Management of antenatally detected kidney malformations

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.

Ultrasound and magnetic resonance imaging features of fetal urogenital anomalies: A pictorial essay

This pictorial essay focuses on ultrasound (US) and magnetic resonance imaging (MRI) features of fetal urogenital anomalies. Fetal urogenital malformations account for 30%-50% of all anomalies discovered during pregnancy or at birth. They are usually detected by fetal ultrasound exams. However, when ultrasound data on their characteristics is insufficient, MRI is the best option for detecting other associated anomalies. The prognosis highly depends on their type and whether they are associated with other fetal abnormalities.

Congenital anomalies of the kidney and urinary tract: antenatal diagnosis, management and counselling of families

Congenital anomalies of the kidney and urinary tract are collectively one of the most commonly diagnosed antenatal conditions. Clinicians have several tools available to diagnose anomalies, including imaging, biomarkers, family history and genetic studies. In certain cases, antenatal interventions such as vesico-amniotic shunting may be considered to improve postnatal outcomes.Congenital kidney anomalies detected antenatally can vary in clinical significance from almost no impact postnatally to significant morbidity and perinatal mortality. Prognosis broadly depends on kidney size, structure and amount of amniotic fluid, alongside genetics and family history, and progression on subsequent scans. It is important to counsel parents appropriately using a parent-focused and personalised approach. The use of a multidisciplinary team should always be considered.

Comparison of early surgical and conservative therapy in children with ureteropelvic junction obstruction

BACKGROUND

Ureteropelvic junction obstruction is a relatively common urologic problem in children. Most cases present with pelvicaliceal dilatation in antenatal period. Historically most UPJO cases were treated with surgical procedures, but recently many of these children have been treated by nonsurgical observational plans. We compared the outcome of children with UPJO treated in surgical and observational ways.

METHODS

In a retrospective study, we assessed the medical history of patients diagnosed as UPJO, march 2011 to march 2021. The case definition was based on grade 3-4 hydronephrosis and obstructive pattern in dynamic renal isotopes can. Patients were put into two groups; Group 1 children were treated with a surgical procedure, and group 2 patients without any surgical procedure for at least a six months' period after diagnosis. We assessed long-term events and improvement of obstruction.

RESULTS

Seventy-eight children (mean age 7.32mo., 80% male) enrolled in the study, 55 patients in group one and 23 as group 2. Severe hydronephrosis was the problem of 96% of all patients significantly led to 20% in group 1 and 9% in group 2 (P < 0.001). Severe kidney involvement was observed at 91% in group 1 and 83% in group 2, decreased to 15% and 6%, respectively (P < 0.001). There were no significant differences in sonographic and functional improvement between the two intervention groups. Long-term prognostic issues; growth, functional impairment, and hypertension were not different between the two groups, but group 1 children experienced more recurrence of UTI than group 2 patients.

CONCLUSION

Conservative management is as effective as early surgical treatment in the management of infants with severe UPJO.

Congenital Anomalies of the Kidneys and Urinary Tract

Congenital anomalies of the kidneys and urinary tract (CAKUT) are some of the most common abnormalities detected on prenatal imaging assessment. It is estimated that CAKUT comprises 20% to 30% of all major birth defects. More than 200 clinical syndromes currently include CAKUT as a component of the phenotype. This chapter outlines the evaluation and management of the most common forms of CAKUT.

The causes and consequences of paediatric kidney disease on adult nephrology care

Adult nephrologists often look after patients who have been diagnosed with kidney disease in childhood. This does present unique challenges to the adult nephrologist, who may be unfamiliar with the underlying cause of kidney disease as well as the complications of chronic kidney disease (CKD) that may have accumulated during childhood. This review discusses common causes of childhood CKD, in particular congenital anomalies of the kidney and urinary tract (CAKUT), autosomal dominant tubulointerstitial kidney disease (ADTKD), polycystic kidney disease, hereditary stone disease, nephrotic syndrome and atypical haemolytic uraemic syndrome. The long-term consequences of childhood CKD, such as the cardiovascular consequences, cognition and education as well as bone health, nutrition and growth are also discussed.

Sonographic Detection of Multicystic Dysplastic Kidneys

Multicystic dysplastic kidney (MCDK) is a common nonhereditary cystic dysplasia that can be detected antenatally. This disorder commonly manifests in utero and presents unilaterally; however, this patient’s case demonstrates bilateral MCDKs. The use of sonography is essential in diagnosing this disorder both antenatally and following birth. Bilateral MCDKs present as large anechoic cysts overtaking renal parenchyma and halting all normal renal physiologic functions. This case study demonstrates the importance of early detection, the progression of this disorder, as well as the large part sonographic imaging plays in visualizing the MCDK.

Clinical Management of Children with a Congenital Solitary Functioning Kidney: Overview and Recommendations

CONTEXT

A congenital solitary functioning kidney (cSFK) is a common developmental defect that predisposes to hypertension and chronic kidney disease (CKD) as a consequence of hyperfiltration. Every urologist takes care of patients with a cSFK, since some will need lifelong urological care or will come with clinical problems or questions to an adult urologist later in life.

OBJECTIVE

We aim to provide clear recommendations for the initial clinical management and follow-up of children with a cSFK.

EVIDENCE ACQUISITION

PubMed and EMBASE were searched to identify relevant publications, which were combined with guidelines on related topics and expert opinion.

EVIDENCE SYNTHESIS

Initially, cSFK diagnosis should be confirmed and risk factors for kidney injury should be identified using ultrasound. Although more research into early predictors of kidney injury is needed, additional congenital anomalies of the kidney or urinary tract and absence of compensatory kidney hypertrophy have repeatedly been associated with a worse prognosis. The role of voiding cystourethrography and antibiotic prophylaxis remains controversial, and is complicated by the exclusion of children with a cSFK from studies. A yearly follow-up for signs of kidney injury is recommended for children with a cSFK. As masked hypertension is prevalent, annual ambulatory blood pressure measurement should be considered. During puberty, an increasing incidence of kidney injury is seen, indicating that long-term follow-up is necessary. If signs of kidney injury are present, angiotensin converting enzyme inhibitors are the first-line drugs of choice.

CONCLUSIONS

This overview points to the urological and medical clinical aspects and long-term care guidance for children with a cSFK, who are at risk of hypertension and CKD. Monitoring for signs of kidney injury is therefore recommended throughout life. Large, prospective studies with long-term follow-up of clearly defined cohorts are still needed to facilitate more risk-based and individualized clinical management.

PATIENT SUMMARY

Many children are born with only one functioning kidney, which could lead to kidney injury later in life. Therefore, a kidney ultrasound is made soon after birth, and other investigations may be needed as well. Urologists taking care of patients with a solitary functioning kidney should realize the long-term clinical aspects, which might need medical management.

Renal cystic diseases during the perinatal and neonatal period

Renal cystic diseases are a clinically and genetically diverse group of renal diseases that can manifest in utero, infancy, or throughout childhood and adulthood. These diseases may be unilateral or bilateral with a single cyst or multiple cysts, or with increased echogenicity of the renal cortex without macroscopic cysts. Certain cystic renal diseases are life-threatening, with many developing chronic kidney and hepatic disease if not recognized early enough. Therefore, due to the prevalence and life-altering complications of this specific group of diseases in vulnerable populations, it is crucial for clinicians and healthcare providers to have an overall understanding of cystic diseases and how to pre-emptively detect and manage these conditions. In this review, we discuss in detail the epidemiology, genetics and pathophysiology, diagnosis, presentation, and management of numerous genetic and sporadic renal cystic diseases, such as polycystic kidney disease, multicystic dysplastic kidney, and calyceal diverticula, with an emphasis on prenatal care and pregnancy counseling.

Management of antenatal hydronephrosis

Antenatal hydronephrosis (AHN) is the most frequently detected abnormality by prenatal ultrasonography. Differential diagnosis of AHN includes a wide variety of congenital abnormalities of the kidney and urinary tract ranging from mild abnormalities such as transient or isolated AHN to more important ones as high-grade congenital vesicoureteral reflux or ureteropelvic junction obstruction. It is well known that the outcome depends on the underlying etiology. Various grading systems have been proposed for the classification of AHN on prenatal and postnatal ultrasonography. Mild isolated AHN represents up to 80% of cases, is considered to be benign, and majority of them resolve, stabilize, or improve during follow-up. Controversies exist regarding the diagnosis and management of some important and severe causes of AHN such as high-grade vesicoureteral reflux and ureteropelvic junction obstruction. Current approach is becoming increasingly conservative during diagnosis and follow-up of these patients with less imaging and close follow-up. However, there is still no consensus regarding the clinical significance, postnatal evaluation, and management of infants with AHN. The aim of this review is to discuss the controversies and provide an overview on the management of AHN.

Molecular diagnostic in fetuses with isolated congenital anomalies of the kidney and urinary tract by whole-exome sequencing

BACKGROUND

In prenatal care, accumulating evidences has demonstrated that whole-exome sequencing (WES) expedites the genetic diagnosis of fetal structural anomalies. However, the clinical value of WES in the diagnosis of prenatal isolated congenital anomalies of the kidney and urinary tract (CAKUT) is unknown.

METHODS

Forty-one fetuses with unexplained isolated CAKUT, normal karyotype and negative chromosomal microarray analysis (CMA) results, underwent WES and were accordingly grouped as (a) Group 1: complex cases with bilateral renal abnormalities (N = 19); and (b) Group 2: cases with isolated unilateral fetal renal abnormalities (N = 22).

RESULTS

The detection rate of WES for pathogenic variants and incidental variants was 7.32% (3/41) and 2.4% (1/41), respectively. The three pathogenic variants were identified in the genes ACTA2 (multisystem smooth muscle dysfunction syndrome), PKHD1 (autosomal recessive form of polycystic kidney disease), and PKD1 (autosomal dominant polycystic kidney disease type 1). The incidental variants were detected in genes PPM1D (syndromic neurodevelopmental disorders). Furthermore, all above fetuses carrying pathogenic variants came from bilateral kidney anomalies. Thus, the detection rate was 0 for fetuses with unilateral fetal renal abnormalities and 15.7% (3/19) for bilateral renal abnormalities.

CONCLUSION

This cohort shows that prenatal WES is a supplementary approach for the etiologic diagnosis of unexplained isolated CAKUT with negative CMA, especially for fetuses with bilateral renal abnormality.

Genetic Testing in Pediatric Kidney Disease

The advent of next gene sequencing technology has led to the publication of a profusion of papers on monogenic contributions to pediatric kidney disorders. It started with the discovery of mutations in the podocin gene in steroid resistant nephrotic syndrome (SRNS). It is realized now that genetic disorders contribute to about 30% of chronic renal diseases in children, and significantly to many other kidney disorders. This paper covers briefly the new genetic technologies, the benefits of genetic testing, and the indication for genetic testing in various kidney disorders. It covers SRNS, congenital anomalies of the kidney, cystic kidney disease, tubulopathies, nephronophthisis, Fabry disease, Alport and Lowe syndrome. Atypical hemolytic uremic syndrome, renal tubular acidosis and nephrolithiasis are also covered briefly. It is hoped that this paper will encourage the pediatricians to investigate monogenic disorders of the kidney as it helps in their proper classification, informs prognosis, suggests specific treatment and aids in genetic and reproductive counseling.

Fetal kidney charts of a novel measurement of the renal parenchymal thickness to evaluate fetal kidney growth and potential function

OBJECTIVE

The objective of this study was to develop new standard growth charts for fetal renal parenchymal thickness, length, and volume to define normal ranges for use in clinical practice and to assess the reliability of these measurements.

METHODS

This was a prospective, longitudinal study of 72 low-risk singleton pregnancies undergoing serial ultrasound examinations at least every four weeks. Multiple renal measurements were performed on both kidneys at each scan. The renal parenchymal thickness was measured in the mid-sagittal plane. Standard charts were developed and the intra and interobserver reliability for the renal measurements was analysed.

RESULTS

Standard charts were developed for fetal renal parenchymal thickness, length, and volume.

CONCLUSION

We present novel charts, which demonstrate the growth of the fetal renal parenchyma during pregnancy. They will be useful in clinical practice to identify any alterations from these normal ranges, which may be an important criterion for assisting prenatal diagnosis of renal pathologies and future studies in the prediction of kidney function.