Nuclear nephrology

NUCLEAR NEPHROLOGY
AN EVIDENCE BASED
APPROACH
Ramin Sadeghi, MD

FETAL ANDNEONATAL
HYDRONEPHROSIS

DEFINITION AND GRADING
Definition
 dilation of the renal pelvis with or without dilation of the renal calyces
Scoring systems differ based upon the fetal ultrasound criteria used
and include:
●Renal pelvic diameter (RPD)
●Society of Fetal Urology (SFU) criteria
●Urinary tract dilation (UTD) classification system

RENAL PELVIC DIAMETER (RPD)
Most experts in the field use a value above 4 to 5 mm as the lowest
cutoff for fetal hydronephrosis in the second trimester.
Mild renal pelvic dilation, also referred to as pyelectasia, is defined as
an RPD of ≥4 to 10 mm in the second trimester
 Although most cases of mild renal pelvic dilation will resolve and not have a clinical
impact on neonatal renal development, there are reports of persistent cases that
require postnatal intervention
In general, RPD >10 mm in the second trimester is associated with an
increased risk of significant congenital anomalies of the kidney and
urinary tract (CAKUT)

SOCIETY OF FETAL UROLOGY
(SFU)
based upon the degree of pelvic dilation, number of calyces seen, and
the presence and severity of parenchymal atrophy

URINARY TRACT DILATION (UTD)
CLASSIFICATION SYSTEM
It is based on six ultrasound findings (anterior and posterior RPD,
calyceal dilation, renal parenchymal thickness, renal parenchymal
appearance, bladder abnormalities, and urologic abnormalities)

EPIDEMIOLOGY
Hydronephrosis occurs approximately twice as often in males as in
females.
It is bilateral in 20 to 40 percent of cases
The reported incidence of fetal hydronephrosis ranges from 0.6 to
4.5 percent of pregnancies

ETIOLOGY
Transient hydronephrosis
 seen in 41 to 88 percent of cases
 Mild hydronephrosis with renal pelvic diameter (RPD) <6 mm in the second
trimester or <8 mm in the third trimester is usually associated with transient
hydronephrosis.
Congenital anomalies of the kidney and urinary tract (CAKUT)
 the underlying cause of fetal hydronephrosis in one-third of the patients
 UPJO was the most common diagnosis and increased in frequency with the severity
of hydronephrosis.
 In contrast, VUR, the second most common diagnosis, was not associated with the
severity of fetal hydronephrosis.

ETIOLOGY
Other less common causes of fetal hydronephrosis due to CAKUT
include
 ●Megaureter
 ●Multicystic dysplastic kidney (MCDK)
 ●Ureterocele
 ●Posterior urethral valves (PUV)
 ●Ectopic ureter
 ●Prune-belly syndrome
 ●Urachal cyst
 ●Duplex collecting system
 ●Urethral atresia

SEVERITY OF HYDRONEPHROSIS
The likelihood that an infant postnatally will have a significant CAKUT
increases with the severity of persistent fetal hydronephrosis
 •Mild hydronephrosis (≤7 mm in the second trimester and/or ≤9 mm in the third
trimester) − 12 percent
 •Moderate hydronephrosis (7 to 10 mm in the second trimester and/or 9 to 15 mm
in the third trimester) − 45 percent
 •Severe hydronephrosis (>10 mm in the second trimester and/or >15 mm in the
third trimester) − 88 percent

TIMING AND REPEAT ULTRASOUND
TESTING
However, fetal hydronephrosis is most commonly detected during
routine fetal ultrasonography, which typically occurs in the second
trimester (18 to 22 weeks gestation).
We repeat testing for fetuses with hydronephrosis detected by
ultrasound in the second trimester

ULTRASOUND EXAMINATION
The following parameters should be reported
 Severity and persistence of hydronephrosis
 Unilateral versus bilateral involvement
 Ureter
 Dilation of the ureter can be consistent with vesicoureteral reflux (VUR) or obstructive uropathy distal to the
ureteropelvic junction (eg, ureterocele, megaureter, or posterior urethral valves [PUV]
 Renal parenchyma
 Thinning of the parenchyma and/or cortical cysts indicate injury or impaired development of the renal cortex.
 Bladder
 Abnormalities of the bladder such as increased thickness and trabeculation of the bladder wall are consistent with
obstructive uropathy distal to the bladder (eg, PUV). In addition, dilation of the proximal urethra (keyhole sign)
may indicate PUV in male fetuses with a thickened bladder wall and hydronephrosis
 Presence of urinoma or urinary ascites
 the presence of a fetal urinoma is associated with a nonfunctional dysplastic ipsilateral kidney in 80 percent of
cases

POSTNATAL MANAGEMENT OF
FETAL HYDRONEPHROSIS
The goals of postnatal management of infants with fetal
hydronephrosis are to identify patients with significant CAKUT while
avoiding unnecessary testing in patients with physiologic or clinically
insignificant hydronephrosis.
It is important to remember that it is rarely necessary to operate on
an obstructed kidney in a neonate in the first few days or weeks of
life
 An important exception are patients with posterior urethral valves (PUV), who
require intervention to relieve post-bladder obstruction as soon as possible after
birth.

PHYSICAL EXAMINATION
●The presence of an abdominal mass that could represent an enlarged
kidney due to obstructive uropathy or multicystic dysplastic kidney (MCDK).
●A palpable bladder in a male infant, especially after voiding, may suggest
posterior urethral valves (PUV).
●A male infant with prune-belly syndrome will have deficient abdominal wall
musculature and undescended testes.
●The presence of outer ear abnormalities is associated with an increased
risk of CAKUT.
●A single umbilical artery is associated with an increased risk of CAKUT,
particularly vesicoureteral reflux (VUR).
●Spinal and/or lower extremity abnormalities suggesting a neurogenic
bladder, which may result in hydronephrosis and dilated ureters.

IMAGING STUDIES
Postnatal evaluation of a newborn with fetal hydronephrosis begins
with an ultrasound examination.
The timing of ultrasonography and the need for other studies depend
upon the severity of fetal hydronephrosis and whether there is
bilateral involvement or an affected single kidney.

US
In general, postnatal evaluation is performed for cases that reach a
minimum prenatal renal pelvic diameter (RPD) of 10mm based on an
antenatal ultrasound performed in the third trimester
Examination should be avoided in the first two or three days after
birth, because hydronephrosis may not be detected due to
extracellular fluid shifts
Infants with bilateral hydronephrosis and those with a hydronephrotic
single kidney require more urgent evaluation within 48 hours of birth

VOIDING CYSTOURETHROGRAM
is performed in neonates with persistent postnatal hydronephrosis
(RPD ≥10 mm) to identify patients with bladder outlet obstruction,
most commonly posterior urethral valves (PUV), and to detect
vesicoureteral reflux (VUR)

DIURETIC RENOGRAPHY
Usually ordered after a VCUG has demonstrated no VUR
The test requires insertion of a bladder catheter to relieve any
pressure that can be transmitted to the ureters and kidneys
Split renal function is the most useful measure to detect differences
in renal function between the two kidneys.
 As a rule of thumb, spilt renal function of less than 5 percent difference is unlikely
to be clinically significant.

DIURETIC RENOGRAPHY
In patients with unilateral hydronephrosis (which is the most common
clinical scenario), if the normal nonhydronephrotic kidney and
hydronephrotic kidney both have similar function (ie, difference in
split renal function <5 percent), conservative management without
surgery is a safe option.
Subsequent studies can be compared to the initial baseline scan to
determine whether kidney function remains stable or whether
increasing differences in split renal function develop

DIURETIC RENOGRAPHY
In a dilated system, if washout occurs rapidly after diuretic
administration (<15 minutes), the system is not obstructed. If
washout is delayed beyond 20 minutes, the pattern is consistent with
obstructive uropathy.
However, a delayed washout must be interpreted with caution
 in a series of 39 infants with antenatal unilateral hydronephrosis followed without
surgery, diuretic renography indicated obstruction in 24 patients whose renal
function never decreased and thus could not have been obstructed [10]. These
results may partly be due to the normally low neonatal glomerular filtration rate
(GFR) that can be refractory to diuretic therapy.

DIURETIC RENOGRAPHY
A number of factors can affect the accuracy of the diuretic renogram.
This includes
 the state of hydration of the infant,
 the functionality of the bladder catheter
 the timing of diuretic administration
 the accuracy of physically outlining the renal tissue in the presence of severe
hydronephrosis
 the background effect from the liver and spleen.

APPROACH
Timing of US
 In bilateral cases in the first 48 hours
 In unilateral cases we can wait for the infant to gain his/her birth weigth.
antibiotic prophylaxis (amoxicillin, 12 to 25 mg/kg given orally per
day) is started after delivery in infants with high-grade fetal
hydronephrosis (ie, Society of Fetal Urology [SFU] grade IV or an RPD
>10 mm in the third trimester) until the diagnosis of VUR or
obstructive uropathy is excluded

PERSISTENT POSTNATAL
ULTRASOUND FINDINGS
infants with persistent postnatal moderate to severe hydronephrosis
(RPD >10 mm) should have a VCUG to detect VUR
 Infants who have VUR demonstrated on VCUG should remain on antibiotic
prophylaxis
 If the VCUG does not show reflux, antibiotics are discontinued.

ULTRASOUND FINDINGS
Further evaluation if there is no VUR is dependent on the degree of
hydronephrosis
Infants with persistent postnatal severe hydronephrosis (RPD ≥15
mm) should have diuretic renography (renal scan with technetium-
99m-mercaptoacetyltriglycine [Tc99mMAG3]) to detect possible
obstruction.
 In general, diuretic renography can be performed after six weeks of life because
surgical intervention is rarely required prior to this time
The use of antibiotic prophylaxis in patients with severe
hydronephrosis without VUR remains controversial.
 In our practice, antibiotic prophylaxis is continued for cases with severe SFU grade
IV hydronephrosis

ULTRASOUND FINDINGS
infants with moderate postnatal hydronephrosis (RPD 10 to <15 mm) have a
repeat ultrasound when they reach four to six months of age.
The majority of cases with mild or moderate postnatal hydronephrosis
resolve by 18 months of age.
If the degree of hydronephrosis increases in subsequent ultrasounds,
diuretic renography may be performed to determine if there is an obstructive
process.
if there is persistent dilation at three months of age, we continue to monitor
the degree of hydronephrosis with an ultrasound performed at one year of
age, and if needed, between three and five years of age. In symptomatic
cases, or if there is a marked increase in dilation, diuretic renography may
be performed to determine if there is an obstructive process.

ULTRASOUND FINDINGS
Infants with a normal postnatal examination or mild hydronephrosis
(defined as an RPD ≤10 mm without any evidence of calyceal or
ureteric dilation, or signs of renal dysplasia or anomalies) require no
further evaluation.

CONGENITAL URETEROPELVIC
JUNCTION OBSTRUCTION
UPJ obstruction is the most common pathologic cause of antenatally
detected hydronephrosis.

EPIDEMIOLOGY
The reported incidence of UPJ obstruction is 1 in 500 live births
Boys are affected with UPJ obstruction more commonly than are girls.
Lesions are found more frequently on the left than on the right side.
The reported rate of bilateral involvement is approximately 10
percent

PATHOPHYSIOLOGY
Most cases are thought to be due to partial obstruction
In the fetus and infant, the pelvis, because of its increased
compliance, can stretch and thereby accommodate large volumes of
urine

ETIOLOGY
usually caused by intrinsic stenosis of the proximal ureter at that UPJ,
and less commonly by extrinsic compression
Intrinsic narrowing
 In most cases of UPJ obstruction, the upper segment of the ureter is narrowed at
the UPJ or kinked as the ureter enters the pelvis
 Other causes of intrinsic UPJ obstruction, albeit rare, include valvular mucosal folds,
persistent fetal ureteral convolutions, and ureteral polyps
Extrinsic compression
 In approximately 10 percent of pediatric UPJ obstruction, an aberrant or accessory
renal artery or arterial branch may cross the lower pole of the kidney, resulting in
compression of the UPJ and blockage of urinary flow

Intermittent ureteropelvic
junction obstruction due to an
accessory crossing blood vessel
(black arrow in panel D). Panels A
and B show changes in renal
pelvis dilatation, which
corresponded to the timing of
symptoms. Pain corresponded
with increased renal dilatation
and evidence of obstruction on
sonography and at the time of
surgery (yellow arrow in panels C
and D).

CLINICAL PRESENTATION
Fetal and neonatal
 In geographic areas where maternal ultrasound screening is commonly performed,
most cases of UPJ obstruction are diagnosed during the postnatal evaluation of
antenatal hydronephrosis.
 In the absence of antenatal screening, newborns may present with a palpable
abdominal mass caused by an enlarged obstructed kidney. Other presentations
include urinary tract infection, hematuria, or failure to thrive. Renal failure is an
unusual presentation
Older children
 Clinical manifestations in older children include intermittent flank pain or
abdominal pain (referred to as Dietl's crisis). The pain may worsen during brisk
diuresis (for example, after consumption of caffeine or alcohol). These symptoms
may be accompanied by nausea and vomiting

DIAGNOSIS
The diagnosis of UPJ obstruction is generally suspected when imaging
studies, typically ultrasonography, demonstrate hydronephrosis. The
diagnosis is confirmed by diuretic renography

ULTRASONOGRAPHY
Most cases of UPJ obstruction present as a result of detecting
hydronephrosis by prenatal ultrasonographic screening
In older children with abdominal pain and suspected UPJ obstruction,
an ultrasound examination should be performed during the acute
painful episode (Dietl's crisis) to demonstrate hydronephrosis.
 When the pain subsides, the sonogram is frequently normal or only demonstrates
mild dilation.

VCUG
Ten percent of patients with UPJ obstruction have contralateral low-
grade vesicoureteral reflux.
In addition, VCUG assesses the patency of the urethra in males to
detect posterior urethral valves (PUV).
Identification of VUR may be important because children with
concurrent VUR and UPJ obstruction may be at higher risk for severe
infection.
The VCUG may be omitted in the work-up, especially in older children

DIURETIC RENOGRAPHY
Diuretic renography (renal scan and the administration of a diuretic)
is used to diagnose urinary tract obstruction.
The washout measurement correlates with the degree of obstruction.
In general, a half-life greater than 20 minutes to clear the isotope
from the kidney is considered indicative of obstruction, although
other urologists use split function, comparing the function of the two
kidneys, as a means to identify patients for surgery.

DIFFERENTIAL DIAGNOSIS
The differential diagnosis of UPJ obstruction includes other causes of
hydronephrosis. Imaging studies (eg, diuretic renography, serial
ultrasounds, and voiding cystourethrogram [VCUG]) differentiate UPJ
obstruction from the following conditions:
 ●Vesicoureteral reflux (VUR)
 ●Transient hydronephrosis
 ●Functional hydronephrosis
 ●Other urological anomalies including posterior urethral valves, congenital
megaureter, ureterocele, and multicystic dysplastic kidney (MCDK)

EVALUATION
Algorithms above should be used for neonatal period
Older child
 Ultrasonography should be performed in older patients with symptoms that are
suggestive of UPJ obstruction.
 The examination should be conducted when the child is symptomatic, as the
obstruction may be intermittent.
 The diagnosis of intermittent UPJ obstruction is confirmed if hydronephrosis is
present when the child is symptomatic, and resolves when the child is well. A
diuretic renal scan will document baseline renal function and may also provoke
symptoms during the diuretic phase of the study

MANAGEMENT
Symptomatic patients
Children who are symptomatic usually require operative intervention.
If radiographic evaluation reveals hydronephrosis during pain, which
resolves when symptoms subside, surgical intervention is warranted
These patients may have been initially evaluated with a computed
tomography (CT) scan for an acute abdominal pain, which identifies
the obstructed kidney.
In our practice, we document the renal function in the obstructed and
contralateral normal kidney with diuretic renogram
A follow-up ultrasound should be obtained approximately 4 to 12
weeks after surgery.

SYMPTOMATIC PATIENTS
Pyelonephritis — Patients with UPJ obstruction who present with acute
pyelonephritis are treated with antibiotics. Surgical repair is
performed when the infection has resolved. If pyelonephritis does not
respond to antibiotics, a temporary percutaneous pyelostomy tube
should be placed to relieve the obstruction.
Kidney stones — Kidney stones sometimes develop in the obstructed
renal pelvis. Treatment involves open pyelolithotomy and pyeloplasty.

ASYMPTOMATIC PATIENTS
Observation
 For experts in the field who consider observation an option, the main criterion for
observation in cases with significant hydronephrosis on sonogram is demonstration
of greater than 40 percent of split renal function of the affected kidney by diuretic
renography, even if washout is delayed
 Renal ultrasound examinations are performed every four months until the child
reaches one year of age, every six months for the next two years, and then annually
 If the renal sonogram shows increasing hydronephrosis, diuretic renography is
repeated to confirm that renal function is stable. If renography shows deterioration
of >10 percent on the affected side, or relative function less than 40 percent,
surgery is recommended.

Observation
 These studies are performed more frequently (every three to four months) if relative
renal function is borderline, and significant hydronephrosis is present.
 Of note, relative renal function may not be a reliable measure in patients with
bilateral involvement. In patients with bilateral disease, glomerular filtration rate
can be measured with serum creatinine and/or by renal scan. If renal function is
significantly decreased, surgery is indicated to relieve obstruction.

Surgery
Many clinicians recommend surgery when significant hydronephrosis
(grade IV) is noted on the sonogram regardless of the relative renal
function of the two kidneys

SUMMARY OF APPROACH
observation is appropriate for asymptomatic patients with UPJ-type
hydronephrosis that is mild to moderate in severity (ie, Society of
Fetal Urology [SFU] grade II to III)
 ultrasound examination every four (grade III) to six (grade II) months in the first
year of life, then every 12 to 18 months thereafter.
If there is an increase in the degree of hydronephrosis, diuretic
renography is performed.
 If the affected kidney has less than 40 percent of split renal function, or there is a
serial loss greater than 10 percent from a previous study, surgical intervention is
recommended.

SUMMARY OF APPROACH
SFU grade IV hydronephrosis
requires closer observation.
 a diuretic renogram at six to eight weeks of age. If the hydronephrotic kidney has
decreased renal function (less than 40 percent of split renal function) compared with its
normal contralateral mate, we recommend surgical intervention.
 Otherwise, we repeat a sonogram in four to six weeks.
If the sonogram shows improvement, we continue to follow with serial
ultrasounds at three to four month intervals.
If we see any worsening of the hydronephrosis, we repeat a diuretic
renogram.
 These serial sonograms usually show continued SFU grade IV hydronephrosis without
substantial change from previous studies. In this case, we offer the family either
continued observation, which will require ongoing monitoring with sonograms and
possible diuretic renography, or surgical intervention.

SUMMARY OF APPROACH
Of note, in our practice, the washout curve or half-life calculation is
not typically used to determine the need for surgery in any of these
patients;
The relative renal function typically does not change if the initial and
follow-up renograms demonstrate stable renal function.

SUMMARY OF APPROACH
Surgery — Surgical intervention is performed for the following
indications:
 ●Symptoms including pain, infection, and renal stones.
 ●Increasing grade of hydronephrosis, and decrease in function of the affected
kidney so that it is less than the threshold of 40 percent of split renal function, or
there is a serial loss greater than 10 percent.
 ●Parental and/or patient preference to avoid continued invasive testing, and allow
definitive correction of the problem.
 ●Massive hydronephrosis with an RPD >50 mm.

SUMMARY OF APPROACH
Postoperative follow-up
Renal ultrasonography is performed four to six weeks
postoperatively.
 If the ultrasound shows improvement (ie, decrease in the severity of
hydronephrosis), the patient can then be followed by repeat ultrasound at
increasing time intervals (ie, initially one year and then every two to three years).
 If the follow-up ultrasound does not show improvement, diuretic renography is
performed to detect persistent obstruction, which may require an additional
surgical procedure.

PRIMARY MEGAURETER IN
INFANTS AND CHILDREN

DEFINITION
Megaureter is defined as a ureter that exceeds the upper limits of
normal size. In children, any ureter greater than 7 mm in diameter is
considered a megaureter based on measurements in fetuses greater
than 30 weeks gestation and children <12 years

CLASSIFICATION
according to the presence or absence of reflux and obstruction. The
types of megaureter are as follows:
 ●Refluxing, nonobstructed – This common variant is high grade (ie, grades IV
through V) vesicoureteral reflux with a dilated ureter
 ●Refluxing, obstructed – This rare variant is often associated with an ectopic ureter
 ●Nonrefluxing, nonobstructed – This common variant is also called primary dilated
megaureter
 ●Nonrefluxing, obstructed – This rare variant presents with symptoms or with a
decrease in renal function

EPIDEMIOLOGY
Primary megaureter is the second most common cause of
hydronephrosis in the newborn (after ureteropelvic obstruction),
accounting for approximately 20 percent of cases.
The incidence of primary megaureter is estimated as 0.36 per 1000
live births
Boys are affected more commonly than girls, and lesions are found
more frequently on the left than on the right side
The reported rate of bilateral involvement ranges from 30 to 40
percent

PATHOPHYSIOLOGY
The pathogenesis of primary megaureter is uncertain.
It appears to be most commonly due to an abnormality or delay in the
development of the muscle in the distal ureter at 20 weeks gestation
The refluxing megaureter also has an abnormal ureterovesical (UV)
tunnel that allows urine to reflux up the ureter during bladder filling,
but more commonly during voiding when the bladder pressure is
highest

usually is detected on antenatal ultrasonography. The ultrasound
demonstrates both hydronephrosis and a dilated ureter (>7 mm in
diameter)
Affected newborn infants are asymptomatic and typically have a
normal physical examination, urinalysis, and serum creatinine.
When the condition is not detected antenatally, children can present
at any age after the newborn period with urinary tract infection,
hematuria, abdominal pain and/or mass, or uremia, or be incidentally
diagnosed during evaluation of other conditions.

DIAGNOSIS
Ultrasonography confirms the diagnosis of megaureter.
If an antenatal diagnosis is made, a postnatal ultrasound is obtained
to confirm the presence of megaureter
Ultrasound examination should be performed after the first two days
after birth, preferably at one week of age or later, because
hydronephrosis may not be detected due to physiologic volume
depletion and relative oliguria

FURTHER EVALUATION
VCUG
 A VCUG must be performed to detect reflux and any evidence of urethral
obstruction (eg, posterior urethral valves).
 If severe reflux is present and the ureter drains poorly, the megaureter is likely a
refluxing, obstructed type.
 If no reflux is detected, then diuretic renography is used to differentiate between
the nonrefluxing, obstructed megaureter and the nonrefluxing, nonobstructed type

FURTHER EVALUATION
Diuretic renography
It is performed in patients without reflux, or in those with reflux and
poor ureter drainage suggestive of a refluxing, obstructed
megaureter.

DIFFERENTIAL DIAGNOSIS
●Ureteropelvic junction obstruction (UPJO)
 Ultrasonography that demonstrates dilation of both the renal pelvis and ureter
usually differentiates primary megaureter from UPJO.
●Posterior urethral valves (PUV)
 On ultrasound, a normal bladder size distinguishes primary megaureter from
posterior urethral valves, which is characterized by a dilated
bladder and/or increased thickness and trabeculation of the bladder wall, and a
dilated posterior urethra (keyhole sign).
 Voiding cystourethrography that demonstrates the dilated and elongated posterior
urethra associated with PUV differentiates this condition from primary megaureter.
●Ureterocele
 Ultrasonography differentiates ureterocele from primary megaureter with the
detection of a well-defined intravesical mass in the posterior portion of the
bladder.

POSTNATAL MANAGEMENT
In general, postnatal management decisions are determined by the
presence or absence of reflux and/or obstruction.
US
 Postnatal ultrasonography after the first week of life is performed to confirm the
diagnosis of primary megaureter with unilateral megaureter, and within 24 to 72
hours for those with bilateral involvement.
voiding cystourethrogram
 is performed to detect the presence or absence of vesicoureteral reflux (VUR).
Diuretic renography
 is performed in infants without VUR, or with VUR and poor ureteral drainage,

NONOBSTRUCTIVE,
NONREFLUXING MEGAURETER
These patients are followed by annual renal ultrasonography to
monitor renal growth and hydroureteronephrosis. Antibiotic
prophylaxis is prescribed for more severe cases until the patient is
toilet trained.
 •If the megaureter remains stable, sonogram evaluation continues at longer
intervals (yearly until age three to five, then every other year, and once every five
years in adolescence) until resolution.
 •If the megaureter and/or hydronephrosis worsens, a diuretic renogram is
performed to assess overall renal function and possible obstruction. A 10 percent
decrease in renal function is an indication for surgery.
 •Surgical intervention is performed in patients who develop symptoms, calculi,
recurrent infection, hematuria, or a decrease in the function of the affected kidney.

REFLUXING, NONOBSTRUCTED
MEGAURETER
The management choices of patients with high-grade VUR (ie, grades
III to V) include medical management with ongoing monitoring and
prophylactic antibiotics, or surgical correction.

OBSTRUCTED MEGAURETER
Surgical intervention is indicated in patients with obstructed lesions
documented by increasing hydroureteronephrosis and/or the
presence of a prolonged diuretic renographic drainage pattern.

OUTCOME
As a rule, the outcome of patients with megaureter is excellent
Poor renal outcome appears to be due to the concomitant presence of
congenital renal abnormalities (eg, renal hypoplasia and dysplasia)
rather than as a consequence of primary megaureter, except in the
setting of high-grade or worsening obstruction

URETEROCELE
A ureterocele is a cystic dilatation of the terminal ureter within the
bladder and/or the urethra
It may present as an incidental finding on antenatal ultrasonography,
or postnatally because of symptoms due to urinary tract infection
(UTI) or obstruction.

EPIDEMIOLOGY
Ureteroceles occur four to six times more frequently in females than
in males, and more commonly in Caucasians than in other races.
Unilateral ureteroceles occur with similar frequency on the right and
left, and in 10 percent of cases there is bilateral involvement.

CLASSIFICATION
ureteroceles are classified as intravesical (ie, entirely within the
bladder) or ectopic (ie, a portion extends beyond the bladder neck
into the urethra)
Ureteroceles also may be classified depending upon whether they are
associated with either a single collecting system (ie, single ureter and
kidney) or a double collecting (duplex) system (complete ureteral
duplication).
 Approximately 80 percent of ureteroceles are associated with the upper pole of a
duplex collecting system, and 60 percent of these are ectopic,
 whereas intravesical ureteroceles are more common in single systems.

Antenatal — Many ureteroceles are detected incidentally on antenatal
ultrasonography.
 Approximately 2 percent of cases of antenatal hydronephrosis are caused by
ureteroceles, which obstruct the distal end of the affected ureter
Postnatal — The most common postnatal presentation is during an
evaluation for urinary tract infection (UTI) in the first few months after
birth
 Other patients have a more insidious course that may include intermittent
abdominal or pelvic pain, or failure to thrive
 In older children, stasis and infection may predispose to stone formation.
Hematuria is a rare presentation
 Some patients may present with a palpable abdominal mass due to ureterocele
obstruction of the distal ureter.

DIAGNOSIS AND EVALUATION
Ultrasound — Ultrasonography usually will reveal a well-defined cystic
intravesical mass in the posterior portion of the bladder. A dilated proximal
ureter also may be seen. In duplex systems, there is approximately an 80
percent chance that the other side will be duplex
Voiding cystourethrogram — A voiding cystourethrogram (VCUG) is
important to identify whether VUR is present. Reflux into the ipsilateral lower
pole occurs in approximately 50 percent of patients, where it may be
massive, and occurs on the contralateral side in 25 percent
Renography — A renal scan is used to evaluate the relative function of all
renal segments. In particular, in patients with a duplex system, the pole that
is associated with the affected ureter may contribute little or no function,
and may not be worth preserving when surgery is performed. In addition, a
delay in the isotope washout (especially after the administration of lasix)
demonstrates impaired urinary drainage.

MANAGEMENT
With ureteroceles associated with VUR
 early endoscopic puncture is performed to decompress the dilated urinary tract and
decrease the risk of development of pyelonephritis.
 Antibiotic prophylaxis is administered until reevaluation at one year of age when
definitive surgical therapy is typically performed.

MANAGEMENT
Patients without VUR
 and a poorly functioning upper pole moiety are placed on antibiotics until definitive
surgery by either open or laparoscopic heminephrectomy, which is usually
performed around six months of age.
 Uretero-ureteostomy (anastomosis of the upper ectopic ureter to the normal lower
pole ureter at the level of the bladder) is performed in patients with a well-
functioning upper pole without VUR.

POSTERIOR URETHRAL VALVES
Posterior urethral valves (PUV) are obstructing membranous folds
within the lumen of the posterior urethra that are the most common
etiology of urinary tract obstruction in the newborn male, occurring in
1 in 5000 to 8000 pregnancies.
PUV are also the most common cause of chronic renal disease due to
urinary tract obstruction in children

CLASSIFICATION
●Type 1 valve − The most common form is composed of a ridge from
the verumontanum that divides into two leaflets, which attaches to
the anterior urethra.
●Type 2 valve − This type of valve is no longer considered a form of
PUV but is believed to be a dissection artifact. It was reported to
extend from the verumontanum towards the internal sphincter and
bladder neck.
●Type 3 valve − This form is a diaphragm distal to the
verumontanum with a central perforation, which may be a result of an
attempt to place an urethral catheter.

CLINICAL MANIFESTATIONS
Prenatal — Prenatal ultrasonographic findings of bilateral
hydronephrosis, dilated bladder, and a dilated posterior urethra
(keyhole sign) in a male fetus is suggestive of PUV

Postnatal — Patients who are not detected prenatally usually are
diagnosed as neonates or young infants. About half will present with
urinary tract infections
 ●Neonates − Some neonates will present with respiratory distress due to lung
hypoplasia.
 ●Infants − Male infants with PUV may present with failure to thrive, urosepsis, poor
urinary stream, and straining or grunting while voiding.
 ●Older boys − Older boys may present with urinary tract infections, day time and
nocturnal incontinence (enuresis), and other symptoms of voiding dysfunction
including frequency, straining to void, a poor urinary stream, and a large urinary
volume at each void

Renal and urologic manifestations — Renal and urologic
manifestations are common in patients with PUV. They include:
●Chronic kidney disease
 About 15 to 20 percent of patients progress to end-stage renal disease (ESRD)
●Vesicoureteral reflux (VUR)
 VUR is present in about one-third to one-half of patients with PUV
●Bladder dysfunction
 Bladder outlet obstruction results in muscular hypertrophy of the bladder wall and
collagen deposition. These result in the ultrasonographic appearance of a thickened
bladder wall or trabeculations and diverticula seen on voiding cystourethrogram
(VCUG).

DIAGNOSIS
The diagnosis is made by voiding cystourethrogram (VCUG) that
demonstrates the hallmark findings of a dilated and elongated
posterior urethra during the voiding phase when the urethral catheter
is no longer present.
Based upon the VCUG findings, cystoscopy is performed to confirm
the diagnosis and ablate the PUV.
Renal and bladder ultrasonography is also performed to measure the
degree of hydroureteronephrosis, if present, and assess renal
parenchymal cortical thickness and renal corticomedullary
differentiation.

RADIONUCLIDE SCANS
Static radionuclide scan using the radiotracer 99mTc–
dimercaptosuccinic acid (DMSA) is the most useful modality for
detection of focal renal parenchymal abnormalities and the
differential assessment of renal function between the two kidneys.
Following intravenous injection, DMSA is taken up by proximal
tubular cells with only a minimal amount excreted in the urine, so the
tracer accumulates over several hours within the tubule, providing a
static image of functioning nephrons.
The MAG-3 radionuclide scan in conjunction with lasix (ie, diuretic
renography) is used to diagnose urinary tract obstruction in infants
with hydronephrosis. It measures the drainage time of the radiotracer
from the renal pelvis and assesses total and each individual kidney's
renal and excretory function.

Because of the high morbidity rate associated with fetal intervention
and the lack of evidence that intervention reduces the risk of chronic
kidney disease (CKD), we suggest that fetal surgery should only be
considered in select patients with a high risk of perinatal mortality
and be performed in centers with expertise in these procedures
(Grade 2C)

The postnatal management of PUV includes stabilization of the
patient and drainage of the urinary tract. Medical management
includes correction of electrolyte abnormalities, and treatment for
possible complications such as respiratory distress and infection.
With advancements in surgical technique and instruments, primary
ablation during cystoscopy has become the preferred surgical
procedure to relieve the obstruction. It can be performed in most
neonates with PUV, including some premature infants. If primary
valve ablation cannot be done, vesicostomy is the next preferred
procedure.

Although all patients with PUV are at risk for developing CKD,
patients with a persistently elevated creatinine after relief of their
urinary obstruction (eg, PUV ablation) are at increased risk for end-
stage renal disease. In addition, a significant number of patients will
have persistent bladder dysfunction, vesicoureteral
reflux, and/or hydronephrosis, which in some cases may require
clean intermittent catheterization and anticholinergic medications.

CONGENITAL ANOMALIES OF THE
KIDNEY AND URINARY TRACT (CAKUT)

INTRODUCTION
Congenital anomalies of the kidney and urinary tract (CAKUT)
constitute approximately 20 to 30 percent of all anomalies identified
in the prenatal period
CAKUT play a causative role in 30 to 50 percent of cases of end-stage
renal disease (ESRD) in children
Patients with malformations involving a reduction in kidney numbers
or size are most likely to have a poor renal prognosis

RENAL DEVELOPMENT AND CAKUT
CAKUT represent a broad range of disorders and are the result of the
following abnormal renal developmental processes
 Malformation of the renal parenchyma resulting in failure of normal nephron
development, as seen in renal dysplasia, RA, renal tubular dysgenesis, and some
types of nephronophthisis

RENAL DEVELOPMENT AND CAKUT
●Environmental factors, such as prenatal exposure to teratogens, can
also disrupt renal morphogenesis resulting in CAKUT.
●Abnormalities of embryonic migration of the kidneys, as seen in
renal ectopy (eg, pelvic kidney), and fusion anomalies, such as
horseshoe kidney.
●Abnormalities of the developing urinary collecting system, as seen
in duplicate collecting systems, posterior urethral valves, and
ureteropelvic junction obstruction.

EPIDEMIOLOGY
The overall rate of CAKUT in live and stillborn infants is 0.3 to 1.6 per
1000
The incidence is higher in offspring with a family history of CAKUT,
and maternal history of either renal disease or diabetes
Of all antenatal renal anomalies, the most frequent abnormality is
hydronephrosis (ie, upper urinary tract dilatation).

RENAL PARENCHYMAL
MALFORMATIONS
Malformations of the renal parenchyma result in failure of normal
nephron development, as seen in renal dysplasia, renal agenesis (RA),
renal tubular dysgenesis, and cystic dysplasia

SIMPLE RENAL HYPOPLASIA
Simple renal hypoplasia, which consists of a lower number of
structurally normal nephrons, is an entity distinct from renal
dysplasia, which is characterized by renal parenchymal
malformations. Although it remains unknown what causes renal
hypoplasia, genetic determinants are thought to play a role.
The clinical diagnosis of renal hypoplasia is suggested when all of the
following criteria are met
 Reduction of renal size by two standard deviations for the mean size by age.
 Exclusion of renal scarring by 99mTc-dimercaptosuccinic acid (DMSA) radionuclide
scan.
 Unequivocal diagnosis is based upon histologic examination, which is rarely
performed.

RENAL DYSPLASIA AND
HYPODYSPLASIA
Renal dysplasia is characterized by the presence of malformed kidney
tissue elements
Dysplastic kidneys are variable in size, but most are smaller than
normal resulting in renal hypodysplasia. Size is often determined by
the presence or absence of cysts.
Renal dysplasia may be unilateral or bilateral and occurs in two to
four per 1000 births. The male-to-female ratio for bilateral renal
dysplasia is 1.3:1, and for unilateral dysplasia is 1.9:1

RENAL DYSPLASIA AND
HYPODYSPLASIA
•Neonates may present with pneumothorax, intrauterine growth
restriction (IUGR), feeding difficulties, metabolic acidosis, and
impaired renal function based on an
elevated serum/plasma creatinine level.
•Older infants typically present with failure to thrive, anorexia, and
vomiting.
•Children commonly present with proteinuria discovered incidentally
on routine urine examination.

EVALUATION
Because of the frequent association of renal dysplasia with a
collecting system anomaly, voiding cystourethrography may be
considered in patients with renal dysplasia with or without a UTI
DMSA radionuclide scan can provide further information on the
differential function of each kidney
 Imaging studies may be useful in defining baseline renal function and risk of future
renal damage.

MULTICYSTIC DYSPLASIA
MCDK is a nonfunctioning dysplastic kidney with multiple cysts,
which is thought to arise from an alteration in renal parenchymal
differentiation
MCDK consists of a nonreniform mass of cysts and connective tissue,
and is most commonly detected by routine antenatal screening. Most
infants with unilateral MCDK are asymptomatic.

Because the natural history of MCDK is involution of the affected
kidney and there are usually no associated complications, we
recommend conservative management of MCDK.
Management consists of serial renal ultrasounds to monitor
contralateral kidney growth and any evidence of renal scarring, and
involution of the affected kidney. In addition, routine follow-up
includes blood pressure measurements to detect hypertension,
urinalysis to detect proteinuria, and renal function studies.

DMSA renal scan is routinely performed in many centers for diagnosis
of MCKD however
 in some cases, there is detectable function of MCDK on renal scintigraphy making
this an unreliable diagnostic study

RENAL AGENESIS
RA is defined as congenital absence of renal parenchymal tissue, and
results from major disruption of metanephric development at an early
stage. Males are more commonly affected than females, with a male-
to-female ratio of 1.7:1
Unilateral RA accounts for 5 percent of renal malformations. When a
solitary kidney is detected, it is usually an incidental finding
 Associated CAKUT anomalies were observed in about one-third of patients with
solitary kidneys, of which vesicoureteral reflux was the most common finding (24
percent of patients)

RENAL AGENESIS
In all patients with a solitary kidney, a renal ultrasound is the initial imaging
study that measures the size of the solitary kidney and determines if there
are any other renal abnormalities.
If there is no compensatory renal hypertrophy, further imaging, particularly
in the pelvic area, should be performed to determine whether or not an
ectopic kidney is present.
 Thus, a finding of an empty renal fossa should direct the search for an ectopic kidney.
The clinician may choose to perform a static renal scan with DMSA to confirm the
diagnosis of RA
Some clinicians obtain a voiding cystourethrogram (VCUG) in infants who are
diagnosed by antenatal ultrasound because of the association of
vesicoureteral reflux (VUR) with unilateral RA. However, VUR is typically low-
grade and appears to have little clinical significance, particularly in the
absence of UTI.

GENETIC CYSTIC DISEASES
Genetic cystic renal diseases are due to mutations of genes involved
in primary ciliary function.
Autosomal recessive polycystic kidney disease (ARPKD) – ARPKD is
characterized by multiple microscopic cysts, principally involving the
distal collecting ducts. It is caused by mutations in the PKHD1 gene,
which codes for fibrocystin.
 Clinical manifestations include oligohydramnios, pulmonary hypoplasia,
hypertension, congestive cardiac failure, liver disease, and renal failure.

GENETIC CYSTIC DISEASES
Autosomal dominant polycystic kidney disease (ADPKD) – ADPKD is
characterized by bilateral renal enlargement secondary to multiple
cysts. It is caused by mutations in either PKD1 (85 percent of
patients) or PKD2 genes (15 percent), which encode polycystin 1 and
polycystin 2, respectively.
 There is a greater variability in clinical manifestations of ADPKD, with most patients
having significant clinical findings only in adulthood.

ANOMALIES OF RENAL
EMBRYONIC MIGRATION
Disruption of the normal embryologic migration of the kidneys
results in renal ectopia (eg, pelvic kidney) and fusion anomalies
 In general, patients with an ectopic or fused kidney(s) are asymptomatic and
diagnosed coincidentally, usually by antenatal ultrasonography. In patients
diagnosed symptomatically with either anomaly, symptoms at presentation are
generally related to associated complications including urinary tract infection (UTI),
obstruction, and renal calculi.
Patients with renal ectopy or fused kidneys are at increased risk for
other anomalies, especially genitourinary abnormalities, such as
vesicoureteral reflux (VUR).

ANOMALIES OF THE COLLECTING
SYSTEM
●Renal pelvis
●Ureter
●Bladder
●Urethra

DUPLICATION
Complete or partial duplication of the renal collecting system, also referred
to as duplex system, is the most common congenital anomaly of the urinary
tract
 0.8-5 percent
The ureter from the lower collecting system usually enters the bladder in the
trigone, whereas the ureter from the upper collecting system can have a
normal insertion in the trigone or be inserted ectopically in the bladder or
elsewhere.
 In boys, insertion can occur in the posterior urethra, ejaculatory ducts, or epididymis,
and in girls into the vagina or uterus. Ectopic insertion of the ureter can result in
obstruction or vesicoureteral reflux (VUR).
In patients with asymptomatic uncomplicated (no dilation) duplication of the
collecting system, no further intervention or referral is needed. However, if
there is a history of urinary tract infection (UTI) or dilatation (typically due to
obstruction), referral to a pediatric urologist is warranted for surgical repair

EVALUATION OF CONGENITAL
ANOMALIES OF THE KIDNEY AND
URINARY TRACT (CAKUT)

HISTORY AND PHYSICAL
EXAMINATION
After delivery, a detailed maternal and pregnancy history, and careful
physical examination should be performed in all infants with an antenatally
detected renal malformation.
 Pulmonary evaluation especially in fetuses with severe oligohydramnios
 ●Examination of the abdomen to detect the presence of a mass that could represent an
enlarged kidney due to obstructive uropathy or multicystic dysplastic kidney (MCDK).
 ●A palpable bladder in a male infant, especially after voiding, may suggest bladder
outlet obstruction such as the presence of posterior urethral valves.
 ●A male infant with prune belly syndrome (also known as Eagle-Barrett syndrome) will
have deficient abdominal wall musculature and undescended nonpalpable testes. The
presence of associated anomalies should be investigated.
 ●The presence of outer ear abnormalities is associated with an increased risk of
congenital anomalies of the kidney and urinary tract (CAKUT).
 ●A single umbilical artery is associated with an increased risk of CAKUT, particularly
vesicoureteral reflux (VUR).

TIMING OF POSTNATAL RENAL
STUDIES
Postnatal evaluation by ultrasonography is performed within the first
24 hours of life for neonates with bilateral involvement, a solitary
kidney, and/or a history of oligohydramnios because they are at
increased risk for a serious renal anomaly that may be amenable to
intervention.
In general, conditions, which have unilateral involvement, do not need
immediate attention. Renal ultrasonography is recommended after
the infant returns to birth weight (after 48 hours of age and within
the first week of life) to ensure volume repletion and increased urine
output as renal plasma flow and glomerular filtration rate (GFR) rise in
the first 48 hours of life

SERUM CREATININE
Serum creatinine should be measured after the first 24 hours to avoid
overestimation of creatinine that may be high and reflective of
maternal creatinine values.

VOIDING CYSTOURETHROGRAPHY
VCUG is the definitive study to demonstrate VUR, which often
accompanies other CAKUT (eg, multicystic dysplastic, hypoplastic, or
ectopic kidney).
VUR is detected in as many as 15 percent of infants with antenatal
hydronephrosis.
Infants with postnatal hydronephrosis (without evidence of another
cause of the hydronephrosis) are candidates to undergo VCUG.

DYNAMIC RENAL SCAN
Dynamic renal scans are used to differentiate between obstructive
versus nonobstructive causes of hydronephrosis.

DMSA RENAL SCAN
There is no minimum age at which a DMSA scan can be performed.
However, the quality of both dynamic and static radionuclide scans
improves with renal maturity.
DMSA scan is used to assess whether a suspected renal lesion
contains normal-functioning nephrons, the differential function of
the two kidneys and/or detection of renal scarring.
 If possible, the DMSA renal scan should be performed four to six weeks after birth
in a full-term infant as poor function measured by DMSA renal scan does not
necessarily imply irreversible damage in a neonate, but may be a reflection of
immature renal function.
 A repeat scan should be undertaken over three months of age or following
therapeutic intervention because there may be recovery of renal function after
surgical intervention.

SERIAL ULTRASOUND
Serial ultrasounds are used to assess compensatory renal growth of
unaffected kidneys in patients with unilateral CAKUT. In our practice,
growth is monitored by ultrasound scans every six months in the first
year of life, and then yearly or every second year until puberty is
completed.
In addition, serial ultrasounds are used to monitor for progressive
hydronephrosis in patients with mild/moderate obstructive uropathy
or changes in the affected kidneys (eg, size of multicystic dysplastic
kidney).

RENAL ECTOPIC AND FUSION
ANOMALIES

INTRODUCTION
Renal ectopy and fusion are common congenital anomalies of the
kidney and urinary tract (CAKUT), and result from disruption of the
normal embryologic migration of the kidneys.
Although children with these anomalies are generally asymptomatic,
some children develop symptoms due to complications, such as
infection, renal calculi, and urinary obstruction.

RENAL ECTOPY
Renal ectopy occurs when the kidney does not normally ascend to the
retroperitoneal renal fossa (level of the second lumbar vertebra).
Ectopic kidneys that do not ascend above the pelvic brim are
commonly called pelvic kidneys. Rarely, the ectopic kidney is found in
the thorax. Bilateral renal ectopy has also been reported, but is a rare
occurrence.
The ectopic kidney fails to rotate normally, resulting in a shift of the
renal axis so that the renal pelvis is directed anteriorly rather than
medially.
The incidence of renal ectopy is reported as 1 in 1000 autopsies.

RENAL ECTOPY
Clinical findings of renal ectopy
 The majority of patients with renal ectopy are asymptomatic.
 In patients diagnosed symptomatically, findings at presentation are generally
related to associated complications, such as urinary tract infection, obstruction, and
renal calculi.
 The ectopic kidney generally has decreased function
 Rarely in female patients, persistent urinary incontinence characterized by
continuous dampness of their underwear can be secondary to a small ectopic pelvic
kidney
 A high clinical suspicion should initiate evaluation with a DMSA scan and/or magnetic resonance imaging
urogram to look for a dilated ureter and associated ectopic renal nubbin.

RENAL ECTOPY
In our practice, further evaluation is based upon the results of these three
studies (postnatal ultrasound, VCUG, and serum creatinine) as follows:
 ●In the patient with a normal-appearing contralateral kidney and no evidence of
hydronephrosis in the ectopic kidney, no further evaluation is required.
 ●If the serum creatinine is elevated or if the contralateral kidney appears abnormal, a
99mTc-DMSA renal scan should be performed to assess the differential renal function of
both kidneys. In patients with decreased renal function, urologic or nephrologic
consultation should be sought.
 ●If there is severe hydronephrosis and the VCUG examination is normal, then a diuretic
renogram with (99mTc)-mercaptotriglycylglycine (MAG-3) or technetium 99mTc-
diethylenetriamine pentaacetic acid (DTPA) should be performed to detect obstruction.
 ●If the hydronephrosis is mild or moderate and the VCUG examination is normal, then
follow-up ultrasonography should be performed three to six months later. If there is
progressive hydronephrosis, then a MAG-3 or DTPA diuretic renogram should be
performed to detect obstruction.

RENAL FUSION
Renal fusion occurs when a portion of one kidney is fused to the
other. The most common fusion anomaly is the horseshoe kidney,
which involves abnormal migration of both kidneys (ectopy), resulting
in fusion.

HORSESHOE KIDNEY
The most common fusion anomaly is the horseshoe kidney, which occurs
with fusion of one pole of each kidney.
The reported incidence based upon data from birth defect registries varies
from 0.4 to 1.6 in 10,000 live births
In more than 90 percent of cases, fusion occurs at the lower poles; as a
result two separate excretory renal units and ureters are maintained. The
isthmus (fused portion) may lie over the midline (symmetric horseshoe
kidney) or lateral to the midline (asymmetric horseshoe kidney). Depending
on the degree of fusion, the isthmus can be composed of renal parenchyma
or a fibrous band
Early fusion also causes abnormal rotation of the developing kidneys. As a
result, the axis of each kidney is shifted so that the renal pelvis lies
anteriorly and the ureters either traverse over the isthmus of the horseshoe
kidney or the anterior surface of the fused kidney

HORSESHOE KIDNEY
Clinical findings — The majority of patients with horseshoe kidneys
are asymptomatic.
Hydronephrosis is reported to occur in approximately 80 percent of
children with horseshoe kidneys.
 Causes of hydronephrosis include vesicoureteral reflux (VUR), or obstruction of the
collecting system by ureteropelvic junction obstruction (UPJO), renal calculi, or
external ureteric compression by an aberrant vessel.
Renal calculi are reported to occur in 20 percent of cases
Patients with a horseshoe kidney are at increased risk for infection
because of the increased likelihood of urinary stasis.

HORSESHOE KIDNEY
One-third to one-half of patients with horseshoe kidneys will have
another congenital anomaly, particularly another urological
abnormality (eg, VUR) or a genital anomaly
Patients with a horseshoe kidney appear to have an increased risk for
Wilms tumor.

EVALUATION OF RENAL FUSION
In our practice, further evaluation is based upon the results of these
three studies (postnatal ultrasound, VCUG, and serum creatinine) as
follows:
 ●In the patient with normal serum creatinine for age and no evidence of
hydronephrosis, no further evaluation is required.
 ●If the serum creatinine is elevated, additional evaluation of renal function by
DMSA renal radionuclide scan should be performed to assess differential renal
function and evidence of renal scarring.
 ●Patients with hydronephrosis not due to VUR should be evaluated by a diuretic
radionuclide scan with either (99mTc)-mercaptotriglycylglycine (MAG-3) or
technetium 99mTc-diethylenetriamine pentaacetic acid (DTPA) to differentiate
hydronephrosis due to obstruction from nonobstructive urinary stasis. If
obstruction is present, then a urological consultation should be sought.

CROSSED FUSED ECTOPY
In crossed fused ectopy, the ectopic kidney and ureter crosses the midline to
fuse with the contralateral kidney, but the ureter of the ectopic kidney
maintains its normal insertion into the bladder.
The estimated incidence from autopsy data is approximately 1 in 2000
Most patients with crossed fused ectopy are asymptomatic and are detected
coincidentally, often by antenatal ultrasonography. Associated reported
anomalies include sacral agenesis, scoliosis, and cardiovascular and
gastrointestinal abnormalities
Renal ultrasonography can detect the crossed fused ectopic kidney. In
symptomatic cases, magnetic resonance urogram is often required to
characterize the complete anatomy of the fused kidneys and corresponding
ureters. The evaluation and treatment of patients with crossed fused ectopy
is similar to that of patients with horseshoe kidneys.

INTRODUCTION
Ectopic ureter is diagnosed when the ureteral orifice is caudal to the normal
insertion on the trigone of the bladder.
In many instances, an ectopic ureter is not detected because the affected
individual is asymptomatic.
In other cases, especially in females, an ectopic ureter commonly presents
with urinary incontinence; in both sexes, it may present as an antenatal
diagnosis, urinary tract infection (UTI), or, rarely, urinary obstruction.
Ectopic ureters are commonly associated with a double (duplex) collecting
system. In these cases, the double collecting system is thought to result
from duplication of the ureteric bud.
 The cranial or superior ureteral bud is associated with the lower renal pole, and the
caudal or inferior ureteral bud with the upper renal pole

LOCATION OF THE ORIFICE
In the male, the most common site is the posterior urethra, occurring
in approximately 50 percent of cases
 The ectopic ureter is always above the external urinary sphincter. Therefore, males
with an ectopic ureter do not have urinary incontinence, but typically present
secondary to a prenatal diagnosis of hydroureteronephrosis or symptomatic urinary
tract infection (UTI).
In contrast, females (not detected by prenatal sonogram) present
postnatally with a history of urinary incontinence, because their
ectopic ureters terminate at sites that bypass the urethral external
sphincter.

SINGLE VERSUS DUPLEX SYSTEM
In published case series from the United States and Great Britain, the
majority of ectopic ureters are associated with a duplex kidney, with
rates that vary from 75 to 90 percent
In contrast, ectopic ureters associated with a single-kidney system
appear to be more common in India and Japan

DIAGNOSIS AND EVALUATION
Renal ultrasound is the initial diagnostic test
Computed tomography (CT) and magnetic resonance imaging (MRI) with
contrast is helpful, especially in suspected cases of ectopic ureters and a
normal ultrasound
A voiding cystourethrogram (VCUG) should be performed when the diagnosis
of an ectopic ureter is considered.
A renal scan is used to assess renal function prior to surgery, as the function
of the renal moiety associated with the ectopic ureter will impact surgical
decisions.
 In patients with dysplastic kidneys that have little function, a static renal scan that uses
the isotope DMSA may be more helpful to locate a poorly functioning ectopic kidney
than the dynamic scan that uses technetium-99m-mercaptoacetyltriglycine
(Tc99mMAG3).
 In patients with hydronephrosis and/or dilated ureter, diuretic renography (renal scan
and the administration of a diuretic) is performed to diagnose urinary obstruction

MANAGEMENT
Duplex system — Most cases of ectopic ureter in a duplex system are
associated with a dysplastic upper pole renal segment. Excision of
this segment along with the proximal ureter is usually curative. When
the upper pole has good function, the ectopic ureter is reimplanted
into the bladder or anastomosed outside the bladder to the normal
pole ureter (ureteroureterostomy).
Single system — In patients with an ectopic ureter in a single system,
the affected kidney is usually small and poorly functional, and the
base of the bladder (hemitrigone) is poorly developed. Management
usually consists of nephrourecterectomy. If the kidney is functional,
the treatment is resection of the distal ectopic ureter and
reimplantation into the bladder.

URINARY TRACT INFECTIONS IN
NEONATES

INTRODUCTION
Neonatal urinary tract infection (UTI) is associated with bacteremia,
especially in preterm infants, and congenital anomalies of the kidney
and urinary tract (CAKUT).
Upper tract infections (ie, acute pyelonephritis) may result in renal
parenchymal scarring and chronic kidney disease.

EPIDEMIOLOGY
The reported prevalence of UTI in febrile term neonates and young
infants varies from 7 to 15 percent.
 UTI is uncommon in the first three days after birth and generally presents in the
second week after birth.
 The incidence is higher in uncircumcised males, and the risk appears to increase
with decreasing gestational age in preterm infants.
In term neonates with community-acquired UTI, Escherichia coli is the
most common organism, accounting for up to 80 percent of UTIs.
In hospitalized neonates, especially preterm infants, coagulase-
negative Staphylococcus and Klebsiella are more likely causes of UTI,
and E. Coli is less commonly seen.

RISK FACTORS
Host factors associated with neonatal UTIs include male sex,
particularly those who are not circumcised, CAKUT, and prematurity,
especially extremely low birth weight (ELBW) (BW <1000 g). We
suggest circumcision should be performed in uncircumcised male
infants with recurrent UTIs (Grade 2C).

The signs and symptoms of neonatal UTIs are numerous and
nonspecific.
 They include fever, failure to thrive, conjugated hyperbilirubinemia, and vomiting.
 In addition, apnea and hypoxia are also seen in preterm infants. Initial laboratory
testing may include complete blood count and urinalysis, neither of which is
sufficiently sensitive to make the diagnosis of UTI.

DIAGNOSIS
Diagnosis of neonatal UTI is based upon culture of an organism from
either a specimen obtained by suprapubic bladder aspiration (SPA) or
bladder catheterization.
 A sample obtained from a sterile bag should not be used for culture.
We define a positive result based on isolating a uropathogenic
bacteria with any growth of a urinary pathogen in specimens obtained
by SPA (ie, >1000 colony forming units [CFU]/mL); or in a
catheterized specimen of a growth of a single uropathogenic
pathogen with a colony count of ≥50,000 CFU/mL, or a colony count
between 10,000 and 50,000 CFU/mL with associated pyuria detected
on urinalysis.

DIAGNOSIS
Because of the associated risk of bacteremia, we suggest that blood
cultures should be obtained in all neonates in whom UTI is suspected
(Grade 2B). In addition, we suggest that a culture of the cerebrospinal
fluid (CSF) be performed in ill-appearing neonates or those with a
fever (Grade 2C).

WORK UP
Because of the high prevalence of CAKUT, we suggest that a
radiographic evaluation is performed in all neonates with UTI (Grade
2B).
 In our practice, this evaluation includes ultrasonography to detect structural
abnormalities, and a voiding cystourethrogram (VCUG) to identify reflux. Other
experts in the field may perform a VCUG only in infants with an abnormal
ultrasound.
Similarly to older children, neonates with upper tract UTIs are at risk
for developing renal scarring, which is associated with hypertension
and chronic kidney disease.
 DMSA can be helpful especially in the follow up setting

CHILDREN: EPIDEMIOLOGY AND RISK
FACTORS

EPIDEMIOLOGY
The prevalence of urinary tract infection (UTI) in febrile children
younger than two years varies from <1 to 16 percent depending upon
age, sex, circumcision status in boys, and race/ethnicity
The prevalence of UTI in older children with urinary tract
symptoms and/or fever is approximately 8 percent.
Escherichia coli is the most common bacterial cause of UTI.

RISK FACTORS
A variety of host factors influence the predisposition to UTI in
children.
 These include female sex, genetic factors, urinary tract anomalies, bladder and
bowel dysfunction, vesicoureteral reflux (VUR), sexual activity, and bladder
catheterization in addition to those mentioned above for febrile young children (eg,
lack of circumcision, temperature >39° C [102.2°F]).
Bladder and bowel dysfunction is an important and often overlooked
factor in the pathophysiology of UTI in children.
 It is characterized by an abnormal elimination pattern (frequent or infrequent voids,
urgency, infrequent stools), bladder and/or bowel incontinence, and withholding
maneuvers.

RISK FACTORS FOR SCAR
Children with an abnormal renal ultrasonographic finding or with a
combination of high fever (≥39°C) and an etiologic organism other
than E. coli are have a higher risk of developing renal scarring than
children without these characteristics.

INFANTS AND CHILDREN OLDER THAN
ONE MONTH: CLINICAL FEATURES AND
DIAGNOSIS

Fever may be the only sign of urinary tract infection (UTI) in infants
and young children. Older children may have urinary symptoms (eg,
abdominal pain, back pain, dysuria, frequency, new-onset urinary
incontinence).
Important aspects of the history in a child with suspected UTI include
features of the acute illness (eg, fever, urinary symptoms) and risk
factors for UTI

The examination of the child with suspected UTI should include
measurement of blood pressure, temperature, and growth
parameters; abdominal examination for tenderness or mass;
assessment of suprapubic and costovertebral tenderness;
examination of the external genitalia; evaluation of the lower back for
signs of occult myelomeningocele; and a search for other sources of
fever.
The laboratory evaluation for the child with suspected UTI includes
obtaining a urine sample for a dipstick and/or microscopic evaluation
and urine culture.
 Urine culture is necessary to make the diagnosis.

We suggest that urine samples be obtained for urinalysis and culture in the
following patients
 •Febrile girls and uncircumcised boys younger than two years with at least one risk
factor for UTI (history of UTI, temperature >39ºC, fever without apparent source
[particularly if the child will be treated with antibiotics], ill appearance, suprapubic
tenderness, fever >24 hours, or nonblack race).
 •Febrile circumcised boys younger than two years with suprapubic tenderness or at least
two risk factors for UTI (history of UTI, temperature >39ºC, fever without apparent
source, ill appearance, suprapubic tenderness, fever >24 hours, or nonblack race).
 •Girls and uncircumcised boys older than two years with any of the following urinary or
abdominal symptoms (abdominal pain, back pain, dysuria, frequency, high fever, or
new-onset incontinence).
 •Circumcised boys older than two years with multiple urinary symptoms (abdominal
pain, back pain, dysuria, frequency, high fever, or new-onset incontinence).
 •Febrile infants and children with abnormalities of the urinary tract or family history of
urinary tract disease.

DIAGNOSIS
Catheterization is the preferred method of urine collection for infants
and children who are not toilet-trained. Clean catch is the preferred
method of collection for toilet-trained children. We recommend that
urine obtained in a sterile bag not be used for culture.
 We suggest that urine culture be performed routinely for all children in whom UTI is
a diagnostic consideration and in whom a sample for urinalysis or dipstick is
collected.

DIAGNOSIS
The diagnosis of UTI requires laboratory confirmation. UTI is best
defined as significant bacteriuria in a patient with pyuria on dipstick
or microscopic urinalysis. We define significant bacteriuria as
recovery of ≥100,000 CFU/mL of a uropathogen from a clean catch
specimen, ≥50,000 CFU/mL of a uropathogen from a catheterized
specimen, and any uropathogenic bacteria from a suprapubic
aspirate.
If the urine culture demonstrates significant growth
of Enterococcus, Klebsiella, or Pseudomonasaeruginosa in a child with
symptoms of UTI, UTI may be diagnosed in the absence of pyuria.

INFANTS OLDER THAN ONE MONTH
AND YOUNG CHILDREN: ACUTE
MANAGEMENT, IMAGING, AND
PROGNOSIS

TREATMENT
Most children with urinary tract infection (UTI) can be managed as outpatients.
 Indications for hospitalization may include age <2 months, clinical urosepsis, immunocompromised patient,
vomiting or inability to tolerate oral medication, lack of outpatient follow-up, and failure to respond to
outpatient therapy.
Empiric antimicrobial therapy immediately after appropriate urine collection is warranted
in children with suspected UTI and a positive urinalysis.
We recommend that empiric therapy for UTI in children include an antibiotic that provides
adequate coverage for Escherichia coli (Grade 1B). The agent of choice should be guided
by local resistance patterns. Definitive therapy is based upon the results of urine culture
and sensitivities.
 We suggest a cephalosporin (eg, cefixime, cefdinir, ceftibuten, cephalexin) as the first-line oral agent in the
treatment of UTI in children without genitourinary abnormalities (Grade 2A). Amoxicillin or ampicillin should
be added if enterococcal infection is suspected. (See 'Oral therapy' above.)
 Cephalosporins (eg, cefotaxime, ceftriaxone, cefepime) and aminoglycosides (eg, gentamicin) are
appropriate first-line parenteral agents for empiric treatment of UTI in children.
●The duration of therapy depends upon the age of the child and the clinical scenario.
 Febrile children are usually treated for 10 days
 Afebrile children are usually treated for shorter periods (3 to 5 days)

IMAGING IN PEDIATRIC UTI
Rationale — The rationale for imaging in young children with UTI is to
identify abnormalities of the genitourinary tract that require
additional evaluation or management (eg, obstructive uropathies,
dilating vesicoureteral reflux [VUR]).
Evidence to support the utility of routine imaging in reducing long-
term sequelae (renal scarring, hypertension, renal failure) is limited

ULTRASONOGRAPHY
The American Academy of Pediatrics (AAP) recommends RBUS for all
infants and children 2 to 24 months following their first febrile UTI.
NICE guideline on UTI in children recommends RBUS for infants
younger than six months and for children older than six months who
have atypical or recurrent UTI.
 They define atypical UTI as serious illness, poor urine flow, abdominal or bladder
mass; elevated creatinine, septicemia, infection with an organism other than E. coli,
and failure to respond to antibiotics within 48 hours; they define recurrence as ≥2
episodes of upper UTI, one episode of upper UTI plus ≥1 episode of lower UTI, or
≥3 episodes of lower UTI.

ULTRASONOGRAPHY
Timing — When the RBUS should be performed depends upon the
clinical situation.
 In infants and young children with unusually severe illness or failure to improve as
expected after initiation of antimicrobial therapy, RBUS should be performed as
soon as possible during the acute phase of illness to identify complications (eg,
renal or perirenal abscess, pyonephrosis).
 However, for infants and young children who respond as expected to appropriate
antimicrobial therapy, RBUS should be performed after the acute phase (to reduce
the risk of false positive results secondary to renal inflammation during the acute
episode)

VOIDING CYSTOURETHROGRAM
Approximately 25 to 30 percent of children (0 to 18 years) with a first
UTI have VUR
Indications — we suggest performance of a VCUG to diagnose VUR in:
 ●Children of any age with two or more febrile UTIs, or
 ●Children of any age with a first febrile UTI and:
 •Any anomalies on renal ultrasound, or
 •The combination of temperature ≥39°C (102.2°F) and a pathogen other than E. coli, or
 •Poor growth or hypertension

VCUG
Timing — Although VCUG is often scheduled several weeks after UTI,
it may be performed as soon as the patient is asymptomatic. Early
imaging (as early as the first week) does not appear to falsely
increase the detection of VUR.
To avoid the use of prophylactic antibiotics in children without VUR,
we prefer to conduct VCUGs during the last days of antimicrobial
therapy or immediately after completion of antimicrobial therapy for
UTI.

RENAL SCINTIGRAPHY
Renal scintigraphy using dimercaptosuccinic acid (DMSA) can be used
to detect acute pyelonephritis and renal scarring in the acute and
chronic settings, respectively

INDICATION
The role of renal scintigraphy in the management of children with
acute UTI is controversial. Scintigraphy at the time of an acute UTI
provides information about the extent of renal parenchymal
involvement. In addition, DMSA will identify most (>70 percent)
children with moderate to severe VUR (grade III or higher).
This observation has prompted some experts to suggest that DMSA
be used as the initial imaging test to identify children at higher risk
for renal scarring (the "top down" approach)
 However, using DMSA as the initial test to identify high-risk children is more
expensive, and involves greater exposure to radiation. Furthermore, since most
young febrile children with UTI have pyelonephritis and a positive DMSA, this
strategy may lead to identification of a large number of children who may or may
not be at risk for future UTI

INDICATION
The NICE guidelines recommend DMSA four to six months after acute
infection for children younger than three years with atypical or
recurrent UTI and for children older than three years with recurrent
UTI.
 They define atypical UTI as serious illness, poor urine flow, abdominal or bladder
mass; elevated creatinine, septicemia, infection with an organism other than E. coli,
and failure to respond to antibiotics within 48 hours; they define recurrence as ≥2
episodes of upper UTI, one episode of upper UTI plus ≥1 episode of lower UTI, or
≥3 episodes of lower UTI.

PROGNOSIS
PROGNOSIS — The short-term outcome of first UTI in children (<19
years) was described in a systematic review of 33 studies, including
4891 children:
 ●Twenty-five percent had vesicoureteral reflux (VUR); 2.5 percent had grade IV or V
VUR
 ●VUR was associated with an increased risk of developing acute pyelonephritis
(relative risk [RR] 1.5, 95% CI 1.1-1.9) and renal scarring (RR 2.6, 95% CI 1.7-3.9);
grade III or higher VUR was associated with increased risk of renal scarring
compared with lower grades (RR 2.1, 95% CI 1.4-3.2)
 ●Fifteen percent (95% CI 11-18 percent) of children had evidence of renal scarring
on follow-up dimercaptosuccinic acid (DMSA) scan (5 to 24 months later); the long-
term significance of scarring, as identified by DMSA, remains to be determined
 ●Eight percent (95% CI 5-11 percent) of children had at least one recurrence

LONG TERM MANAGEMENT OF UTI
IN CHILDREN
Families of young children with urinary tract infection (UTI) should
receive instruction about the risk of recurrent UTI and be advised to
seek medical attention promptly for fever and/or urinary symptoms.
The evaluation for episodes of fever and/or urinary symptoms should
include a properly collected urine specimen (using bladder
catheterization in children who are not toilet trained) which is then
sent for urinalysis, urine culture, or both.
The treatment of bladder and bowel dysfunction may include timed
voiding, "double voiding," the use of laxatives, and/or referral to a
urologist.
Routine surveillance cultures in asymptomatic children after their first
UTI are unnecessary.

PROPHYLAXIS
We suggest antimicrobial prophylaxis in children without
vesicoureteral reflux (VUR) who have frequent recurrent UTIs (three
febrile UTIs in six months or four total UTIs in one year) (Grade 2B).
Antimicrobial prophylaxis also may be warranted for children with
more severe initial UTI episodes or those with additional UTI risk
factors (eg, bladder and bowel dysfunction). Trimethoprim-
sulfamethoxazole or nitrofurantoin may be used for prophylaxis.
Prophylactic antibiotics are usually continued for six months. They
can be discontinued if no infection occurs during the period of
prophylaxis. Resumption of prophylaxis may be warranted if infection
recurs.
We do not routinely suggest cranberry juice for the prevention of
recurrent UTI in children (Grade 2B).

CLINICAL PRESENTATION, DIAGNOSIS,
AND COURSE OF PRIMARY
VESICOURETERAL REFLUX

DEFINITION
VUR is the retrograde passage of urine from the bladder into the
upper urinary tract. It is divided into two categories: primary and
secondary based on the underlying pathogenesis.

TYPES
Primary VUR — Primary VUR, the most common form of reflux, is due
to incompetent or inadequate closure of the ureterovesical junction
(UVJ), which contains a segment of the ureter within the bladder wall
(intravesical ureter). Normally, reflux is prevented during bladder
contraction by fully compressing the intravesical ureter and sealing it
off with the surrounding bladder muscles.
Secondary VUR — Secondary VUR is a result of abnormally high
voiding pressure in the bladder that results in failure of the closure of
the UVJ during bladder contraction. Secondary VUR is often
associated with anatomic (eg, posterior urethral valves) or functional
bladder obstruction (eg, bladder bowel dysfunction [BBD] and
neurogenic bladder)

EPIDEMIOLOGY
Primary VUR is the most common urologic finding in children, occurring in
approximately 1 percent of newborns. The prevalence increases for neonates
with prenatal hydronephrosis (up to 15 percent), and for children with febrile
urinary tract infections (UTIs) (ranging from 30 to 45 percent)
●Ethnicity – White children were three times more likely.
●Sex – In this cohort, girls were twice as likely to have reflux as boys.
However, the sex difference is smaller in countries where circumcision is not
routinely performed. In contrast, there is a male predominance in patients
who present with prenatal hydronephrosis
●Age – Young children and infants (younger than two years of age) were
more likely to have VUR than older children as there is spontaneous
resolution with growth in the majority of affected children.

Prenatal presentation — The presence of VUR is suggested by the
finding of hydronephrosis on prenatal ultrasonography.
Postnatal presentation — Postnatal diagnosis of VUR is usually made
after a diagnosis of a febrile UTI, and less commonly after family
screening.

DIAGNOSTIC APPROACH
Prenatal presentation
Repeat renal ultrasonography postdelivery.
 Unilateral fetal hydronephrosis – Renal ultrasound is optimally performed after the first week of delivery,
when urine output is well-established
 Bilateral fetal hydronephrosis – A renal ultrasound and VCUG should be performed soon after delivery
●VCUG is performed:
 If the postnatal ultrasound shows persistent moderate or severe hydronephrosis (renal pelvis diameter [RPD]
>10 mm), and/or ureteral dilatation.
 If there is another renal anomaly that is likely to be associated with VUR regardless of whether or not there
is hydronephrosis. These include ureteropelvic junction obstruction, ureteral duplication, bladder
diverticulum, renal agenesis, renal ectopia, ureterocele, and multicystic dysplastic kidney.
 Selectively, if there is a family history of VUR.
●If the postnatal renal ultrasonography demonstrates mild hydronephrosis (RPD ≤10
mm), we discuss the risks and benefits with the family of performing a VCUG or
conservative management with observation and monitoring for an episode of UTI. If
observation is elected by the family, ultrasonography is repeated several months later.
VCUG is recommended if there is persistent hydronephrosis or there is an episode of UTI

PRENATAL PRESENTATION
An alternative approach is to perform both postnatal renal ultrasound
and voiding cystourethrogram (VCUG) in all patients. This ensures no
patient with VUR is missed but results in performing an invasive
procedure in the majority of neonates with prenatal hydronephrosis
who do not have VUR.

POSTNATAL PRESENTATION
●A routine renal and bladder ultrasound is obtained in any child after
an initial UTI to assess the size and shape of the kidneys, and detect
any renal anatomical abnormality.
 Other experts in the field obtain ultrasonography after the first febrile UTI in
children younger than two years who did not have a normal prenatal
ultrasonography at a reputable center at >30 to 32 weeks of gestation and for
children with poor growth, hypertension, or a family history of renal or urologic
disease; or in children of any age after recurrent UTI.

VCUG to diagnose VUR is obtained in the following clinical settings
 Children who are not toilet-trained with a first febrile or symptomatic UTI.
 Children of any age with a first febrile UTI with one or more of the following:
 -Any anomalies on renal ultrasound.
 -The combination of temperature ≥39°C (102.2°F) and a pathogen other than E. coli. Other experts in the
field would perform a VCUG in children with a first well-documented febrile UTI with a temperature ≥39°C
(102.2°F) regardless of the pathogen.
 -Parental preference.
 -Concern with family compliance regarding medical advice/care.
 -Systemic signs of chronic kidney disease (eg, hypertension and poor growth);
 Children of any age with recurrent febrile or symptomatic UTI.

VCUG versus RNC — despite the increased radiation exposure
associated with VCUG, VCUG provides greater anatomic detail.
Specifically, RNC does not reliably show bladder wall appearance or
Grade I reflux. RNC also does not demonstrate urethral anatomy in
boys, which may be important in secondary causes of VUR (eg,
posterior urethral valves).
 For this reason, in many centers (including ours), RNC is not used as the initial
study, but may be used to monitor for persistent reflux in follow up studies.

GRADING
In the literature, the severity of reflux has been organized into two different
classifications.
The first classification:
 ●Mild – Grades I and II
 ●Moderate – Grade III
 ●Severe – Grades IV and V
VUR has also been divided into:
 ●Low – Grades I through III
 ●High – Grades IV and V
A system based upon RNC findings utilizes three grades and correlates with the
IRSG VUR grades as follows:
 ●Grade 1 for mild reflux – VUR Grade I
 ●Grade 2 for moderate reflux – VUR Grades II and III
 ●Grade 3 for severe reflux – VUR Grades IV and V

Dimercaptosuccinic acid (DMSA) renal scan is superior in detecting
renal cortical abnormalities compared with other imaging modalities
and should be obtained in patients who are at risk for scarring or
appear to have loss of renal parenchyma on renal ultrasound.
 The NICE guidelines recommend DMSA four to six months after acute infection for
children younger than three years with atypical or recurrent UTI and for children
older than three years with recurrent UTI.
 They define atypical UTI as serious illness, poor urine flow, abdominal or bladder mass; elevated
creatinine, septicemia, infection with an organism other than E. coli, and failure to respond to antibiotics
within 48 hours; they define recurrence as ≥2 episodes of upper UTI, one episode of upper UTI plus ≥1
episode of lower UTI, or ≥3 episodes of lower UTI.

SCREENING OF FAMILY MEMBERS
Our approach, which is consistent with the AUA guidelines, is to
selectively screen immediate family members with a renal and
bladder ultrasound and voiding cystourethrogram (VCUG) or
radionuclide cystogram (RNC).
We screen younger siblings and offspring (under age five years) when
there is a history of BBD or UTI, or if there is concern that the family
will not be compliant in seeking medical attention when there are
symptoms suggestive of UTI or unexplained fever

PROGNOSIS AND COMPLICATIONS
Likelihood of resolution — There is spontaneous VUR resolution in
the majority of cases with primary VUR. The likelihood of resolution
increases as the severity of reflux decreases, when the age of
diagnosis is below two years of age, and there is only unilateral
involvement

PROGNOSIS AND COMPLICATIONS
Recurrent urinary tract infection — Children with VUR are at risk for
recurrent febrile or symptomatic urinary tract infections (UTIs),
especially those with more severe VUR.

LOSS OF RENAL PARENCHYMA
Loss of renal parenchyma — Loss of renal parenchyma is a common
finding in patients with VUR. Reduction in renal parenchyma may lead
to decreased renal function, and in some affected individuals with
severe bilateral involvement to end-stage renal disease (ESRD). It is
caused by the following mechanisms:
●Acquired scarring due to reflux-related recurrent pyelonephritis
●Abnormal renal development resulting in congenital renal
hypodysplasia

RENAL SCARRING
VUR is a risk factor for recurrent pyelonephritis and potentially
subsequent renal scarring. The risk of scarring increases with the
severity of reflux.
 CONCLUSIONS: Significantly more renal scarring was seen in relatively older
children and in those with a second episode of febrile or symptomatic UTI before
randomization. Preexisting and new renal scars occurred significantly more in renal
units with grade 4 VUR than in those with low-grade or no VUR. Antimicrobial
prophylaxis did not decrease the risk of renal scarring.
 CONCLUSIONS AND RELEVANCE: Children and adolescents with an abnormal renal
ultrasonographic finding or with a combination of high fever (≥39°C) and an
etiologic organism other than E coli are at high risk for the development of renal
scarring.

CONGENITAL RENAL
HYPODYSPLASIA
In a large Japanese cohort of children with congenital renal and
urinary tract anomalies (CAKUT), the presence or history of VUR was
not an associated risk factor with progression of chronic kidney
disease (CKD) even though the rate of UTI was significantly higher in
those with VUR as compared with those without VUR
These data support the thesis that VUR is only a concomitant finding
in patients with renal hypodysplasia and plays no causative role in the
reduction of renal parenchyma.

MANAGEMENT OF
•We suggest all children with Grades III through V reflux be treated
(Grade 2B).We initially place all patients on prophylactic antibiotic
therapy.
In these patients, surgical correction is reserved for all patients with
Grades III to IV with breakthrough infection or who have serious
adverse effects from prophylactic antibiotic therapy. In addition,
surgical correction is performed in patients with persistent Grade IV
and V beyond two or three years of age.

MANAGEMENT OF
Children with Grade I to II reflux are at the lowest risk for renal
scarring, but remain at risk for recurrent UTI. The different treatment
options of observation or antibiotic prophylaxis are presented to the
family, who play a major role in the final therapeutic decision.
However, we suggest prophylactic antibiotic therapy for patients with
BBD, as it reduces the risk of UTI (Grade 2B). We also suggest
prophylactic antibiotic therapy for patients who are not toilet-trained
(Grade 2B).
We do not initially recommend surgical correction in patients with
low-grade reflux unless there is breakthrough UTI on medical
therapy, as there is a high likelihood of spontaneous resolution
(Grade 1B).

MANAGEMENT OF
Patients who are treated with antibiotic prophylaxis or by "watchful
waiting" require mandatory urine cultures whenever there are
symptoms suggestive of UTI or unexplained fever, and monitoring by
repeat cystogram for the continued presence of VUR. Following a
breakthrough or additional UTI, while under observation or antibiotic
prophylactic management, DMSA scans can be obtained, looking for
evidence of new renal scarring. These scans can be compared with
any prior scans, if they were performed at the time of presentation.
New scarring would be compelling evidence for a change in
management.

MANAGEMENT OF
Long-term follow-up includes annual assessment of linear growth,
measurement of blood pressure, and urinalysis. Families should be
aware of the association of VUR with increased risk of chronic kidney
disease (CKD) (eg, hypertension, renal impairment, or proteinuria).

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