Reduced differential renal function in scintigraphy predicted high-grade vesicoureteral reflux in children with antenatal hydronephrosiss

Stratifying Antenatal Hydronephrosis: Predicting High-Grade VUR Using Ultrasound and Scintigraphy

(1) Background: Antenatal hydronephrosis (AHN), detected in approximately one percent of prenatal ultrasounds, is caused by vesicoureteral reflux (VUR) in 15-21% of cases, a condition with significant risks such as urinary tract infections and renal scarring. Our study addresses the diagnostic challenges of VUR in AHN. Utilizing renal ultrasonography and scintigraphy, we developed a novel scoring system that accurately predicts high-grade VUR, optimizing diagnostic precision while minimizing the need for more invasive methods like voiding cystourethrogram (VCUG); (2) Methods: This retrospective study re-analyzed renal ultrasonography, scintigraphy, and VCUG images from infants admitted between 2003 and 2013, excluding cases with complex urinary anomalies; (3) Results: Our analysis included 124 patients (75% male), of whom 11% had high-grade VUR. The multivariate analysis identified visible ureter, reduced renal length, and decreased differential renal function (DRF) as primary predictors. Consequently, we established a three-tier risk score, classifying patients into low, intermediate, and high-risk groups for high-grade VUR, with corresponding prevalences of 2.3%, 22.2%, and 75.0%. The scoring system demonstrated 86% sensitivity and 79% specificity; (4) Conclusions: Our scoring system, focusing on objective parameters of the visible ureter, renal length, and DRF, effectively identifies high-grade VUR in AHN patients. This method enhances diagnostics in ANH by reducing reliance on VCUG and facilitating more tailored and less invasive patient care.

Risk factors for renal scarring and clinical morbidity in children with high-grade and low-grade primary vesicoureteral reflux

INTRODUCTION

Primary vesicoureteral reflux (VUR) is associated with urinary tract infections (UTIs) and renal damage. However, the importance of early diagnosis of VUR has been questioned. Moreover, most studies have few patients with high-grade VUR. Hence, we retrospectively analyzed a large cohort of patients with primary high-grade and low-grade VUR and assessed risk factors for renal damage and clinical morbidity.

MATERIAL AND METHODS

We included patients (<18 years) at diagnosis with low-grade (1-3) or high-grade (4-5) primary VUR and noted their clinical history and presence of hypertension, low eGFR (<60ml/in/1.73 m²), renal scarring (focal or generalised) and reduced differential renal function (DRF; <45%). Risk factors were assessed (in patients and renal units) by logistic regression and generalised estimating equation.

RESULTS

Of 399 primary VUR patients, 255 (64%) had high-grade VUR. Indications for voiding cystourethrogram were recurrent UTI (38%), first UTI (28%) and antenatal hydronephrosis (17%). At diagnosis, 252 (65%) had renal scars (focal in 170 [44%], generalised in 82 [21%]), and 188 (47%) had reduced DRF. High-grade VUR patients were more likely than low-grade VUR patients to have renal scarring (75% vs. 49%, p < 0.01), low eGFR (23% vs. 13%, p = 0.04) and significant hypertension (26% vs. 13%, p = 0.02). High-grade VUR was associated with generalised scars (odds ratio [OR] 11, p < 0.001), focal scars (OR 3.1, p < 0.001) and reduced DRF (OR 2.3, p < 0.001) shown in the table. Male sex was a risk factor for generalised scars (OR 2.3, p = 0.005). Focal scars were associated with recurrent UTIs (OR = 1.8, p = 0.004) and reduced DRF (OR 1.4, p = 0.027). Patients with multiple focal scars were diagnosed at an older age (2 years [1,4] than those with single scars (1.5 years [1,4] or no scars (1 year [0, 3]), p = 0.04).

DISCUSSION

The prevalence of renal damage and clinical morbidity at VUR diagnosis was higher than other studies. High-grade VUR patients had a greater prevalence of renal damage, low eGFR and hypertension than low-grade VUR patients and was a risk factor for focal scars, generalised scars and reduced DRF. Focal scars were independently associated with recurrent UTI. Those with multiple scars were diagnosed later than those with single scars or no scars.

CONCLUSIONS

High-grade VUR was associated with renal damage and clinical morbidity. Our study highlights the importance of diagnosing VUR early to identify patients who may warrant long-term follow-up and intervention to minimize morbidity.

Kidney damage associated with vesico ureteric reflux

PURPOSE OF REVIEW

The aim of this review is to highlight the most recent developments in the understanding of kidney damage associated with vesico ureteral reflux. The severe damage, with major adverse long-term sequelae, was thought to be, for the most part, the result of pyelonephritis, predisposed to by vesico ureteral reflux.

RECENT FINDINGS

It is now recognized that there are two distinct forms of kidney damage (congenital and acquired), in association with reflux. We examined the most recent research regarding these two conditions.

SUMMARY

The most recent articles focus on an understanding and the possible interventions for the congenital and acquired abnormalities of the kidney, associated with reflux. Of particular interest in congenital disorders, is the importance of urothelium and gene mutations in normal and aberrant development of the urinary tract. As regards the predisposition to urinary tract infections and kidney scarring, the importance of uromodulin in the defence mechanism preventing infection, and the role of interventions aimed at reducing scarring, such as vitamin A and steroids during the acute phase of the infection, are discussed. A recent article of particular value demonstrated the absence of long-term adverse outcomes during pregnancy, in women investigated for urinary tract infections in childhood.

Relationship of Urinary Tract Infection to Lower Urinary Tract Dysfunction and Kidney Scar Formation in Children

Background:

Urinary tract infection (UTI) is the most common infection during childhood. Lower urinary tract dysfunction (LUTD) is a broad term that indicates an abnormal voiding pattern in a child without anatomical and neurological impairment. The purpose of this study was to determine the relationship between UTI and LUTD.

Methods:

This study was conducted at the Children Medical Center Hospital in 2014–2016. The inclusion criteria of this study were at least one UTI confirmed by a positive urine culture and active urine analysis in children who were well toilet-trained previously. Complete physical examination of the genitourinary and skeletal systems was performed to identify patients with anomalies in these systems. The patients with genitourinary system anomalies and obvious and prediagnosed neurological defects of the urinary system such as neurogenic bladder were excluded from the study. To confirm the presence of LUTD, the scoring system of Akbal et al. was applied.

Results:

A total of 260 patients including 9.2% of males and 90.8% of females were included in this study. The prevalence of LUTD was 63.8% (166 cases) in these patients. In this study, the prevalence of LUTD in patients with a single episode of UTI was 50.5%, while in patients with recurrence of UTI it was 88.9%. In patients with unilateral kidney scar formation, 90.9% had a recurrence of UTI (P = 0.003) which shows a strong correlation of unilateral scar formation with recurrence of UTI.

Conclusions:

These data suggest that there is a significant relationship between UTI and LUTD in children, so evaluation of voiding dysfunction is necessary in this group. With early diagnosis and appropriate treatment, we can reduce the possible serious and permanent sequels of LUTD in patients with UTIs.