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

Clinical value of serum MMP-3 in chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is defined as the progressive deterioration of renal parenchyma and decline in renal unit function. In the early stages of CKD(G1 + G2), symptoms are usually not obvious and cannot be effectively recognized on the basis of available clinical markers. Progression to the middle and late stages of CKD results in severe kidney damage with multiple complications causing adverse outcomes, including death. Therefore, the early diagnosis and monitoring of CKD is critical. Matrix metalloproteinase-3 (MMP-3), an extracellular matrix-degrading enzyme, plays an important role in kidney diseases. However, the clinical significance of serum MMP-3 levels in CKD has rarely been reported.

METHODS

We quantified the serum MMP-3 levels of 237 patients with CKD and 96 healthy individuals by using a highly sensitive time-resolved fluorescence immunoassay and analyzed differences in MMP-3 levels among the stages of CKD and the correlations of these changes with clinical indicators.

RESULTS

The serum MMP-3 concentrations of patients with CKD (171.76 ± 165.22 ng/mL) were significantly higher than those of healthy controls (34.05 ± 22.93 ng/mL; P < 0.0001). In CKD, serum MMP-3 levels were significantly correlated with estimated glomerular filtration rate (eGFR) (r =  - 0.5804, P < 0.0001), serum creatinine (CREA) (r = 0.5823, P < 0.0001), blood urea nitrogen (BUN) (r = 0.6106, P < 0.0001), and protein-to-creatinine ratio (r = 0.4992, P < 0.0001). Randomized forest analysis finds CREA, BUN, and MMP-3 most significant influences on CKD disease severity. The critical value of MMP-3 concentration of 40.39 ng/mL combined with eGFR was effective in diagnosing positive patients in the early (G1 + G2) stage of CKD and showed a positivity rate of 73.45 %. Moreover, in the early stages of CKD, patients with CKD who had serum MMP-3 concentration > 100 ng/mL had more severe renal impairment and inflammation than those with CKD who have lower serum MMP-3 concentrations.

CONCLUSION

Elevated serum MMP-3 levels are correlated with decreased kidney function in CKD progression, and patients with concomitant inflammation may express high levels of serum MMP-3. Serum MMP-3 may assist eGFR in improving the diagnosis of patients with early CKD.

Kidney disease among children in sub-Saharan Africa: systematic review

The global burden of kidney disease is increasing, and several etiologies first begin in childhood. Risk factors for pediatric kidney disease are common in Africa, but data regarding its prevalence are lacking. We completed a systematic review of community-based studies describing the prevalence of proteinuria, hematuria, abnormal imaging, or kidney dysfunction among children in sub-Saharan Africa (SSA). Medline and Embase were searched. Five hundred twenty-three references were reviewed. Thirty-two references from nine countries in SSA were included in the qualitative synthesis. The degree of kidney damage and abnormal imaging varied widely: proteinuria 32.5% (2.2-56.0%), hematuria 31.1% (0.6-67.0%), hydronephrosis 11.3% (0.0-38.0%), hydroureter 7.5% (0.0-26.4%), and major kidney abnormalities 0.1% (0.0-0.8%). Serum creatinine was reported in four studies with insufficient detail to identify the prevalence renal dysfunction. A majority of the studies were performed in Schistosoma haematobium endemic areas. A lower prevalence of kidney disease was observed in the few studies from nonendemic areas. Published data on pediatric kidney disease in SSA are highly variable and dependent on S. haematobium prevalence. More community-based studies are needed to describe the burden of pediatric kidney disease, particularly in regions where S. haematobium infection is nonendemic.

Obstructive uropathy is associated with polyomavirus viremia in pediatric kidney transplantation

BKVN leads to allograft dysfunction following kidney transplantation and is preceded by BK viremia. Studies in pediatric kidney transplant recipients reveal an incidence of viruria ranging from 18% to 33%, viremia 6-16%, and BKVN 2-8%. Specific risk factors have not been clearly elucidated. Retrospective chart review of pediatric kidney transplants performed from January 2005 through December 2009; to identify risk factors associated with BK viremia in pediatric kidney transplant recipients from a single center. Of the 93 patients who received kidney transplants in the study period, 22 (24%) developed BK viruria, including 12 (13%) who developed viremia. One patient with viremia (1.6%) had BKVN. Obstructive uropathy was identified as the cause of ESKD in 22 (24%) of all recipients. 27% (n = 6) of these 22 patients developed viremia, while only 8.5% (6/71) with ESKD from another cause had viremia (p = 0.001). No other examined variable differed between the two groups. Although the overall incidence was no higher than other reported series, we identified that BK disease was more frequent in children with OU. A higher index of suspicion for invasive BK disease is necessary in patients with OU who receive kidney allografts. Transplant protocols may need to consider underlying cause of ESKD when designing screening protocols for BK disease in children after kidney transplantation.

Long-term follow-up of renal function in patients after surgery for obstructive uropathy

In this prospective study, selected biochemical markers of glomerular and tubular function, proteinuria, and ultrasound findings in 62 pediatric patients who underwent surgery for obstructive uropathy were examined. Patients were younger than 12 months, normocreatininemic at the time of surgery, and examined at a mean age of 6.3+/-0.9 years. Out of the markers tested, serum concentration of cystatin C was significantly higher in patients when compared with the control group (p<0.001), and serum creatinine concentration was within reference interval in all patients. With respect to tubular function, 26% of patients had decreased concentration ability. Proteinuria was detected in 4.8% of patients. On ultrasound, 66.7% of kidneys after surgery had residual dilatation of the renal pelvis. The patients thrive well, and their somatic parameters do not differ from their peers. Half of the patients had one or more urinary tract infections from the date of surgery to the date of examination. Study results support the need for long-term nephrologic follow-up in patients after surgery for obstructive uropathy. The hypothesis that renal function in patients undergoing surgery aged younger than 3 or 6 months is better when compared with those aged 6 to 12 months has not been confirmed.

A review of compliance studies in kidney transplanted adolescents

Strong evidence exists that compliance with the treatment regimen is a major problem for many transplant patients. Noncompliance with the treatment regimen is particularly evident among kidney-transplanted adolescents. Research has not examined the adolescents' experience of living with a kidney transplant. Provides a review of the literature seeking to explain the causes of noncompliance in the population group. Although the studies referred to here provide insights into the situation, many lack reliability and validity because of methodological limitations. They also point to a gap in understanding the condition from the point of view of the adolescent. A more useful approach, therefore, is to use a qualitative research methodology. Such an approach has been shown to be useful in a study of diabetic adolescents, and offers promise for the greater understanding of kidney-transplanted adolescents and the impact the medical regimen has on them. With improved understanding comes the ability of health practitioners to better meet their needs in terms of improving the quality of their post-operative lives.

PREVENTION OF RENAL FIBROSIS BY SPIRONOLACTONE IN MICE WITH COMPLETE UNILATERAL URETERAL OBSTRUCTION

PURPOSE

Recent data suggest that aldosterone directly mediates cardiac fibrosis and hypertensive nephrosclerosis. We conducted experiments to determine whether administration of spironolactone, a mineralocorticoid receptor antagonist, reduced renal fibrosis in an experimental model of obstructive uropathy.

MATERIALS AND METHODS

Complete unilateral ureteral obstruction (UUO) was created surgically in 8 to 10-week-old male C57BL/6 mice by placing sutures around the right ureter. Spironolactone (50 mg/kg/daily) or 1% dimethyl sulfoxide vehicle was administered by subcutaneous injection for 1 to 2 weeks, and renal fibrosis was assessed by measuring trichrome staining and type I collagen deposition in the kidney.

RESULTS

UUO lasting 1 week was associated with minimal parenchymal damage and spironolactone had no demonstrable effect. In contrast, administration of the mineralocorticoid antagonist (8 mice) for a 2-week period significantly reduced renal fibrosis in the obstructed kidney, compared to mice given the dimethyl sulfoxide vehicle (9). The beneficial effect of spironolactone treatment was not associated with any changes in serum potassium or aldosterone concentration, or urinary concentrations of sodium or potassium.

CONCLUSIONS

Administration of spironolactone reduced renal fibrosis in mice with UUO. These findings suggest that clinical trials are warranted to determine the efficacy of aldosterone antagonists in conjunction with angiotensin converting enzyme inhibitors and/or angiotensin receptor blockers as renoprotective agents in patients with obstructive uropathy.

Beneficial effects of continuous overnight catheter drainage in children with polyuric renal failure

OBJECTIVE

To determine the possible beneficial effect of providing decompression of the collecting system by continuous overnight catheter drainage (COCD) in children with progressive renal disease and dysfunctional bladder syndrome, commonly associated with polyuria which may overwhelm bladder capacity.

PATIENTS AND METHODS

COCD was used in seven patients (four boys) with progressive polyuric kidney failure associated with dysfunctional bladders (current age 18.7 years, SD 5; age at COCD 12 years, SD 6). Five children had surgical bladder augmentation and all were prescribed daytime intermittent catheterization (IC) for a mean (SD) of 4.7 (3.4) years before COCD. All had significant polyuria, with a mean (SD) urine output of 2370 (971) mL/m2 per day.

RESULTS

The mean (SD) glomerular filtration rate at the start of COCD was 48 (21) mL/min/1.73 m2, which is currently stable in the five patients continuing treatment. The mean (SD) duration of COCD was 4.9 (2) years. One patient showed no improvement and had a pre-emptive transplant within 1.2 years; another was transplanted after 5.5 years. Six patients showed evidence of benefit from COCD, with significant attenuation in the slope of renal functional decay (P = 0.02) and a mean (sd) prolongation of the predicted time to end-stage renal disease of 12.2 (5.6) years (P < 0.002). Hospitalization for febrile urinary tract infections was decreased from a mean (sd) of 1.7 (1.4) to 0.4 (0.7) times (P = 0.03) in the first year of COCD and eliminated by the second year (P < 0.01).

CONCLUSION

COCD of the dysfunctional bladder in patients with progressive polyuric renal failure appears to offer the potential for preserving kidney function in selected patients. It does not replace surgical bladder augmentation or daytime IC in the core management.

Idiopathic focal segmental glomerulosclerosis

Idiopathic focal segmental glomerulosclerosis (FSGS) is a primary glomerular disease that essentially represents a form of chronic, progressive renal fibrosis for which there is no discernible cause. Often presenting with or eventually manifesting the nephrotic syndrome, this disease is increasing in incidence in both children and adults. Therapy continues to be a challenge, although some patients clearly respond to corticosteroids or cyclosporine with a decrease in, or remission of, proteinuria. A favorable response is associated with a decreased likelihood of progression to kidney failure. Given our clinical experience and recent advances in understanding the genetics of FSGS, a stochastic model of disease pathogenesis can be proposed.

Role of endogenous nitric oxide in unilateral ureteropelvic junction obstruction in children

BACKGROUND

Obstructive nephropathy leads to tubulointerstitial fibrosis and loss of renal function. Nitric oxide has been shown to have antifibrotic properties. We examined nitric oxide synthase (NOS) activity and expression in kidneys from children who underwent surgery release of unilateral ureteropelvic junction (UPJ) obstruction in relation to clinical and histologic parameters.

METHODS

NOS activity and the expression of NOS isoforms measured at the mRNA level by reverse transcription-polymerase chain reaction (RT-PCR) assay were determined in tissue obtained by biopsy from obstructed kidneys of 18 children at the time of pyeloplasty. Tissue from kidneys removed because of various malignancies were issued as control.

RESULTS

A significant increase in calcium/calmodulin-independent NOS activity (iNOS) and iNOS mRNA expression was found in the medulla of obstructed kidneys. Calcium/calmodulin-dependent NOS activity (cNOS) and endothelial (eNOS) mRNA, by contrast, were increased in the cortex from obstructed kidneys. A role of tumor necrosis factor-alpha (TNF-alpha) on enhanced iNOS was suggested by the finding of increased urine levels in obstructed pelvis. Increased interstitium macrophage number, by immunolabeling of CD68, was related to the delay in obstruction release and to decreased glomerular filtration rate (GFR) at surgery. A positive linear relationship was found between cNOS activity in cortex and creatinine clearance. The degree of interstitial fibrosis correlated negatively with cNOS activity in cortex.

CONCLUSION

In kidneys from children with UPJ obstruction an increased activity and expression of iNOS in medulla and cNOS-dependent eNOS in cortex were demonstrated. A role of cNOS in modulating GFR and interstitial fibrosis can be suggested. Prolonged UPJ obstruction would lead to a worsened prognosis on renal injury.

Antenatally detected, unilateral dilatation of the renal pelvis: a critical review. 1. Postnatal non-operative treatment 20 years on--is it safe?

BACKGROUND

Non-operative postnatal treatment of antenatally detected hydronephrosis, consistent with pyelo-ureteral obstruction, has functioned well during follow-ups of up to 17 years. However, doubts are still expressed and, admittedly, the final verdict on this new policy is still remote. The purpose of this review is to define the state of art and to serve as a background for future randomized clinical trials, which still are missing.

METHODS AND MATERIAL

From the literature, 6 patient series were chosen based on the following criteria: publication during the 1990s to allow for a longer follow-up and better diagnostic tools; consecutive patient series; and compliance with a 50-point form. Data, from 593 kidneys, were then pooled. Result of the compilation: Four hundred and seventy-four kidneys, with differential function >40%, were allocated to expectancy and followed for 2-144 (mean 23) months. Four hundred and twenty-five (90%) were successful, independent of presence of caliectasis. Forty-nine (10%) had delayed pyeloplasty, after which declined function mostly improved / normalized - similar to 108 kidneys with early pyeloplasty because of an initial differential function <40%. Hydronephrotic size and isotope wash out rate did not predict outcome.

CONCLUSIONS

These figures agree with other reports: few cross-overs and functional recovery also after delayed operations. Thus, so far, with a caveat for future deterioration, expectancy seems safe and promising, in unilateral and probably in bilateral cases with normal function, although perhaps not in solitary kidneys. Hopefully, this review, together with a forthcoming communication on long-term risks and urgent research needs, will help to design future randomized clinical trials.

Dysplastic and polycystic kidneys: diagnosis, associations and management

Cystic and bright kidneys can pose a significant diagnostic dilemma when discovered as an incidental finding at the time of a routine fetal ultrasound scan. There are diverse aetiologies with equally variable implications for the prognosis in the affected fetus, and for future pregnancies. Accurate antenatal diagnosis in the absence of any positive family history is often not possible and a team approach to management (to include the fetal medicine specialist, paediatric nephrologist or urologist, geneticists and in some cases, pathologist) is essential. In this review we will attempt to describe the embryology and aetiology of these conditions and suggest an approach to management.

Obstructive nephropathy in children: long-term progression after relief of posterior urethral valve

BACKGROUND

Approximately one third of children with end-stage renal disease have the illness because of urinary tract malformations, obstructive uropathy, and hypoplasia/dysplasia. The significant drop in infant mortality from obstructive uropathies in recent decades, attributable to prenatal diagnosis with renal ultrasonography and coordinated surgical and medical care, necessitated a reevaluation of the long-term outcome.

METHODS

To that end, we examined the long-term progression of obstructive nephropathy after neonatal relief of posterior urethral valves in our center over a span of 21 years, with diagnosis and care being provided by the same pediatric and urology team.

RESULTS

The 10 consecutive cases of posterior urethral valves represented 7% of all patients with congenital malformative uropathies seen over this period. The following procedures were performed: primary valve ablation (90%) and vesicostomy (40%). Seventy percent of patients progressed to end-stage renal disease over a (mean +/- standard error of the mean) follow-up of 11.3 +/- 2.1 years. The linear plot of the log of the inverse of serum creatinine versus time suggested unrelenting progression. The rate of progression was rapid after serum creatinine exceeded 5 mg/dL but the rate was slow and steady from serum creatinine of 1.5 to 5 mg/dL.

CONCLUSIONS

To test the effect of a therapeutic intervention to ameliorate the rate of progression, this steady and prolonged progression of 0.5 mg/dL per year between serum creatinine concentration of 1.5 to 5 mg/dL would seem the optimal study.

Ventricular flutter in a neonate--severe electrolyte imbalance caused by urinary tract infection in the presence of urinary tract malformation

Male infants under the age of 3 months presenting with pyelonephritis in the presence of urinary tract malformation (UTM) are prone to transient pseudohypoaldosteronism. This may resemble congenital adrenal hyperplasia (CAH). Hyponatremia, hyperkalemia, dehydration, and metabolic acidosis are the primary findings that permit the diagnosis of CAH. We report a case of transient pseudohypoaldosteronism resulting from pyelonephritis and vesicouretric reflux. The 17-day-old boy presented with a salt-losing episode simulating adrenal insufficiency. An initial diagnosis of CAH was made. The severe metabolic imbalance resulted in ventricular flutter that resolved after correction of the metabolic acidosis and the electrolyte and volume depletion. Early diagnosis is essential because both conditions are potentially fatal and treatment differs significantly. Differential diagnosis may be achieved by urinalysis and abdominal ultrasound scan.

Balance between matrix synthesis and degradation: a determinant of glomerulosclerosis

In glomerular health and disease, the balance between extracellular matrix (ECM) protein synthesis and degradation determines the amount of matrix that accumulates locally. While cell and whole animal regulation of ECM synthesis has been the subject of ongoing study, attention has become focused on proteases that degrade matrix components only recently. Two major ECM protease systems have been defined. The plasminogen activators (PAs) are serine proteases that have matrix-degrading capability and also activate plasminogen to plasmin. Plasmin not only degrades ECM proteins, but also may activate members of the matrix metalloproteinase (MMP) family which comprise the second major matrix-degrading system. Specific biological antagonists of both the PAs and the MMPs tightly regulate proteolysis by these enzymes. All of these enzymes and inhibitors have been detected in the kidney, and their expression may be altered to facilitate ECM accumulation in conditions associated with matrix expansion, such as glomerulosclerosis. Work is in progress to determine how these systems are regulated in the kidney and to further define their contribution to the sclerotic process.

The posterior urethral valve uropathy: results of treatment

Nineteen children treated for posterior urethral obstruction due to congenital valve in the University of Benin Teaching Hospital, Benin City, Nigeria, over a 9-year period have been analysed. Their ages ranged from birth to 12 years. Results show that associated kidney pathology may be irreversible even after successful excision of the valve. This determines the final prognosis, which is worse the younger the child at presentation.

Familial renal adysplasia

Renal dysplasia and agenesis as isolated findings are usually considered sporadic, noninherited abnormalities. We report three kindreds with familial renal adysplasia. Two or more children were affected in each of the families and at least one member--whether proband, sibling, or parent--had a clinically silent anomaly. Normal kidneys in the parents did not preclude the occurrence of renal adysplasia in more than one child. The empiric risks for offspring and first-degree relatives were 50% and 25%, respectively, suggesting a strong genetic factor such as a major dominant gene with variable expression. Because the disease appears to be genetic in some cases of renal adysplasia, careful screening of the proband's family, subsequent children, and pregnancies is important for the purpose of accurate genetic counseling.

Urinary PGE2 in rats with chronic partial unilateral ureteral obstruction

Urinary prostaglandin E2 (PGE2) was measured in Munich-Wistar rats with surgically created chronic partial unilateral ureteral obstruction (UUO). Mean values of bladder urine PGE2 were higher in sham than in UUO (24.5 +/- 14.4 vs 12.9 +/- 8.2 ng/mg creatinine, respectively, P less than 0.05). Following diuresis, both ureters were cannulated and urine was collected. PGE2 excretion was increased in sham (66.5 +/- 34.4 and 70.1 +/- 44.5 ng/mg creatinine, left and right, respectively). But in UUO, the obstructed kidney excreted less PGE2 than the contralateral kidney (32.1 +/- 6.0 vs 62.3 +/- 40.4 ng/mg creatinine, obstructed vs contralateral, respectively, P = 0.08). PGE2 synthesis was then determined in separated renal medullary and cortical slices. Renal medullary slices from kidneys with severe obstruction synthesized less PGE2 than the contralateral unobstructed side (3.30 +/- 1.22 vs 10.52 +/- 3.23 ng/mg wet wt-30 min, respectively, P less than 0.05) and failed to respond to arachidonic acid stimulation with any significant increase in PGE2 synthesis (3.30 +/- 1.22 vs 4.47 +/- 1.04 ng/mg wet wt-30 min, baseline vs stimulated). In contrast, contralateral unobstructed kidney slices responded with a significant increase in PGE2 synthesis (10.52 +/- 3.23 vs 21.10 +/- 2.50 ng/mg wet wt-30 min, baseline vs stimulated, P less than 0.05). We conclude that chronic partial UUO in the Munich-Wistar rats resulted in significantly less PGE2 elaboration.

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)

Fetal intervention in obstructive uropathy: prognostic indicators and efficacy of intervention

Management of the fetus with bilateral hydronephrosis is controversial; ability to predict outcome and efficacy of prenatal intervention are unknown. We studied 40 fetuses referred for ultrasonography, examination of fetal urine, and possible therapy. We retrospectively assigned fetuses to a good prognosis group if fetal urine was hypotonic (sodium less than 100 mEq/L, chloride less than 90 mEq/L, osmolarity less than 210 mOsm/L) and there was no ultrasonographic evidence of dysplasia; we assigned fetuses to a poor prognosis group if even one criterion was abnormal. Survival was greater in the good prognosis group than in the poor prognosis group (81% vs 12.5%; 87% vs 30%, excluding abortions) (p less than 0.005). We then attempted to assess the efficacy of prenatal urinary decompression by comparing outcome within the good and poor prognosis groups. Survival with intervention was greater in both the good prognosis group and the poor prognosis group (89% vs 70% and 30% vs 0%). In 6 of the 8 survivors in the good prognosis group, severe oligohydramnios was reversed by decompression. We conclude the fetal urine electrolyte levels and ultrasonographic appear helpful in predicting residual fetal renal function and neonatal outcome and that prenatal decompression may prevent the development of fatal pulmonary hypoplasia.

Follow-up of infants with obstructive uropathy detected in utero and treated surgically postnatally

Thirty-four infants with obstructive uropathy detected by prenatal ultrasonography at 34 +/- 0.56 weeks (SE) had surgery during the first 2 years of life. The growth and renal function of the 25 children after being followed for over 1 year are described. Twelve children had unilateral disease, and 13 had bilateral disease. All 12 children with unilateral disease grew at or above the fifth percentile and had normal renal function (glomerular filtration rate, 101 +/- 7 mL/min/1.73 m2). Thirteen children with bilateral disease were followed for 26.1 +/- 3.4 months. Growth was good: 10 of the 13 grew at or above the fifth percentile. The serum creatinine was 0.7 +/- 0.2 mg/dL, and the glomerular filtration rate was 91 +/- 10 mL/min/1.73 m2. One child required chronic dialysis. The prenatal diagnosis of urinary tract anomalies followed by early intervention may improve the long-term outcome of children with obstructive uropathy.

Urinary obstruction reduces glomerulogenesis in the developing kidney: a model in the rabbit

To study the effect of unilateral ureteral obstruction upon the development of the kidney a fetal rabbit model was developed. A total of 27 rabbits underwent ureteral ligation in utero (24 days after conception) and 34 underwent ureteral ligation at term (30 days after conception). Two rabbits undergoing in utero ureteral ligation underwent decompression at term. Fetal development was evaluated by glomerular counts of mid sagittal sections of the kidney and compared to that of 67 normal rabbits, 43 littermates of rabbits undergoing surgery, 12 rabbits with missed ligation of the ureter and 4 whose ureters were ligated after the period of nephrogenesis had ended (57 days after conception). In the normal rabbit term occurred at 31 days after conception but nephrogenesis continued until 48 days when the cortical glomerular count reached approximately 650. Ligation of the ureter at 24 days led to a rapid decrease in cortical glomerular counts in the obstructed kidney but glomeruli developing within the nephrogenic cap were more resistant to the effects of the obstruction. Glomerular counts in the nonobstructed kidney were similar to those of littermates. Ligation of the ureter at 30 days produced similar findings. All operated fetuses and their littermates showed glomerular counts less than that of normal animals of the same age. In the 2 fetuses who underwent ureteral ligation at 24 days after conception and decompression at 30 days after conception sacrifice at 42 days after conception revealed that glomerular counts that had been reduced by 95 per cent by the obstruction showed 80 per cent recovery after decompression. It appears that renal development can be quantified by glomerular counts in the rabbit. Obstruction during fetal development reduces these counts while in a limited sample decompression of the obstructed kidney partially restores them. This model appears to be suitable for the study of the effects of fetal surgery upon renal function.

Risk of progressive kidney damage after acute leukemia

In order to evaluate potential long-term renal sequelae of childhood leukemia, we studied 62 consecutive patients successfully treated for acute leukemia in 1971-83. At the time of this follow-up study they had been off therapy for 1-9 years and they were all in complete remission. Relative renal length was measured from X-ray films of intravenous pyelograms. Median relative renal length prior to the start of chemotherapy was +1.0 SD (range -1.5 to +4.0, n = 35), at discontinuation of therapy +0.5 SD (range -1.5 to +2.2, n = 22), and at follow-up -0.3 SD (range -3.9 to +2.6, n = 61). The mean calculated decrease in relative kidney size was 0.1 SD unit per year during the follow-up time. The median glomerular filtration rate was 110 ml/min/1.73 m2 (range 70 to 164). Six of 60 patients had glomerular filtration rates below 85 ml/min/1.73 m2. Three patients had some evidence of tubular dysfunction documented by increased excretion of urinary amino acids and/or beta-2-microglobulin or by reduced concentrating capacity. In spite of these abnormalities, we conclude that in most long-term survivors of childhood leukemia renal size and function are relatively well preserved. However, slightly reduced glomerular filtration rates in some patients indicated renal damage. A longer follow-up time is needed to find out whether the decrease in relative renal length is still continuing.

Posterior urethral valves. Role of temporary and permanent urinary diversion

Between 1960 and 1983, 67 boys were treated for posterior urethral valves. Despite adequate valve ablation, azotemia eventually developed in 19, and they underwent permanent urinary diversion. Normal renal function was not achieved in any of these children. Diversion does not appear to have changed the natural course of their renal insufficiency, which is most likely secondary to damage incurred prior to their initial presentation. Prognostic factors useful to identify this select population are examined.

Prospective management of neonates with pelviureteric junction stenosis. Therapeutic strategy based on 99m Tc-DPTA studies

A prospective therapeutic strategy based on separate glomerular filtration rate (SGFR) was evaluated in 14 prenatally detected asymptomatic neonates, suspected of having pelviureteric junction obstruction. The patients with low SGFR were referred for pyeloplasty with the hope to improve the renal function. A marked improvement occurred in only one patient, although the drainage function (furosemide test) did improve in all cases. A conservative attitude was adopted for those children with normal SGFR. In 6 of them, a progressive increase of SGFR was noted, related to the normal maturation of the function, followed by a stabilization in the normal range. In 1 patient, a sudden decrease of SGFR was observed around 1 year and the patient was shifted into the surgical group. In this patient, an initial partial response of the kidney to a furosemide injection changed into a persistent non-response, whereas in the other non-operated patients, partial or good response was always recorded, although the responses were essentially variable on successive tests. On the basis of these data, the protocol was slightly modified, the patients with persistent non-response to furosemide after 6 months of life being shifted to the surgical group.

Urosepsis in infants with vesicoureteral reflux masquerading as the salt-losing type of congenital adrenal hyperplasia

Three male infants with vomiting, dehydration, hyponatremia, hyperkalemia and metabolic acidosis were found to have vesicoureteral reflux (VUR) and urinary tract infection. Two were initially thought to have the salt-losing form of congenital adrenal hyperplasia. Although prompt diagnosis of this potentially fatal condition is critical, its mimicry by urosepsis in infants with VUR is actually more common. Infection probably causes unresponsiveness of the distal renal tubules to aldosterone.

Early experience with open fetal surgery for congenital hydronephrosis

The fetus with severe bilateral hydronephrosis and associated oligohydramnios in the second trimester is doomed at birth by ongoing pulmonary and renal damage. Since decompression with percutaneously placed catheters anesthetic, surgical, and tocolytic techniques for open fetal anesthetic, surgical, and tocolytic techniques for open fetal urinary tract decompression in animals, and have now applied those techniques to a small group of five patients. One had bilateral ureterostomies and the subsequent four had marsupialization of the bladder. All pregnancies proceeded to cesarean delivery at 32 to 35 weeks' gestation. There was no long-term maternal morbidity, and two mothers have since experienced normal pregnancies. Three fetuses had return of normal amniotic fluid dynamics, and all three had adequate pulmonary function at birth, suggesting that fatal pulmonary hypoplasia associated with early severe oligohydramnios had been reversed. Two neonates died at birth with pulmonary hypoplasia. One had no amniotic fluid even after decompression, and the other had some amniotic fluid after decompression but a tiny chest cavity due to the long period of severe oligohydramnios before decompression. Of the three surviving infants, one had normal renal function when she died of unrelated causes at 9 months of age. One has normal renal function at 23 months and the third had failing renal function at 2 1/2 years and has grown and developed normally, but will require renal transplantation. We have now developed selection criteria that would exclude from treatment the two fetuses who died of pulmonary hypoplasia and the one who developed renal failure.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Prenatal diagnosis and management of bilateral hydronephrosis

This report reviews the management of the fetus with congenital hydronephrosis (CH), a challenging diagnostic and therapeutic problem. Experimental models of obstructive uropathy have produced histologic changes similar to those seen in kidneys of human neonates with congenital hydronephrosis. Relief of obstruction in utero in these models has been shown to prevent some of the dysplastic changes caused by obstruction. These studies have formed the theoretical basis for in utero decompression to restore amniotic fluid dynamics to prevent death from pulmonary hypoplasia, and reverse or arrest dysplastic morphogenesis. The development of prognostic criteria has greatly aided in selection of appropriate fetuses for intervention. These criteria include: (1) Na less than 100 mEq/l; (2) Cl less than 90 mEq/l; (3) osmolarity less than 210 mosmol; (4) sonographic appearance of the fetal kidneys; (5) amniotic fluid status; (6) urine output at fetal bladder catheterization. All fetuses should have ultrasonography to exclude other anomalies, and karyotype analysis to exclude chromosomal abnormality. If amniotic fluid volume is normal, the pregnancy is followed with serial ultrasound examinations. If oligohydramnios develops, a prognostic evaluation is performed, including fetal bladder catheterization. If the fetus has poor residual renal function, on the basis of prognostic criteria, appropriate counseling may be given. If the fetus has good residual renal function, depending on lung maturity, it can be delivered early for corrective surgery. If diagnosed prior to lung maturity in utero, decompression by either vesicoamniotic shunting or open fetal surgery may be attempted in the highly selected case.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term follow-up of separate glomerular filtration rate in partially obstructed kidneys. Experimental study

An often encountered assumption is that non-relieved renal obstruction will lead soon or late to progressive deterioration of the renal function. The effect of non-relieved partial ureteral obstruction on the separate glomerular filtration rate (SGFR) was studied throughout the whole life of a series of rats, who were submitted at the age of 3 months to partial obstruction of the left ureter. An initial and variable postoperative SGFR decrease was gradually observed, but after this period, SGFR remained stable until the natural death of the animal.

Fetal surgery for obstructive uropathy: rational considerations

The widespread use of high resolution dynamic ultrasound imaging methods in obstetrics now permits recognition of structural and/or functional developmental anomalies of fetal genitourinary tract with some considerable accuracy. Detection of congenital obstructive uropathy in the human fetus may occur as early as 16 weeks gestation. In the fetal lamb model, experimental occlusion of the outflow tract results in progressive hydronephrosis, pulmonary hypoplasia, and oligohydramnios. The renal parenchymal changes vary with the fetal age at obstruction ranging from simple hydronephrosis with later obstruction to dysgenesis with earlier obstruction. The pulmonary damage, and to some extent the renal damage, may be halted or even reversed with release of obstruction. These advances in diagnosis and an understanding of the pathophysiology have prompted attempts at chronic in utero diversion therapy in the human fetus with obstructive uropathy yielding encouraging, but as of yet, unproven success. In this report, the methods for such therapy, the rationale for the therapy, and the results of the therapy is reviewed.

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.

Radioisotopic evaluation of the renal parenchymal function in children with ureteropelvic junction obstruction. A retrospective study

Separate glomerular filtration rates were evaluated in 21 children with uni- or bilateral ureteropelvic junction stenosis, using the Tc-99m DTPA complex and the scintillation camera. The grade of alteration seen on urograms has influenced the surgeon in his decision to use a conservative or a surgical treatment, whereas the type of intervention (pyeloplasty or nephrectomy) was mainly based on the scintigraphic quantitation. The morphological data provided by an excretory urogram could not predict the degree of functional impairment. The scintigraphic evaluation of single kidney clearance was useful in the evaluation of the effects of medical and surgical treatment.

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.

Acute tubular dysfunction in infants with obstructive uropathy

Eleven patients are described with severe hyponatraemia, hyperkalaemia and metabolic acidosis associated with a urinary tract infection and obstructive uropathy. This clinical entity resembles adrenocortical disorders. Urine culture investigation in combination with abdominal ultrasound examination will reveal urinary tract obstruction. Differential diagnosis, pathogenesis and treatment are discussed. In most patients correction of the metabolic disturbance can be achieved with antibiotic treatment, occasionally in combination with surgical therapy. Some degree of polyuria will generally persist.

Prognostic features in infants with obstructive uropathy due to posterior urethral valves

The histories of 22 infants presenting during the first year of life with obstructive uropathy due to posterior urethral valves were analyzed to determine outcome and prognostic features. Mean patient age at the time of the initial surgical intervention was 39 days, and the mean duration of followup inclusive of renal function data was 5.8 years. One patient died (5 per cent) and one had end stage renal disease. The mean preoperative and postoperative serum creatinine concentrations during the initial hospitalization were 3.1 and 1.4 mg. per dl., respectively. Neither value was significantly predictive of the creatinine concentration at final followup. In contrast, the nadir creatinine value during the first year of life correlated significantly with final renal function. Children with nadir creatinine values less than or equal to 0.8 mg. per dl. by 12 months of age maintained creatinine levels less than or equal to 1.1 mg. per dl. at the time of final evaluation, whereas children with higher values during the first year of life were likely to have progressive renal failure. Of 19 final creatinine determinations 6 were normal and 5 exceeded 1.5 mg. per dl. Proteinuria, hypertension, renal biopsy findings, urinary infection, unilateral nephrectomy and type of surgery did not correlate significantly with functional outcome. Followup studies of longer duration are needed to determine the ultimate outcome of these patients, more than half of whom had some degree of renal insufficiency at final evaluation.

Prenatal diagnosis improves the prognosis of children with obstructive uropathies

Five neonates with gross obstructive uropathies diagnosed in utero were operated during the first few days of life. Follow-up studies of up to 2 years postoperatively showed normal development of all the children. Radiologic investigations showed no obstruction and normal growth of renal parenchyma in all but one case, thus differing markedly from infants with gross obstructive uropathies who were diagnosed and referred to us some months after birth. The importance of prenatal diagnosis and hence early post partum treatment of obstructive uropathies appears to us proven.

Obstruction of the fetal urinary tract: a role for surgical intervention in utero?

Obstruction of the lower urinary tract was diagnosed by ultrasound in 11 fetuses. One pregnancy was therapeutically aborted. Four of the neonates died within 48 hours because of pronounced pulmonary hypoplasia, which is associated with obstruction of the urinary tract. The remaining six survived with adequate renal function but one, now aged 4, is obviously too small for his age. Intervention in utero for obstruction of the urinary tract is safe, but those fetuses for whom it is appropriate cannot yet be identified because of difficulties in diagnosing the condition of the whole fetus.

Fetal urinary tract obstruction: is active intervention before delivery indicated?

Obstruction of the urinary tract was diagnosed by ultrasound in four fetuses at 16-30 weeks: three of these diagnoses were confirmed after delivery; the fourth fetus had multicystic kidneys with hydroureter and hydronephrosis but no obstruction. The fetus with obstruction diagnosed at 16 weeks was terminated: it had lung hypoplasia with the prune-belly syndrome. The other two fetuses with obstruction were diagnosed at 25 and 34 weeks; the urinary tracts of both were drained for 5-14 days with reduction of distension. Both were born alive but that diagnosed at 25 weeks died of lung hypoplasia, the other survived, required nephrectomy and at the age of 3 is small but developing normally. Fetal urinary tract obstruction may prevent normal development of the lungs, be associated with other anomalies which cannot be diagnosed before delivery and retard infant development in survivors. Drainage of the dilated urinary tract does not harm the fetus or mother but has not been shown to improve neonatal survival or infant development.

Management of the fetus with congenital hydronephrosis

Twenty-six fetuses with dilated urinary tracts were studied with serial sonograms. Eight fetuses with unilateral hydronephrosis were followed without intervention; all are well after postnatal surgical correction. Three cases of bilateral hydronephrosis resolved spontaneously before birth. Eight fetuses with bilateral hydronephrosis had evidence of poor function: Three were not treated and died shortly after birth with small lungs and dysplastic kidneys; three others had diagnostic intervention that demonstrated irreversible disease and allowed termination of the pregnancy; two had obstruction successfully corrected in utero, but renal damage proved irreversible and precluded survival at birth. Seven fetuses with bilateral hydronephrosis and equivocal function underwent early decompression. Four were delivered early and corrected ex utero; 1 has renal failure and the other 3 are well. Three had obstruction relieved in utero by a catheter shunt placed percutaneously; 1 had multiple anomalies and died; the other 2 are well. Serial sonographic observation improves perinatal management of the fetus with a dilated urinary tract. The need for diagnostic or therapeutic intervention depends on the type and severity of obstruction and the time in gestation when it is discovered. Most fetuses do not require treatment before birth; a few may benefit from early decompression in or ex utero.

Correction of congenital hydronephrosis in utero II. Decompression reverses the effects of obstruction on the fetal lung and urinary tract

Urethral obstruction and urachal ligation at 93-107 days gestation produced severe hydronephrosis, hydroureter, megacystis, and urinary ascites as well as significant pulmonary hypoplasia in 17 fetal lambs. Obstructions in 9 fetuses subsequently were relieved in utero by suprapubic cutaneous cystostomy. At birth, all 4 liveborn obstructed lambs had respiratory insufficiency, and only 1 survived. Four others were stillborn. The lungs were significantly hypoplastic by weight and volume (p less than 0.025). All 8 had advanced megacystis, hydroureter, and hydronephrosis but no cystic or dysplastic renal changes. In contrast, 7 liveborn lambs diverted in utero had far less respiratory difficulty and all survived (p = 0.002). Two were stillborn. The lung weight was significantly increased (p less than 0.05). All lambs undergoing in utero decompression showed significant resolution of the severe urinary tract dilatation seen in the obstructed lambs. In utero decompression of the obstructed fetal urinary tract allows the abnormally small lungs to grow and develop and hydronephrosis to resolve.