Renal Ultrasonography in Newborns With Prenatally Detected Hydronephrosis: Why Wait?

Symptomatology and Clinic of Hydronephrosis Associated With Uretero Pelvic Junction Anomalies

The most common cause of hydronephrosis in the pediatric age group is ureteropelvic junction-type hydronephrosis (UPJHN). Since the advent of widespread maternal ultrasound screening, clinical presentation of hydronephrosis associated with UPJ anomalies has changed dramatically. Today most cases are diagnosed in the prenatal period, and neonates present without signs or symptoms. For those who are not detected at birth, UPJHN eventually presents throughout childhood and even adulthood with various symptoms. Clinical picture of UPJHN highly depends on the presence and severity of obstruction, and whether it affects single or both kidneys. Abdominal or flank pain, abdominal mass, hematuria, kidney stones, urinary tract infections (UTI), and gastrointestinal discomfort are the main symptoms of UPJHN in childhood. Other less common findings in such patients are growth retardation, anemia, and hypertension. UTI is a relatively rare condition in UPJHN cases, but it may occur as pyelonephritis. Vesicoureteric reflux should be kept in mind as a concomitant pathology in pediatric UPJHN that develop febrile UTI. Although many UPJHN cases are known to improve over time, close clinical observation is critical in order to avoid irreversible kidney damage. The most appropriate approach is to follow-up the patients considering the presence of symptoms, the severity of hydronephrosis and the decrease in kidney function and, if necessary, to decide on early surgical intervention.

Prognostic significance of maternal urinary carbohydrate antigen 19-9 for antenatal diagnosis of posterior urethral valve associated with fetal hydronephrosis

PURPOSE

To evaluate the predictive role of maternal urinary CA 19-9 as a non-invasive marker for diagnosing antenatal posterior urethral valve (PUV).

METHODS

A total of 40 women in the third pregnancy trimester were enrolled. Case group (group A) consisted of 20 women with a diagnosis of antenatal PUV. Twenty women with similar gestational age, fetal sex, normal US, and no history of congenital anomalies were chosen as a control group (group B). Maternal urine samples were collected and urinary CA 19-9 was measured in both groups. The correlations between maternal urinary CA 19-9 and APD (measured during pregnancy and the initial evaluation of the newborn) were assessed. CA 19-9 level in first urine of neonates was also evaluated.

RESULTS

The mean ± SD of maternal urine CA 19-9 was higher in PUV group compared to the control group (131.6 ± 23.8 vs. 13 ± 2.7 U/mL). In addition, there was a significant correlation between maternal urinary CA 19-9 and the APD measured at the third trimester (p < 0.001) and the initial evaluation of fetus after birth according to SFU grading system (p < 0.001). However, no significant difference was found between gestational age and urinary CA 19-9 level (p = 0.34). There was also a significant correlation between the CA 19-9 level in first urine of neonates and CA 19-9 level of maternal urine (p < 0.001).

CONCLUSIONS

This is the first time that maternal urinary CA 19-9 has been applied as a noninvasive and practical diagnostic marker in antenatal PUV.

Determination of the Need for Surgical Intervention in Infants Diagnosed with Fetal Hydronephrosis in China

Background

Hydronephrosis is a common congenital condition. The detection of fetal hydronephrosis by ultrasound presents a treatment dilemma. This study aims to examine postnatal follow-up and treatment for hydronephrosis diagnosed prenatally.

Material/Methods

This was a retrospective study of 210 infants with hydronephrosis diagnosed at the Qilu Hospital (Shangdong, China) between January 2005 and January 2013. The patient cohort was divided into four groups based on prenatal ultrasound examinations using the Society for Fetal Urology (SFU) classification system. Data on follow-up investigations and treatment methods were extracted from the charts and analyzed.

Results

Patients with SFU grade 1, 2, and 3 hydronephrosis (n=125, n=74, and n=11, respectively) were followed for two years. In all, 2.4%, 18.9%, and 90.9% of patients with SFU grade 1, 2, and 3 hydronephrosis, respectively, underwent surgery. SFU grade 3 (HR=9.23, 95% CI: 1.43–59.74, p=0.02), APD (HR=2.81, 95% CI: 1.11–7.10, p=0.03), and parenchymal thickness (HR=0.42, 95% CI: 0.24–0.71, p=0.001) were independently associated with the occurrence of surgery. For anterioposterior diameter, using a cut-off point of 1.1, the area under the curve was 0.86, Youden index was 0.556, sensitivity was 70.4%, and specificity was 85.3%. For parenchymal thickness, using a cut-off point of 5, AUC was 0.79, Youden index was 0.478, sensitivity was 74.1%, and specificity was 73.8%.

Conclusions

Patients with SFU grade 2 hydronephrosis require long-term follow-up. Surgery and close postsurgical observation may be necessary for patients with SFU grade 3 and 4 hydronephrosis. An initial B-mode ultrasound screening at 7–10 days after birth may help make an optimal diagnosis and treatment selection.

Incidence and outcomes of antenatally detected congenital hydronephrosis

BACKGROUND AND OBJECTIVES

Antenatally detected urinary tract abnormalities (ADUTA) are increasingly recognized. Our aims were to determine the incidence and outcomes of antenatally diagnosed congenital hydronephrosis in a large cohort.

DESIGN AND SETTINGS

We recorded the number of total deliveries over 4 years at King Abdulaziz University Hospital (KAUH) between January 2008 and December 2011 from the number of nursery and neonatal intensive care unit (NICU) admissions.

PATIENTS AND METHODS

We reviewed the records of 18 853 deliveries between January 2008 and December 2011 at KAUH, Saudi Arabia. ADUTA were recorded, and their postnatal medical records were reviewed for demographic and radiological data.

RESULTS

ADUTA were diagnosed in 327 fetuses (1.7%). The commonest pathology was congenital hydronephrosis (n=313, 95.7%). Cystic renal anomalies were reported in 4 babies (1.2%), and 10 children (3.1%) were reported to have other renal anomalies, including duplex kidneys or a single kidney. A total of 240 babies with congenital hydronephrosis were followed up. Hydronephrosis resolved in 99 children (41.2%) within 2 months of birth. A total of 29 subjects had underlying renal anomalies (12.1%), including vesicoureteral reflux (n=12, 5%), pelvi-ureteric junction obstruction (n=14, 5.8%), and posterior urethral valve (n=3, 1.3%). The best predictor for nonresolving congenital hydronephrosis and underlying anatomical abnormalities was the anteroposterior diameter on the first postnatal scan. A cut-off point of 5 mm was found to be 83% sensitive in predicting nonresolving hydronephrosis, while 7 mm was 88% sensitive and 10 mm was 94% sensitive.

CONCLUSIONS

Congenital hydronephrosis is the commonest ADUTA. A large percentage resolved within 2 months of birth, but underlying anatomical abnormalities were found in 12.1%. All babies with antenatally detected hydronephrosis should be examined by ultrasound postnatally but further radiological investigations should only be performed for persistent significant AP dilatation >=10 mm.

Current management of antenatal hydronephrosis

The strategy for the management of children with urinary tract anomalies has changed considerably as a result of the development of ultrasound equipment and techniques that allow for detailed fetal evaluation. Hydronephrosis is the most common urogenital anomaly detected, suggesting that an obstructive process may be potentially present. The goal of postnatal management is to identify and treat those patients whose renal function is at risk, while leaving alone the high percentage of patients who are at no risk of renal damage. This management involves a spectrum of radiological, medical, and surgical interventions for diagnosis, surveillance, and treatment. In this article, we review our current understanding of the natural history of antenatal hydronephrosis and its management.

Feasibility of measuring 3-dimensional renal parenchymal volume to predict postnatal renal function in near-term fetuses with congenital hydronephrosis: a preliminary study

OBJECTIVES

The purposes of this study were to evaluate the feasibility of predicting kidney function using the fetal renal parenchymal volume as determined by prenatal 3-dimensional (3D) sonography and to determine the association among the prenatal renal pelvic diameter, renal parenchymal volume, and postnatal renal function in near-term fetuses with unilateral hydronephrosis.

METHODS

This retrospective study included 42 kidneys (21 normal and 21 hydronephrotic) from 21 fetuses between 30 and 39 weeks' gestation. We used the extended imaging virtual organ computer-aided analysis (XI VOCAL; 10 planes) technique for the prenatal volumetric measurements, and postnatal renal function was estimated using renal scintigraphy. An independent-samples Student ttest, Spearman's rank correlation, and simple linear regression were used for the statistical analyses. Reproducibility was confirmed with a paired Student t test and intraclass correlation coefficients.

RESULTS

The renal pelvic diameter correlated well with the renal parenchymal volume Spearman ρ = 0.765; P < .001). The postnatal renal function correlated with the adjusted 3D renal parenchymal volume (Spearman ρ = -0.321; P = .043) but did not correlate with the prenatal renal pelvic diameter (Spearman ρ = -0.291; P = .062).

CONCLUSIONS

This preliminary study showed that 3D renal parenchymal volume could be a coparameter for predicting postnatal renal function with the renal pelvic diameter. Further studies in a larger population are required to obtain robust results.

Postnatal imaging of neonates with prenatally diagnosed genitourinary abnormalities: a practical approach

The advent of prenatal US and, more recently, fetal MRI has changed our pattern of referrals. In the current clinical algorithms, most neonates evaluated for genitourinary abnormalities are asymptomatic. These infants are referred for multidisciplinary consultation, imaging and surveillance. Evaluation of these children commences following pertinent review of available prenatal studies; this is appropriate, as in certain instances prenatally gathered information of potential prognostic significance can be inferred or can obviate the need for multiple examinations. US remains the first-line imaging modality for diagnosing urinary abnormalities in neonates and young infants, although it offers primarily morphological assessment. However, US coupled with MAG-3 scanning results in a powerful combination that provides anatomical and functional information. Recently, MRI and MR urography have been increasingly regarded as one-stop-shop examinations that can deliver both anatomical and functional information, and play an increasing role in the evaluation of ureteral ectopia and genital anomalies. Fluoroscopic examinations are reserved to exclude vesicoureteral reflux, to delineate urethral obstruction or to provide additional information to support a diagnosis. A practical approach to postnatal imaging of the neonate is discussed and the important genitourinary anomalies in this age group are presented and illustrated.

The role of routine post-natal abdominal ultrasound for newborns in a resource-poor setting: a longitudinal study

Background-

Neonatal abdominal ultrasound is usually performed in Nigeria to investigate neonatal symptoms rather than as a follow up to evaluate fetal abnormalities which were detected on prenatal ultrasound. The role of routine obstetric ultrasonography in the monitoring of pregnancy and identification of fetal malformations has partly contributed to lowering of fetal mortality rates. In Nigeria which has a high maternal and fetal mortality rate, many pregnant women do not have ante-natal care and not infrequently, women also deliver their babies at home and only bring the newborns to the clinics for immunization. Even when performed, most routine obstetric scans are not targeted towards the detection of fetal abnormalities.

The aim of the present study is to evaluate the benefit of routinely performing abdominal scans on newborns with a view to detecting possible abnormalities which may have been missed ante-natally.

Methods-

This was a longitudinal study of 202 consecutive, apparently normal newborns. Routine clinical examination and abdominal ultrasound scans were performed on the babies by their mother's bedside, before discharge. Neonates with abnormal initial scans had follow-up scans.

Results-

There were 108 males and 94 females. There were 12 (5.9%) abnormal scans seen in five male and seven female neonates. Eleven of the twelve abnormalities were in the kidneys, six on the left and five on the right. Three of the four major renal anomalies- absent kidney, ectopic/pelvic kidney and two cases of severe hydronephrosis were however on the left side. There was one suprarenal abnormality on the right suspected to be a possible infected adrenal haemorrage. Nine of the abnormal cases reported for follow- up and of these, two cases had persistent severe abnormalities.

Conclusions-

This study demonstrated a 5.9% incidence of genito urinary anomalies on routine neonatal abdominal ultrasound in this small population. Routine obstetric USS is very useful but inadequate availability of skilled personnel and cost implications create great challenges in poor resource settings like Nigeria. However, awareness should be created so that parents who can afford such investigations can make informed decisions.

The predictive value of the first postnatal ultrasound in children with antenatal hydronephrosis

OBJECTIVE

To evaluate the effectiveness of the first postnatal ultrasound (US) in predicting the final postnatal diagnosis using a database of children followed prospectively for antenatal hydronephrosis, and to compare these findings with a systematic review of the literature.

METHODS

The study involved 1441 children who had their radiological evaluation between 3 and 60 days of life, including an US, performed at our institution in 1998-2006. Univariate and multivariate analyses were performed. A systematic review of articles on prenatal hydronephrosis resulted in 31 studies with 2202 patients who met the inclusion criteria for analysis.

RESULTS

62.0% of renal units (RUs) had transient or non-obstructive hydronephrosis. Increasing degree of hydronephrosis correlated with increased risk of urological pathologies (from 29.6% RUs in the mild group to 96.3% RUs in the severe group). A systematic review of the literature indicated very poor quality data, but the findings appeared to be concordant with those from our patient population.

CONCLUSION

The findings from this study will help to quantify the incidence of postnatal pathology based upon the first postnatal US parameters. This information is useful for counseling and for determining which postnatal radiological tests will be necessary.

Management of fetal hydronephrosis

Prenatally detected hydronephrosis has become a common diagnosis for both pediatric nephrologists and urologists. Hydronephrosis is most commonly assessed by the Society for Fetal Urology grading system or anterior-posterior diameter of the renal pelvis in the transverse plane. Some cases of bilateral obstruction, most commonly from posterior urethral valves, can be life-threatening and require close monitoring or, occasionally, fetal intervention. The majority are unilateral and of no threat to the growing fetus. The crux of postnatal management is the separation of the minority of patients whose renal function is at risk from the majority who will suffer no renal consequences. This management involves a regimen of ultrasounds, voiding cystourethrograms, and nuclear renograms for diagnosis and surveillance. Recent literature has been aimed at the timing and necessity of these studies in order to minimize extraneous studies without compromising renal function.

Current diagnosis and management of fetal genitourinary abnormalities

Prenatal assessment with ultrasonography provides excellent imaging of fluid-filled structures (eg, hydronephrosis, renal cysts, and dilated bladder) and renal parenchyma. This information allows for the generation of a differential diagnosis, identification of associated anomalies, and assessment of the prenatal and postnatal risks of a given anomaly. This enhances parental education and prenatal and postnatal planning. This article discusses the current methods of diagnosis and management of fetal genitourinary anomalies, and also the postnatal evaluation and treatment of these conditions.

Antenatal renal pelvic dilatation; the long-term outlook

AIM

The purpose of this study was twofold: first to provide data for more accurate counselling of parents with regard to prognosis, and second, to ensure that by following a policy of selective micturating cystourethography (MCUG), significant pathology is not missed, in particular vesicoureteric reflux (VUR). (MCUG is only undertaken if the renal pelvic diameter (RPD) is >/= 10 mm or if there is calyceal or ureteric dilatation.)

MATERIAL AND METHODS

Data were collected prospectively over a 6-year period. Pre and postnatal imaging findings were collected for all infants in whom a RPD of >/= 5 mm was identified at any gestational age. The imaging records of all patients were reviewed in 2005 for evidence of pathology detected after re-presentation with symptoms. The age range at review varied from 2-8 years.

RESULTS

Complete data were available in 527 infants. The risk of significant pathology was related to the degree of antenatal renal pelvic dilatation varying from 6% for a RPD of 5 mm at 20 weeks gestation to 38% at 10 mm. At 28-33 weeks gestation the risk varied from 5% at 5mm to 15% at 10 mm. Subsequent imaging record review revealed only one patient with grade II VUR in the study population not picked up by our selective MCUG policy.

CONCLUSION

The present study provides prognostic information that can be given to parents both antenatally and postnatally, and reassurance that a selective MCUG policy is appropriate.

Prenatal hydronephrosis

Hydronephrosis is the most common genitourinary tract anomaly identified on prenatal ultrasound studies. Ureteropelvic junction obstruction accounts for approximately 50% of the cases of prenatally detected hydronephrosis. Postnatal evaluation allows for the identification of the cause and further management. Rarely, in utero intervention may be performed for severe oligohydramnios associated with hydronephrosis. Prenatal consultation with a pediatric urologist is useful in decreasing parental anxiety and facilitating postnatal management.

Sonographic diagnosis of urethral anomalies in infants: value of perineal sonography

OBJECTIVE

To assess the value of urethral sonography including a perineal approach in evaluating urethral anomalies in infants.

METHODS

A radiology database review identified 88 patients (mean age +/- SD, 64 +/- 84 days) who underwent voiding cystourethrography (VCUG) and urethral sonography as part of extended sonography of the urinary tract. Sonographic and VCUG images and reports were reviewed to assess agreement between both modalities for detection of urethral anomalies.

RESULTS

Sonography facilitated the correct diagnosis of all 3 posterior urethral valves. The only urethral diverticulum, the only ectopic ureteric insertion into the urethra, the only urogenital sinus, and the only urethrovaginal fistula were also shown on sonography. In 73 (94%) of 78 cases, sonography correctly showed the absence of anomalies. In 5 infants, sonography could not reliably assess the urethra and showed indirect signs of urethral anomalies; however, these patients had normal urethras on VCUG.

CONCLUSIONS

Our data show that sonography of the urethra is a valuable tool for diagnosis of urethral anomalies. Especially, negative findings on sonography are highly suggestive of the absence of urethral anomalies. Positive or equivocal sonographic findings should indicate VCUG.

Antenatal Hydronephrosis: Negative Predictive Value of Normal Postnatal Ultrasound—a 5-year Study

AIM

To determine whether normal postnatal ultrasound, as part of a strict screening protocol for the detection and follow-up of antenatal hydronephrosis, effectively excludes the majority of babies with congenital urinary tract abnormalities that would otherwise present with a urinary tract infection.

MATERIALS AND METHODS

We retrospectively reviewed all babies who had postnatal follow-up of antenatally detected hydronephrosis over a 5-year period at our institution, a district general Trust with a specialist paediatric unit. We then studied all babies presenting with urinary tract infection before their first birthday to our institution over the same period. By cross-referencing these two study groups we were able to determine which babies developed a urinary tract infection having been previously discharged after normal postnatal ultrasound.

RESULTS

Four hundred and twenty-five babies had postnatal follow-up of antenatal hydronephrosis. Of these, 284 were investigated with ultrasound alone. In the same 5-year period, 230 babies presented with urinary tract infection before their first birthday. Only three of these babies had been previously discharged after normal postnatal ultrasound. The negative predictive value of a normal postnatal ultrasound was therefore 98.9% (281/284) for babies who subsequently presented with a urinary tract infection before their first birthday.

CONCLUSION

Careful antenatal and postnatal ultrasound with strict protocols is effective in detecting congenital renal tract abnormalities. Infants discharged after normal postnatal ultrasound are highly unlikely to still have an undetected urinary tract abnormality. We suggest that all babies with antenatal hydronephrosis are started on prophylactic antibiotics at birth, pending further investigation. All babies without features of severe obstruction antenatally should have their postnatal ultrasound delayed for a month. We recommend selective use of micturating cystourethrogram (MCUG), and delaying this investigation until the baby is 3 to 4 months old to allow for spontaneous resolution of vesicoureteric reflux. We do not believe that all babies with antenatal hydronephrosis require MCUG, providing a clear protocol is followed.

Sonography of the neonatal genitourinary tract

Ultrasound has become the modality of choice for the evaluation of the neonatal genitourinary tract. High frequency linear, vector, and curved array transducers (7 MHz, 5 MHz, 12 MHz) and portability of the equipment make a rapid bedside evaluation with exquisite anatomic detail possible. A major advantage of sonography over other modalities is real time observation and circumvention of sedation.