The Magnitude of Fetal Renal Pelvic Dilatation can Identify Obstructive Postnatal Hydronephrosis, and Direct Postnatal Evaluation and Management

Division of Urology, and Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
The Journal of Urology (Impact Factor: 4.47). 09/2006; 176(2):724-7; discussion 727. DOI: 10.1016/j.juro.2006.03.079
Source: PubMed


Up to 1% of prenatal ultrasounds will detect fetal renal pelvic dilatation. We sought to evaluate and determine whether fetal renal pelvic measurements may appropriately direct prenatal counseling and postnatal evaluation and management.
We performed a retrospective analysis of prospectively collected measurements of anteroposterior renal pelvic dilatation obtained at a single fetal maternal medicine center between 1990 and 2003. Fetuses with renal pelvic dilatation 4 mm or greater at less than 33 weeks of gestation, or 7 mm or greater at more than 33 weeks of gestation were evaluated postnatally at a single pediatric urology center. Infants with renal pelvic dilatation were evaluated with ultrasound, voiding cystourethrograms and renal scintigraphy. Renal obstruction was the main outcome measure assessed. Obstruction was defined as the need for surgery and was not based on the renal scan drainage time. Indications for surgery included declining function and increasing hydronephrosis.
There were 257 neonates with prenatally detected renal pelvic dilatation. A mean maximum prenatal renal pelvic dilatation of 11.8 mm was seen in 195 patients with nonobstructive dilatation. In the 62 patients with obstruction there was a nearly 2-fold increase in the mean renal pelvic dilatation (22.3 mm), which was statistically significant. Receiver operating characteristic analysis revealed that when 15 mm renal pelvic dilatation is used as a threshold it correctly discriminates obstruction in at least 80% of fetuses with a sensitivity of 73% and a specificity of 82%.
The magnitude of fetal renal pelvic dilatation is predictive of obstruction. Our results suggest that 15 mm renal pelvic dilatation represents a significant threshold. Receiver operating characteristic analysis provides a useful guide for prenatal counseling and may help to direct the postnatal evaluation.

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    • "More specifically, the risk of ureteropelvic junction obstruction (UPJO) increased significantly with greater degrees of PNH [9], but the risk of vesicoureteral reflux (VUR) was not significantly different among all severity groups. Most studies also have shown that a single postnatal US is unable to predict the presence or severity of VUR [6] [10] [11]. Consequently, postnatal management is heterogeneous, with some centers advocating detailed investigations including voiding cystourethrography (VCUG) in all cases and others indicating a less intensive approach [12] [13] [14] [15] [16]. "
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    ABSTRACT: Fetal hydronephrosis is the most common anomaly detected on antenatal ultrasound, affecting 1-5% of pregnancies. Postnatal investigation has the major aim in detecting infants with severe urinary tract obstruction and clinically significant urinary tract anomalies among the heterogeneous universe of patients. Congenital uropathies are frequent causes of pediatric chronic kidney disease (CKD). Imaging techniques clearly contribute to this purpose; however, sometimes, these exams are invasive, very expensive, and not sufficient to precisely define the best approach as well as the prognosis. Recently, biomarkers have become a focus of clinical research as potentially useful diagnostic tools in pediatric urological diseases. In this regard, recent studies suggest a role for cytokines and chemokines in the pathophysiology of CAKUT and for the progression to CKD. Some authors proposed that the evaluation of these inflammatory mediators might help the management of postnatal uropathies and the detection of patients with high risk to developed chronic kidney disease. Therefore, the aim of this paper is to revise general aspects of cytokines and the link between cytokines, CAKUT, and CKD by including experimental and clinical evidence.
    Full-text · Article · Aug 2013 · Clinical and Developmental Immunology
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    • "In spite of such advances, however, the issue of antenatal hydronephrosis remains a common and challenging problem, with postnatal influences [2] [3]. There have been a number of studies assessing the accuracy of fetal renal pelvic dilatation (RPD) as an indicator of urinary tract anomalies [4] [5] [6] [7] [8]. The single most widely used parameter is the anteroposterior diameter (APD) of the renal pelvis, a simple parameter whose application is now widespread in prenatal diagnostics [9]. "
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    ABSTRACT: Purpose. It was to quantify the intraobserver and interobserver variability of the sonographic measurements of renal pelvis and classify hydronephrosis severity. Methods. Two ultrasonographers evaluated 17 fetuses from 23 to 39 weeks of gestation. Renal pelvis APD were taken in 50 renal units. For intraobserver error, one of them performed three sequential measurements. The mean and standard deviation from the absolute and percentage differences between measurements were calculated. Bland-Altman plots were used to visually assess the relationship between the precision of repeated measurements. Hydronephrosis was classified as mild (5.0 to 9.9 mm), moderate (10.0 to 14.9 mm), or severe (≥15.0 mm). Interrater agreement were obtained using the Kappa index. Results. Absolute intraobserver variation in APD measurements was 5.2 ± 3.5%. Interobserver variation of ultrasonographers was 9.3 ± 9.7%. Neither intraobserver or interobserver error increased with increasing APD size. The overall percentage of agreement with the antenatal hydronephrosis diagnosis was 64%. Cohen's Kappa to hydronephrosis severity was 0.51 (95% CI, 0.33 to 0.69). Conclusion. Inter and intraobserver APD measurement errors were low in these group, but the agreement to hydronephrosis diagnosis and classification was fair. We suggest that standard and serial APD measurement can better define and evaluate fetal hydronephrosis.
    Full-text · Article · May 2011 · Obstetrics and Gynecology International
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    • "To date there is no consensus on the optimal APD threshold for determining the need for postnatal follow up. Coplen et al. [16]. suggests that a cut-off of 15 mm is ideal for determining obstruction, yielding a sensitivity of 73% and specificity of 82%. "
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    ABSTRACT: The evaluation and management of fetuses/children with antenatal hydronephrosis (ANH) poses a significant dilemma for the practitioner. Which patients require evaluation, intervention or observation? Though the literature is quite extensive, it is plagued with bias and conflicting data, creating much confusion as to the optimal care of patients with ANH. In this article, we summarized the literature and proposed recommendations for the evaluation and management of ANH. © 2010 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.
    Full-text · Article · Jun 2010 · Journal of pediatric urology
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