title: Vesicoureteral reflux and urinary tract infection in children with a history of prenatal hydronephrosis--should voiding cystourethrography be performed in cases of postnatally persistent grade II hydronephrosis?
abstract: OBJECTIVE
  The clinical relevance of prenatal hydronephrosis is not well-defined. We determined the risk of febrile urinary tract infection in the absence of screening for vesicoureteral reflux, and whether postnatal voiding cystourethrography should be performed in patients with a history of prenatal hydronephrosis and postnatally persistent Society for Fetal Urology grade II hydronephrosis.
  
  
  METHODS
  From a longitudinal database of patients with prenatal hydronephrosis maintained since 1998 we identified those with postnatally persistent grade II hydronephrosis. This cohort was divided into patients who were and were not screened with an initial voiding cystourethrogram. The rates of vesicoureteral reflux and development of febrile urinary tract infection were determined.
  
  
  RESULTS
  Of 2,076 patients with prenatal hydronephrosis 1,514 had grade II hydronephrosis. Of the patients 76% underwent an initial voiding cystourethrogram and vesicoureteral reflux was found in 28%. There was no relation between laterality of hydronephrosis and incidence of vesicoureteral reflux. There was no difference between nonscreened and screened patients with respect to gender and laterality of hydronephrosis. Urinary tract infection developed in 1.3% of the patients who were screened and did not have vesicoureteral reflux and, therefore, were not receiving antibiotics. Of the screened patients with vesicoureteral reflux who were receiving prophylactic antibiotics urinary tract infection developed in 1.6% at a mean age of 9.4 months. In 363 patients who did not undergo an initial voiding cystourethrogram we estimated (based on the screened population) that 101 would have vesicoureteral reflux and 5 would have a urinary tract infection. However, a febrile urinary tract infection developed in 16 patients (4.4% overall, p <0.0001) at a mean age of 9.3 months. Voiding cystourethrogram performed in these 16 patients revealed vesicoureteral reflux in 12. Of all the patients with a urinary tract infection who were ultimately observed to have vesicoureteral reflux (including those initially screened and those discovered to have reflux after a urinary tract infection) the laterality of hydronephrosis, grade of reflux and laterality of reflux were comparable.
  
  
  CONCLUSIONS
  In patients with a history of prenatal hydronephrosis who are observed to have postnatally persistent grade II hydronephrosis identification of vesicoureteral reflux and use of prophylactic antibiotics significantly reduce the risk of febrile urinary tract infection. Therefore, we recommend that patients with a history of prenatal hydronephrosis and postnatally persistent hydronephrosis be screened with voiding cystourethrography early in life, and be placed on prophylactic antibiotics until the screening results are known.
authors.affiliation: Department of Urology, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts 02115, USA. carlos.estrada@childrens.harvard.edu
authors.forename: Carlos R
authors.initials: CR
authors.lastname: Estrada
authors.forename: Craig A
authors.initials: CA
authors.lastname: Peters
authors.forename: Alan B
authors.initials: AB
authors.lastname: Retik
authors.forename: Hiep T
authors.initials: HT
authors.lastname: Nguyen
mesh_terms: D002908:Chronic Disease; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006869:Hydronephrosis / Q000000981:diagnostic imaging* / Q000453:epidemiology; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D015997:Neonatal Screening; D011247:Pregnancy; D011859:Radiography; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016216:Ultrasonography, Prenatal; D014521:Urethra / Q000000981:diagnostic imaging*; D001743:Urinary Bladder / Q000000981:diagnostic imaging*; D014552:Urinary Tract Infections / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000209:etiology; D014718:Vesico-Ureteral Reflux / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000209:etiology