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Society of Fetal Urology (SFU) Recommendations for Postnatal Evaluation of Antenatal Hydronephrosis: Will Fewer Voiding Cystourethrogram's Lead to More Urinary Tract Infections?

Sunday, October 21, 2012: 12:51 PM
Grand Ballroom B (Hilton Riverside)
Melissa A. St.Aubin, Medical, Student1, Katie H. Willihnganz-Lawson, MD2, Briony K. Varda, MD2, Matthew Fine, M.D.3, Jane M. Lewis, MD4, Tracy Prosen, MD5 and Aseem Shukla, M.D.2, (1)Pediatric Urology, University of Minnesota Amplatz Children's Hospital, St. Paul, MN, (2)Pediatric Urology, University of Minnesota Amplatz Children's Hospital, Minneapolis, MN, (3)Department of Urologic Surgery, UNIVERSITY OF MINNESOTA AMPLATZ CHILDREN'S HOSPITAL, Minneapolis, MN, (4)Pediatric Urology, University of Minnesota Amplatz Chidren's Hospital, Minneapolis, MN, (5)Maternal Fetal Medicine, University of Minnesota Amplatz Children's Hospital

Purpose

There is no consensus on the extent and mode of postnatal imaging after a diagnosis of antenatal hydronephrosis (ANH). The need for antibiotic prophylaxis and incidence of urinary tract infections (UTI) is also unclear. The purpose of this study was to validate our practice paralleling the current SFU recommendations in limited use of VCUG’s during the postnatal workup of ANH, and to examine a single institutional experience with the rate of urinary tract infections in those evaluated infants. 

Methods

A consecutive cohort of infants with a history of ANH was evaluated in accordance with SFU recommendations guidelines, and outcomes were retrospectively reviewed.  Third trimester antenatal ultrasonography (US) was used to evaluate SFU grade, laterality, and anteroposterior diameter (APd) of the renal pelvis.  Postnatally, all patients underwent ultrasonography by 4 weeks of age, and only those with bilateral moderate to severe ANH (SFU grade II-IV), or unilateral high grade hydronephrosis (SFU grade III-IV) underwent VCUG.  Prophylactic antibiotics were administered until follow-up imaging at one month, and then continued if VUR was present. The incidence of UTI was also examined across SFU grades, APd, and in the presence or absence of vesicoureteral reflux (VUR).  We used Cox proportional hazard model and Chi square analysis to evaluate predictors for resolution and surgical intervention.

Results

A total of 117 consecutive infants were evaluated for ANH, and results retrospectively reviewed.  Thirty infants with multicystic dysplastic kidney, posterior urethral values, ureteroceles, and primary obstructive megaureter were eliminated, so 87 infants (148 renal units) with ANH were included in the final analysis with a median follow-up of 33.5 months (range 18-64). The median time to physiologic resolution of ANH was 8 months (Range: 0.25-38 months), while the median time to progression to surgery for 20 infants (16.2%) requiring correction of ureteropelvic junction obstruction was 4.5 months (Range: 0.25 - 18 months). Postnatal VCUG was obtained in 42 infants, of which 7 patients and 12 renal units (16.7% of those tested) had VUR.  There was no relationship between ANH SFU grade, APd, laterality, or gender and VUR.   Six infants (0.08%) developed a febrile UTI over the follow-up interval.  No UTI’s occurred in an infant with VUR, and UTI’s occurred immediately after a VCUG in 3 infants. 

Conclusion

Adherence to SFU recommendations in evaluating infants with ANH led to VCUG’s being avoided in about one-half of evaluated infants.  Fewer VCUG’s, and the subsequent diminished cohort with diagnosed VUR was associated with a minimal incidence of UTI’s, and catheterization at time of VCUG was proximately associated with UTI’s in 50% of the cases.  Diagnostic modalities that eliminate the need for catheterization are needed, and use of VCUG’s may be actively curtailed in contemporary evaluation of ANH.