Congenital anomalies of the kidney and urinary tract: defining risk factors of disease progression and determinants of outcomes

SGLT2 Inhibitors in Patients with Urogenital Malformations and Urinary Diversions: Risks, Benefits, and Clinical Considerations

Background: Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are increasingly used in patients with type 2 diabetes, chronic kidney disease, and heart failure. However, their safety and efficacy in patients with congenital or surgically altered urogenital anatomy remains underexplored. Methods: We conducted a narrative review of current evidence regarding the use of SGLT2i in patients with urinary tract malformations, urinary diversions, and functional voiding disorders. Key risks, clinical considerations, and management strategies were synthesized from the existing literature and case reports. Results: Patients with benign prostatic hyperplasia, vesicoureteral reflux, neurogenic bladder, nephrostomies, and ileal conduits may face increased risks of urinary tract infections, fungal colonization, and therapy-related complications due to persistent glycosuria and altered urinary flow. Nevertheless, these patients may still benefit from SGLT2i's systemic renal and cardiovascular effects. Individualized risk assessment, close monitoring, and multidisciplinary management are essential. Conclusions: Patients with urological abnormalities represent a high-risk but potentially high-reward population for SGLT2i therapy. A cautious, tailored approach is necessary, and future dedicated research is urgently needed to better guide clinical practice.

Assessing masked hypertension and ambulatory arterial stiffness index in children congenital kidney malformations

BACKGROUND

Patients diagnosed with congenital kidney malformations are at an increased risk of developing hypertension, proteinuria, and progressing to chronic kidney disease (CKD). The present study aimed to determine the frequency of masked hypertension and ambulatory arterial stiffness index (AASI) in patients with congenital kidney malformations.

METHODS

The study included 174 patients with congenital kidney malformations (48 patients with unilateral renal agenesis (URA), 40 patients with ectopic kidney (EK), 36 patients with horseshoe kidney (HK), 31 patients with multicystic dysplastic kidney (MCDK), 19 patients with unilateral renal hypoplasia (URH), and 45 healthy controls.

RESULTS

The mean age was 12.9 ± 2.9 years, and the male-to-female ratio was 1.5. No significant differences were observed between the congenital kidney malformations groups concerning age, sex, follow-up period, proteinuria, or estimated glomerular filtration rate (eGFR) (P > 0.05). Nevertheless, the prevalence of masked hypertension exhibited a statistically significant increase in the congenital kidney malformations groups (except the URH group) compared to the control group (P < 0.05). The AASI was significantly greater in the congenital kidney malformations groups than in the control group (P < 0.05). The nighttime diastolic blood pressure (DBP), mean arterial pressure (MAP), and DBP index were significantly different between the congenital kidney malformations groups (P < 0.05). However, there were no significant differences in nondipping pattern, proteinuria, or masked hypertension between the congenital kidney malformations groups.

CONCLUSIONS

Patients with congenital kidney malformations should be periodically evaluated throughout life for BP. Based on the present findings, we strongly recommend ABPM for the diagnosis of masked hypertension and outcomes, including AASI score.

Particularities in the "Oldie but Goldie" Tc-99m DMSA Renography: A Retrospective Reference Centre Overview of 931 Children

Background/Objectives: The Tc-99m dimercaptosuccinic acid (DMSA) renal scan clearly images the renal cortex, highlighting functional tissue areas and indicating regions of renal scarring, infection, malformations, or other types of renal damage. To enhance the management of paediatric cases involving renal malformations and to reduce the incidence of chronic and progressive kidney diseases in "future adults", our study aims to identify and categorise various renal anomalies. Methods: This has been achieved by analysing the Tc-99m DMSA renal scans of a large cohort of 931 children diagnosed with different renal pathologies. After interpreting the scans, we categorised the renal malformations and cortical modifications into four groups: kidney number anomalies, positional anomalies, structural anomalies, and shape anomalies. Results: There has been a notable increase in the demand for renal scintigraphy in recent years, rising from 82 cases in 2019 to 183 cases in 2024. Structural anomalies were the most common type of malformations (73% from all patients), featuring a significant variety of cortical modifications. In total, 98 cases (93% from kidney number anomalies and 10.5% from all children) were diagnosed with renal agenesis. Additionally, 30 children (3.2% from all patients) had positional anomalies, primarily ectopic kidneys, and 54 patients (5.8% from all cases) had shape malformations, especially fused kidneys. Conclusions: Combining the Tc-99m DMSA renal scan with ultrasound provides a more reliable diagnosis of paediatric renal progressive diseases. A more accurate diagnosis allows for quicker treatment and prevention of potential complications, ultimately improving the quality of life and decreasing hospital costs of paediatric patients becoming adults.

Kidney Transplantation in Congenital Abnormalities of Kidney and Urinary Tract (CAKUT)

Congenital anomalies of the kidney and urinary tract (CAKUT) are a common cause of chronic kidney disease in children. Most patients will reach end-stage renal function and dialysis or transplantation in childhood or early adulthood. Patients with CAKUT deserve a careful evaluation before a kidney transplant; detailed imaging and functional studies are necessary, particularly in the presence of lower urinary tract abnormalities, and surgical procedures are advisable in selected cases. A higher incidence of complications has been reported after a kidney transplant in CAKUT, mainly urinary tract infections. However, in the long term, the prognosis seems to be comparable to other kidney diseases. A large number of reports are available in the literature on medical and surgical management of patients with CAKUT before, during, and after a kidney transplant; almost all recommendations of surgical procedures before a kidney transplantation are based on retrospective not controlled studies or personal opinions; prospective controlled studies are needed. In this narrative, nonsystematic review, we report the results of recently published selected studies and underline questions that should be addressed in future guidelines.

Economic burden of hospitalization for Chinese children with chronic kidney disease: a comparison between patients with and without infection

Objective

To assess hospitalization costs in pediatric chronic kidney disease (CKD) patients, compare the economic burden between those with and without infections, and identify key factors influencing these costs, emphasizing the significant financial impact on families and healthcare systems.

Methods

This retrospective analysis included pediatric patients with CKD hospitalized between May 2011 and April 2020. Clinical characteristics, including demographics, etiology, urinary protein level, estimated glomerular filtration rate, and CKD stage, were analyzed. Hospitalization costs were compared between groups with and without infection using appropriate statistical methods.

Results

Among 721 pediatric CKD patients included in this study, 388 had primary kidney disease and 333 had secondary kidney disease. Patients in the infection group had significantly higher urine protein levels, longer hospital stays, and higher total hospital fees than those without infection (all P < 0.05). In the primary kidney disease cohort, patients aged 14-18 years incurred the highest costs (16,706 CNY, P = 0.009), while those with 1 + urine protein levels had expenses averaging 29,813 CNY (P = 0.035). In the secondary kidney disease cohort, the 3 + urine protein group had the highest costs (62,841 CNY, P < 0.001). Multiple linear regression identified age, urine protein level, and length of hospital stay as significant cost determinants. Patients with infection in the secondary kidney disease cohort had an average additional expenditure of 13,572.55 CNY compared to those without infection (P = 0.001).

Conclusion

This study highlights the economic burden of infection during pediatric CKD hospitalization, emphasizing the need for effective infection management strategies to reduce financial strain and improve outcomes.

Cystinuria-Related Urinary Stone as the Cause of Repeated Urinary Tract Infections (UTIs) in a Child

Urinary tract infections (UTIs) are one of the most common bacterial infections in children and are associated with both acute and long-term complications. Most UTIs typically resolve after antibiotic treatment. However, UTIs may be the initial clinical manifestation of a potential congenital anomaly of the kidneys and the urinary tract (CAKUT) or may indicate the presence of a renal stone. Especially in pediatric patients presenting with early and recurrent episodes of UTIs, a thorough clinical and radiographical evaluation is warranted.  Our manuscript presents a case of a four-year-old male patient diagnosed with a 4.4 cm-diameter stone in his bladder. The patient was investigated for recurrent Enterococcus faecalis lower UTIs and was finally diagnosed with cystinuria-related urolithiasis.

Maternal and fetal risk factors for congenital anomalies of the kidney and urinary tract: a birth cohort study in urban China

BACKGROUND

Congenital anomalies of the kidney and urinary tract (CAKUT) are among the most common causes of kidney diseases in children. Previous studies on CAKUT etiologies have been predominantly focused on non-modifiable genetic risk factors. The existing nongenetic studies are limited by lack of comprehensive investigation of potentially modifiable risk factors and the inability to distinguish among various phenotypes of CAKUT. Therefore, this study aimed to comprehensively evaluate both maternal and fetal risk factors of CAKUT, sorted by disease phenotype.

METHODS

A prospective birth cohort study was conducted among 10,179 women who delivered a singleton live newborn in Lanzhou, China, between 2010 and 2012. Face-to-face interviews were conducted among the participants within 1-3 days after delivery using standard questionnaires to collect information on maternal demographics and characteristics. All newborns underwent postnatal renal ultrasonographic screening during their routine 1-month checkup. Clinical data, including birth outcomes and maternal complications, were confirmed by reviewing their medical records. Maternal and fetal risk factors were compared in children with and without CAKUT. Multivariable logistic regression analysis was performed to identify independent risk factors of CAKUT and their phenotypes, respectively.

RESULTS

A total of 489 (4.8%) cases of CAKUT were identified. Logistic regression revealed that maternal overweight (pre-pregnancy), gestational diabetes, preterm birth, and low birth weight were independent risk factors for CAKUT. Maternal overweight increased the risk of vesicoureteral reflux (VUR, odds ratio (OR) = 1.441, 95% confidence interval (CI) 1.010-2.057) and posterior urethral valves (PUV, OR = 1.868, 95% CI 1.074-3.249). Gestational diabetes increased the risk of ureteropelvic junction obstruction (UPJO, OR = 1.269; 95% CI 1.044-1.543) and posterior urethral valves (OR = 1.794; 95% CI 1.302-2.474). Preterm birth increased the risk of ureteropelvic junction obstruction (OR = 1.056; 95% CI 1.004-1.111).

CONCLUSIONS

Our study identified various risk factors associated with different CAKUT phenotypes, stressing the importance of separate analyses for each phenotype. Our findings may provide helpful guidance on developing targeted and effective CAKUT prevention programs in the future.

Practical Approach to Congenital Anomalies of the Kidneys: Focus on Anomalies With Insufficient or Abnormal Nephron Development: Renal Dysplasia, Renal Hypoplasia, and Renal Tubular Dysgenesis

Congenital anomalies of the kidney and urinary tract (CAKUT) accounts for up to 30% of antenatal congenital anomalies and is the main cause of kidney failure in children worldwide. This review focuses on practical approaches to CAKUT, particularly those with insufficient or abnormal nephron development, such as renal dysplasia, renal hypoplasia, and renal tubular dysgenesis. The review provides insights into the histological features, pathogenesis, mechanisms, etiologies, antenatal and postnatal presentation, management, and prognosis of these anomalies. Differential diagnoses are discussed as several syndromes may include CAKUT as a phenotypic component and renal dysplasia may occur in some ciliopathies, tumor predisposition syndromes, and inborn errors of metabolism. Diagnosis and genetic counseling for CAKUT are challenging, due to the extensive variability in presentation, genetic and phenotypic heterogeneity, and difficulties to assess postnatal lung and renal function on prenatal imaging. The review highlights the importance of perinatal autopsy and pathological findings in surgical specimens to establish the diagnosis and prognosis of CAKUT. The indications and the type of genetic testing are discussed. The aim is to provide essential insights into the practical approaches, diagnostic processes, and genetic considerations offering valuable guidance for pediatric and perinatal pathologists.

Genetic and Clinical Factors Influencing Congenital Anomalies of the Kidney and Urinary Tract in Children: Insights from Prenatal and Postnatal Assessments

Congenital anomalies of the kidney and urinary tract (CAKUT) significantly contribute to pediatric morbidity, often necessitating ureterorenal surgery. This study explored the relationship between genetic mutations, renal surgery requirements, and prenatal, postnatal, and parental risk factors in children with CAKUT. A retrospective analysis of 651 children diagnosed with CAKUT included patient demographics, parental risk factors, ultrasound findings, genetic mutations, and surgical incidence. Antenatal ultrasounds showed normal findings in 32.1%, hydronephrosis in 46.9%, and other abnormalities in 21% of cases. Surgical intervention correlated with higher hydronephrosis reduction than non-intervention. Genetic mutations were identified in 5.4% of cases, with 24.6% requiring surgery. Low neonatal birth weight (odds ratio [OR] = 0.98, p < 0.001), advanced maternal age (OR = 1.06, p < 0.001), and postnatal abnormal ultrasound findings (OR = 2.62, p < 0.001) were associated with increased genetic mutation risks. Antenatal hydronephrosis (OR = 3.85, p < 0.001) and postnatal urinary tract infections (OR = 4.85, p < 0.001) increased the likelihood of surgical intervention. Neonatal birth weight, maternal age, and postnatal ultrasound findings were identified as independent risk factors for genetic mutations, while no significant link was found between these genetic factors and the need for surgery. Surgical needs were associated with urinary tract infections and antenatal hydronephrosis, indicating that timely surgical intervention may benefit these patients.

Herlyn-Werner-Wunderlich Syndrome Complicated with Vesicovaginal Fistula: A Rare Case Report

Herlyn-Werner-Wunderlich (HWW) syndrome is characterized by obstructed hemivagina and ipsilateral renal anomaly, a rare congenital anomaly of the genitourinary tract, resulting from malformations of the renal tract associated with Müllerian duct anomalies. The initial symptoms of HWW frequently present after menarche and may be nonspecific, leading to a delayed diagnosis. We presented a 19-year-old female with 3-year hematuria and abdominal pain. The final diagnosis of HWW syndrome with a rare vesicovaginal fistula was made. The treatment of HWW syndrome typically involves surgical intervention. The primary treatment is resection or removal of the obstructed vaginal septum. The patient underwent excision of vaginal septum and vaginal reconstruction via hysteroscopy, as well as repair of the vesicovaginal fistula. The patient improved well after surgery and fully recovered without sequelae after 3 months. In addition, unilateral renal agenesis is one of congenital abnormalities of the kidney and urinary tract, which are the most frequent cause of chronic kidney disease (CKD) in children. This report describes a patient of HWW syndrome with rarely combined vesicovaginal fistula, and highlights the importance of early recognition and management to prevent associated complications.

Müllerian anomalies in girls with congenital solitary kidney

BACKGROUND

The prevalence of Müllerian anomalies (MA) among patients with congenital solitary functioning kidney (SFK) is not well defined. A delay in diagnosis of obstructive MA can increase the risk of poor clinical outcomes. This study describes the prevalence of MA in patients with congenital SFK.

METHODS

A retrospective review was performed of patients within the Nationwide Children's Hospital system with ICD9 or ICD10 diagnostic codes for congenital SFK defined as either unilateral renal agenesis (URA) or multicystic dysplastic kidney (MCDK) and confirmed by chart review. Patients with complex urogenital pathology were excluded. Renal anomaly, MA, reason for and type of pelvic evaluation, and age of diagnosis of anomalies were evaluated.

RESULTS

Congenital SFK occurred in 431 girls due to URA (209) or MCDK (222). Pelvic evaluation, most commonly by ultrasound for evaluation of abdominal pain or dysmenorrhea, occurred in 115 patients leading to MA diagnosis in 60 instances. Among 221 patients ages 10 years and older, 104 underwent pelvic evaluation and 52 were diagnosed with an MA of which 20 were obstructive. Isolated uterine or combined uterine and vaginal anomalies were the most common MA. MA were five-fold more common in patients with URA compared to MCDK. In 75% of patients, the SFK was diagnosed prior to the MA.

CONCLUSIONS

The prevalence of MA in patients with congenital SFK was 24% among those age 10 years or older, and 38% were obstructive. This justifies routine screening pelvic ultrasound in girls with congenital SFK to improve early diagnosis.

A Pilot Comparative Study between Creatinine- and Cystatin-C-Based Equations to Estimate GFR and Kidney Ultrasound Percentiles in Children with Congenital Anomalies of the Kidney and Urinary Tract

Congenital anomalies affecting the kidneys present significant challenges in pediatric nephrology, needing precise methods for assessing renal function and guiding therapeutic intervention. Bedside Schwartz formula with the cystatin-C-based Full Age Spectrum formula and Chronic Kidney Disease in Children (CKiD) U 25 formula used in estimating glomerular filtration rate (eGFR) and also to assess if the eGFR in association with kidney length percentiles can be a monitoring parameter for the progression of chronic kidney disease in children with congenital anomalies of the kidney and urinary tract (CAKUT). A total of 64 pediatric patients (median age at diagnostic was 12 months with an interquartile range of 2 to 60) were diagnosed with congenital anomalies in the kidney and urinary tract between June 2018 and May 2023 at "Louis Turcanu" Emergency Hospital for Children in Timisoara, Romania. Baseline characteristics, CAKUT types, associated pathologies, CKD staging, and eGFR using creatinine and cystatin C were analyzed. The mean age at the moment of examination was 116.50 months; (65, 180). Chronic kidney disease staging revealed a predominance of patients in CKD stages G1 and A1. Analysis of eGFR methods revealed a small mean difference between eGFR estimated by creatinine and cystatin C, with a moderate-strong positive correlation observed between the eGFR and ultrasound parameters. Using cystatin-C-based formulas for eGFR, in conjunction with ultrasound measurements, may offer reliable insights into renal function in pediatric patients with congenital anomalies affecting the kidney and urinary tract. However, the economic aspect must be taken into consideration because cystatin C determination is approximately eight times more expensive than that of creatinine. An interdisciplinary approach is crucial for managing patients with CAKUT.

Hypertension in children with congenital anomalies of the kidney and urinary tract

BACKGROUND

Congenital anomalies of the kidney and urinary tract (CAKUT) are the most common cause of childhood chronic kidney disease (CKD). We hypothesized that hypertension varies across CAKUT categories and increases the risk of CKD.

METHODS

This was a retrospective cohort study and included cases with a multicystic dysplastic kidney (MCDK, n = 81), unilateral kidney agenesis (UKA, n = 47), kidney hypoplasia (KH, n = 130), and posterior urethral valves (PUV, n = 75). Hypertension was defined as systolic or diastolic blood pressure ≥ 95th percentile for age, sex and height, and CKD as an estimated glomerular filtration rate < 60 ml/min/1.73 m2, both at 2 consecutive clinic visits at least 3 months apart.

RESULTS

Sixty-two (19%) out of 333 cases developed hypertension, with significant difference according to CAKUT type. Patients with smaller kidney size (7.7 vs. 8.3, p = 0.045), kidney anomalies in addition to the primary diagnosis (aCAKUT) (53 vs. 38%, p = 0.03), proteinuria (46 vs. 12%, p < 0.001), and CKD (51 vs. 23%, p < 0.001) were more likely to develop hypertension. When adjusted for kidney size, the diagnoses of PUV (OR 10.9, 95%CI 3.0, 40.5), UKA (OR 6.4, 95%CI 1.6, 24.9) and KH (OR 4.2, 95%CI 1.1, 16.1), and aCAKUT (OR 2.1, 95%CI 1.2, 3.9) were independent risk factors for hypertension. Hypertension increased the risk of developing CKD by twofold (HR 1.9, 95%CI 1.19, 2.94).

CONCLUSION

Hypertension is common in children with CAKUT and increases the risk of CKD. These findings will aid in the development of a standardized clinical pathway for the care of hypertensive children with CAKUT.

Nuclear medicine and pediatric nephro-urology: a long-lasting successful partnership

Congenital anomalies of the kidney and urinary tract, as well as urinary infections, are very frequent in children. After the clinical and laboratory evaluation, the first imaging procedure to be done is a renal and bladder ultrasound, but afterwards, a main contribution comes from nuclear medicine. Through minimally invasive and sedation-free procedures, nuclear medicine allows the evaluation of the functional anatomy of the urinary tract, and the quantification of renal function and drainage. If pediatric dosage cards provided by scientific societies are used, radiation exposure can also be low. In the pediatric conditions previously mentioned, nuclear medicine is used both for initial diagnosis and follow-up, mostly in cases of suspicion of ureteropelvic or ureterovesical junction syndromes, as well as vesicoureteral reflux or renal scars of febrile infectious episodes. Pediatric nephro-urology constitutes a significant workload of pediatric nuclear medicine departments. The following paragraphs are a revision of the renal radiopharmaceuticals, as well as the nuclear nephro-urology procedures - dynamic and static renal scintigraphy, and direct and indirect radionuclide cystography. A summary of the techniques, main indications, interpretation criteria and pitfalls will be provided. Some future directions for the field are also pointed out, among which the most relevant is the need for nuclear medicine professionals to use standardized protocols and integrate multidisciplinary teams with other pediatric and adult health professionals that manage these life-long pediatric pathologies, which are recognized as an important cause of adult chronic kidney disease.

Predicting outcomes in children with congenital anomalies of the kidney and urinary tract

BACKGROUND

Congenital anomalies of the kidney and urinary tract (CAKUT) are the most frequent causes of childhood chronic kidney disease (CKD). Using a large CAKUT cohort, we sought to identify the predictors of CKD and to develop a prediction model that informs a risk-stratified clinical pathway.

METHODS

This was a retrospective cohort study including cases with multicystic dysplastic kidneys (MCDK), unilateral kidney agenesis (UKA), kidney hypoplasia (KH), and posterior urethral valves (PUV). We identified risk factors for CKD (estimated glomerular filtration rate [eGFR] <60 ml/min/1.73 m2) and tested their performance in an adjusted multivariate binary regression model. Prediction probability scores for CKD were used to separate cases likely to develop complications from those not needing specialist follow-up.

RESULTS

We identified 452 eligible cases of CAKUT with 22% developing CKD. Strongest associations with CKD included primary diagnosis (OR 3.5, 95% CI 2.6-4.6), preterm delivery (OR 2.3, 95% CI 1.2-4.4), non-kidney anomalies (OR 1.8, 95% CI 1.1-3), first eGFR<90 (OR 8.9, 95% CI 4.4-18.1), small kidney size (OR 9, 95% CI 4.9-16.6), and additional kidney anomalies (OR 1.6, 95% CI 1.2-2.8). PUV (OR 4.7, 95% CI 1.5-15.3), first eGFR <90 (OR 4.4, 95% CI 2-9.7), and kidney length to body length ratio <7.9 (OR 4.2, 95% CI 1.9-9.2) were independent predictors of CKD. The regression model had a prediction accuracy of 80% and a prediction probability c-statistic of 0.81.

CONCLUSION

Using a large combined CAKUT cohort we identified risk factors for CKD. Our prediction model provides the first steps towards a risk-stratified clinical pathway. A higher resolution version of the Graphical abstract is available as Supplementary information.