Reflux nephropathy and hypertension

Long term renal outcome and risk of elevated blood pressure in children undergoing complete primary repair of bladder exstrophy (CPRE)

INTRODUCTION

Since the initiation of staged reconstruction for bladder exstrophy (BE), hypertension has been a known complication of the procedure. Hypertension is a well-established risk factor for chronic kidney disease (CKD) progression and associated with cardiovascular/cerebrovascular morbidity and mortality. Few studies exist evaluating the risk of developing hypertension among patients with bladder exstrophy who underwent CPRE. We hypothesized that long-term blood pressure levels may be elevated in males vs females, and may be correlated with presence of hydronephrosis, bladder neck reconstruction, or continence status.

OBJECTIVE

We sought to revisit our long-term experience with CPRE and determine factors associated with incidence of elevated blood pressures.

METHODS

We reviewed all BE patients undergoing CPRE at our institution from 1999 to 2019. Patients were considered eligible for inclusion if last renal ultrasound was obtained at least 5 years after repair. Upper tract outcomes based on imaging, history of pyelonephritis and renal function tests measured by serum creatinine and estimated glomerular filtration rate (eGFR, Schwartz formula) were reviewed. Systolic/diastolic blood pressures (SBP/DBP) from all encounters were captured. All blood pressure values were age adjusted by percentile.

RESULTS

A total of 36 patients were considered eligible for review. Median follow-up of this cohort was 10.01 (5.16-21.47) years. The mean creatinine for the patients available was 0.58 mg/dL (SD = 0.20), at mean age of 8.90 years Neither SBP or DBP were significantly elevated in males vs females, but had lower odds of elevation >90th percentile for those with higher eGFR, lower renal length, and reimplantation. Pyelonephritis incidence was 38% (n = 14) with first episode at mean age of 8.8 years, and mean of 3.7 episodes per patient.

DISCUSSION

At long term follow up, blood pressures following CPRE were not significantly elevated, despite the relatively frequent occurrence of CKD, and hydronephrosis. Male gender does appear to suggest higher risk for long-term deterioration in this regard. Higher eGFR, higher renal length, and presence of ureteral reimplantation were associated with lower likelihood of systolic/diastolic blood pressure elevation. Continence status and bladder neck reconstruction were not associated with likelihood of blood pressure elevation.

CONCLUSIONS

Blood pressure and upper-tract outcomes for patients undergoing CPRE at birth are positive for the majority of patients. To avoid complications from hypertension, patients should be closely evaluated as the risks associated with elevated blood pressure are significant. Ultimately, larger-scale prospective and multi-institutional studies are further needed to characterize risks of hypertension in this complex patient population.

Study of prognostic significance of antenatal ultrasonography and renin angiotensin system activation in predicting disease severity in posterior urethral valves

Aims:

Study on prognostic significance of antenatal ultrasonography and renin angiotensin system activation in predicting disease severity in posterior urethral valves.

Materials and Methods:

Antenatally diagnosed hydronephrosis patients were included. Postnatally, they were divided into two groups, posterior urethral valve (PUV) and non-PUV. The studied parameters were: Gestational age at detection, surgical intervention, ultrasound findings, cord blood and follow up plasma renin activity (PRA) values, vesico-ureteric reflux (VUR), renal scars, and glomerular filtration rate (GFR).

Results:

A total of 25 patients were included, 10 PUV and 15 non-PUV. All infants with PUV underwent primary valve incision. GFR was less than 60 ml/min/1.73 m² body surface area in 4 patients at last follow-up. Keyhole sign, oligoamnios, absent bladder cycling, and cortical cysts were not consistent findings on antenatal ultrasound in PUV. Cord blood PRA was significantly higher (P < 0.0001) in PUV compared to non-PUV patients. Gestational age at detection of hydronephrosis, cortical cysts, bladder wall thickness, and amniotic fluid index were not significantly correlated with GFR while PRA could differentiate between poor and better prognosis cases with PUV.

Conclusions:

Ultrasound was neither uniformly useful in diagnosing PUV antenatally, nor differentiating it from cases with non-PUV hydronephrosis. In congenital hydronephrosis, cord blood PRA was significantly higher in cases with PUV compared to non-PUV cases and fell significantly after valve ablation. Cord blood PRA could distinguish between poor and better prognosis cases with PUV.

Estimation of pro-renin as a prognostic marker for renal function in PUV patients

OBJECTIVE

To estimate serum pro-renin, and its clinical significance, as a marker of chronic renal disease in posterior urethral valve (PUV) patients.

PATIENTS AND METHODS

Forty patients with a PUV that were admitted to the hospital between 2010 and 2012 were reviewed. Twenty age-matched patients who were admitted for other non-urological diseases were selected for control. Clinical parameters, serum creatinine, urea, eGFR (estimated glomerular filtration rate) and serum pro-renin were analysed before and after valve ablation.

RESULTS

Forty patients with PUV were included in the study. Three groups were formed according to age: <1 year, 1-3 years, >3 years. Pro-renin was measured using an ELISA (enzyme linked immunosorbent assay) kit and 'Graph Pad Prism' Software. The Spearman's rho test was used for correlation. Serum pro-renin had a negative correlation with the age group (correlation coefficient -0.395, P-value 0.012), eGFR (correlation coefficient -0.850, P-value<0.001) and follow-up eGFR (correlation coefficient -0.471, P-value 0.002). The pro-renin level correlated positively with serum creatinine at presentation (correlation coefficient 0.671, P-value<0.001), blood urea at initial presentation (correlation coefficient 0.684, P-value<0.001), serum creatinine at follow-up (correlation coefficient 0.546, P-value<0.001) and blood urea at follow-up (correlation 0.603, P-value<0.001).

CONCLUSION

Pro-renin measured before PUV repair is associated with renal function three months after surgery.

Posterior urethral valve: Prognostic factors and renal outcome

OBJECTIVE

The aim was to study the outcome of posterior urethral valve (PUV) cases treated by stepladder protocol and the prognostic factors affecting the outcome.

MATERIALS AND METHODS

Hospital records of all PUV patients treated by stepladder protocol between January 1992 and December 2013 were reviewed. The studied parameters were: Age at presentation, serum creatinine, types of surgical intervention, vesicoureteral reflux (VUR) on initial voiding cystourethrogram (VCUG), renal cortical scars, plasma renin activity (PRA), and glomerular filtration rate (GFR).

RESULTS

Of 396 PUV patients treated during the study period, 152 satisfied study criteria. The age at presentation ranged from 2 days to 15 years (mean 31.3 months). The mean follow-up period was 5 years (range: 2-18 years). Primary endoscopic valve ablation was the most common initial procedure. Chronic renal failure was seen in 42.7% patients at the last follow-up. Serum creatinine at presentation, initial PRA levels, initial GFR, and PRA levels at last follow-up were significant predictors of final renal outcome. Age at presentation (<1 vs. >1 year), presence/absence of VUR on initial VCUG and renal cortical scars had no significant correlation with ultimate renal function.

CONCLUSION

Our study confirms the high prognostic significance of initial serum creatinine, PRA levels and GFR in cases with PUV. PRA also holds promise in long-term follow-up of these patients as a marker of progressive renal damage.

Plasma renin activity: An early marker of progressive renal disease in posterior urethral valves

Introduction:

A significant number of children with posterior urethral valves (PUV) develop chronic renal failure (CRF) due to activation of the renin angiotensin system (RAS). We investigated the role of plasma renin activity (PRA) in these cases and sought to establish a relationship between the accepted criteria of renal damage and PRA.

Aims and Objectives:

The aim of this study is to establish the relationship between PRA and CRF.

Materials and Methods:

The records of 250 patients with PUV were reviewed. Multiple linear regression analysis was used to assess correlations between PRA, grade of reflux, presence of scars and raised creatinine and decrease in glomerular filtration rates (GFR). A P < 0.5 was considered as significant.

Results:

A total of 58 patients were included. Their mean age was 16 years, range 5.3-24.2 years, mean follow-up period was 12.6 ± 3.6 years. At diagnosis, 22/58 (38%) patients were in CRF and 36/58 (62%) patients had normal renal function (RF). The mean PRA after treatment was higher in those who developed CRF than in those with normal RF (12.6 ± 10.2 vs. 34.6 ± 14.2 ng/ml/24 h, P = 0.02). Mean GFR at 1 year of age were 48 ± 9.8 ml/min/1.73 m² and 86 ± 12.5 ml/min/1.73 m² respectively (P = 0.005). PRA correlated negatively with GFR, t = –2.816,

Confidence Interval:

P = 0. 007. In the temporal plot over a period of 14 years, a rise in PRA preceded the fall in GFR in patients who developed CRF.

Conclusions:

This study shows that RAS is activated earlier in kidneys susceptible to damage. PRA could be investigated as a marker for the early detection and prevention of ongoing renal damage.

Hypertension in pediatric patients with renal scarring in association with vesicoureteral reflux

OBJECTIVE

To examine the reflux nephropathy rate and severity as well as the hypertension rate in pediatric patients with vesicoureteral reflux (VUR).

METHODS

The study included 240 patients with VUR. Renal scarring (RS) was demonstrated by renal parenchymal examination using technetium-99m-labeled dimercaptosuccinic acid (99mTc-DMSA) scintigraphy. Office measurements of arterial blood pressure and ambulatory blood pressure monitoring (ABPM) of VUR patients were done during the follow-up period.

RESULTS

Follow-up was a mean duration of 24 months. Rates of RS and hypertension increased parallel to increases in the degree of VUR. A gradual elevation in hypertension rates was evident during the follow-up period. All patients with hypertension had RS. Severe RS in 56 patients was associated with increasing blood pressure readings by 24-hour ABPM or office measurements in 19 patients (33.9%). ABPM measurements enabled us to detect additional patients compared with office measurements alone.

CONCLUSION

Hypertension is a serious complication in children with reflux nephropathy and is associated with the severity of RS and VUR grade. ABPM seems to be superior over office measurements of blood pressure in identifying patients with hypertension.

Investigating febrile UTI in infants: is a cystogram necessary?

OBJECTIVE

Current imaging recommendations for investigating any infantile febrile urinary tract infection (UTI) are ultrasound scan (US), micturating cystourethrogram (MCUG) and dimercaptosuccinic acid (DMSA) scan. The aim of this retrospective cohort study was to determine the need and indications for MCUG in the investigation of a first febrile infantile UTI, as doubts have been raised over its benefit.

PATIENTS AND METHODS

Information on 427 infants who had undergone US, MCUG and DMSA following a first febrile UTI was prospectively recorded. The infants were divided into two groups: A (354) with normal renal US and B (73) with abnormal US. DMSA findings were correlated with findings on MCUG. Main outcome measures were incidence of recurrent UTIs, change in management or intervention as a result of MCUG, and outcome at discharge.

RESULTS

Only 21/354 (6%) infants in Group A had both scarring on DMSA and vesicoureteric reflux (VUR), predominantly low-grade on MCUG. In Group B (abnormal US), 23/73 (32%) had scarring on DMSA and vesicoureteric reflux, predominantly high grade on MCUG. Of the infants with non-scarred kidneys, 73% had dilating reflux. Successful conservative treatment was performed in 423 infants, and 4 infants in Group B required surgery.

CONCLUSION

We recommend US and DMSA in all infantile febrile UTI cases. Where US is normal, MCUG should be reserved for those cases with abnormal DMSA. Where US is abnormal, MCUG should be performed irrespective of findings on DMSA scan. A randomized prospective study is necessary to evaluate this further.

Plasma renin activity for monitoring vesicoureteric reflux therapy: mid-term observations

OBJECTIVE

To study plasma renin activity (PRA) as an early marker for monitoring treatment of vesicoureteric reflux (VUR).

PATIENTS AND METHODS

Fifty-nine children (35 males and 24 females), mean age 43.3+/-26.5 (range 4.5-89) months, with various grades (I-V) of primary VUR were enrolled. PRA, renal scars, split renal function (SRF), glomerular filtration rate (GFR), serum creatinine, blood pressure and episodes of breakthrough urinary tract infection were monitored at regular intervals. Surgery was performed as per currently accepted criteria. PRA values were used for post-hoc analysis of results.

RESULTS

Thirty-eight children (64.4%) underwent anti-reflux surgery during the mean follow up of 17.1+/-3.1 months; 21 (35.6%) continued on non-operative follow up. Rise in PRA up to the time of surgery was seen in all patients. It normalized after surgery in 86%, and reduced but plateaued at a higher level than normal in 13.8% in the surgical group. While improvement in SRF and GFR was seen only in 2/38 (5.2%) and 12/38 (31.6%), respectively, blood pressure stabilized in 30.7% and serum creatinine showed inconsistencies. In non-operatively managed cases, improvement in SRF was seen in only one case and GFR in 14.2% of cases. However, 80.9% children showed a progressive rise in PRA throughout the period of non-operative follow up.

CONCLUSION

Current end points of non-operative management already cause irreversible renal damage by the time surgery is indicated. Our results suggest that serial measurement of plasma renin activity may help in better stratification of patients with moderate to high grade (III-V) VUR with respect to management and prognosis.

Posterior urethral valves: preliminary observations on the significance of plasma Renin activity as a prognostic marker

PURPOSE

A significant number of children with posterior urethral valves (PUVs) have chronic renal failure due to tubulointerstitial damage. Activation of the renin-angiotensin system is known to inflict this injury. We investigated the role of plasma renin activity (PRA) in patients with PUVs and sought to establish a relationship between renal damage and PRA.

MATERIALS AND METHODS

The records of patients with PUVs were reviewed regarding the time of valve ablation, serum creatinine, scars, grade of reflux and glomerular filtration rate (GFR). PRA was measured before and after valve ablation.

RESULTS

A total of 25 patients had PUVs (mean age 3.2 +/- 2.4 years, mean period of observation 4.5 +/- 1.2 years). Mean PRA was increased before valve ablation in all patients irrespective of age, and decreased after ablation. Of 25 patients 14 (56%) had renal damage, with a mean PRA of 36 +/- 4.5 ng/ml per hour compared to 26 +/- 8.2 ng/ml per hour in patients with normal renal function (chi-square 4.2 p = 0.01). Of the 14 patients with renal damage 9 (64%) had normal GFR at age 1 year but increased PRA. Of these 14 patients the accepted criteria for renal damage of increased serum creatinine, high grade reflux, scars and decreasing GFR were present in only 6 (43%), 3 (21%), 2 (14%) and 4 (29%), respectively. PRA was increased in all 14 cases.

CONCLUSIONS

PRA was increased before valve ablation and decreased after ablation. It is increased in patients with early renal damage. Our preliminary observations indicate that PRA may be helpful in identifying patients with early renal damage.

Role of plasma renin activity in the management of primary vesicoureteric reflux: A preliminary report

BACKGROUND

Nonoperative management is the choice of therapy in most patients with primary vesicoureteric reflux (VUR). Such patients are regularly monitored for breakthrough urinary tract infection, deterioration of renal function, and progression/ appearance of new scars as the indicators for switching over to surgical intervention. In this descriptive study, we report our additional observations on serial measurement of plasma renin activity (PRA) in a group of such children followed prospectively.

METHODS

Twenty-six children (16 males and 10 females) with various grades (grades I to V) of primary VUR were enrolled. Besides the conventional investigations, we also monitored PRA. Ureteric reimplantation was performed based on established international criteria. PRA levels were correlated with the need for surgical intervention retrospectively.

RESULTS

Mean age at presentation was 39.3 months (range, 12 to 120 months). Nineteen children (73%) were subjected to ureteric reimplantation. The mean PRA in this group (N = 19) was 6.97 ng/mL/hour versus 3.28 ng/mL/hour in patients who were continued on nonoperative management (N = 7). Postoperatively, the PRA reduced and stabilized in all 18 patients at a mean value of 5.4 ng/mL/hour.

CONCLUSION

The currently accepted end points of medical management are inconsistent. On the other hand, 94.7% of children in the surgical group had shown an activation and a progressive increase in PRA. Postoperatively, the PRA was reduced and stabilized in all these patients. Our preliminary observations suggest that high PRA is a more sensitive indicator for surgical intervention as compared to the existing criteria.

A nurse led education and direct access service for the management of urinary tract infections in children: prospective controlled trial

OBJECTIVES

To determine whether a nurse led education and direct access service improves the care of children with urinary tract infections.

DESIGN

Prospective cluster randomised trial.

SETTING

General practitioners in the catchment area of a UK paediatric nephrology department.

PARTICIPANTS

88 general practices (346 general practitioners, 107 000 children).

MAIN OUTCOME MEASURES

Rate and quality of diagnosis of urinary tract infection, use of prophylactic antibiotics, convenience for families, and the number of infants with vesicoureteric reflux in whom renal scarring may have been prevented.

RESULTS

The study practices diagnosed twice as many urinary tract infections as the control practices (6.42 v 3.45/1000 children/year; ratio 1.86, 95% confidence interval 1.42 to 2.44); nearly four times more in infants (age < 1 year) and six times more in children without specific symptoms. Diagnoses were made more robustly by study practices than by control practices; 99% v 89% of referred patients had their urine cultured and 79% v 60% had bacteriologically proved urinary tract infections (P < 0.001 for both). Overall, 294 of 312 (94%) children aged under 4 years were prescribed antibiotic prophylaxis by study doctors compared with 61 of 147 (41%) by control doctors (P < 0.001). Study families visited hospital half as much as the control families. Twice as many renal scars were identified in patients attending the study practices. Twelve study infants but no control infants had reflux without scarring.

CONCLUSION

A nurse led intervention improved the management of urinary tract infections in children, was valued by doctors and parents, and may have prevented some renal scarring.

Day- and night-time blood pressure elevation in children with higher grades of renal scarring

OBJECTIVE

We used 24-hour ambulatory blood pressure measurement (ABPM) to screen for early changes in children with renal scarring compared with healthy controls, and we investigated correlations between the extent of renal damage and blood pressure (BP). Study design Untreated patients (n = 61) with renal scars associated with recurrent urinary tract infection and vesico-ureteric reflux were investigated and compared with 904 healthy controls.

RESULTS

A significant positive correlation between the extent of renal scarring and systolic and diastolic BP standard deviation score (SDS) was found by using ABPM. Mean systolic day-time BP SDS in ABPM was significantly elevated in girls with renal scars compared with healthy controls, but failed to be significant in boys. Mean systolic and diastolic night-time BP SDS were significantly elevated in patients. Compatible with these results, diastolic dipping was significantly lower in patients compared with controls.

CONCLUSIONS

The increase in BP obtained by ABPM is positively correlated with the degree of scarring in our group of patients. Elevated night-time BP might be the most sensitive indicator of BP elevation in these children.

Ambulatory blood pressure 16-26 years after the first urinary tract infection in childhood

OBJECTIVE

To evaluate blood pressure in a population-based cohort with urographic renal scarring after childhood urinary tract infection.

DESIGN

Follow-up investigation 16-26 years after the first recognized urinary tract infection.

SETTING

University out-patient clinic for children with urinary infections serving the local area.

PATIENTS

From the original cohort of 1221 consecutive children with first urinary tract infection diagnosed during 1970-1979, 57 of 68 with non-obstructive renal scarring participated as well as 51 matched subjects without scarring.

MAIN OUTCOME MEASURE

24 h ambulatory blood pressure.

RESULTS

Acceptable blood pressure monitorings were obtained from 53 individuals with and 47 without scarring. There were no significant differences between the two groups even when only patients with the most extensive scarring (individual kidney clearance < 30 ml/min per 1.73 m2) or patients with bilateral scarring were compared with the non-scarring group. Mean systolic or diastolic blood pressure above +2 SD were found in 5/53 (9%) and 3/47 (6%) in the scarring and non-scarring group, respectively. Plasma renin activity, angiotensin II and aldosterone concentrations were not significantly different, but atrial natriuretic protein was significantly higher in the scarring group (P = 0.004).

CONCLUSION

This study demonstrates a low risk of hypertension two decades after childhood urinary tract infection. It should be stressed that the patients with renal scarring were under close supervision throughout childhood. Those with scarring had higher concentrations of atrial natriuretic protein which might indicate a counter-regulation mechanism.

Office laboratory procedures, office economics, parenting and parent education, and urinary tract infection

These authors review four areas of office pediatric practice: office laboratory procedures, office economics, parenting and parent education, and urinary tract infections. Thomas Ball reviews the literature published this past year on physician office laboratories, with updates on the Clinical Laboratories Improvement Amendments, laboratory utilization, and office diagnosis of infectious mononucleosis. Eve Shapiro offers an update on office economics, discussing physician organizations and managed care, and a medical ethics evaluation of medical economics. Burris Duncan provides an update on parenting and parent education, with emphasis on defining "the best interests of the child." Richard Wahl summarizes the past year's publications on pediatric urinary tract infections, reviewing the circumcision debate, dysfunctional voiding, vesicoureteral reflux, and the diagnosis and follow-up of acute pyelonephritis.