Diagnosis of fetal hydronephrosis in utero using ultrasound

Postnatal evaluation of intrauterine hydronephrosis due to ureteropelvic junction obstruction

PURPOSE: Fetal hydronephrosis is a frequent finding due to advances in prenatal ultrasonography. The definition of fetal and neonatal urinary tract obstruction is a very difficult task requiring confirmation of reduced renal function and hydronephrosis. In this study we followed a series of consecutive patients with intrauterine hydronephrosis that persisted during post-natal life. METHODS: 116 newborns with antenatal hydronephrosis diagnosed by ultrasound and submitted to a specific post-natal evaluative protocol with a follow-up period of 6 years. RESULTS: In 45 (38.8%) of 116 patients, ureteropelvic junction (UPJ) obstruction was confirmed and surgical correction of the UPJ obstruction was done in 19 patients. From 26 children who were initially submitted to non-surgical treatment, only 6 (23%) needed a surgical approach during follow up. Overall analysis showed that surgery was performed in 25 patients with UPJ obstruction, and the others 20 patients were kept under clinical observation, since normal renal function was confirmed by scintigraphy scans. CONCLUSION: Fetal hydronephrosis due to UPJ obstruction deserves careful postnatal evaluation. UPJ obstruction is the most frequent anomaly and its surgical treatment has very precise indications. The evaluative protocol was useful in identify patients that could be followed-up with a non-surgical approach.

Urinary biomarkers in prenatally diagnosed unilateral hydronephrosis

The introduction of prenatal ultrasonography as a screening method entails an increasing number of infants diagnosed with prenatal hydronephrosis. Ureteropelvic junction obstruction accounts for 35% of prenatal hydronephrotic cases. Urinary tract obstruction that occurs during early kidney development affects renal morphogenesis, maturation and growth, and in the most severe cases this will ultimately cause renal insufficiency. A major challenge in the clinical management of these patients is to preserve renal function by selection of the 15%-20% who require early surgical intervention, leaving those for whom watchful waiting may be appropriate because of spontaneous resolution/stabilization without significant loss of renal function. Today, this requires medical surveillance, including repetitive invasive diuretic renograms relying on arbitrary threshold values, and therefore there is a need for non-arbitrary, non-invasive urinary biomarkers that may be used as predictors for renal structural changes and/or decreasing renal function, and thereby provide the surgeon with more clear indications for surgical intervention. In this review, we summarize the currently well-known facts about urinary biomarkers in ureteropelvic junction obstruction concerning renal function, and we also suggest potential novel urinary biomarkers.

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?

PURPOSE

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.

MATERIALS AND 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.

Outcome of hydronephrosis diagnosed antenatally

We evaluated 23 neonates with prenatally diagnosed dilatation of the renal pelvis involving 33 renal units. The dilatation was graded from 0 to 4 by ultrasonography. Diuresis renography was used to evaluate differential renal function. The patterns of the excretory curve following administration of furosemide were analyzed. Antegrade pyelography and pressure flow studies were done in selected patients. The mean follow-up was 34 weeks. The single most important prognostic indicator in this group of patients was the degree of dilatation on ultrasonography. Six of 7 renal units with grade I hydronephrosis improved and 1 remained stable on follow-up. Four of the 12 renal units with grade II hydronephrosis improved spontaneously; 1 remained stable. Three of 11 renal units with grade III hydronephrosis either improved or remained stable. The measurement of differential renal functions on DTPA renography did not correlate well with the degree of dilatation when renal size and parenchymal thickness were adequate. The excretory curves after lasix administration were not helpful to determine treatment in the neonatal period. Seventeen renal units (7 grade II, 9 grade III, 1 grade IV) were treated surgically due to persistent dilatation, evidence of obstruction on either DTPA renography or the Whitaker test, or because of impaired renal function. Sixteen of the 33 renal units diagnosed prenatally improved with observation. Of all the parameters studied only the degree of dilatation on ultrasonography correlated well with the prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Antenatally diagnosed fetal hydronephrosis. Five year's follow up

Over a one year period 13 fetuses with urinary tract abnormalities were detected by antenatal ultrasound. Extra-renal dilatation was found in six, in two abnormalities requiring an intervention after delivery. Intra-renal hydronephrosis was present in five cases, of which three required surgery during the neonatal period to relieve the obstruction. Other abnormalities detected were one case with unilateral multicystic kidney and one case with small dysplastic kidneys. Multicystic kidney was removed and the infant with dysplastic kidneys died soon after delivery. Our limited numbers of antenatally detected hydronephrosis will point to the early diagnosis and intervention to avoid renal damage.

Pyeloplasty in the young infant

The urgency, safety and benefits of performing pyeloplasty during the first weeks of life currently are being questioned. We reviewed our experience with 114 pyeloplasties in 103 infants and young children performed between 1983 and 1987. The 34 patients who underwent an operation before they were 3 months old were compared to 69 operated upon after 3 months. The surgical results in the 2 groups were equally good, with 90 per cent of the cases having an improved or stable postoperative excretory urogram or renal scan. Complications were few and were more common in the older age group, in which 7 children required a secondary procedure, including 2 for recurrent obstruction at the ureteropelvic junction. No patient in the younger age group required a secondary procedure for treatment of a complication or recurrent obstruction. Our findings indicate that the success of pyeloplasty performed during the first weeks of life is equal to that performed at a later patient age and were not more likely to be followed by a complication.

Pediatric pyeloplasty: 50 patients with 59 hydronephrotic kidneys

A report of 59 hydronephrotic kidneys due to pelviureteric junction (PUJ) obstruction in 50 children less than 12 years of age is presented. Thirty-two percent of the patients were less than 1 year of age, with their main presenting feature being an abdominal mass (88%). For older children, loin or abdominal pain was the chief presenting symptom (68%). During infancy, the left and right sides were equally affected, followed closely by bilateral involvement. On the other hand, in older children, the left side was predominantly affected, being twice as common as the right, and the latter again was twice as common as bilateral involvement. Dismembered pyeloplasty was the procedure used in most cases (88%); the nephrectomy rate was 8% for grossly dilated or dysplastic kidneys. During follow-up (of 6 months to 10 years) of 54 pyeloplasties, improvement was seen in 36 (67%), 12 were unchanged (22%), and one reverted to normal (2%) after the initial operation. Two (4%) worsened initially but achieved stabilization after reoperation; the remaining 3 patients (6%) showed unsatisfactory results. Stents were used in 65% of the cases and nephrostomies in 53%.

Ureteropelvic junction obstruction in the neonate

The widespread use of maternal ultrasonography has resulted in an increasing number of asymptomatic newborns being diagnosed with hydronephrosis. A total of 89 neonates with hydronephrosis secondary to ureteropelvic junction obstruction have been referred for evaluation and treatment during the last 6 years. In the majority the condition was diagnosed readily with ultrasonography, voiding cystography and excretory urography. Twenty-five per cent underwent more quantitative assessment using nuclear renal imaging. Only 2 patients (8 per cent) had a percutaneous study. Early reconstruction was performed in 75 per cent of the patients and it proved to be safe and effective. Twenty-three neonates were followed nonoperatively. One patient (4 per cent) demonstrated clinical deterioration necessitating later surgical intervention. Careful surveillance is mandatory in all infants followed nonoperatively.

Perinatal management of fetal hydronephrosis with normal bladder

This report covers 30 cases of prenatal diagnosis of uni- or bilateral hydronephrosis not associated with an overdistended bladder. Oligohydramnios was observed only in four cases while polyhydramnios occurred in three affected fetuses. In no case was fetal urine aspirated or drained prenatally. Early delivery was performed in four cases with oligohydramnios. Sixteen newborns required surgical correction of the lesion as it was confirmed by urography, following at least two sonographic examinations which confirmed a moderate to severe hydronephrosis after birth. The most frequent lesion was pyelo-ureteric junction obstruction (12 cases). Thirteen cases were normal at follow-up, and in two of these the dilation cleared up during intrauterine life. One case of severe hydronephrosis proved to be a multicystic kidney. In this series isolated hydronephrosis, both uni- or bilateral did not result in fetuses being at high risk for survival (only one infant died after surgery) nor as regards to associated malformations and perinatal morbidity. Provided a properly timed surgical correction was performed, renal function resulted to be good at follow-up.

Ultrasonographic anatomy and diagnosis of fetal uropathies affecting the upper urinary tract. I. Obstructive uropathies

The authors describe the ultrasonographic anatomy and semiology of allowing detection of the main types of fetal uropathies. The results of the author's personal experience in this domain are compared to data from the literature. Differential features of the uropathies are given and the limitations and practical significance of prenatal and postnatal ultrasonography are discussed.

The prognosis of surgically treated congenital hydronephrosis after diagnosis in utero

Nine patients with a prenatal ultrasonic diagnosis of unilateral ureteropelvic junction obstruction underwent pyeloplasty in early neonatal life. Based on radiological and renographical assessment of the results, immediate postnatal intervention had no demonstrable advantage over those subjects in a control group who underwent an operation after presenting with symptoms. Half of the children in both groups had normal parenchymal function of the hydronephrotic kidney. Because of the operative complications we found it unacceptable to operate on neonates without symptoms and with normal function of the affected kidney. The advantage of prenatal diagnosis lies in the early recognition of the necessity of close surveillance. The primary indications for surgical intervention should be symptoms and impairment of the hydronephrotic kidney function.

Ureteropelvic junction obstruction in newborns and infants

Of 11 patients less than 1 year old with ureteropelvic junction obstruction 9 presented with an abdominal mass. The ideal method evaluation of such patients with an abdominal mass includes sonography followed by isotope renal scan if the mass is determined to be urinary in origin. Visualization by excretory urography in this age group is often impaired by poor renal concentrating ability and excessive bowel gas. Repair was achieved successfully using a nonintubated, nonstented, dismembered pyeloplasty in 10 of 13 kidneys. The average postoperative hospital stay for this group was 4.8 days. Three kidneys were diverted temporarily by nephrostomy, leading to a complication in 1 that required secondary repair. Average postoperative hospital stay in the diverted group was 15 days. Renal function was excellent following repair in all patients, suggesting that early repair is highly desirable in this age group.