eMedicine Specialties > Radiology > Pediatrics
Posterior Urethral Valve: Follow-up
Updated: Feb 21, 2010
Intervention
Prenatal intervention is essentially experimental and limited to a few centers. Options include percutaneous placement of a vesicoamniotic shunt, open fetal surgery, and fetal cystoscopic ablation. Significant complications may occur, resulting in maternal or fetal morbidity, as well as fetal loss.8 It is unclear whether prenatal intervention has a significant effect on the long-term prognosis of males with posterior urethral valves. Pulmonary function has been shown to benefit from the reversal of oligohydramnios, but no renal benefit has been noted.
In newborn males with suspected posterior urethral valves, ultrasonography should be performed in the first 24 hours to document bladder dilatation and changes in the upper tract. After the study, a 5F feeding tube may be placed as a urethral catheter. Some pediatric urologists favor a suprapubic catheter for the initial bladder drainage; however, urethral catheterization may be difficult because the valves obstruct retrograde passage of the catheter or the catheter may obliterate more flimsy valves, making later VCUG more difficult to interpret.
When VCUG is performed, ideally the urethral catheter should be removed during voiding to optimally demonstrate the valves. When the valves are diagnosed, the urethral catheter should then be replaced to continue decompression of the bladder. A serum creatinine level is determined to assess renal function. If the renal function is stable, transurethral valve ablation is performed through a cystoscope with a cold knife, electrocautery, or laser energy. If the serum creatinine level does not stabilize and if the upper tracts show no improvement, more drastic measures for bladder drainage may be required. Vesicostomy may be performed in such cases or if the urethra is too small to accept the small cystoscope. Routine performance of more proximal upper-tract diversion (pyelostomy, cutaneous ureterostomy) is reserved for rare circumstances.
The symptomatic older child usually undergoes cystoscopy for diagnosis with endoscopic ablation of the valves, if seen.
Medicolegal Pitfalls
- Despite antenatal diagnosis of posterior urethral valves, severely affected male fetuses may die in utero or early in life. Early diagnosis may require the clinician to make recommendations regarding the potential viability and quality of life for an affected male fetus so that parents may make informed decisions regarding the elective termination of pregnancy. The upper gestational age limit for elective termination varies among states and countries.
- Lack of definitive documentation of the valves on radiologic studies does not rule out their presence. Newborns with suspected lower tract obstruction and findings on VCUG should undergo decompression with a catheter until definitive therapy is performed. Ultimate renal function may improve as long as the obstruction is relieved early. Cystourethroscopy may ultimately be required to make the diagnosis.
- Cystourethroscopy and endoscopic management may lead to urethral stricture formation. Incontinence of urine due to iatrogenic sphincter injury may not be seen until the boy reaches the normal age of continence. Retrograde ejaculation after puberty may be seen and be a cause of infertility.
- Voiding dysfunction (urgency, frequency, and enuresis) is not uncommon in boys and typically improves spontaneously. If the symptoms are severe or do not improve, obstruction due to posterior urethral valve must be ruled out with VCUG. A missed diagnosis of obstruction may result in permanent bladder dysfunction, with possible renal failure.
More on Posterior Urethral Valve |
| Overview: Posterior Urethral Valve |
| Imaging: Posterior Urethral Valve |
Follow-up: Posterior Urethral Valve |
| Multimedia: Posterior Urethral Valve |
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References
Young HH, Frontz WA, Baldwin JC. Congenital obstruction of the posterior urethra. J Urol, 3: 289-365, 1919. J Urol. Jan 2002;167(1):265-7; discussion 268. [Medline].
Heikkilä J, Rintala R, Taskinen S. Vesicoureteral reflux in conjunction with posterior urethral valves. J Urol. Oct 2009;182(4):1555-60. [Medline].
Otukesh H, Sharifiaghdas F, Hoseini R, et al. Long-term upper and lower urinary tract functions in children with posterior urethral valves. J Pediatr Urol. Aug 11 2009;[Medline].
Youssif M, Dawood W, Shabaan S, et al. Early valve ablation can decrease the incidence of bladder dysfunction in boys with posterior urethral valves. J Urol. Oct 2009;182(4 Suppl):1765-8. [Medline].
Sarhan O, El-Dahshan K, Sarhan M. Prognostic value of serum creatinine levels in children with posterior urethral valves treated by primary valve ablation. J Pediatr Urol. Feb 2010;6(1):11-14. [Medline].
Imaji R, Dewan PA. The clinical and radiological findings in boys with endoscopically severe congenital posterior urethral obstruction. BJU Int. Aug 2001;88(3):263-7. [Medline]. [Full Text].
Williams CR, Pérez LM, Joseph DB. Accuracy of renal-bladder ultrasonography as a screening method to suggest posterior urethral valves. J Urol. Jun 2001;165(6 pt 2):2245-7. [Medline].
Soliman SM. Primary ablation of posterior urethral valves in low birth weight neonates by a visually guided fogarty embolectomy catheter. J Urol. May 2009;181(5):2284-9; discussion 2289-90. [Medline].
Bani Hani O, Prelog K, Smith GH. A method to assess posterior urethral valve ablation. J Urol. Jul 2006;176(1):303-5. [Medline].
Glassberg KI, Horowitz M. Urethral valve and other anomalies of the male urethra. In: Belman AB, King LR, Kramer SA, eds. Clinical Pediatric Urology. 4th ed. London, UK: Martin Dunitz Ltd; 2002:899-946.
Krishnan A, de Souza A, Konijeti R, Baskin LS. The anatomy and embryology of posterior urethral valves. J Urol. Apr 2006;175(4):1214-20. [Medline].
Salam MA. Posterior urethral valve: outcome of antenatal intervention. Int J Urol. Oct 2006;13(10):1317-22. [Medline].
Further Reading
Clinical guidelines:
Daytime lower urinary tract conditions. In: Guidelines on paediatric urology. European Association of Urology - Medical Specialty Society
European Society for Paediatric Urology - Medical Specialty Society. 2008 Mar (revised 2009 Mar). 4 pages. NGC:007221
Posterior urethral valves. In: Guidelines on paediatric urology. European Association of Urology - Medical Specialty Society
European Society for Paediatric Urology - Medical Specialty Society. 2008 Mar (republished 2009 Mar). 6 pages. NGC:006514
Keywords
posterior urethral valve, hydronephrosis, hydronephrosis kidney, PUV, urethral dilation, posterior urethral, posterior urethral valves, voiding dysfunction, renal hydronephrosis, bladder outlet obstruction
Follow-up: Posterior Urethral Valve