OBJECTIVETo investigate the proportion of children with congenital abnormalities of the kidney and urinary tract (CAKUT) among those who received screening, analyze the rate, diagnosis and treatment of each abnormality, and evaluate the value of ultrasonography in the CAKUT diagnosis.

METHODTotally 489 of 26 989 children who received screening for urinary tract abnormalities were found to have CAKUT and were followed up by telephone interviews and were asked whether they had defined diagnosis of CAKUT, had clinical symptoms and received treatment. Children who had been operated on were also asked about the operation time, surgical procedure, postoperative diagnosis, and outcome. Children who had never been reviewed or still had no diagnosis were arranged to Beijing Children's Hospital for ultrasound follow-up. The final data were summed up for a retrospective analysis.

RESULT1) The proportion of children with CAKUT was 1.67%. Most children with CAKUT had no clinical manifestations. 2) Of the 489 cases, 320 were followed up, and 169 were lost. Of the cases who were followed up, 16 out of 295 cases who had clear diagnosis showed inconsistent results in ultrasound screening. 3) Hydronephrosis was identified in 137 cases (0.78%), among whom 111 were males and 26 were females, in 98 cases the hydronephrosis was on the left, in 28 on the right and in 11 were bilateral. Ureterovesical junction obstruction occurred in 33 cases (0.19%), 25 males and 8 females, in 22 cases on the left, in 10 on right and bilateral in 1 case. Renal dysplasia was shown in 30 cases (0.17%), 22 males and 8 females; renal cysts in 26 cases (0.15%); duplex kidney in 24 cases (0.14%); solitary kidney in 22 cases (0.12%); ureterocele in 16 cases (0.09%); fused kidney in 10 cases (0.06%); renal hypoplasia in 9 cases (0.05%); ectopic kidney in 5 cases (0.03%); polycystic kidney in 3 cases (0.02%). Primary vesicoureteral reflux, posterior urethral valves, renal malrotation, branch renal pelvis, extrarenal pelvis in 1 case each. 4) Totally 114 of the 295 cases (38.6%) who were followed up for CAKUT in screening test required surgical treatment. Only one case of ureteropelvic junction obstruction (UPJO) failed in surgery.

CONCLUSIONThe proportion of children with CAKUT was high. CAKUT is difficult to detect since there is no significant clinical manifestations in early ages. More than one third of patients with CAKUT needed surgical treatment. Ultrasonography showed obvious advantages in detecting children's CAKUT, proven to be the most preferred method of screening, thus could be recommended as a routine of children's physical examination.