Prenatal and Postnatal Assessment of Posterior Urethral...
Transcript of Prenatal and Postnatal Assessment of Posterior Urethral...
Prenatal and Postnatal Assessment of Posterior
Urethral ValveKatie Rose Clapham, HMS Year III
Gillian Lieberman, MDJuly 19, 2010
Outline
• Normal kidney and urinary tract development• Normal fetal kidney and urinary tract on
ultrasound • Types of kidney and urinary tract malformations• Case of posterior urethral valve
- prenatal evaluation- postnatal evaluation
• Interventions and long-term outcome
Development of the Kidney
Image from UpToDate. Overview of CAKUT. Waters, A. and Rosenblum, N. http://www.uptodate.com/online/content/topic.do ?topicKey=pedineph/18797&selectedTitle=1%7 E150&source=search_result. 7/15/10.
Part of kidney
Appears Functional Gives rise to
Pronephros 4th week Never functional
Pronephric ducts used by mesonephros
Mesonephros 4th week Functions for 4 weeks
Contributes to male genital structures and bladder
Metanephros 5th week Starts functioning at 9th week
UG bud gives rise to ureters and collecting ductsMetanephric blastema gives rise to the rest of the kidney
Urogenital (UG) Sinus
Bladder and urethra
Development of Urethra• Mesonephric (Wolffian) duct fuses with UG sinus and
contributes to urethra• Caudal UG sinus (genital tubercle) forms phallic urethra• Urethra formation is complete by 14 weeks
Image from Lawrentschuk N., and Frydenberg M. Benign Prostate Disorders. Endotext. http://www.endotext.org/male/male9/male9.html. Accessed [7/18/10]
Outline
• Normal kidney and urinary tract development• Normal fetal kidney and urinary tract on
ultrasound • Types of kidney and urinary tract malformations• Case of posterior urethral valve
- prenatal evaluation- postnatal evaluation
• Interventions and long-term outcome
Normal Fetal Kidney on Ultrasound
•Cannot reliably see fetal kidney on ultrasound during 1st trimester.
•Visualized by 16-22 weeks.
•Can visualize cortex and pyramids by 23-26 weeks, and fine anatomy by 30 weeks.
•Fetal kidney length in mm is roughly equal to the fetal menstrual age in weeks.
Normal Fetal Bladder on Ultrasound (18 wks)
Bladder
PACS, BIDMC
*
Transverse View
Normal Fetal Kidney on Ultrasound (18 wks)
SpineKidneys
PACS, BIDMC
*
*
Transverse View
Ultrasound Evaluation of Kidney Function
• Fetal kidney function is assessed by-visualization of urine in the bladder by 13- 16 weeks (the ureters are not normally seen)- measurement of amniotic fluid (subjective measures appear to be as good as summing the depth of amniotic fluid pockets in four quadrants)
Outline• Normal kidney and urinary tract development• Normal fetal kidney and urinary tract on
ultrasound • Types of kidney and urinary tract
malformations• Case of posterior urethral valve
- prenatal evaluation- postnatal evaluation
• Interventions and long-term outcome
Types of Kidney Malformations: Parenchymal
•Hypoplasia
•Dysplasia
•Renal agenesisGross Hypoplastic Kidney
Massey, H.D. Lab I.j Congenital Malformations. Renal Pathology for Medical II Students. http://www.pathology.vcu.edu/education/renal/lab1.j.ht ml. Accessed [7/15/10].
Multicystic Kidneyon Ultrasound
PACS, BIDMC
•Multicystic kidney
•Genetic cystic disease (ARPKD, ADPKD, NPH)
Types of Kidney Malformations: Migration
• Ectopia• Fusion
Crossed Fused Ectopic Kidneyon CT with contrast
PACS, BIDMC
Horseshoe Kidney on IVUIrshad, A, Ackerman, S., Ravenel, J.G. Horseshoe Kidney. http://emedicine.medscape.com/article/378396-overview. Accessed [7/15/10].
Types of Kidney Malformations: Collecting System
• Pelvis: UPJ obstruction• Ureter: megaureter, ectopic ureter, VUR• Bladder: exstrophy• Urethra: posterior urethral valve
(PUV)
Ectopic ureter on CTPACS, BIDMC
Outline
• Normal kidney and urinary tract development• Normal fetal kidney and urinary tract on
ultrasound • Types of kidney and urinary tract malformations• Posterior urethral valve
- prenatal evaluation- postnatal evaluation
• Interventions and long-term outcome
Patient 1: Posterior Urethral Valve
• Congenital defect• Affects males• The ‘valve’ is a membranous fold between
urethral wall and verumontanum (crest where seminal vesicles enter urethra) that obstructs the urethra
Patient 1: Posterior Urethral Valve
Image from Belman, A., King, L.R., and Kramer, S.A. Clinical pediatric urology. 4th
edition. London, England: Martin Dunitz Ltd; 2002.
Dilated ureter
Hydronephrotic kidney
Dilated bladder
The valve may originate from incomplete canalization or an aberrant insertion of the
Wolffian duct into the cloaca
Site of membranous ‘valve’
Image from Lawrentschuk N., and Frydenberg M. Benign Prostate Disorders. Endotext. http://www.endotext.org/male/male9/male9.html. Accessed [7/18/10]
Prostate
Gross Appearance
Posterior Urethral Valve
Key Findings on Ultrasound
HydronephrosisDilated bladder with possible
wall thickening
Dilated posterior urethra
Patient 2: Male Fetus on Ultrasound (18 wks)
PACS, BIDMC
GenitaliaLegs
Patient 2: “Keyhole Sign”: Dilated Bladder and Prostatic Urethra on Ultrasound
PACS, BIDMC
Dilated bladder
Dilated prostatic urethra
**
Sagittal View
Patient 2: Bladder Dilatation on Ultrasound (20 wks)
Bladder (20 wks) measures 4.14 by 2.04 cm on sagittal view
PACS, BIDMC
Normal bladder (18 wks) measures 0.44 cm on transverse view
Anechoic space demonstrates no flow on Doppler imaging, suggesting a dilated bladder rather than a vascular structure
Sagittal View Sagittal View
Transverse View
*
Patient 2: Enlarged Hydronephrotic Kidneys on Ultrasound (20 wks)
Left kidney measures 3.42 cm
Right kidney measures 2.80 cm
PACS, BIDMC
SpineAmniotic
Fluid
Bladder
Normal kidney size: 1 mm/week x 20 weeks = 20
mm or 2 cm
Sagittal view
Sagittal view
*
*
Patient 2: Dilated Renal Pelvis on Ultrasound (20 wks)
Dilated Pelvis of Right Kidney (0.66 cm)
Dilated Pelvis of Left Kidney (0.53 cm)
PACS, BIDMC
At 20 wks: Pelvis <5 mm is normal but can be 6-9 mm and normal.
Here, pelvis>5 mm plus other findings suggest obstruction.
Transverse view
Transverse view
*
*
Patient 2: Amniotic Fluid Measurement on Ultrasound
Amniotic Fluid estimate: 14.23 mL at 20 weeks
5-25 mL is the normal range for most of pregnancyPACS, BIDMC
Patient 3: Visible Ureters and Dilated Renal Pelvices on Ultrasound
Renal Pelvis
BladderUreter
Image courtesy of Dr. Tejas Mehta, BIDMC
*
*
*
Differential Diagnosis for Ultrasound Findings
• Mechanical obstruction – PUV– Urethral atresia– Caudal regression syndrome– Megacystis-microcolon-intestinal hypoperistalsis syndrome– Prune Belly Syndrome (hypotonic abdominal wall, megacystis,
ureterectasis, cryptorchidism). • Functional obstruction
– Abnormality in the sphincter, innervation, or musculature of the bladder
PUV is suggested by the keyhole sign, the absence of other associated findings, and the severity of obstruction
Diagnosis is confirmed postnatally
Accuracy of Ultrasound Evaluation
• In one study:- 6 fetuses had catheters placed for dilated
urinary tracts thought to be caused by PUV (5) or obstructed megaureter (1)
- 2 were found to have PUV postnatally
Prognostic Indicators
Patients with PUV often have chronic kidney disease, VUR, and bladder dysfunction.
Risk factors for poor renal function:
•Diagnosis of PUV before 24 weeks
•Oligohydramnios – when present in 2nd
trimester, mortality is 90-95%
•Serum creatinine >1.0 mg/dL
•Bladder dysfunction
Renal Outcome
It is unclear whether PUV and renal dysplasia are associated because there is:
- A common developmental injury- Damage caused by high back pressure- Recurrent infection causing scarring
Outline
• Normal kidney and urinary tract development• Normal fetal kidney and urinary tract on
ultrasound • Types of kidney and urinary tract malformations• Case of posterior urethral valve
- prenatal evaluation- postnatal evaluation
• Interventions and long-term outcome
Clinical Presentation
Neonates: respiratory distress, dilatated bladder, urinary ascites, difficulty urinating
Infants: Failure to thrive, urosepsis, difficulty urinating
Boys: UTIs, incontinence, difficulty urinating
Postnatal Evaluation: Menu of Tests
Voiding Cystourethrogram (VCUG) is the study of choice
• Contrast is injected via a catheter into the bladder • During micturition, the flow of urine is observed on
fluoroscopyUltrasound can be used to assess hydrouteronephrosis
and renal parenchymaIf VCUG is not diagnostic, cystourethroscopy can be usedMRI is a developing technology
-fast sequences or patient sedation required in pediatric population
Patient 4: VCUG Demonstrates Obstruction and Unilateral Reflux Postnatally
1/3-1/2 of patients with PUV have reflux, which may be unilateral or bilateral
*
*
***
*
Dilated renal pelvisDilated and torturous ureterDilated bladderDilated prostatic urethraTrabeculationsDiverticulum
Children’s Hospital Boston
Unilateral or Bilateral Reflux
• In one retrospective study of 200 patients with PUV, 27% had unilateral vesicoureteral reflux on VCUG and 37% had bilateral reflux
• Unilateral reflux may be due to protective mechanisms increasing reflux in one kidney in order to preserve contralateral kidney function (vesicoureteral reflux and dysplasia syndrome)
Patient 4: Lateral VCUG shows Dilated Bladder and Prostatic Urethra
Dilated bladder with trabeculations and diverticula
Dilated prostatic urethraChildren’s Hospital Boston
**
Outline
• Normal kidney and urinary tract development• Normal fetal kidney and urinary tract on
ultrasound • Types of kidney and urinary tract malformations• Case of posterior urethral valve
- prenatal evaluation- postnatal evaluation
• Interventions and long-term outcome
InterventionsPrenatalIn general, prenatal intervention is avoided because the benefits have not been shown to outweigh prenatal and maternal morbidity
Vesicoamniotic shuntOpen fetal surgery Cystoscopic ablation
Newborn Bladder drainage via feeding tube or catheterCystoscopic ablationVesicotomy if needed
Older boys Cystoscopic ablation
Cystoscopy
The cystoscope allows visualization of the
urinary tract
Surgical instruments may be passed
through the cystoscope
Cystoscopy. Mayo Clinic. http://www.mayoclinic.com/health/medical/IM00166/undefine d. Accessed [7/18/10]
Long-Term Outcome
• Perinatal mortality, caused by pulmonary hypoplasia and sepsis, has decreased to <10% due to better management
• Long term outcome depends on renal parenchymal function
• Renal transplant has been shown to be effective in a setting where the bladder permits transplant survival
ReferencesBelman A., King L.R., and Kramer S.A. Clinical pediatric urology. 4th edition. London, England: Martin Dunitz Ltd; 2002. Cystoscopy. Mayo Clinic. http://www.mayoclinic.com/health/medical/IM00166/undefined. Accessed [7/18/10]DeFoor W., Clark C., Jackson E., Reddy P., Minevich E., and Sheldon C. Risk factors for end stage renal disease in children with posterior urethral
valves. J Urol. 2008;180(4 Suppl):1705-8; discussion 1708. Goldstein R.B., and Filly R.A. Sonographic estimation of amniotic fluid volume: subjective assessment versus pocket measurements. J Ultrasound
Med 1988; 7:363.Heikkilä J., Rintala, R., and Taskinen S.. Vesicoureteral reflux in conjunction with posterior urethral valves.
J Urol. 2009;182(4):1555-60. Holmes, N. Clinical presentation and diagnosis of posterior urethral valves. UpToDate.
http://www.uptodate.com/online/content/topic.do?topicKey=pediatri/2371&selectedTitle=1%7E150&source=search_result. Accessed [7/14/10].Holmes, N. Management of posterior urethral valves. UpToDate.
http://www.uptodate.com/online/content/topic.do?topicKey=pediatri/2087&selectedTitle=1%7E22&source=search_result. Accessed [7/14/2010].
Irshad A, Ackerman S., and Ravenel J.G. Horseshoe Kidney. eMedicine. http://emedicine.medscape.com/article/378396-overview. Accessed [7/13/10].
Lawrentschuk N., and Frydenberg M. Benign Prostate Disorders. Endotext. http://www.endotext.org/male/male9/male9.html. Accessed [7/18/10]Massey H.D. Lab I.j Congenital Malformations. Renal Pathology for Medical II Students. http://www.pathology.vcu.edu/education/renal/lab1.j.html
Accessed [7/15/10]. Moore K.L., and Persaud T.V.N. The Developing Human: Clinically Oriented Embryology. 8th edition. Saunders Elsevier Health Sciences, 2007. Romero R., Pilu G., Jeanty P., et al. Prenatal diagnosis of Congenital Anomalies. Norwalk: Appleton and Lange, 1998. Rumack C., Wilson S.R., and Charboneau J.W. Diagnostic Ultrasound. 1st edition. St. Louis, Missouri: Mosby-Year Book, Inc.; 1991. Rutherford S.E., Phelan J.P., Smith C.V., et al. The four-quadrant assessment of amniotic fluid volume: an adjunct to antepartum fetal heart rate
testing. Obstet Gynecol 1987; 70:353. Sarhan O., Zaccaria I., Macher M.A., Muller F, Vuillard E., Delezoide A.L., Sebag G., Oury J.F., Aigrain Y., and El-Ghoneimi A. Long-term outcome
of prenatally detected posterior urethral valves: single center study of 65 cases managed by primary valve ablation. J Urol. 2008;179(1):307- 12; discussion 312-3.
Sholder, A.J., Maizels, M., Depp, R., Firlit, C.F., Sabbagha, R., Deddish, R., Reedy, N. Caution in antenatal intervention. J Urol. 1988; 139(5):1026-9Waters, A. and Rosenblum, N. Evaluation of congenital anomalies of the kidney and urinary tract (CAKUT). UpToDate.
http://www.uptodate.com/online/content/topic.do?topicKey=pedineph/17792&selectedTitle=1%7E40&source=search_result. Accessed [7/11/10].
Waters, A. and Rosenblum, N. Overview of congenital anomalies of the kidney and urinary tract (CAKUT). UpToDate. http://www.uptodate.com/online/content/topic.do?topicKey=pedineph/18797&selectedTitle=1%7E150&source=search_result. Accessed [7/11/10].
Wiener, J.S., Gaca, A. M., Sekula, J. Posterior Urethral Valve. eMedicine. http://emedicine.medscape.com/article/412226-overview. Accessed [7.15.10].
Acknowledgments
• Dr. Gillian Lieberman• Dr. Mai-Lan Ho• Dr. Iva Petovska• Dr. Tejas Mehta• Maria Levantakis