Fetal hydronephrosis: what is the urologist to do?

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.

[Severe primary congenital unilateral hydronephrosis. A review of 98 cases]

INTRODUCTION

Currently, consensus is lacking on the indications for surgery in primary congenital unilateral hydronephrosis.

OBJECTIVES

To analyze the clinical characteristics, treatment and outcome of severe asymptomatic primary congenital unilateral hydronephrosis (grades 3 and 4).

PATIENTS AND METHODS

We performed a retrospective study of 98 neonates with severe primary congenital unilateral hydronephrosis. Diagnostic techniques consisted of ultrasound, renogram, and DMSA scan.

RESULTS

The mean age at diagnosis was 24 days. The mean length of follow-up was 4 years. Forty-eight percent of cases were grade 3 and the remaining cases were grade 4. Fifty-six percent of the patients received conservative treatment. Forty-four percent underwent surgery. Surgical indications consisted of prolonged T1/2, reduced differential renal function and/or very severe hydronephrosis. The mean age at surgery was 5.5 months. In 94 % of the patients who received conservative treatment, hydronephrosis resolved spontaneously. In this group, renal parenchyma and renal function were normal in all patients except two. In 97 % of the patients who received surgical treatment, hydronephrosis was corrected or improved after pyeloplasty. At diagnosis, 19 kidneys had reduced function. In the postsurgical renogram, although T1/2 had markedly improved, 8 kidneys showed reduced function. DMSA performed in 63 patients belonging to both groups, outside the active phase of hydronephrosis, revealed 8 atrophic kidneys, 4 with moderately reduced renal size and function and 4 with scarring and normal renal size and function. During the study period, overall function was maintained in all patients and none developed hypertension.

CONCLUSIONS

Severe congenital unilateral hydronephrosis resolves spontaneously in most patients. Consequently, clinicians increasingly adopt a conservative approach. The available diagnostic techniques cannot identify patients who will benefit from pyeloplasty. In general, accepted surgical indications are an increase in hydronephrosis and/or worsening of renal function. In our series, 15 % of the patients with hydronephrosis had an irreversible lesion of variable severity, which in some patients seemed to have developed during embryogenesis. Kidneys at risk of presenting a lesion were those that had grade 4 hydronephrosis.

Analysis of trends on serial ultrasound for high grade neonatal hydronephrosis

PURPOSE

We sought to validate the role of serial ultrasound studies for detecting and excluding obstruction in high grade neonatal hydronephrosis.

MATERIALS AND METHODS

Between January 1996 and December 1998 all patients with prenatally diagnosed hydronephrosis underwent a protocol of antibiotic prophylaxis, ultrasound and voiding cystourethrography. All reflux-free patients underwent diuretic renography. Patients with high grade isolated unilateral hydronephrosis were included in the study. They were followed with 3 serial ultrasound examinations every 3 months in year 1 of life, biannually in year 2 and yearly thereafter. The trends in the changes in these studies were studied.

RESULTS

Of the 153 patients 45 (29%) met study inclusion criteria. During a mean followup of 38 months (range 23 to 52) 16 patients (36%) who showed a trend of progressive hydronephrosis underwent pyeloplasty. The remaining 29 patients showed a trend of improvement in hydronephrosis. The drainage pattern on initial diuretic renography had only 63% sensitivity and 59% specificity for diagnosing obstruction. The same was true for the decrease in differential function of below 40% with 56% sensitivity and 66% specificity. Logistic regression analysis revealed that neither the initial grade of hydronephrosis on prenatal ultrasound nor the drainage-functional pattern on initial diuretic renography was a predictor of the subsequent need for pyeloplasty. All 16 patients who underwent pyeloplasty had improved or stabilized hydronephrosis after pyeloplasty.

CONCLUSIONS

A trend of progressive hydronephrosis on 2 consecutive serial renal ultrasound examinations serves as an early diagnostic sign of obstruction. Initial grade of hydronephrosis on initial ultrasound as well initial functional-drainage patterns on diuretic renography are not predictors of obstruction. Serial ultrasound is noninvasive and could replace serial invasive renal scans. Diuretic renal scans still have a role, especially as a baseline study to guide the frequency of serial ultrasound examinations.

Fetal pyelectasis: is it always "physiologic"?

OBJECTIVE

Our purpose was to determine the degree of fetal pyelectasis predictive of neonatal renal pathologic processes.

STUDY DESIGN

Eighty-four cases of pyelectasis were identified during the study period (1989 through 1993). Fetuses with anteroposterior diameter of the renal pelvis > or = 4 mm before 33 weeks or > or = 7 mm after 33 weeks without caliectasis were included. Fetuses with an anteroposterior diameter of > 10 mm were excluded. Postnatal evaluation included renal sonogram, voiding cystourethrogram, and renal flow and function studies.

RESULTS

Sixteen cases were excluded because of incomplete postnatal workup. Renal pathologic processes were found in 30 of 68 (44%) at birth; the most common were ureteropelvic junction obstruction (37%) and vesicoureteral reflux (33%). Only four cases required surgical intervention (13%), and the remaining 87% were managed conservatively. A normal urinary tract was found in 25% of the infants and the remaining 21 of 68 (31%) had regression of pyelectasis before birth. Fetuses with a dilated anteroposterior diameter > or = 8 mm after 28 weeks' gestation were found to have renal pathologic features in two of three of the cases, with sensitivity, specificity, and positive and negative predictive values of 87%, 41%, 66.7% and 70%, respectively.

CONCLUSION

Fetuses with an anteroposterior diameter of the renal pelvis > or = 8 mm after 28 weeks' gestation require appropriate urologic evaluation after birth.

Management and outcome of antenatally diagnosed hydronephrosis

From March 1989 to December 1992, we encountered 25 kidneys in 21 patients with a suspicious ureteropelvic junction (UPJ) obstruction detected only on prenatal ultrasound. In all these patients other urological abnormalities were excluded by voiding cystourethrography and other radiological findings. Diuretic renography (DR) was initially performed at an age ranging from 15 days to 32 months in all patients and repeated a total of 39 times. Both the split renal function (SRF) and diuretic drainage half-time clearance (DT1/2) of radioagent were within their normal ranges in the case of 15 (60%) of the kidneys on initial DR. In these kidneys, there were no aggravated signs on repeated DR. Decreased SRF was found in 3 kidneys (12%) on initial DR. Of these, the renal function spontaneously reverted to normal in 2 cases with bilateral hydronephrosis. Another 1 kidney revealed significant UPJ obstruction assessed by pressure flow study and continuous nephrostomy drainage had brought relief from the obstruction 1 year later. Prolonged DT1/2 with normal SRF was found in 7 (28%) kidneys. The renal function did not deteriorate and the diuretic response improved on repeat DR except for 1 kidney, whose function deteriorated and on which ultimately, pyeloplasty was performed at 7 months of age. Prenatally diagnosed hydronephrosis is usually asymptomatic and clinically significant UPJ obstruction should be always verified. Although even today there is still no examination which can detect a definite obstruction, we can identify one as significant by careful repeat examinations and thus avoid unnecessary surgery without causing any renal deterioration.