Anh

1. ANTENATAL HYDRONEPHROSIS AND
MANAGEMENT
Presenter- Dr. MRINAL TANDON
PDT UROLOGY

2. FETAL HYDRONEPHROSIS
 Fetal Urinary tract dilation (UTD) represents the second most common anomaly detected during
prenatal screening following cardiac defects.
 Occurs with a frequency of 1% to 3%.
 It is Twice as common in Male Fetus and can be Bilateral in 30% Cases.

3. • Antenatal HDN is present if the-
APD is greater than or equal to 4mm in second trimester.
APD is greater than and equal to 7mm in third trimester.
• A majority of UTD cases are detected in the second trimester, which affords the
opportunity for parental counseling in a setting that occurs well before delivery.

4. • In most cases, renal pelvic dilation is a transient physiologic state,
however, congenital anomalies of the kidney and urinary tract (CAKUT)
can present with fetal hydronephrosis due to urinary tract obstruction and
vesicoureteral reflux (VUR).

5. ETIOLOGY OF ANH
MC CAUSE OF ANTENATAL HYDRONEPHROSIS- TRANSIENT /PHYSIOLOGICAL

7. PRENATAL IMAGING
MATERNAL-FETAL ULTRASOUND
• Although fetal metanephric kidney begins at the 28th day of gestation, urine production
begins in earnest at 14 weeks’gestation and can be detected on prenatal ultrasonography.
• The American College of Obstetricians and Gynecologists (ACOG) recommends that
the initial screening ultrasonography be performed between 18 and 20 weeks’
gestation (ACOG, 2009)

8. • The role of ultrasound in the evaluation of fetal urinary tract-
(A). To identify the Fetuses with any anomalies involving urinary tract.
(B).To monitor these lesions and characterize their effect on the overall
health of fetus.
Increasing degrees of urinary tract dilation and/or an abnormal amniotic fluid index (AFI)
should prompt referral.

9. AMNIOTIC FLUID INDEX
• The AFI is an assessment of amniotic fluid that include the cumulative
measurement of 4 Largest pockets of fluid .
• Normal AFI is 8 to 18
• Oligohydramnios- AFI is less than 5 or 6
• Polyhydramnios –AFI is 20 to 24.

10. Lee et al. (2006) Demonstrated that Prenatal Ultrasonography shows linear
relationship between increasing severity of prenatal UTD and UPJO but the linear
relationship does not exist with other common condition such as VUR .
Ultrasonography cannot reliably predict the severity of disease for all urologic conditions.
Ultrasonography tends to correlate best with obstructive lesions such as UPJO or posterior
urethral valve (PUV) and less with VUR.
Lee RS, Cendron M, Kinnamon DD, et al. Antenatal hydronephrosis as a predictor of postnatal outcome: a metaanalysis.
Pediatrics.
2006;118(2):586–593.

11. Liu, Dennis B.; Armstrong, William R.; Maizels, Max (2014). Hydronephrosis. Clinics in Perinatology, 41(3), 661–678. doi:10.1016/j.clp.2014.05.013

12. GRADING SYSTEMS FOR URINARY TRACT DILATATION
• Several systems have been developed to diagnose and grade the severity of fetal
hydronephrosis
 Antero Posterior Renal pelvic diameter (APRPD/APD)
 Society of Fetal Urology (SFU) criteria
 Urinary tract dilation (UTD) classification system

13. ANTERIOR-POSTERIOR RENAL PELVIC DIAMETER
The most common system used prenatally by maternal-fetal specialists.
Measurement of the maximum anteroposterior diameter of the fetal renal
pelvis (APPD), - in the transverse plane.
Fetal hydronephrosis graded according to the RPD during the second
and/or third trimester of pregnancy.
The renal hilum - the optimal location of this measurement.

15. • There remains a lack of consensus on the threshold RPD that defines clinically
significant fetal hydronephrosis, which has a high likelihood for renal pathology
requiring postnatal follow-up.
• Lee et al. (2006) demonstrated that the severity of prenatal dilation
demonstrates a linear relationship with obstructive lesions such as
UPJO and posterior urethral valve (PUV) while demonstrating an
inconsistent relationship with VUR .

16.  RPD >10 mm in the second trimester is associated with an increased risk for CAKUT
 RPD >15 mm during the third trimester are at the greatest risk for CAKUT
Factors affecting RPD- Gestational Age, Maternal hydronephrosis, Maternal hydration, and
the degree of bladder distention.
 An APD of 15 in the third trimester demonstrates reasonable positive predictive value for the need for
surgery for UPJO.

17. DRAWBACK TO THIS SYSTEM
Operator dependent, which may lead to inaccurate measurements.
Does not reflect the extent of hydronephrosis and parenchymal changes,
such as increased echogenicity, thinning, or caliectasis.

18. SOCIETY FOR FETAL UROLOGY GRADING
SYSTEM (SFU)

20. DRAWBACK OF SFU GRADING SYSTEM
• It does not take into account the entire collecting system including the
urinary bladder and ureter, which may affect postnatal decision
making.
The SFU system has been demonstrated to be predictive the need for
surgical intervention in patients with prenatal urinary tract dilation.

21. URINARY TRACT DILATION (UDT) GRADING SYSTEM
• The grading system consists of a 6-point template that combines two of
the most common systems employed (APD and SFU) with the
additional inclusion of the lower urinary tract.
• Standardized reporting system and include risk stratification.

23. • In effort to mitigate postnatal overtesting, the UTD working group established a
normative value for postnatal APD, which paralleled those observed for the prenatal
period.
An APD cutoff of less than 10 mm with absence of calyceal or ureteral
dilatation represent nonpathologic renal pelvis dilation.

24. NORMATIVE THRESHOLDS FOR PRENATALAND POSTNATALANTERIOR
POSTERIOR DIAMETER

27. RISK STRATIFICATION AND MANAGEMENT FOR
PRENATAL URINARY TRACT DILATION
• The UTD system is used to assign two levels of risk prenatally –
A1 - Low risk
A2/A3 - increased risk

29. • A1 (low risk) defined as
4 to 7 mm APD (16 to 27 weeks)
7 to 10 mm APD (from and after 28 weeks)
• Aside from central calyceal dilation all other parameters measured were normal.
• A2/A3 (increased risk) defined as
APD greater than 7 mm (16 to 27 weeks)
APD greater than 10 mm (after 28 weeks) and/or positive
values for one of the other five parameters

31. FOLLOW-UP WITHIN THE PRENATAL PERIOD DEPENDING UPON RISK
ASSESMENT
• For A1 UTD - a second ultrasound should be performed
after 32 weeks’ gestation.
• For A2/A3, the recommendation is to obtain an ultrasound
every 4 -6 weeks until delivery.

32. PRENATAL MANAGEMENT
Theoretically, a fetus with oligohydramnios and good renal function can benefit
from intervention in utero.
• The Goal of Prenatal management of Fetus with congenital
hydronephrosis –
To prevent sequelae of obstructive process
To prevent renal maldevelopment as seen in renal dysplasia
To prevent pulmonary hypoplasia

34. USG Findings suggestive of Dysplasia-
Detection of cortical cysts indicates presence of severe renal dysplasia.
Indicates irreversible renal damage.
Amniotic Fluid-
Amniotic Fluid is not a very useful prognostic indicator except at the extreme of
oligohydroamnios or anhydramnios

35. FETAL URINE ELECTROLYTE SAMPLING-
• Fetal Kidneys begin making urine at 14 weeks of gestation, which is hypertonic
• Between 16 and 21 weeks of gestation, fetal urine becomes progressively more
hypotonic.
• A healthy fetus produces hypotonic urine
 Fetus with poor renal function produce Isotonic urine.

36. NORMAL FETAL URINE BIOCHEMISTRY PROFILE-
• Sodium <100 mg/dL
• Calcium <8 mg/dL
• Osmolarity <200 mOsM/L
• Total protein <20 mg/dL
• β2-Microglobulin <4 mg/L

37. • In the presence of progressive renal damage that impairs
proximal tubular function- Urine becomes isotonic .
Indicator of renal injury and potentially irreversible
dysplasia- Elevations in urinary sodium, chloride, calcium, alpha2-
microglobulin, and osmolality.
Urinary calcium is currently the most sensitive predictor of renal
dysplasia.

38. Individual values are believed to have variable accuracy, but the
combination of urinary sodium less than 100 mg/dL, osmolality less than
200 mOsm/L, and total protein less than 20 mg/dL on the third or fourth
bladder tap is generally associated with normal renal function
 Currently, evaluation of urinary components by means of vesicocentesis is an extremely
valuable tool in determining which fetuses are candidates for in-utero intervention.

42. FETAL INTERVENTION
• Fetal intervention carries significant risk to the pregnancy, and thus all procedures are performed in
the controlled environment of the operating room with epidural anesthesia, with informed consent.
• The fetal anesthesia consists of injection of narcotics and/or paralytics into the umbilical vein with
the aid of ultrasonography.
• Fetal Intervention includes-
Vesicoamniotic Shunt Placement
Fetal Cystoscopy

43. VESICOAMNIOTIC SHUNT

46. FETAL CYSTOSCOPY
• Direct visualization of the cause for LUTO has improved the ability to obtain a fetal diagnosis and affords the
opportunity for directed intervention.
• The clear advantage of fetal cystoscopy is the ability to directly visualize the posterior
urethra and establish the diagnosis allowing for directed intervention.

47. VESICOAMNIOTIC SHUNT PLACEMENT VERSUS FETAL
CYSTOSCOPY
• Both VAS placement and FCA demonstrated a clear survival advantage when
compared with observation alone for all cases of LUTO.
• Interestingly, for those diagnosed postnatally with PUV, FCA demonstrated an
improvement in both 6-month survival ( P < 0.01) and renal function ( P = 0.01), and
VAS only demonstrated an improvement in 6-month survival ( P < 0.01) and had no
effect on renal function.
Ruano R, Sananes N, Sangi-Haghpeykar H, et al. Fetal intervention for severe lower urinary tract obstruction: a multicenter case-control study comparing
fetal cystoscopy with vesicoamniotic shunting. Ultrasound Obstet Gynecol.2015;45(4):452–458.

48. RUANO CLASSIFICATION SEVERITY OF DISEASE
The purpose was an attempt to better identify patients that may benefit from fetal
intervention..

49. POSTNATAL EVALUATION AND MANAGEMENT
GOAL
• The goal of postnatal management of infants with fetal hydronephrosis is
to identify those with clinically significant CAKUT while avoiding
unnecessary testing in patients with physiologic or clinically insignificant
hydronephrosis.
• In addition, early identification of infants with significant disease allows
initiation of interventional therapy that may minimize adverse effects of
CAKUT.

50. PHYSICAL EXAMINATION OF BABY WITH
ANTENATAL HYDRONEPHROSIS POST NATALLY
• The Need for neonatal physical examination is to-
Identify abnormalities that are indicative of congenital anomalies of the
kidney and urinary tract (CAKUT), which are associated with fetal
hydronephrosis.

51. PHYSICAL EXAMINATION INCLUDE
 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). As a result, early
evaluation is warranted.
 A male infant having deficient abdominal wall musculature and undescended testes. s/o prune-belly syndrome
 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.

52. TIMING OF INITIAL POSTNATAL ULTRASOUND
 Since infants are relatively dehydrated at birth, the initial postnatal ultrasonography
should be performed after 48 h of birth.
 Day two of life is preferred to enable adequate hydration after delivery but circumstances
pertaining to early discharge following delivery may not allow this. Also breast fed
neonates may not be adequately hydrated until a steady milk flow is established.

53. IDEAL TIME OF FIRST POSTNATAL ULTRASOUND IS PREFERABLY DONE BETWEEN
5-7 DAYS AFTER BIRTH.
 The exceptions to this are:
(1) Suspected lower tract obstruction e.g., Posterior urethral valves
(2) Severe bilateral hydronephrosis with or without hydroureter
(3) Solitary kidney with hydronephrosis especially if the APD is > 15 mm or it is SFU grade 2 or more in the
third trimester.
In these cases Ultrasound should be done within 48 Hours of Birth.

54. POSTNATAL UTD RISK CLASSIFICATION

56. UNILATERAL OR B/L CENTRAL CALYCEAL
DILATATION
Ultrasonography- Repeat at 3 Months age
Antibiotics- Discretion of clinician
VCUG –Discretion of clinician
Renal Scan- Not Recommended
>48 Hrs
APRPD 10 -15mm
UTD P1, LOW RISK GROUP

57. UNILATERAL OR B/L PERIPHERAL CALYCEAL
DILATATION
Ultrasonography- Repeat at 6-12 Weeks age
Antibiotics- Continue till Follow up with urology
VCUG-Not Required, at discretion of urology
Renal Scan-At 4-6 weeks age,to rule out
UPJO,FMRI preferred if complex anatomy present
UNILATERAL OR B/L + URETERS ABNORMAL
Ultrasonography- Repeat at 6-12 Weeks age
Antibiotics- Continue till Follow up with urology
VCUG- Recommended to rule out
bladder outlet obstruction,severe VUR
Renal Scan-At 4-6 weeks age if concern for
concurrent upper tract obstruction
>48 Hrs
APRPD >_15mm
UTD P2, INTERMEDIATE RISK GROUP

58. >48 Hrs
APRPD>_15mm
UNILATERAL OR B/L Peripheral
Calyceal Dilatation
Parenchymal Thickness
Abnormal
Parenchymal Appearance
Abnormal
Bladder and Ureter Normal
USG- Repeat at 4 weeks age
Antibiotics- Continue until follow up with
urology
VCUG- Consider to rule out concurrent
VUR,at discretion of urology
MAG3/fMRU-Recommended at 4-6 Weeks
old
UNILATERAL OR B/L
Ureter Abnormal
Bladder Abnormal
USG- Repeat at 4 weeks age
Antibiotics- Continue until follow up with
urology
VCUG- Recommended to evaluate for
Bladder outlet obstruction ou severe VUR.
MAG3/fMRU-Consider to rule out concurrent
upper tract obstruction
UTD P3, HIGH RISK GROUP

59. MANAGEMENT BASED ON POSTNATAL ULTRASOUND
RESULTS
• Management decisions are based on the severity of hydronephrosis.
• Severity is determined by measuring the Renal pelvic diameter [RPD]) on postnatal
ultrasound or Society of Fetal Urology (SFU) grading system
•<10 mm – Normal or mild hydronephrosis. SFU grade 1.
•10 to 15 mm – Moderate hydronephrosis. SFU grade 2.
•>15 mm – Severe hydronephrosis(These infants are at the greatest risk for significant
kidney disease, which may require surgical correction) . SFU grade 3 and 4.

60. ULTRASONOGRAPHY AT 5-7 D WOULD SHOW ONE OF THE
FOLLOWING SCENARIOS:
(1) No hydronephrosis-Normal pelvicalyceal system;
(2) Unilateral hydronephrosis;
(3) Bilateral hydronephrosis;
(4) Unilateral Hydronephrosis with hydroureter
(5) Bilateral hydronephrosis with bilateral hydroureter.

61. NO HYDRONEPHROSIS POSTNATALLY
 Reasons for this is-
Any immaturity of the pacemaker in the renal pelvis might lead to poor co-ordination of the peristaltic
activity- impediment of the emptying of the renal pelvis resulting in urinary stasis in the renal pelvis.
The pacemaker in the renal pelvis does not mature at an early gestational age.
Maturation of this pacemaker and ureteral peristalsis starts around 28 wk of gestation, after which
equilibrium is gradually established between pelvicalyceal filling and bladder filling/emptying in the fetus.
Postnatal ultrasound will be normal in 41%-88% of cases diagnosed to have hydronephrosis
antenatally.

62. RECOMMENDATION NO HYDRONEPHROSIS POSTNATALLY
DIAGNOSED ANTENATALLY
 A repeat scan at 3-6 month is mandatory.
 If the scans, on both occasions, do not show hydronephrosis, than a diagnosis of transient hydronephrosis can be safely and surely
made.
 Emphasizing the need for a second scan is of paramount importance as late worsening or recurrent hydronephrosis is seen in
nearly 15% of infants.
 These infants have a 25% incidence of associated vesico ureteral reflux (VUR)
 Hence some investigators have proposed antibiotic prophylaxis and a Voiding Cysto Urethrogram (VCUG) stu in these patients.

63. UNILATERAL HYDRONEPHROSIS BUT NO HYDROURETER
This constitutes the largest category of patients with prenatally detected
hydronephrosis.
50%-70% of these would have transient or physiologic hydronephrosis which
regresses with time.
Pelviureteric Junction (PUJ) obstruction accounts for the remaining 30%-50% of
cases.

64. THE FOLLOWING QUESTIONS NEED TO BE ADDRESSED WHEN THESE
PATIENTS ARE BEING EVALUATED:
• (1) When and how to evaluate them initially?
• (2) How to do follow up?
• (3) When to do a functional study?
• (4) How to differentiate non obstructed from obstructed systems?
• (5) How long to follow them?
• (6) When to Intervene?

65. WHEN AND HOW TO EVALUATE INITIALLY ?
The first evaluation should be on the 5th to 7th day after birth and is by ultrasound.
The categorization of this category of patients in Mild, Moderate and Severe
types, based on APD and SFU grading.

66. HOW TO FOLLOW UP?
The important questions to be answered during follow up of these infants are:
• (1) Do they need prophylactic antibiotics
• (2) Do they need VCUG
• (3) When to repeat ultrasound?

67. DO THEY NEED PROPHYLACTIC ANTIBIOTICS ?
• Regardless of gender, prophylactic antibiotics are not recommended for patients
with mild degree of hydronephrosis because of the low risk of developing a
urinary tract infection or need for subsequent surgery.
Prophylactic antibiotics are indicated in those with moderate or severe degree of
hydronephrosis till VCUG is done.

68. DO THEY NEED VCUG
• Patients with mild degree of hydronephrosis do not need VCUG.
• Though a small subset will have associated VUR, majority of the times it is a low
grade VUR which subsides on its own.
Moderate to Severe hydronephrosis need a VCUG.
VUR would be diagnosed in about 20% of these patients.

69.  The timing of VCUG in this group of patients should be at 4-6 wk.
 A conventional VCUG would not only diagnose lower grade of VUR but would also
exclude the possibility of posterior urethral valve, which can present indolently.

70. • It is recommended that if no reflux is seen then chemoprophylaxis can be stopped
unless it is a solitary kidney (to avoid the slightest chance of infection affecting a
solitary renal unit) and severe hydronephrosis.
• In those with VUR chemoprophylaxis should be continued.

71. WHEN TO REPEAT ULTRASOUND?
• .
• It confirms the -Severity of hydronephrosis
Progression/regression of hydronephrosis.
Recategorized into mild, moderate and severe type again.
Irrespective of the grade of hydronephrosis a repeat ultrasound is warranted at 4 wk
birth

72. INTERVALS FOR REPEAT USG
• Mild and moderate hydronephrosis at One Month.
• Repeat ultrasound is indicated at 3 month six monthly till the age of 3 years
and then yearly till the age of six years.
• Whenever the sonography shows resolution of hydronephrosis a repeat
ultrasonography at 3-6 month is warranted

73. • For severe grade of hydronephrosis -at One month further sonography is done
based on the need for intervention.
• If conservative management is opted (in cases with differential function > 40% on
radionucleotide study) then ultrasonography should be done at monthly intervals
for 3 month, then bimonthly till the age of 1 year.
• Any sign of increasing hydronephrosis would warrant intervention or a further
radionuclide study to determine the need for intervention.

74. WHEN TO DO A FUNCTIONAL STUDY?
• A diuretic renogram is indicated in those with severe degree of hydronephrosis at
4 wk after birth.
• The functional evaluation should be by mercapto acetyl triglycine (MAG3) or ethyl cysteine (EC)
Renogram using a F-15 or F0 protocol.
• Due to lack of maturity of the kidneys and a very high background activity resulting in erroneous
calculation of differential function a DTPA renogram should be avoided in the first 6 months of life.

75. HOW LONG TO FOLLOW THEM?
No increasing hydronephrosis on serial ultrasounds child needs to be
followed up till the age of 6 years.
A stable dilated system at 6 years would not warrant further study except around
puberty when it would be worthwhile having a look at the kidneys by ultrasound
to rule out any deterioration of hydronephrosis.
Renogram should be done at 6 Years before stopping follow up

76. WHEN TO INTERVENE ?
Babies with unilateral hydronephrosis is the category where the clinician faces the biggest
dilemma of differentiating a non obstructed dilated system, where hydronephrosis will regress
spontaneously over a period of time (or remain stable) from a dilated but obstructed system.

77.  Though a diuretic renogram has been considered the gold standard to
diagnose obstruction but Hafez et al in 2002 had shown that drainage curves
from the initial renogram are not always predictive of cases which need
surgical intervention.
 T half > 15-20 min reflecting an obstruction and a short T half excluding
obstruction.

78.  The major pitfall in this interpretation is what has been called the “reservoir
function”.
 When there is a dilated system, the tracer, even under the influence of
frusemide has to fill the renal pelvis before leaving the kidney, even if there is
no significant restriction to urinary flow.
 One can end up the test with no or limited renal pelvis emptying, simply due
to this reservoir effect
 It is therefore not acceptable to conclude that the kidney is obstructed simply
because of poor drainage

79. TWO NEW PARAMETERS WHICH HAVE SHOWN PROMISE IN DIFFERENTIATING AN
OBSTRUCTED FROM A NON OBSTRUCTED SYSTEM ARE-
A. Post micturition and post erect images acquired 1 hour after tracer
injection
B. The cortical transit time.
 The post micturition post erect images- taken at 60 min showing retained tracer are more
indicative of poor drainage and obstruction then the post frusemide curves.

80. • Cortical Transit time- It is the passage of the tracer from the outer cortex to the
inner structures i.e., the medulla and collecting system.
In a normal kidney one expects a rapid transit with more or less homogenous
kidney filling in about 2 min.
A delay in this suggests obstruction.
The decision to operate is simple when the differential renal function is < 40%. But
the dilemma persists in kidneys with function > 40%.

81.  Recently, Sharma et al, demonstrating the utility of comparing APD measurements in
patients with unilateral hydronephrosis in supine and prone positions.
At present, this is the simplest way of differentiating a dilated but non obstructed system
from a dilated and obstructed system.
Urinary bladder should be empty as a full bladder interferes with the drainage form the
pelvicalyceal system.
Baby should be adequately hydrated.

82.  They found that in those cases where the APD decreases in prone position by
> 10% as compared to supine position, the hydronephrosis decreases over
a period of time or does not increase, resulting in preserved differential
function. These cases did not need surgery.
 In contrast, if the APD does not change in prone position or increases in
prone position then these cases needed surgical intervention as their
differential function showed a substantial drop.

83.  Principle behind this is- The pelvicalyceal system drains better in prone
position, hence the obstructed systems would not show better drainage and
the APD would remain the same or increase in prone position as the urine
from the different calyces pools in the pelvis.
 If it is a dilated but non obstructed system that in the dependent prone
position there would be better drainage and the APD would decrease in
prone position as compared to supine position.

84. ALGORITHM TO MANAGE THESE PATIENTS WITH UNILATERAL HYDRONEPHROSIS

85. RECOMMENDATIONS FOR THE CONSIDERATION FOR SURGERY FOR UPJO
INCLUDE-
1. Increased APD and urinary tract dilation on serial ultrasonography
2. Decreased differential function (<40%) and/or a delayed drainage curve
3. Increased retention of radiotracer on delayed upright imaging on MAG3
renal scan.

86. BILATERAL HYDRONEPHROSIS
• Infants with bilateral hydronephrosis are at an increased risk of infection
compared to children with unilateral hydronephrosis.
• The risk of renal function deterioration is high in this group

87. MANAGEMENT OF PATIENTS WITH BILATERAL HYDRONEPHROSIS WITH
NO HYDROURETER

88. UNILATERAL HYDRONEPHROSIS WITH UNILATERAL
HYDROURETER
• Definition of megaureter-retrovesical ureteric diameter > 7 mm from 30
wk gestation onwards is taken as megaureter
• Antibiotic prophylaxis-is recommended for the first 6-12 months of life
as the risk of UTI is higher with uretero vesical junction obstruction
than with PUJ obstruction.

89. • VCUG-an early VCUG is recommended as 14% of these patients may
have an associated posterior urethral valves
• VCUG not only would rule out bladder outflow obstruction but also would
confirm or rule our reflux and thus define further course of management

90. Renogram- is indicated using MAG3 or EC in patients with ureteric
dilatation > 10 mm
Defining obstruction-Interpretation of renogram in the presence of a
dilated ureter may be difficult, as delayed transit may be caused by an
increased capacity of the dilated ureter andpelvis

91. BILATERAL HYDRONEPHROSIS WITH BILATERAL
HYDROURETER
Postnatal ultrasound is performed within 48 hours of birth
Most of these cases are associated with Bladder outflow obstruction and/or
bilateral reflux.
• The following recommendations are the now standardized protocol-
(1) Antibiotic prophylaxis-recommended
(2) VCUG-to be done at the earliest to confirm or rule out posterior urethral valves
(3) Renogram-to be done using MAG3 or EC within the first 4 wk of life, in cases of
bilateral megaureter(not refluxing and not associated with posterior urethral
valves)

92. MEASURES TO BE TAKEN WITHIN FIRST 48 H AFTER BIRTH IN INFANTS
DIAGNOSED WITH ANTENATAL HYDRONEPHROSIS

93. URINARY TRACT INFECTION AND PROPHYLACTIC
ANTIBIOTICS
UTI will occur in 8% to 22% of patients with prenatal UTD.
The degree of kidney dilation is predictive of risk for UTI in patients with prenatal UTD.
Current recommendations restrict the use of PA to those at increased risk for UTI.
Risk factors for UTI for prenatal UTD include female gender, intact foreskin (Uncircumcised
status), high-grade kidney dilation (P3, SFU 4), ureteral dilation, and VUR.
Patient age and hepatic maturity should be factors used to select the appropriate antibiotic, which
includes: amoxicillin (newborn and up), first generation cephalosporins (newborn and up),
nitrofurantoin (8 weeks of age and up), and trimethoprim (8 weeks of age and up) derivatives.

95. Fetal Magnetic Resonance Imaging
 The use is limited for the evaluation of prenatal UTD.
 The main indication for this modality is the need for specific anatomic detail
 Particularly helpful in cases of oligohydramnios, where the acoustic window for us is
limited.
 On T2-weighted sequences, the fetal kidneys are seen as ovoid structures with intermediate
signal .
 The presence of T2 bright urine allows the visualization of the collecting system.
 MRI can help to evaluate the area of abnormality with analysis of the collecting system,
ureters, bladder, and urethra.
 Thickness of cortex and signal intensity (when compared to maternal kidneys) can help in
the evaluation of possible dysplasia.

96. • The common genitourinary indicators for fetal mri include-
Polycystic kidney disease
Multicystic dysplastic kidney
Ureteropelvic junction (upj) obstruction
Posterior urethral valves in the male fetus