Antenatal Monitoring a In fetuses with unilateral hydronephrosis, we recommend that at least one follow up ultrasound be performed in the third trimester 1B. The frequency of monitoring varies from weeks, depending on gestation at which ANH was detected, its severity and presence of oligohydramnios. The gestation at which hydronephrosis is detected and its course on sequential ultrasound scans has prognostic value [21,32,]. Patients with persistence or worsening hydronephrosis in the third trimester show higher rates of postnatal pathology and require close follow up [,21,23,32,62]. Sairam, et al.

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Antenatal Monitoring a In fetuses with unilateral hydronephrosis, we recommend that at least one follow up ultrasound be performed in the third trimester 1B. The frequency of monitoring varies from weeks, depending on gestation at which ANH was detected, its severity and presence of oligohydramnios. The gestation at which hydronephrosis is detected and its course on sequential ultrasound scans has prognostic value [21,32,]. Patients with persistence or worsening hydronephrosis in the third trimester show higher rates of postnatal pathology and require close follow up [,21,23,32,62].

Sairam, et al. Hence, an ultrasound in the third trimester is valuable for identifying fetuses that require postnatal evaluation and follow up. The risk of in utero worsening is higher for bilateral than for unilateral disease [60].

While a recent report suggests that patients with mild to moderate isolated bilateral hydronephrosis have a favorable outcome [63], close follow up is necessary since a proportion may show progression or require surgery [40]. Although there are limited studies that address frequency of monitoring [7], we suggest that fetal imaging be repeated every weeks depending on severity of hydronephrosis, gestation and presence of oligohydramnios. Fetuses with findings suggestive of lower urinary tract obstruction bilateral hydroureteronephrosis, dilated bladder and oligohydramnios might require even more frequent monitoring.

Guideline 4. Fetal Intervention a We suggest that diagnostic and therapeutic interventions be considered for fetuses with suspected lower urinary tract obstruction and oligohydramnios only at specialized centers, following one-to-one counseling 2A.

If antenatal ultrasonography shows evidence of lower urinary tract obstruction e. The predominant cause for lower urinary tract obstruction is posterior urethral valves in male fetuses.

In fetuses with suspected lower urinary obstruction and favorable indices, parents should be counseled regarding the role of vesicoamniotic shunting or in utero endoscopic ablation of valves [10, 68, 69]. The benefits of such intervention, usually performed during mid second trimester, are equivocal. Meta-analyses show that prenatal bladder drainage, by vesicoamniotic shunt, improves perinatal survival in fetuses with severe obstruction, with benefits chiefly in those with poor predicted prognosis [70,71].

There is no evidence that this intervention improves long term renal outcome or reduces mortality in fetuses with less severe disease [68,72,73]. Moreover, vesicocentesis and other interventions carry considerable risk of fetal loss, chorioamnionitis and preterm labor. While current evidence is insufficient, ongoing trials shall provide clarity on the efficacy and safety of these procedures [74].

Pregnancy in fetuses with unilateral or bilateral ANH should proceed to term, except if complicated by severe oligohydramnios or major structural anomalies. Early delivery is not indicated, and carries risks of prematurity and low birth weight. Timing of Initial Ultrasound a We recommend that all newborns with history of antenatal hydronephrosis should have postnatal ultrasound examination within the first week of life 1B.

All newborns with a history of ANH, including those in whom it had resolved prenatally, should undergo postnatal evaluation [10,25]. Reports suggest that hydronephrosis that has resolved postnatally does not merit prolonged follow up and has satisfactory outcome [75,76].

In a cohort of infants with ANH and normal postnatal ultrasound, followed for 2 years without prophylaxis, the outcome was satisfactory without progression of hydronephrosis or occurrence of UTI [76].

Patients with persistent postnatal hydronephrosis require additional evaluation, the intensity of which is determined by the severity of findings [1,5,7,10].

A systematic review of 31 studies concluded that the risk of postnatal pathology was In another study, the negative predictive value of a normal postnatal ultrasound for UTI was Nepple, et al. It is emphasized that an ultrasound in the first few days of life underestimates the degree of pelvic dilatation due to dehydration and a relatively low urine output [79, 80].

Despite this limitation, an early ultrasound, within hr of birth, is necessary in neonates with suspected lower urinary tract obstruction, oligohydramnios and bilateral severe hydronephrosis or severe hydronephrosis in a solitary kidney [10]. In others, the first ultrasound examination should ideally be delayed until the end of first week.

Since there is a risk that a proportion of patients might be lost to follow up [81], we propose that neonates with unilateral or mild to moderate bilateral hydronephrosis be screened by ultrasonography prior to hospital discharge. Guideline 6. Diagnosis and Grading of Postnatal Hydronephrosis a We recommend that assessment of severity of postnatal hydronephrosis be based on the classification proposed by Society for Fetal Urology or anteroposterior diameter of the renal pelvis 1B.

Common classifications for diagnosis and grading of postnatal hydronephrosis are those based on measurement of renal pelvic APD [7,82,83] and that proposed by the SFU [84]. The latter assesses renal pelvic fullness, dilatation of major and minor calyces and cortical thickness Fig.

Grade 1: Slight separation of the central renal echo complex. Grade 2: Renal pelvis is further dilated and a single or a few calyces may be visualized.

Grade 3: Renal pelvis is dilated and there are fluid filled calyces throughout the kidney, but renal parenchyma is of normal thickness. Grade 4: As grade 3, but renal parenchyma over the calyces is thinned. Grading the severity of hydronephrosis enables identification of infants that require close follow-up.

In a systematic review, Paserotti, et al. In a retrospective review, SFU grade were found to be associated with high odds for surgery [91]. Ultrasonography should include evaluation for calyceal or ureteric dilation, cortical cysts and echogenicity, bladder wall abnormalities, ureterocele and bladder emptying [92,93]. Increased parenchymal echogenicity, loss of corticomedullary differentiation and presence of cortical cysts on postnatal ultrasound predict impaired renal function or dysplasia in patients with pelviureteric obstruction and posterior urethral valves [].

Guideline 7. Postnatal Monitoring a We recommend that neonates with normal ultrasound examination in the first week of life should undergo a repeat study at weeks 1C. A single ultrasound in the first week of life might not detect all abnormalities of the kidneys or urinary tract, due to low urine flow secondary to dehydration and low glomerular filtration rate. An ultrasound at 6 weeks is more sensitive and specific for obstruction, than that in the first week of life [89].

All newborns with a normal ultrasound at first week, therefore, require a repeat study at weeks [10]. The presence of two normal postnatal renal ultrasounds excludes presence of significant renal disease including dilating VUR [21,99]. The frequency of subsequent monitoring in patients with persistent postnatal hydronephrosis depends on its severity, and includes evaluation for increasing pelvicalyceal or ureteric dilatation and cortical thinning.

Since progression might occur in the first 2-years of life, and occasionally until years [], follow up studies are scheduled at 3- and 6-months, and then monthly until resolution []. The intensity of evaluation for milder grades of hydronephrosis has therefore declined []. Recent cohorts with unilateral or bilateral hydronephrosis with APD up to 10 mm [] or 15 mm [63,] have been followed successfully, relying on clinical features, ultrasonography and counseling parents for surveillance for UTI.

Hydronephrosis resolves in most such patients during the first two years of life, and radiologic investigations or antibiotic prophylaxis is usually not necessary. The policy to follow these neonates with sequential ultrasonography to monitor for resolution of hydronephrosis therefore seems satisfactory. Various experts propose that infants with renal APD exceeding 10 mm or SFU grade at onset require close follow up [1,10,16,,]. Guideline 8. In other cases, the procedure should be done at weeks of age.

Lower urinary tract obstruction most commonly posterior urethral valves in boys; occasionally bilateral ureteroceles is an important cause of ANH and requires prompt management. Ultrasonographic findings of posterior urethral valves are: i bilateral hydrouretero-nephrosis, ii dilated, thick walled bladder that fails to empty, and iii dilated posterior urethra.

Since these patients are at risk for progressive kidney disease and recurrent UTI, an early MCU within days of life enables prompts intervention. While there is increased risk of UTI, there is lack of evidence that antibiotic prophylaxis in patients with mild VUR confers clinical benefit [].

Multiple studies and a systematic review suggest that the severity of ANH does not correlate with the grade of reflux [7,25,], and that patients with VUR may have normal postnatal ultrasound [11,23,94,,]. Although evidence for timing is lacking, the procedure is performed at weeks of age, unless lower urinary tract obstruction is suspected see above. MCU is also required in patients with history of milder grades of ANH who show worsening hydronephrosis, progressive parenchymal thinning or occurrence of UTI [].

Physicians should be aware that this investigation is associated with risks of UTI [] and exposure to radiation []. Guideline 9. The differential function is estimated and renogram curve inspected for pattern of drainage. The procedure may be repeated after months in infants where ultrasound shows worsening of pelvicalyceal dilatation 2D.

Pelviureteric junction obstruction should be considered in infants with hydronephrosis, where dilating VUR is excluded. The likelihood of detecting obstruction is considerably higher in patients with SFU grade 4 or renal APD exceeding mm [7,25,26]. The possibility of vesicoureteric junction obstruction or megaureter is considered in patients with hydronephrosis and dilated ureter where MCU is normal. Diuretic renography allows differentiation between obstructive and non-obstructive hydronephrosis and estimating relative renal function [].

Radiopharmaceuticals such as 99mtechnetium mercaptoacetyltriglycine MAG3 or ethylenedicysteine EC are preferred, since they show greater renal extraction and higher kidney to background ratio compared to diethylenetriaminepentaacetic acid DTPA [].

However, DTPA is inexpensive and widely available. Since immaturity of renal function results in reduced radiotracer uptake, renography is done at weeks of life but may be performed earlier in patients with severe hydronephrosis and cortical thinning.

Box 2 lists guidelines for renography [,]. Intravenous hydration and bladder catheterization are not necessary [,,], the latter indicated in patients with poor bladder emptying on late films neurogenic bladder , severe bilateral reflux or megaureters. A normal renogram curve is characterized by an early peak minutes , rapidly descending phase and almost complete renal emptying by 20 minutes. Drainage is influenced by state of hydration, and composite and differential kidney function [,].

The presence of satisfactory drainage spontaneously, or following IV frusemide and micturition excludes significant obstruction. An obstructive pattern is defined by an ascending or plateau phase over 20 minutes, that fails to empty following diuretic administration and on post-micturition views [,].

Box 2. Oral hydration suffices; administer an additional feed prior to study Bladder catheterization Catheterization is not necessary, except in patients with suspected bladder abnormality or post micturition films showing persistent contrast in bladder Radiopharmaceutical 99mTechnetium mercaptoacetyltriglycine 99mTc-MAG3 or ethylenedicysteine 99mTc-EC preferred to diethylenetriaminepentaacetic acid 99mTc-DTPA Dose 99mTc-MAG3: 1.

An obstructive pattern is a curve that rises continuously over 20 minutes or appears as a plateau, despite frusemide and post micturition. Many patients require repeat renography, when change in differential function and drainage pattern is compared []. The timing of the repeat procedure is not defined, and varies with patient age, initial renal function and persistence or worsening of ultrasonographic findings.

The tracer used for the first renogram and timing of diuretic administration should be similar during serial evaluations. Guideline Indications for Surgery a We recommend that infants with lower urinary tract obstruction be immediately referred to a surgeon for appropriate intervention 1C.

Infants with posterior urethral valves require early urethral catheterization, correction of electrolyte abnormalities, treatment for possible complications and referral for surgical intervention []. Cystoscopic ablation of the urethral valves is recommended [, ].

Serial ultrasonography is recommended [10,] and repeat renography done if there is persistent or progressive hydronephrosis or parenchymal thinning [,]. Other indications for surgery include presence of pain, palpable renal lump or recurrent febrile UTI []. Few reports describe the management of neonates with bilateral severe hydronephrosis secondary to pelviureteric junction obstruction. While in unilateral hydronephrosis, the affected kidney is compared to normal, in bilateral hydronephrosis the function of both kidneys is potentially at risk.


Revised guidelines on management of antenatal hydronephrosis

E-mail: moc. This article has been cited by other articles in PMC. Abstract Widespread antenatal screening has resulted in increased detection of anomalies of the kidneys and urinary tract. The present guidelines update the recommendations published in



Discussion Of deliveries during this study, 0. Most patients had moderately dilated pelvis with only ten babies seen with pelvis exceeding 20 mm. The earlier estimate of the incidence of hydronephrosis was 1 in , which has now been quoted as 0. Sixty per cent of these are due to impaired drainage across the pelviureteric junction 5,6. The postnatal scans were done after the first 72 hours because physiological oliguria in the postnatal period can lead to false negative results.

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