Studies of renal function in children with chronic hydronephrosis

Ontogeny of the VATER kidney in a rat model

By exposing rat fetuses to adriamycin prenatally, a rat model of VATER association has been created. Absence of the fetal bladder is prominent and the kidneys show features of chronic obstruction with hydronephrosis/hydroureter, loss of parenchyma, fewer glomeruli, and less differentiation. The aim of this study was to elucidate this rat model, to determine exactly when the changes in the kidneys develop, hopefully thereby to expand our understanding of congenital obstructive uropathy. Timed-pregnant Sprague-Dawley rats were injected intraperitoneally with adriamycin on days 6-9 of gestation. The control group received saline. Fetuses were recovered on gestational days (GDs) 20, 19, 18, 17, 16, 15, 14, 12, and 10 (total, 120 control, 121 treated). Macroscopic features were determined. Serial sections were then taken and stained with hematoxylin and eosin. Comparisons were made under light microscopy. The metanephric kidney first became apparent at GD12. The development of the control and treated kidneys appeared similar till GD18. Beyond this day, the treated kidneys exhibited increasing degrees of distension of Bowman's capsule, ducts, and subsequently pelvis and ureter. There were fewer levels of glomeruli, which were also less differentiated. Less differentiation was also noted in the medulla, and with time this became thin in comparison to the control kidneys. By GD20, the renal pelvis was grossly dilated with a blunted papilla, and the renal parenchyma was thin. Prenatal exposure of rat fetuses to adriamycin results in kidneys that are chronically obstructed, as the majority of the fetuses show absence of the bladder. Absence of renal dysmorphology until GD18, when urine is first produced, suggests strongly that the effect of adriamycin on the kidney is indirect, via agenesis of the bladder and secondary to backpressure from early urine production. This is a unique, simple, and reliable model of fetal obstructive uropathy and will be very useful to facilitate further investigation into its pathophysiology and to explore new treatment options.

[Change in management of ureteropelvic junction obstruction]

PURPOSE

The aim of this study was to evaluate the change in ureteropelvic junction management, from surgical correction to observation of the hydronephrosis. We checked wether or not it was deleterious for kidney.

MATERIALS AND METHODS

We retrospectively reviewed 96 charts between 1988 and 1998. Initial ultrasonography, and voiding cystourethrogram were available for all cases. Intravenous urography and diuretic renography were studied when available. Minimal follow-up of patients was one year. Patients were divided into three groups: surgery right away, surgery after observation, and observation only.

RESULTS

Later was the diagnosis, more significant were the hydronephrosis and impairment of renal function (p < 0.01). In group operated on right away (69 cases), drainage improved, hydronephrosis decreased, but renal function did not improve significantly (p = 0.37). Sixteen patients were operated on after observation without deleterious effect for kidney. Eleven patients were only observed: hydronephrosis progressively decreased. Initial radiological results were not different between the last two groups (p > 0.05), and were not predictive of their course.

CONCLUSION

Initial non operative management of hydronephrosis was not dangerous for renal function. It is advisable to detect at the earliest all signs of obstruction, because surgery improves renal drainage but not renal function.

Successful early pyeloplasty in infants

BACKGROUND

Early pyeloplasty for the treatment of congenital ureteropelvic junction obstruction to maximize nephron salvage is justified only if potential hazards of operating on small infants are avoided.

METHODS

The records were analyzed of all infants who underwent pyeloplasty over a 5-year period. Open pyeloplasty was performed if collecting systems had deteriorated or were demonstrated to be obstructed; it was also performed for severe cases of hydronephrosis. Outcome of surgery in the younger infant (patients <2 months of age) was compared with the older infant group (patients >2 months of age). Preoperative evaluation in case of mild or moderate hydronephrosis was directed toward ruling out a non-obstructed collection system and included voiding cystourethrography, and serial ultrasonography and/or dual isotope diuretic renography. Postoperative assessment consisted of serial ultrasonography and/or nuclear imaging to confirm decompression and relief of obstruction.

RESULTS

A total of 24 pyeloplasties were performed on 22 patients in the younger infant group (two bilateral) and 30 were performed on 27 infants in the older infant group (three bilateral). The only significant differences between the groups were as follows: patients in the younger infant group were likely to present in utero (75%, p = 2.69), whereas those in the older infant group were more likely to present with a urinary tract infection (48%, p = 4.12). During follow-up examination, 23 renal units in the younger infant group and 24 in the older infant group were judged to be stable or improved. Four kidneys were not salvaged after pyeloplasty, one in the younger infant group and three in the older infant group.

CONCLUSIONS

Good results of pyeloplasties performed in the infants in this series support early correction of ureteropelvic junction obstruction in infants.

Management of neonatal ureteropelvic junction obstruction

No topic in urology is more contentious than the management of neonatal ureteropelvic junction obstruction. Those favoring early diagnosis and correction of obstruction in early infancy cite excellent return of function and superior surgical results compared with delayed repair. Others believe that hydronephrosis improves or resolves with growth in many instances. In the most widely quoted series, almost all such patients improved. This article attempts to separate opinion from fact. The arguments for early surgery and for observation, even when obstruction has been diagnosed, are reviewed. Several experiences with long-term surveillance are summarized.

How they begin and how they end: classic and new theories for the development and deterioration of congenital anomalies of the kidney and urinary tract, CAKUT

CAKUT are problems that often require surgical intervention or, in the worst case, lead to renal failure and the need for dialysis and/or renal transplantation. It is believed that these anomalies share a common genetic cause and to date there has been no good animal model with which to study these abnormalities. Although the abnormal interaction between the ureteral bud and metanephric blastema leads to renal hypodysplasia, vesicoureteral reflux, and ectopic ureters to name a few, the genetic and biochemical modulation of urinary tract development is not understood. Studies using the mouse strain mutant for angiotensin type 2 (AT2) receptors have given new insight into this mystery. The animals show defective apoptosis of undifferentiated mesenchymal cells in the area surrounding the developing kidney and urinary tract. This abnormal apoptosis may well interfere with the normal interaction between the ureteral bud and metanephric blastema resulting in CAKUT. This abnormal interaction would theoretically lead to preexisting intrinsic abnormalities of the kidney, which are programmed and take effect early in embryonic development. In the worst cases, the renal abnormalities would lead to progressive deterioration of renal function. Undoubtedly, there are more genes and biochemical modulators involved in this process other than the RAS and AT2 receptors. Our current animal model gives new and unique possibilities with which to study development of the kidney and urinary tract and ultimately seek ways of preventing an often debilitating disease process.

Are modern imaging techniques over diagnosing ureteropelvic junction obstruction?

Since the widespread use of real-time ultrasonography in the early 1980s, ureteropelvic junction obstruction has been diagnosed at earlier ages and prenatally on a presumptive basis. However, substantial controversy exists over the diagnosis and treatment of ureteropelvic junction obstruction. We conducted an epidemiological study to determine if modern imaging techniques are leading to the over diagnosis of ureteropelvic junction obstruction. Records were collected retrospectively from 3 hospitals serving 2 adjacent counties to determine the number of pyeloplasties performed in 1970 to 1992. The 2 university hospitals and 1 large private hospital provide a wide variety of services and choice of urologists, and so it was assumed that most patients requiring pyeloplasty in the area would be captured. Of the 555 pyeloplasties 240 (43%) were performed on children 12 years old or younger. Logistic regression analysis revealed an overall increase of pyeloplasties per year of 56.8% in 23 years, which was not markedly different from the population growth in the area in the same period (49.3%). A statistically significant increase in the number of pyeloplasties performed in the first year of life was noted. This trend appeared to begin in 1981: 8 pyeloplasties were performed in the first year of life between 1970 and 1980 compared to 91 between 1981 and 1992. Pyeloplasties in children 1 to 6 years old increased with time at a much lower rate that was not statistically significant and the number of pyeloplasties decreased in those 7 to 12 years old. Therefore, it appears that modern imaging techniques are not leading to an over diagnosis of ureteropelvic junction obstruction but to detection of the disease at an earlier age.

Infant pyeloplasty is a low-risk procedure

Early pyeloplasty for the treatment of congenital ureteropelvic junction obstruction to maximize nephron salvage is only justified if the potential hazards of operating on small infants are avoided. The records of all infants who underwent pyeloplasty by the authors over a 7-year period were analyzed. The outcome of surgery in the younger infant group (YIG; patients less than 2 months of age) was compared with that of the older infant group (OIG; patients more than 2 months of age). Preoperative evaluation in cases of mild or moderate hydronephrosis was directed toward ruling out a nonobstructed collecting system and included voiding cysto-urethrography and serial ultrasonography and/or dual isotope diuretic renography. Open pyeloplasty was performed if collecting systems had deteriorated or were demonstrated to be obstructed; it was also performed for severe cases of hydronephrosis. Postoperative assessment consisted of serial ultrasonography and/or nuclear imaging to confirm decompression and relief of obstruction. Thirty three pyeloplasties were performed in 31 patients in the YIG (two bilateral), and 33 were performed in 32 infants in the OIG (one bilateral). The only significant differences between the groups were as follows. Patients in the YIG were more likely to present in utero (87% v 53%; P < .01), whereas those in the OIG were more likely to present with a urinary tract infection (44% v 0%; P < .01). The YIG was more likely to have nephrostomy drainage postoperatively (67% v 45%; P < .01). In the overall series, there were five complications, all of which were postoperative infections requiring intravenous antibiotic therapy. Two occurred in the YIG and three in the OIG.(ABSTRACT TRUNCATED AT 250 WORDS)

Management of ureteral strictures by different modalities and effect of stents on upper tract drainage

Ureteral strictures were induced experimentally by unilateral partial ligation of the upper ureter on the left side in 56 female rabbits. Six weeks later, stricture stability was documented by intravenous urography. In all cases, there was fibrosis of the muscular wall of the ureter. The lumen, although narrowed to various degrees, was preserved in most animals, and moderate to marked hydronephrosis resulted. Control animals were not treated in order to study the natural progress of the stricture. The other strictures were treated either by dilation (catheter or balloon) with or without ureteral stenting, by intubated external ureterotomy, or by excision of the strictured segment and stented end-to-end anastomosis. Follow-up studies consisted of intravenous urography, renography, and histologic examination for 24 weeks. Ureteral dilation without and with 2 weeks of stenting could be an adequate treatment of strictures associated with a moderate degree of hydronephrosis. Intubated external ureterotomy did not give satisfactory results in any animal. Excision of the strictured segment with a stented anastomosis produced satisfactory results and has a great role in the treatment of the strictured ureter in comparison with the variable outcome of endourologic treatment. Stenting of the unobstructed ureter, tested in six rabbits, showed a positive correlation between renal obstruction and long-term ureteral stenting.

The pathophysiology of ureteral obstruction

Ureteral obstruction can have a variety of causes intrinsic or extrinsic to the kidney. The effects of obstruction are examined from the perspectives of duration, severity, totality, and the presence of complicating factors. There is a difference in the postobstructive pathophysiology depending on whether one or both ureters were obstructed. Atrial natriuretic peptide may be important in postobstructive diuresis, and preliminary evidence suggests a role for it as protection against nephron ischemia in acute obstruction. The potential for recovery of renal function after relief of obstruction depends on the duration and degree of obstruction, the condition of the contralateral kidney, and the presence or absence of infection. Ability to acidify the urine to pH < 6.0 preoperatively may be a good predictor of the recovery potential of an obstructed kidney. Urine concentrations of lysosomal enzymes such as N-acetylglucosaminidase also may be useful for this purpose, as may measurement of creatinine clearance in urine obtained from a nephrostomy tube.

The response of the fetal kidney to obstruction

In a fetal ovine model the renal effects of different anatomic levels of fetal urinary obstruction were studied. Parameters of prenatal renal growth and differentiation were characterized and correlated with the patterns of renal response to in utero obstruction. Complete ureteral or urethral obstruction was produced in the sheep fetus at 55 to 60 days of gestation. Animals were delivered and sacrificed at near term (140 days), and the kidneys were removed and prepared for analysis. Parameters examined included weight, histology, glomerular number and total surface area, as well as urinary sodium, creatinine, osmolarity and N-acetyl glucosaminidase. Three patterns of response were identified, producing hydronephrotic, cystic or dysgenetic kidneys. Hydronephrotic kidneys were usually the result of bladder outlet obstruction or ureteral obstruction with spontaneous urinary decompression. These kidneys were large (20.7 gm. versus normal 10.8 gm., p less than 0.0001), with thinning of cortical parenchyma that was structurally intact. Glomerular number and surface area were normal. Cystic kidneys were large (14.2 gm., p less than 0.05) with grossly visible cysts and an effaced medulla. Cortical structure was distorted by cysts but basic elements were intact. Glomerular number and surface area were not reduced. Dysgenetic kidneys were small (3.9 gm., p less than 0.0001) with markedly abnormal cortical structure and little recognizable medulla. Histological elements similar to fetal structures were present, including cuboidal/columnar tubular epithelium and peritubular mesenchymal collars. Glomerular number and surface area were significantly less than normal (p less than 0.001). The kidneys contralateral to unilaterally obstructed kidneys were significantly larger than normal (16.2 gm., p less than 0.0001), with normal histology, glomerular number and surface area, indicating in utero contralateral renal hypertrophy. Urinary sodium was variably affected in the hydronephrotic kidneys and was identical to plasma in the dysgenetic kidneys. These results indicate the technical feasibility of in utero models of urinary obstruction. Renal growth and patterns of differentiation were markedly affected by in utero obstruction. They should be a major focus in the investigation of congenital obstructive uropathy, since normal processes of renal growth and differentiation form the basis for postnatal function.

Nonoperative management of unilateral neonatal hydronephrosis

We followed nonoperatively 45 neonates with unilateral hydronephrosis and suspected ureteropelvic junction obstruction for 30 months, regardless of the degree of hydronephrosis, shape of diuretic renogram washout curve or initial degree of functional impairment. Of the patients 30 had mild hydronephrosis and no renal deterioration, while 15 had severe hydronephrosis, an obstructed diuretic renogram and markedly decreased hydronephrotic kidney function. During followup percentage and absolute renal function rapidly increased in all patients, hydronephrosis improved in 7 and contralateral compensatory hypertrophy did not develop in any. These findings help to define the natural history of untreated hydronephrosis, suggest that many newborn kidneys with severe hydronephrosis are not obstructed despite even profound initial decreases in renal function and demonstrate that traditional tests for diagnosing obstruction are inaccurate in this age group. Therefore, the methods for assessing obstruction and the indications for surgical intervention in these patients require reexamination.

Antenatally detected pelviureteric junction obstruction. Is non-operation safe?

We report follow-up data (minimum of 1 year) on 63 kidneys with antenatally detected pelviureteric junction obstruction, as defined by renographic criteria. The condition was bilateral in 10 patients (i.e. 20 kidneys), 2 patients had unilateral obstruction with contralateral multicystic dysplastic kidneys, and 41 patients had unilateral obstruction with a normal contralateral kidney. In the latter group, 29 (71%) had good function (greater than 40%) at initial assessment. Of the 63 kidneys, 24 (38%) were operated upon following initial assessment, mainly for impaired function. Of 39 patients, initially managed non-operatively, 8 (21%) were operated upon subsequently: 3 for deteriorating function (2 of whom have been reassessed and both have regained their lost function) and 5 for other renographic or ultrasonic indications). Of the original 63 kidneys, 31 (49%) continue to be managed non-operatively; 16 of these (52%) show improving ultrasound appearances, 8 of 17 studied show improved drainage, and all unilateral cases have stable good function. It is concluded that non-operative management of selected cases of antenatally detected pelviureteric junction obstruction is safe.

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)

Hydronephrotic atrophy after stable mild or severe partial ureteral obstruction: natural history and recovery after relief of obstruction

After stable mild or severe partial unilateral ureteral obstruction in rats, the ratio of renal dry weight to whole body weight changes in two phases. In a "destructive phase" of two to six weeks, slight weight reduction occurs in the kidneys with mild obstruction and pronounced weight reduction occurs in those with severe obstruction. Then, in a "steady-state phase", there is no further weight reduction in kidneys with either mild or severe obstruction. Relief of ureteral obstruction during the steady-state phase does not result in an increase in renal dry weight. We conclude that the development of hydronephrotic atrophy after stable mild or severe partial unilateral ureteral obstruction can not be influenced by relief of obstruction in the steady-state phase.

Simultaneous repair of bilateral ureteropelvic junction obstruction

Fifteen children with bilateral ureteropelvic junction obstruction underwent simultaneous repair as a single procedure. Dismembered pyeloplasty and ureterocalycostomy were the two procedures used. Ten were performed through anterior subcostal incisions. Posterior lumbotomy provided adequate exposure in 5 children and further contributed to shortened hospitalizations. The functional and anatomic results were excellent. Simultaneous bilateral pyeloplasty through posterior lumbotomy is a safe and cost-effective alternative to staged procedures for bilateral ureteropelvic junction obstruction.

A new test to predict reversibility of hydronephrotic atrophy after stable partial unilateral ureteral obstruction

In previous studies we showed that hydronephrotic atrophy develops only in the first weeks after stable partial ureteral obstruction, and does not progress thereafter. Relief of obstruction only in the "destructive phase" and not in the later "steady-state phase" seems to improve or prevent hydronephrotic atrophy. Since the duration of partial ureteral obstruction is often not known, we studied urinary enzymes of rat kidneys after stable partial unilateral ureteral obstruction to identify the destructive phase. We chose as an example of the tubular lysosomal enzyme N-acetyl glucosaminidase (NAG) and as an example of the brush border enzyme gamma-glutamyl-transferase (Gamma-GT). NAG concentration but not so much Gamma-GT concentration was higher in the urine of the obstructed kidneys than in the urine of the contralateral control kidney, in the first two weeks after operation, and then returned to normal. These observations lead to the conclusion that the "destructive phase" after ureteral obstruction can be identified by the appearance of high urinary tubular lysosomal enzyme content. The clinical implication is that the timing of relief of asymptomatic stable partial ureteral obstruction of unknown duration can be based on the concentrations of urinary lysosomal enzymes.

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.

Ureteropelvic junction obstruction: the effect of pyeloplasty on renal function

We studied preoperatively and postoperatively 41 children who underwent pyeloplasty for correction of unilateral ureteropelvic junction obstruction. Conventional radiological studies and quantitative radioiodine hippurate renal scans were obtained to assess the effect of pyeloplasty on the appearance of the kidney and its function. Analysis of the data suggests that the degree of improvement in renal function is related primarily to the age at which the surgical correction is accomplished and whether infection has occurred preoperatively.

Prognosis of radiologically non-functioning obstructed kidneys

Twenty patients found to have unilateral radiologically non-functioning obstructed kidneys on excretory urography (IVU), and who had normal contralateral kidneys, were further evaluated. Ultrasonography, radionuclide imaging and CT scan were carried out pre-operatively to try to predict which of the kidneys were potentially recoverable after relief of obstruction. Percutaneous nephrostomy was also performed on the last consecutive 7 patients 4 weeks before definitive treatment and the function of the kidneys determined daily. The patients were re-evaluated 2 months after the relief of obstruction. Ultrasonography, radionuclide imaging and CT scan were not found to be reliable in predicting whether these kidneys were potentially recoverable. We consider percutaneous nephrostomy a good procedure for obtaining prognostic information prior to definitive surgery.

Results of surgical reconstruction in patients with renal failure owing to ureteropelvic junction obstruction

During the last 6 years we managed 20 patients with renal failure owing to bilateral ureteropelvic junction obstruction (12) or ipsilateral ureteropelvic junction obstruction with contralateral renal agenesis, hypoplasia or dysplasia (8). Of the patients 11 underwent emergency dialysis for hyperkalemia, fluid overload or metabolic acidosis. Mean serum creatinine at presentation was 6.5 mg. per cent. Preliminary decompression of the obstructed kidney was done in 14 patients (20 renal units) with a serum creatinine of more than 3 mg. per cent at presentation. Reconstruction was done in all patients (31 of 36 renal units) after decompression and control of infection. Pyeloplasty was done in 24 renal units, vesicopyelostomy in 3 pelvic kidneys and calicoureteroplasty in 2 renal units with an intrarenal pelvis. Two renal units were removed. All patients showed improvement in renal function and the mean postoperative serum creatinine value was 2.05 mg. per cent. The postoperative serum creatinine value showed a significant positive correlation with the initial value as well as with the initial blood urea levels. However, the postoperative serum creatinine value showed no correlation with patient age, duration of symptoms, serum creatinine level after preliminary nephrostomy and presence or absence of urinary infection. Postoperative recovery (on the basis of postoperative serum creatinine levels) in patients who had bilateral ureteropelvic junction obstruction was not different from those with a solitary functioning kidney and ureteropelvic junction obstruction.

Management of ureteropelvic junction obstruction in neonate

Fetal hydronephrosis demonstrated by maternal ultrasonography should lead to early investigation during the neonatal period. Postnatal confirmation of the diagnosis of ureteropelvic junction obstruction usually can be established by combining the radiologic modalities of ultrasound, diuretic isotope renal scan, and voiding cystourethrography. Rarely should intravenous urography, antegrade pyelography, or cystoscopy and retrograde pyelography be necessary. Findings of high-grade obstruction and/or significantly diminished function on the affected side(s) should prompt early neonatal reconstruction. Pyeloplasty was performed within the first month of life in 17 infants (20 kidneys) diagnosed as having significant ureteropelvic junction obstruction. Early reconstruction in the neonatal period can be performed successfully with minimal complications and a relatively brief period of hospitalization. This may ultimately achieve maximal preservation of renal function.

Developmental determinants of recovery after relief of partial ureteral obstruction

Although obstructive nephropathy is a major cause of renal insufficiency at all ages, the functional consequences of relief of obstruction on the developing kidney are poorly understood. To evaluate recovery from chronic partial ureteral obstruction (CPUO) in the neonatal period, the left ureter of guinea pigs was constricted within the first 48 hours of life, and the obstruction was relieved 10 days later. At three and eight weeks of age, intraureteral pressure, number of perfused glomeruli (NPG), renal blood flow (RBF), and glomerular filtration rate (GFR) were measured. These animals were compared with sham-operated and unrelieved groups. Two additional groups underwent CPUO at five weeks of age, with persistent obstruction or relief in 10 days, and were also studied at eight weeks. In all animals, intraureteral pressure increased during ipsilateral ureteral obstruction and normalized following its release. Recovery of RBF and GFR after relief of ipsilateral CPUO in the newborns was only partial at eight weeks, with no renal growth or increase in NPG from three to eight weeks of age. In contrast, recovery of RBF in the adult was complete 10 days after relief of obstruction, with significant increase in GFR, and no decrease in renal mass or NPG. We conclude that if delayed, relief of CPUO in the neonate may not restore renal growth and functional maturation which have been impaired by CPUO.

Ureteropelvic junction obstruction in the fetus

Ureteropelvic junction (UPJ) obstruction is being detected with increasing frequency before birth. To clarify the natural history of fetal UPJ obstruction, we reviewed our experience managing 28 fetuses; there were 16 bilateral cases for a total of 44 renal units. None required decompression before birth. We found that fetal bilateral UPJ obstruction is associated with significant morbidity and mortality; resolution of fetal hydronephrosis secondary to UPJ obstruction is rare; antenatal diagnosis of UPJ obstruction improves clinical management by allowing early detection and appropriate treatment of otherwise clinically undetectable disease; oligohydramnios in the mature fetus with bilateral UPJ obstruction is an indication for early delivery and immediate repair; and prenatally diagnosed UPJ obstructions should be repaired as early as possible after birth.

Predictors of eventual end stage renal disease in children with posterior urethral valves

We reviewed the long-term outcome of 25 boys born with posterior urethral valves who were followed longitudinally. Patient age at diagnosis varied from 7 months intrauterine to 7 years postnatal, and the mean duration of followup was 9 years. Of the children 40 per cent had retardation of growth by the end of the followup period and 44 per cent had end stage renal disease. Of the various factors delay in diagnosis and the association of persistent vesicoureteral reflux seem to predict eventual end stage status. In 18 of 25 children the diagnosis of posterior urethral valves was made before they were 2 years old. Only 5 of these children have reached end stage disease status. In comparison, of 7 children whose diagnosis was delayed beyond 2 years 6 have end stage disease (p less than 0.01). Similarly, 7 of 9 children with persistent reflux had end stage disease compared to 4 of 16 who did not have persistent reflux (p less than 0.01). Since end stage renal disease status was reached at widely varying intervals a prolonged followup of children with this anomaly is necessary.

Ultrasonographic anatomy and diagnosis of fetal uropathies affecting the upper urinary tract. II. Nonobstructive uropathies

The authors describe the ultrasonographic anatomy and semiology of allowing detection of the main types of fetal non-obstructive 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.

Obstructive uropathies diagnosed in utero. The postnatal outcome--a study of 43 cases

The ultrasonic antenatal diagnosis of obstructive uropathies is now common. This study of 43 cases in which the mean follow-up is more than 2 years already allows us to show the importance of early diagnosis. The importance of a thorough postnatal examination is emphasised as well as the importance of preventing urinary tract infection. Although relief of the obstruction in the neonatal period in many cases allows an excellent recovery due to the exceptional qualities of the urinary tract at this age, there remain serious uropathies associated with significant renal dysplasia, for which ultrasonic diagnosis in utero is still insufficient. The results obtained allow us to be optimistic regarding the prognosis for many of these children.

The case for immediate pyeloplasty in the neonate with ureteropelvic junction obstruction

The 99mtechnetium-diethylenetriaminepentaacetic acid renal scan allows differentiation of ureteropelvic junction obstruction from multicystic kidney in most instances. Although renal function usually will improve at least a little after relief of obstruction, the young infant is privileged and more improvement can be expected than occurs usually in older children. Since an operation is as safe and results of pyeloplasty are as good in the neonate as in older infants or children early correction of ureteropelvic junction obstruction is advocated in otherwise healthy infants as soon as the diagnosis is established.

Recovery of radiologically functionless obstructed kidneys

Eleven patients had radiologically non-functioning and unilaterally obstructed kidneys with normal kidneys on the other side. The kidneys were divided into three groups according to the urinary pH of the obstructed kidney at operation: Group 1 (pH 6.0 or less); Group 2 (pH 6.1-7.1); Group 3 (pH greater than 7.1). The obstruction was corrected in all patients despite the pre-operative radiological findings or the morphological appearance at operation. Radiological recovery was assessed 2 months post-operatively and was found to be good in all patients in Group 1. In Group 2, recovery was good in one patient, moderate in two and absent in one. In Group 3 there was no evidence of radiological recovery in either patient.

Management of ureteropelvic junction obstruction in infants

The frequent use of fetal ultrasound is allowing early (prenatal) diagnosis of numerous uropathies previously delayed until the child either became symptomatic or had a palpable mass. We would anticipate an increasing number of neonates presenting for repair of obstructions, especially ureteropelvic junction obstruction. To evaluate our experience with this disorder in infants we reviewed our experience with ureteropelvic junction obstruction during the last 6 years in 16 infants less than 1 year old. Principles of evaluation, surgical techniques and results are presented. To date, no secondary procedures have been necessary and most neonates have shown dramatic improvement in the parenchymal mass and intrarenal anatomy.

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.

Progression to end-stage renal disease in children with obstructive uropathy

The course of 54 patients (35 boys and 19 girls) with end-stage renal disease resulting from obstructive uropathy was reviewed. The mean age at the initial sign of obstructive uropathy was 3.5 years. Twenty-two patients (41%) manifested evidence of obstructive uropathy during the first year of life. The mean age at the time of onset of ESRD (dialysis) was 12.2 years and was similar in boys and girls. The mean time interval between the first sign of obstructive uropathy and the initiation of dialysis was nine years. Fourteen patients operated upon at less than one year of age developed ESRD one to 20 years (mean ten years) following their initial surgery. Progression to ESRD occurred despite appropriate surgical management, including corrective as well as diversionary urologic procedures. However, because the patients were selectively referred for care of ESRD, no assessment of the incidence of ESRD caused by obstructive uropathy was possible. The data indicate that prolonged follow-up periods are necessary to assess the ultimate outcome of renal function in young patients with obstructive uropathy. Despite early intervention and intact renal function for many years during childhood, progression to ESRD may occur.

Kidney function and histopathological changes in unilateral hydronephrosis with special reference to bilharzial ureter

Fifty-six patients with unilateral hydronephrosis were the subject of this study. The patients were classified into 4 groups according to the stage of hydronephrosis as assessed by radiological criteria. Split kidney function, histopathological studies, and measurement of intraureteral pressure were performed. Urinary Bilharziasis was held responsible for obstructive nephropathy in 77% of cases. Complicating urinary infection was present in 66%. The study has shown that creatinine excretion was slightly decreased in early, moderate, and moderately advanced hydronephrosis. On the other hand, a marked lowering of urine osmolality was found even in the early stages of hydronephrosis. The hydronephrotic kidney was found to be a salt losing one only in early, moderate, and moderately advanced hydronephroses, but not in the very advanced cases. The histopathological changes were mainly tubular, but some cases showed proliferative changes in the glomeruli. Eradication of urinary Bilharziasis and early treatment of this disease would markedly contribute to the prevention of obstructive nephropathies in countries where this disease is endemic.