ANTENATAL HYDRONEPHROSIS HASAN FARSI

What would you do if you have: 32-week fetus with normal amniotic fluid and suspected ureteropelvic junction. 36-week fetus with suspected posterior urethral valves without oligohydramnios. 23-week fetus with suspected PUV and oligohydramnios with bladder electrolytes suggestive of good renal function.

Amniotic Fluid Lungs are correctly formed only in the presence of sufficient amniotic fluid Transudate of maternal plasma Diffusion across fetal skin Fetal urine is 1st produced by the end of 9th week Concentration ability by 12-14th week After 18th week all amniotic fluid is fetal urine UCNA Feb. 1995;21-30

Structural Abnormalities & Antenatal US Detection of renal abnormalities with antenatal ultrasonography 1st reported in the 70s. Most renal abnormalities are detected at 18–20 weeks of gestation 1% 50% CNS 20% GU 15% GI 8% Cardiopulmonary

...... Continue Structural Abnormalities & Antenatal US 2-9/1000 birth M:F=2:1 50–87% hydronephrosis Maximum anteroposterior diameter of renal pelvis Multicystic dysplastic kidney, autosomal recessive polycystic kidney disease, renal agenesis and dysplasia, bladder exstrophy, adrenal hyperplasia, neuroblastoma, mesoblastic nephroma and genital abnormalities

The Society of Fetal Urology Grading System for ANH

Grades of Hydronephrosis Mild hydronephrosis: Pelvic APD <=1.5 cm and normal calyces Moderate hydronephrosis Pelvic APD > 1.5 cm and caliectasis with no parenchymal atrophy Severe hydronephrosis: Pelvic APD > 1.5 cm, caliectasis and cortical atrophy BJU Inter volume 85 Page 987  - May 2000

Grades of ANH grade I: the pelvic APD is 1 cm with normal calycesgrade II, APD 1–1.5 cm with normal calycesgrade III, APD > 1.5 cm with slight caliectasisgrade IV, APD > 1.5 cm with moderate caliectasisgrade V, APD > 1.5 cm with severe caliectasis and cortical atrophy Grignon A, Radiology 1986; 160: 645 7

RPD Measurement & Incidence of ANH 18766 Atenatal scans from Bristol UK (RPD=>5mm) ANH 0.59% 6292 Antenatal scans from Stoke-on-Trent UK (RPD >10mm) ANH 0.65% 6810 Scans from India (RPD >10mm) ANH 0.64 Indian Pediatrics 2001; 38: 1401-1404  

British Journal of Urology volume 81 Page 8 - April 1998 The Final Urological Diagnosis of 426 live-born Infants with Significant Prenatally Detected Uropathy British Journal of Urology volume 81 Page 8  - April 1998

Post Urethral Valves: Antenatal US

Prognosis & Severity of ANH Prognosis & severity of hydronephrosis: (% needed surgery or prolonged follow-up): RPD > 20 mm, 94% RPD 10–15 mm 50% RPD was < 10 mm 3% Grignon A, Filion R, Filiatrault D, et al: Radiology 1986 Sep; 160(3): 645-7 Outcome of fetal renal pelvic dilatation (Surgery or UTI): Mild dilation 0% Moderate dilatation 23% Severe hydronephrosis 64% Ultrasound Obstet Gynecol. 2005 May;25(5):483-8.

Diagnosis & Severity of ANH Mild hydronephrosis (RPD 5–9 mm) the most likely diagnosis is VUR More marked hydronephrosis (RPD> 10 mm, and especially if > 15 mm) PUJ obstruction is the most common cause

Prognostic Factors of Fetal Hydronephrosis Severity Laterality Ureteric dilatation Renal parenchymal changes Abnormalities of bladder size, thickness and emptying The presence of concomitant oligohydramnios

Unfavorable Prognostic Factors Prolonged oligohydramnios Renal cortical cysts Urinary contents: Na =or>100mEq/L Cl>90mEq/L Osmolarity>210mmol Elevated urinary B2-microglobulin Reduced lung area & thoracic or abdominal circumference

Antenatal Counseling Enormous distress to parents Communication difficulties between the relevant specialists Limited understanding of the natural history Many anomalies may have no long term consequence

Resolution of ANH 18 weeks 32 weeks

Fetal Intervention No intervention: Regular US Termination of pregnancy (up to 23 weeks) Induction of labor Prenatal intervention Only at an experienced institution under approved protocols

Intervention Male fetus Second trimester Severe hydroureteronephrosis Bilateral Reasonable fetal urinary indicators Progressive oligohydramnios.

Prenatal Intervention for Urinary Obstruction For most fetuses intervention is not necessary Decompression will restore amniotic fluid---> prevent development of fetal pulmonary hypoplasia ?? Arrest or reverse renal cystic dysplastic changes

Vesicoamniotic Shunting: Technique Vesicostomy or pyelostomy Pigtail shunt Complications: Shunt blockage or migration, preterm labor, urinary ascitis, chorioamnionitis, iatrogenic gastroschisis, intrauterine death Outcome: Perinatal survival 47% Post renal insufficiency 87.5%

Prenatal Evaluation and Treatment for Fetal Lower Urinary Tract Obstruction" The long term outcomes for shunts in fetal bladder outlet obstruction: Etiology: Posterior urethral valves 39% Urethral atresia 22% Prune Belly Syndrome 39%. Outcome: More than 45% had a GFR of >70ml/min 22% had renal insufficiency 33% were ultimately on dialysis 33% had a transplant Society for Fetal Urology 35th Biannual Meeting 2005

Fetal Cystoscopy US guided 1.3mm fetoscope Cannula thru maternal then fetal abdomen then fetal bladder Laser ablation of valves Results 9 fetuses:4 success 2 viable at birth 1 died age 4 months from bronchopneumonia and one died age 3 m from necrotizing enterocolitis

A survey instrument was mailed to all members of the Society for Fetal Urology. 7 case scenarios that addressed critical decision points in patients with antenatally detected genitourinary abnormalities. A total of 112 of 188 Society for Fetal Urology members (60%) completed the survey. J UROL Vol. 164, 1052–1056, September 2000

32-week fetus with normal amniotic fluid and suspected ureteropelvic junction: 99% observation & serial US 36-week fetus with suspected posterior urethral valves without oligohydramnios: Most respondents elected no intervention 27% induce early delivery

…continue 23-week fetus with suspected PUV and oligohydramnios with bladder electrolytes suggestive of good renal function: Intervene antenatally using a vesicoamniotic shunt (71%) Serial aspiration (7%) Amnioinfusion (7%).

Conclusion Situations that warrant antenatal intervention for a genitourinary abnormality are exceedingly low and may include: Cases of oligohydramnios Suspected favorable renal function Absence of life threatening congenital abnormalities. In cases with normal amniotic fluid antenatal intervention is not recommended regardless of the detected abnormality.

……..continue Conclusion No evidence exists demonstrating the benefit of antenatal intervention in terms of renal function and only in a select number of cases will it benefit pulmonary function. To our knowledge no scientific data exist that demonstrate the long-term benefit of early delivery of cases with antenatally detected, genitourinary abnormalities.

Postnatal Investigations Abdominal mass Deficient abdominal wall Undescended testes Palpable bladder Renal profile US within 1 week (earlier ?? false because of the physiological oliguria)

When to perform US post delivery Renal obstruction may be underestimated or missed on a renal sonogram obtained 6 days after birth. A sonogram obtained 6 weeks after birth is more specific for detecting obstruction. AJR Am J Roentgenol. 1995 Apr;164(4):963-7.

…..continue Postnatal Investigations Is it unilateral or bilateral? Is it solitary kidney? Are there associated anomalies? ??? Prophylactic antibiotics Hydronephrosis =obstruction

    Close this Window       Close this Window   Table 1.  Classification of 778 neonatal scans, 92% referred with antenatal pyelectasis Table 1.  Classification of 778 neonatal scans, 92% referred with antenatal pyelectasis Intrauterine Resolution of ANH:- Classification of 778 neonatal scans for evaluation of ANH Normal renal scans 592 (76%) Persisting Pyelectasis 120 (15%) Unilateral renal tract obstruction (pelviureteric junction 6, vesicoureteric junction 1) 7 (1%) Miscellaneous anomalies 59 (8%) Total 778 Australasian Radiology volume 47 Page 354  - December 2003 Normal renal scans 592 (76%) Persisting Pyelectasis 120 (15%) Unilateral renal tract obstruction (pelviureteric junction 6, vesicoureteric junction 1) 7 (1%) Miscellaneous anomalies 59 (8%) Total 778 Normal renal scans 592 (76%) Persisting Pyelectasis 120 (15%) Unilateral renal tract obstruction (pelviureteric junction 6, vesicoureteric junction 1) 7 (1%) Miscellaneous anomalies 59 (8%) Total 778                                           Back to top                                           Back to top

Fate of ANH

Transient Hydronephrosis 30-50% of ANH Etiology ??: Insufficient maturation of UPJ Insufficient maturation of VUJ Increased fetal urinary output (4–6 times greater before than after delivery) Partial or transient anatomical or functional obstructions, e.g. fetal ureteric folds

New Investigative Modalities for Post natal Evaluation of ANH MR urography: MR urography alone was found to be comparable with conventional combination studies of DRS and US or urography. Renal dysplasia Doppler derived renal resistive index measures (RI) The results of this study do not support the clinical use of Doppler ultrasound studies in the diagnostic work-up of congenital hydronephrosis

Repeat US in 3-6m Dudley, J A et al. Arch. Dis. Child. Fetal Neonatal Ed. 1997;76:F31-F34

Persistent Hydronephrosis without Obstruction 10-15% 50% resolves by 12 months Needs long time follow-up

Take Home Messages Antental hydronephrosis is not uncommon With the high percentage of history of consanguinity, the incidence might be higher in Saudi Arabia The Obstetrician should be vigilant in looking for it during the routine antenatal visits.

.....continue Take Home Messages No evidence exists demonstrating the benefit of antenatal intervention in terms of renal function and only in a select number of cases will it benefit pulmonary function. To our knowledge no scientific data exist that demonstrate the long-term benefit of early delivery of cases with antenatally detected, genitourinary abnormalities.

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