or nitrite and ultrasound findings associated with renal size appear to be useful for detection of CAKUT.
