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Congenital Ureteral Anomalies

Updated : January 18, 2024





Background

CAKUT, or Congenital Anomalies of the Kidney and Urinary Tract, refers to a group of diverse medical conditions that impact the development and function of the kidneys and urinary tract. These anomalies can manifest in a variety of ways, ranging from mild symptoms to life-threatening complications, and the severity of the condition can vary widely from one individual to another. Despite these differences, the underlying causes of CAKUT are often linked to genetic and molecular factors that impact kidney development.

Recent advancements in medical technology and genetic testing have provided a better understanding of the underlying causes and have greatly improved the prognosis and quality of life for affected individuals and families. For example, prenatal diagnostics and imaging techniques make early detection and monitoring of CAKUT, while laboratory surveillance and medical management help to manage symptoms and prevent or treat related complications.

 

Epidemiology

Approximately half of the individuals with Congenital anomalies of the kidney and urinary tract present with lower urinary tract abnormalities, including vesicoureteral reflux (25%), obstruction at the ureteropelvic junction (11%), and obstruction at the ureterovesical junction (11%). These anomalies can often be detected during pregnancy, with kidney malformations accounting for 20-30% of all detectable CAKUT.

The severity of these anomalies can vary greatly, with some individuals having mild prenatal pelvic dilation while others may experience a complete absence of both kidneys. CAKUT is estimated to impact approximately 2% of all pregnancies and is frequently associated with additional developmental abnormalities or genetic syndromes.

Studies from large patient databases reveal that Congenital anomalies of the kidney and urinary tract (CAKUT) are a significant source of health issues among pediatric and adolescent populations, contributing to 30-50% of cases of end-stage kidney disease. These anomalies can result in severe morbidity and decreased quality of life, particularly in patients with persistent or progressive renal impairment.

 

Anatomy

Pathophysiology

The process of kidney development in mammals starts with the formation of the nephric duct and proceeds through three stages of embryonic kidneys: pronephros, mesonephros, and metanephros. The metanephros, which becomes the mature kidney, develops as the ureteric bud penetrates the metanephric mesoderm and forms the collecting duct, calyces, renal pelvis, and ureter. The kidney moves from the pelvis to its adult position in the retroperitoneal fossa and rotates 90 degrees to its final position.

During the prenatal period, the kidney maintains amniotic fluid and starts regulating fluid, electrolyte, and acid-base homeostasis after birth. Renal agenesis, the complete loss of one or both kidneys, occurs with failure of metanephros formation and is more common in males. Unilateral renal agenesis is usually asymptomatic, while bilateral renal agenesis results in severe oligohydramnios and fetal loss. Renal agenesis can be associated with anomalies of other organs, both contiguous and non-contiguous.

Ectopic kidneys are a condition in which the kidneys are located outside their normal abdomen position. This can be due to errors in the development of the kidneys during fetal development, causing them to form in an abnormal location. Ectopic kidneys can be found in the pelvis, a rarer location being the thorax. They can be unilateral or bilateral, with bilateral pelvic kidneys sometimes fusing into a single mass of renal tissue called a pancake kidney. In some cases, the ureter of the ectopic kidney crosses the midline, referred to as cross-fused ectopia.

Ectopic kidneys are typically smaller and often hypoplastic, leading to compensatory hyperfiltration and hypertrophy in the contralateral kidney. They are often asymptomatic and were previously detected more frequently in autopsies than in clinical settings. However, with the improvement of ultrasound techniques, it is still being determined how this has changed. If an ectopic kidney is detected on prenatal ultrasound, post-natal renal ultrasound is recommended to confirm its location.

Although some studies have shown no adverse effects on blood pressure and renal function in individuals with ectopic kidneys, it is still recommended to monitor blood pressure and kidney function annually through serum creatinine measurements, urinalysis, and blood pressure monitoring. This is to prevent any long-term consequences, such as chronic kidney disease, that may develop after many years of compensatory glomerular hyperfiltration. Any changes in blood pressure or kidney function should prompt further evaluation and monitoring, as it may indicate renal insufficiency.

 

Etiology

Congenital anomalies, or birth defects, can have a genetic or environmental cause. Approximately 17% of anomalies are caused by single-gene defects, while 10% are caused by chromosomal abnormalities. Environmental factors, such as maternal nutrition, exposure to chemicals, and infections, account for 4-10% of anomalies.

However, the cause remains unknown for 66% of anomalies, which may result from multiple gene variants interacting with environmental factors. Gene-environment interactions have been studied in relation to specific anomalies, such as cleft lip and congenital heart defects, and some prescription medications have been found to increase the risk for anomalies.

 

Genetics

Prognostic Factors

Clinical History

Clinical History

Ureteral anomalies are uncommon medical conditions that occur when there is a deviation from the normal structure or position of the ureters. These anomalies are usually discovered incidentally through routine prenatal ultrasound scans, but in some cases, patients may present with symptoms that prompt further investigation. Clinical signs associated with ureteral anomalies can vary, and often the diagnosis is made after imaging studies have been carried out for unrelated symptoms.

Some common symptoms associated with ureteral anomalies include urinary tract infections, abdominal masses, hematuria, cyclic abdominal pain/flank pain, a cystic mass at the urethral meatus, and prolapsed ureterocele. In some cases, the diagnosis of a ureteral anomaly may be made after the patient has been evaluated for other conditions, such as hypertension, proteinuria, or even renal insufficiency in rare cases of severe bilateral anomalies.

About half of the females with ectopic ureters present with constant urinary incontinence or vaginal discharge. In prepubertal boys, the presence of recurrent epididymitis should prompt consideration of an ectopic ureteral insertion. In post pubertal males, ectopic ureters are most commonly associated with chronic prostatitis, painful intercourse, and ejaculation. It is worth noting that incontinence is never due to an ectopic ureter in males, as the ectopic ureter never inserts distal to the external urethral sphincter.

 

Physical Examination

Physical Examination

A kidney or urinary tract anomaly that goes undetected during prenatal ultrasound may present symptoms in infancy or childhood, such as urinary tract infections, which may be indicated by unexplained fevers. Other signs of the issue could be a swollen belly caused by a bladder that does not empty properly, swelling in the hands or feet, or the face around the eyes. Other symptoms may include nausea, vomiting, a loss of appetite, unusual tiredness, a lack of energy, and poor growth.

When it comes to children, there are a few warning signs that may indicate the presence of ureteral anomalies. These anomalies should be considered in kids who have experienced a single episode of pyelonephritis or have a history of recurrent urinary tract infections. Women who struggle with persistent urinary incontinence may also have ureteral anomalies. Ureteral openings, single or duplicated, can be malpositioned in various locations within the body.

They may be found on the lateral wall of the bladder, near the trigone, at the bladder neck, within the female urethra distal to the sphincter muscle (resulting in continuous incontinence despite normal voiding patterns), in the genital system (prostate and seminal vesicles in males, uterus or vagina in females), or even externally. Lateral ectopic orifices have a high likelihood of causing vesicoureteral reflux, while distal ectopic orifices are more often associated with obstruction and incontinence. It is important to remember that these anomalies are complex and can present in various ways.

 

Age group

Associated comorbidity

Associated activity

Acuity of presentation

Differential Diagnoses

Laboratory Studies

Imaging Studies

Procedures

Histologic Findings

Staging

Treatment Paradigm

In some cases, no intervention is necessary for children with minor issues related to urine flow through the ureters and urethra. Even if a child has only one functioning kidney or has suffered damage to a kidney, they can still lead a healthy life. However, various forms of treatment may be needed in different circumstances to preserve health.

This could range from the use of antibiotics to prevent urinary tract infections, which could potentially spread to the kidneys and bloodstream if urine flows back, to more invasive procedures such as surgery.

For example, surgical procedures may be used to reattach the ureter to the bladder and create a passage that closes when the bladder is full. Other procedures may also be performed to prevent reflux. If congenital anomalies of the kidneys and urinary tract are not detected early, or if treatments cannot prevent serious damage to the kidneys, dialysis may be necessary in cases of kidney failure.

 

by Stage

by Modality

Chemotherapy

Radiation Therapy

Surgical Interventions

Hormone Therapy

Immunotherapy

Hyperthermia

Photodynamic Therapy

Stem Cell Transplant

Targeted Therapy

Palliative Care

Medication

Media Gallary

References

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7451090/

Congenital Ureteral Anomalies

Updated : January 18, 2024




CAKUT, or Congenital Anomalies of the Kidney and Urinary Tract, refers to a group of diverse medical conditions that impact the development and function of the kidneys and urinary tract. These anomalies can manifest in a variety of ways, ranging from mild symptoms to life-threatening complications, and the severity of the condition can vary widely from one individual to another. Despite these differences, the underlying causes of CAKUT are often linked to genetic and molecular factors that impact kidney development.

Recent advancements in medical technology and genetic testing have provided a better understanding of the underlying causes and have greatly improved the prognosis and quality of life for affected individuals and families. For example, prenatal diagnostics and imaging techniques make early detection and monitoring of CAKUT, while laboratory surveillance and medical management help to manage symptoms and prevent or treat related complications.

 

Approximately half of the individuals with Congenital anomalies of the kidney and urinary tract present with lower urinary tract abnormalities, including vesicoureteral reflux (25%), obstruction at the ureteropelvic junction (11%), and obstruction at the ureterovesical junction (11%). These anomalies can often be detected during pregnancy, with kidney malformations accounting for 20-30% of all detectable CAKUT.

The severity of these anomalies can vary greatly, with some individuals having mild prenatal pelvic dilation while others may experience a complete absence of both kidneys. CAKUT is estimated to impact approximately 2% of all pregnancies and is frequently associated with additional developmental abnormalities or genetic syndromes.

Studies from large patient databases reveal that Congenital anomalies of the kidney and urinary tract (CAKUT) are a significant source of health issues among pediatric and adolescent populations, contributing to 30-50% of cases of end-stage kidney disease. These anomalies can result in severe morbidity and decreased quality of life, particularly in patients with persistent or progressive renal impairment.

 

The process of kidney development in mammals starts with the formation of the nephric duct and proceeds through three stages of embryonic kidneys: pronephros, mesonephros, and metanephros. The metanephros, which becomes the mature kidney, develops as the ureteric bud penetrates the metanephric mesoderm and forms the collecting duct, calyces, renal pelvis, and ureter. The kidney moves from the pelvis to its adult position in the retroperitoneal fossa and rotates 90 degrees to its final position.

During the prenatal period, the kidney maintains amniotic fluid and starts regulating fluid, electrolyte, and acid-base homeostasis after birth. Renal agenesis, the complete loss of one or both kidneys, occurs with failure of metanephros formation and is more common in males. Unilateral renal agenesis is usually asymptomatic, while bilateral renal agenesis results in severe oligohydramnios and fetal loss. Renal agenesis can be associated with anomalies of other organs, both contiguous and non-contiguous.

Ectopic kidneys are a condition in which the kidneys are located outside their normal abdomen position. This can be due to errors in the development of the kidneys during fetal development, causing them to form in an abnormal location. Ectopic kidneys can be found in the pelvis, a rarer location being the thorax. They can be unilateral or bilateral, with bilateral pelvic kidneys sometimes fusing into a single mass of renal tissue called a pancake kidney. In some cases, the ureter of the ectopic kidney crosses the midline, referred to as cross-fused ectopia.

Ectopic kidneys are typically smaller and often hypoplastic, leading to compensatory hyperfiltration and hypertrophy in the contralateral kidney. They are often asymptomatic and were previously detected more frequently in autopsies than in clinical settings. However, with the improvement of ultrasound techniques, it is still being determined how this has changed. If an ectopic kidney is detected on prenatal ultrasound, post-natal renal ultrasound is recommended to confirm its location.

Although some studies have shown no adverse effects on blood pressure and renal function in individuals with ectopic kidneys, it is still recommended to monitor blood pressure and kidney function annually through serum creatinine measurements, urinalysis, and blood pressure monitoring. This is to prevent any long-term consequences, such as chronic kidney disease, that may develop after many years of compensatory glomerular hyperfiltration. Any changes in blood pressure or kidney function should prompt further evaluation and monitoring, as it may indicate renal insufficiency.

 

Congenital anomalies, or birth defects, can have a genetic or environmental cause. Approximately 17% of anomalies are caused by single-gene defects, while 10% are caused by chromosomal abnormalities. Environmental factors, such as maternal nutrition, exposure to chemicals, and infections, account for 4-10% of anomalies.

However, the cause remains unknown for 66% of anomalies, which may result from multiple gene variants interacting with environmental factors. Gene-environment interactions have been studied in relation to specific anomalies, such as cleft lip and congenital heart defects, and some prescription medications have been found to increase the risk for anomalies.

 

Clinical History

Ureteral anomalies are uncommon medical conditions that occur when there is a deviation from the normal structure or position of the ureters. These anomalies are usually discovered incidentally through routine prenatal ultrasound scans, but in some cases, patients may present with symptoms that prompt further investigation. Clinical signs associated with ureteral anomalies can vary, and often the diagnosis is made after imaging studies have been carried out for unrelated symptoms.

Some common symptoms associated with ureteral anomalies include urinary tract infections, abdominal masses, hematuria, cyclic abdominal pain/flank pain, a cystic mass at the urethral meatus, and prolapsed ureterocele. In some cases, the diagnosis of a ureteral anomaly may be made after the patient has been evaluated for other conditions, such as hypertension, proteinuria, or even renal insufficiency in rare cases of severe bilateral anomalies.

About half of the females with ectopic ureters present with constant urinary incontinence or vaginal discharge. In prepubertal boys, the presence of recurrent epididymitis should prompt consideration of an ectopic ureteral insertion. In post pubertal males, ectopic ureters are most commonly associated with chronic prostatitis, painful intercourse, and ejaculation. It is worth noting that incontinence is never due to an ectopic ureter in males, as the ectopic ureter never inserts distal to the external urethral sphincter.

 

Physical Examination

A kidney or urinary tract anomaly that goes undetected during prenatal ultrasound may present symptoms in infancy or childhood, such as urinary tract infections, which may be indicated by unexplained fevers. Other signs of the issue could be a swollen belly caused by a bladder that does not empty properly, swelling in the hands or feet, or the face around the eyes. Other symptoms may include nausea, vomiting, a loss of appetite, unusual tiredness, a lack of energy, and poor growth.

When it comes to children, there are a few warning signs that may indicate the presence of ureteral anomalies. These anomalies should be considered in kids who have experienced a single episode of pyelonephritis or have a history of recurrent urinary tract infections. Women who struggle with persistent urinary incontinence may also have ureteral anomalies. Ureteral openings, single or duplicated, can be malpositioned in various locations within the body.

They may be found on the lateral wall of the bladder, near the trigone, at the bladder neck, within the female urethra distal to the sphincter muscle (resulting in continuous incontinence despite normal voiding patterns), in the genital system (prostate and seminal vesicles in males, uterus or vagina in females), or even externally. Lateral ectopic orifices have a high likelihood of causing vesicoureteral reflux, while distal ectopic orifices are more often associated with obstruction and incontinence. It is important to remember that these anomalies are complex and can present in various ways.

 

In some cases, no intervention is necessary for children with minor issues related to urine flow through the ureters and urethra. Even if a child has only one functioning kidney or has suffered damage to a kidney, they can still lead a healthy life. However, various forms of treatment may be needed in different circumstances to preserve health.

This could range from the use of antibiotics to prevent urinary tract infections, which could potentially spread to the kidneys and bloodstream if urine flows back, to more invasive procedures such as surgery.

For example, surgical procedures may be used to reattach the ureter to the bladder and create a passage that closes when the bladder is full. Other procedures may also be performed to prevent reflux. If congenital anomalies of the kidneys and urinary tract are not detected early, or if treatments cannot prevent serious damage to the kidneys, dialysis may be necessary in cases of kidney failure.

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7451090/