The risk of urinary tract infection, necessisty of prophylaxis and natural outcome of hydronephrosis in newborns with prenatal hydronephrosis

Ureteropelvic junction obstruction (UPJO) constitutes 44-65% of prenatal hydronephrosis patients. In patients with prenatal hydronephrosis secondary to UPJO, risk of urinary tract infection (UTI) is obscure; there is no study for evidence of antibacterial prophylaxis in these patients. In this study, the aim is to investigate the difference in the risk of having UTI according to degree of hydronephrosis, which babies should undergo prophylaxis. We also aimed to investigate the progress of prenatal hydronephrotic patients secondary to UPJO in the first year of life; the frequency and the way of progression or regression of hydronephrosis. 84 patients wiht UPJO (56 is male, 28 is female, 100 renal units) whom renal pelvic diameter is greater than 10 mm after 30th weeks of gestation and who had applied to the hospital before postnatal 28th day and who had no history of UTI have been followed prospectively for 12-24 months (mean 18,7 months) without antibacterial prophylaxis. Imaging studies were done according to the algorithm protocol of our Pediatric Nephrology department. Patients were called for follow-up at first week, first month and third month, then every three months. At follow-ups, urine analysis and if indicated, urine culture were done. Care givers of the patients were informed about signs of UTI and preventive measures. Patients' sonographic findings were evaluated according to "Society for Fetal Urology" (SFU). There was grade I in 23 (27%), grade II in 23 (27%), grade III in 20 (24%) and grade IV hydronephrosis in 18 (22%) of patients. UPJO was found in 68 (80%) patients unilaterally among whom 46 (67%) patients had lesion on left side. 16 of 84 patients (19%) had bilateral UPJO.Among kidneys with grade I-II-III hydronephrosis, there was complete remission in 44.4% (36/81), partial remission in 22.2% (18/81), no change in 32% (26/81). A patient with SFU grade III hydronephrosis had progressed to grade IV. The highest frequency of remission was observed in patients with grade I hydronephrosis (70%). Rates of complete remission in patients with grade II and III hydronephrosis were 46% and 12% respectively. Rates of partial remission in patients with grade II and III hydronephrosis were 16.6% and 54% respectively. Among grade IV hydronephrotic kidneys, there was complete remission in one, partial remission in 31.5% (6/19), no change in 26.3% (5/19). 36.8% (7/19) affected kidneys underwent pyeloplasty. Our patients were followed for 18.7 months in average and none had UTI. DMSA scintigraphy was performed and no pyelonephritic scar was found in any of them. It was concluded that whether the hydronephrosis is bilateral, high in degree or not, regular follow-up and good care of baby is enough in preventing infections and there is no necessity for antibacterial prophylaxis for babies with prenatal UPJO. It is concluded that, in a significant portion of babies with prenatal hydronephrosis, hydronephrosis does not disappear. Even if it has a benign progression, it is essential to follow such patients later on.