AUTHOR AND EDITOR INFORMATION

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INTRODUCTION

Section 2 of 11  

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Background

The first description of posterior urethral valves (PUVs) was made by Hugh Hampton Young. PUVs represent a spectrum of severity, ranging from disease incompatible with postnatal life to disease that is minimal and may not manifest until later in life. Treatment of PUVs remains a clinical challenge, requiring active management from infancy into adulthood to avoid progressive dysfunction and deterioration of both the upper and lower urinary tracts.

Pathophysiology

During embryogenesis, the most caudal end of the Wolffian duct is absorbed into the primitive cloaca at the site of the future verumontanum in the posterior urethra. In healthy males, the remnants of this process are the posterior urethral folds, called plicae colliculi. Histological studies suggest that PUVs are formed at approximately 4 weeks' gestation, as the Wolffian duct fuses with the developing cloaca.

Young popularized a classification of PUVs.¹ Abnormally high insertion and fusion of these primitive folds were believed to be the origins of 95% of PUVs; this type was referred to as type I PUVs. Although Young described type II PUVs, most pediatric urologists believe that these are not obstructing valves but simply hypertrophy of the plicae colliculi. Also described by Young, type III PUVs constitute a septum at the junction of the posterior and anterior urethra, instead of a sail-like valve. Type III PUVs are believed to originate from incomplete dissolution of the urogenital membrane. This classification has no clinical value and is now considered outdated.

Congenital obstructing posterior urethral membrane (COPUM) was first proposed by Dewan and Goh and was later supported by histological studies by Baskin.² This concept proposes that, instead of a true valve, a persistent oblique membrane is ruptured by initial catheter placement and, secondary to rupture, forms a valvelike configuration.

PUV represents a spectrum of severity. The degree of obstruction caused by this abnormality widely varies depending on the configuration of the obstructive membrane within the urethra. The morbidity of PUVs is not merely limited to transient urethral obstruction; however, the congenital obstruction of the urinary tract at a critical time in organogenesis may have a profound and lifelong effect on kidney, ureteral, and bladder function.

Renal insufficiency is caused by PUVs in approximately 10-15% of children undergoing renal transplant, and approximately one third of patients born with PUVs progress to end-stage renal disease (ESRD).

Moreover, children with PUVs develop thickened bladders because of increased collagen deposition and muscle hypertrophy within the bladder wall. Hypertrophy and hyperplasia of the detrusor muscle and increases in connective tissue decrease bladder compliance during filling. Bladder emptying occurs with high intravesical pressures, which can be transmitted to the ureters and kidneys. These patients are susceptible to incontinence, infection, and progressive renal damage.

Frequency

United States

PUV is the most common cause of lower urinary tract obstruction in male neonates; the reported incidence is 1 per 8,000 to 1 per 25,000 live births.

Mortality/Morbidity

PUVs are the cause of renal insufficiency in approximately 10-15% of children undergoing renal transplant, and approximately one third of patients born with PUV progress to ESRD.

Sex

PUVs exclusively occur in males. The homolog to the male verumontanum from which the valves originate is the female hymen.

Age

Diagnosis is usually made before birth or at birth when a boy is evaluated for antenatal hydronephrosis. Before the era of prenatal ultrasonography, PUVs were discovered during evaluation of urinary tract infection (UTI), voiding dysfunction, or renal failure. Although rare, adult presentation of PUVs has been described in case reports, with symptoms varying from obstructive voiding symptoms to postejaculatory dysuria. In the presonography era, late presentation of PUV was considered a good prognostic sign suggestive of a lesser degree of obstruction.

CLINICAL

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History

• Prenatal diagnosis
• • The widespread use of antenatal ultrasonography and the sophisticated neonatal care available in most developed countries has enabled diagnosis of posterior urethral valves (PUVs) in many individuals in the prenatal timeframe.
  • Diagnosis is usually made before or at birth when a boy is evaluated for antenatal hydronephrosis.
  • In 1989, Thomas reported that 10% of patients with prenatal hydronephrosis detected by ultrasonography had PUVs.³
  • Despite widespread use of antenatal ultrasonography, some patients with PUVs present later in life.
  • In a 1993 report, Dinneen et al reported the sensitivity of antenatal ultrasonography to be only 45% in detecting PUVs in 45 patients who presented when younger than 6 months.⁴ With improvements in technology, the sensitivity has increased over the last 10 years.
  • Those patients with PUVs not diagnosed on prenatal ultrasonography and who do not manifest overt urinary pathology are at risk of delayed presentation of PUVs.
• Delayed presentation
• • UTI, diurnal enuresis in boys older than 5 years, secondary diurnal enuresis, voiding pain or dysfunction, and decreased force of stream may indicate the presence of PUVs.⁵
  • PUVs are sometimes discovered during evaluation of abdominal mass or renal failure.
• Incidental diagnosis: Hydronephrosis or proteinuria found on examination for unrelated conditions may be the first sign of PUVs.

Physical

Most patients have normal findings upon physical examination. When present, abnormal physical findings are the result of severe renal insufficiency.

• Neonates may present with severe pulmonary distress due to underdevelopment of the lung caused by oligohydramnios. An appropriate volume of amniotic fluid (produced by the kidneys) is necessary for complete and proper branching of the bronchial tree and alveoli. Physical findings can include the following:
• • Poor fetal breathing movements
  • Small chest cavity
  • Abdominal mass (ascites)
  • Potter facies
  • Limb deformities (skin dimpling)
  • Indentation of the knees and elbows due to compression within the uterus
• In older children, physical findings can include poor growth, hypertension, and lethargy. An intermittent or weak urinary stream is a nonreliable sign.

Causes

A PUV is a congenital obstruction caused by a malformation of the posterior urethra. The significance of this obstruction depends on the secondary effects on the bladder, ureters, and kidneys.

• Type I PUV: This type of obstruction is believed to be secondary to abnormal insertion and absorption of the most distal aspects of the Wolffian ducts during bladder development. In the healthy male, the remnants of these ducts are observed as the plicae colliculi.
• Type III PUV: These valves are observed as a membrane in the posterior urethra believed to originate from incomplete canalization between the anterior and posterior urethra.

DIFFERENTIALS

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Other Problems to be Considered

Anterior urethral valves
Urethral stricture disease
Detrusor sphincter dyssynergy
Diurnal urinary incontinence
Pediatric renal insufficiency

WORKUP

Section 5 of 11  

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Lab Studies

• Immediately following birth, the infant's serum chemistries are the same as the mother's. Therefore, serum values for creatinine and BUN should be obtained at least 24 hours after birth. In utero, the placenta functions as the major blood filter for the fetus, with waste passed on to the mother. Observing serum chemistries for several days to weeks is important to determine the true status of the newborn's renal function.
• The normal newborn kidney is still undergoing maturation at birth, and infant glomerular filtration rate (GFR) continues to improve during the first several months of life. Because of renal immaturity at birth, the newborn is unable to concentrate urine and is susceptible to dehydration. This defect is exacerbated by renal dysplasia such as that found with posterior urethral valves (PUVs).
• As renal maturation continues, the serum creatinine clearance normally improves. If significant renal dysplasia or damage has occurred, the serum creatinine fails to reach a normal level during the first year of life. Serum creatinine levels greater than 0.8 mg/dL during the first year of life have been demonstrated to be associated with poor long-term renal function.

Imaging Studies

• Renal and bladder ultrasonography
• • Every child with antenatal hydronephrosis requires renal and bladder ultrasonography assessment in the immediate postnatal period. Focus should be directed towards appearance of the renal parenchyma, evidence of renal collecting system dilatation, bladder wall thickness, and presence of ascites.
  • Because newborns commonly have relative hypovolemia during the first few days of life, perform repeat ultrasonography after the first week of life if previous findings were normal in a child with previously diagnosed antenatal hydronephrosis before making a final determination that the hydronephrosis has resolved (see History).
• Voiding cystourethrography
• • The key to the workup of any child with antenatal hydronephrosis is voiding cystourethrography (VCUG). Perform VCUG during voiding and under fluoroscopy, with imaging of the posterior urethra.
  • The diagnosis of PUV is indicated by visualization of the valve leaflets. Other clues to the diagnosis are a thickened trabeculated bladder, a dilated or elongated posterior urethra, and a hypertrophied bladder neck (see Media files 1-2). Diverticula, cellules, vesicoureteral reflux, and reflux into the ejaculatory ducts secondary to elevated bladder and urethral pressures may also be present (see Media file 2).
• Renal scintigraphy
• • Although not necessary in every child, renal scintigraphy may be helpful in some cases. It should not be performed in the neonatal period because renal immaturity does not allow for accurate estimation of renal function. If renal dysplasia is suspected, nuclear imaging can determine relative renal function. Some children may have secondary ureterovesical junction obstruction due to bladder hypertrophy.
  • Tc-dimercaptosuccinic acid (DMSA), glucoheptonate, and mercaptoacetyl triglycine (MAG-3) renal scintigraphy are cortical imaging studies that provide information about relative renal function (each kidney relative to the other) and intrarenal function (eg, photopenic areas within the kidney indicate scarring or dysplasia). Additionally, the MAG-3 renal scan with furosemide (Lasix) provides information about renal drainage and possible obstruction.

Other Tests

• Urodynamic evaluation provides information about bladder storage and emptying. The mature bladder should store urine at a low pressure and then completely empty at appropriate pressures.
• The term "valve bladder" is used to describe patients with PUV and a fibrotic noncompliant bladder. These patients are at risk of developing hydroureteronephrosis, progressive renal deterioration, recurrent infections, and urinary incontinence.
• Patients with PUV require periodic urodynamic testing throughout childhood because bladder compliance may further deteriorate over time.

Procedures

• Cystoscopy serves both diagnostic and therapeutic functions in these infants. Appropriately-sized cystoscopes (<8F) are needed to avoid injury to the urethra.
• • Diagnostic cystoscopy: Confirmation with cystoscopy is required in every child in whom PUV is suggested after VCUG. In some, the filling defect observed on VCUG may represent only external sphincter contraction during voiding. In others, the valve leaflets are confirmed.
  • Therapeutic cystoscopy (ie, transurethral incision of the PUVs): Multiple techniques have been described for ablating the valves. Disruption of the obstructing membrane by blind passage of a valve hook is now only of historic interest. Currently, valves are disrupted under direct vision by cystoscopy using an endoscopic loop, Bugbee electrocauterization, or laser fulguration. The objective is to relieve the obstruction by cutting the valves at the 12-, 5-, and 7-o'clock positions. Perform this in the least traumatic fashion to avoid secondary urethral stricture or injury to the urethral sphincter mechanism.
• In some patients, the urethra may be too small for the available cystoscopic instrumentation. Fortunately, because of continued advancements in pediatric endoscopic equipment, this is an uncommon occurrence. When this situation arises, a temporary vesicostomy is performed.

TREATMENT

Section 6 of 11  

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Medical Care

The medical management of posterior urethral valves (PUVs) relates to the treatment of the secondary effects of the valves. Adequate care involves a team approach that includes a neonatologist, general pediatrician, pediatric urologist, and pediatric nephrologist. Short-term goals involve treating pulmonary distress, immediate relief of urethral obstruction (placement of 5F feeding tube), and fluid and electrolyte management. In children who survive the pulmonary distress, the long-term issues include treatment of bladder dysfunction and renal insufficiency.

• Renal treatment
• • Newborn period: Few patients present with bilateral renal dysplasia at birth. In the past, if patients did not die from associated pulmonary insufficiency, they died due to progressive renal insufficiency. With recent advances in peritoneal dialysis, some children may be treated successfully from birth. If growth is adequate, renal transplantation is often possible after the first year of life.
  • Delayed renal insufficiency: Approximately one third of patients with PUV progress to ESRD and the need for dialysis or transplantation. Progression of ESRD is accelerated at the time of puberty due to the increased metabolic workload placed on the kidneys. Growth in these children may be significantly below the reference range for the child's age. Adequate caloric intake and protein nutrition are essential to growth but may also accelerate the rise in serum creatinine levels. Renal dysfunction can be accelerated by recurrent infections and elevated bladder pressures. Treatment of the lower urinary tract may influence progression of upper tract disease.
• Bladder management
• • Newborn period: All male children with antenatal hydronephrosis require VCUG shortly after birth to exclude PUV. While awaiting this study, place a 5F or 8F urethral catheter to allow for bladder drainage. If valves are confirmed, they can be incised within the first few days of life. However, the newborn urethra may be too small to accommodate available equipment. In these individuals, a vesicostomy can be performed as a temporary solution until urethral growth has been adequate to allow transurethral incision. Secondary ureterovesical junction obstruction from bladder hypertrophy is a controversial issue. Supravesical urinary diversion procedures (eg, cutaneous ureterostomies) are reserved for patients who appear to have ureterovesical junction obstruction. This is very infrequent.
  • Delayed bladder management: Severe or prolonged urethral obstruction can lead to a fibrotic, poorly compliant bladder. This occurs when the developing bladder is exposed to high pressures from bladder outlet obstruction, leading to increases in bladder collagen deposition and detrusor muscle hypertrophy and hyperplasia. These bladders manifest poor compliance, leading to elevated storage pressures. This, in turn, leads to increased risk of reflux, hydroureteronephrosis, and urinary incontinence. Use of urodynamic testing to assess bladder compliance help identify patients at risk. Some patients may respond to anticholinergic medication, such as oxybutynin. Institution of intermittent clean catheterization may aid some patients achieve continence by preventing the bladder from overfilling. In patients who do not gain adequate bladder capacity and safe compliance despite optimal medical management, augmentation cystoplasty may be required.

Surgical Care

Surgical care of the patient with PUV varies according to age, bladder status, and renal status. Prenatal surgery has been reported in patients diagnosed with PUV with the goal of improving postnatal outcomes. Antenatal hydronephrosis is detectable only after renal development has occurred and urine production has started. With improvement in prenatal ultrasonography, the hope was that earlier intervention with vesicoamniotic shunting would improve postnatal renal function. However, identification of those patients who may benefit form early intervention remains elusive. To date, improvement in renal function has been difficult to demonstrate and prenatal intervention remains experimental.

• Urinary drainage
• • Postnatal primary valve ablation
  • • Ideal treatment involves transurethral incision of the PUV during the first few days of life.
    • Current infant resectoscopes are available in size 8F and smaller.
    • The valves can be incised at the 12-, 5-, and 7-o'clock positions, with either a cold knife or electrocautery.
    • Some surgeons prefer to leave a catheter in place for 2-3 days after the procedure.
    • The timing of the postoperative VCUG varies and ranges from several days to several months.
    • Comparison of posterior urethral diameter to anterior urethral diameter can provide an objective measure of valve ablation. In most patients, the posterior urethra is markedly dilated. Postincision diameter should decrease. 
    • The normal posterior-to-anterior urethral ratio is approximately 2.3. Approximately two thirds of patients have successful valve ablation with one procedure, manifested by a postincision ratio of 3.1 or less.⁶ One third of patients require a second incision to achieve this level of posterior urethral reduction.
  • Vesicostomy: When urethral size precludes safe valve ablation, a communicating channel between the bladder and lower abdominal wall (ie, vesicostomy) can be created to provide bladder drainage. Generally, an 18-20F stoma is created approximately midway between the pubis and umbilicus in the midline. Take care to bring the dome of the bladder to the skin and to limit the stomal size to prevent prolapse of bladder urothelium through the vesicostomy. However, formation of too small a stoma results in stomal stenosis and inadequate bladder emptying. Too large a stoma allows for bladder prolapse. Vesicostomy use has decreased because most patients can be safely drained and can undergo valve ablation.
  • Cutaneous ureterostomies: Bilateral cutaneous ureterostomies can also be placed to provide for urinary drainage. Techniques for cutaneous ureterostomy include end stomal ureterostomy, loop ureterostomy, Y-ureterostomy (in which the ureter is divided and one end is brought to the skin and the other is reanastomosed in a uretero-ureterostomy), and ring ureterostomy techniques. Potential complications of cutaneous ureterostomies include ureteral devascularization, inadequate drainage, and stomal stenosis. These are rare.
• Secondary bladder surgery
• • Augmentation cystoplasty
  • • Indications for bladder augmentation include inadequately low bladder storage volumes and high bladder pressures despite anticholinergic medication and clean intermittent catheterization.
    • The ileum is most commonly used; however, large bowel, stomach, and ureter are also used, depending on clinical conditions and surgeon preference.
    • Before undertaking the augmentation procedure, the implications of bladder augmentation should be carefully reviewed with parent and family. Augmentation should only be offered to patients willing to commit to lifelong intermittent catheterization.
    • Potential complications include bladder rupture (approximately 10% of patients); electrolyte disturbances, which may be worsened by the placement of intestinal mucosa in contact with urine, especially in those with a serum creatinine greater than 2 mg/dL; and mucus production, which can be a source of catheter blockage and may be a nidus for stone formation. 
    • The future risk of neoplasia has not yet been defined in these patients, but several cases of malignant degeneration in augmented bladder have been reported. Despite these risks, augmentation can significantly improve patient lifestyle in those who have intractable incontinence due to poor compliance and bladder overactivity. By lowering intravesical pressures, the upper urinary tract may also be protected.
  • Continent appendicovesicostomy: Also called the Mitrofanoff technique, this procedure involves placement of a nonrefluxing tubular conduit for catheterization between the bladder and skin to provide an alternative channel for catheterization. In children with PUVs, institution of intermittent catheterization through a sensate urethra can be difficult. In addition, some patients may have a very dilated proximal urethra which may not be easily catheterized. The stoma often can be hidden in the umbilicus to provide acceptable cosmesis. The appendix, ureter, and tubularized bowel can be used for formation of this channel.

Consultations

The child with PUV is best cared for using a team approach.

• Pediatrics and neonatology
• • The most life-threatening problem in the newborn period is the potential pulmonary hypoplasia related to in utero renal dysfunction. This may be associated with oligohydramnios. At birth, pneumothoraces may be present, thus complicating the pulmonary management.
  • Upon birth, new metabolic demands are made on the infant kidneys.
  • Urinary stasis and elevated detrusor pressures are risk factors for urosepsis in the newborn.
  • Generally, treatment is coordinated best by establishing a primary pediatrician or pediatric service to coordinate further referrals.
  • Additional pediatric subspecialty consultations often include a neonatal intensivist, a pediatric nephrologist, and a pediatric urologist.
• Radiology
• • Establishing the diagnosis is a priority in the newborn period.
  • Obtain VCUG with proper views of the posterior urethra.
  • Other required studies include a renal sonography and, at times, renal scintigraphy.
• Urology
• • In the newborn period, the first treatment intervention is achieving bladder drainage. Catheterization may be difficult or even impossible because of the thickness of the valves or dilation of the posterior urethra with a hypertrophied bladder neck (see Media file 1). Cystoscopic visualization with incision of the valves should be accomplished in the first few days of life once the child is metabolically stable.
  • After the initial newborn period and successful bladder drainage, either by valve incision or vesicostomy, long-term urologic care is needed. Renal deterioration secondary to progressive bladder dysfunction should be a primary goal and requires follow-up care with serial renal ultrasonographic and bladder urodynamic studies. Management is based on clinical findings, ranging from annual imaging to pharmaceutical management to bladder reconstruction.

Diet

Dietary restrictions depend on renal status.

• Avoiding progression of renal deterioration while supporting growth requires careful regulation of protein intake, which is best managed under the care of a pediatric nephrologist.
• In the absence of renal insufficiency, no modification of diet is needed.

Activity

Unless complications such as renal insufficiency occur, activity can generally remain unrestricted. Urinary incontinence may present a social barrier. This can often be managed with anticholinergic therapy with or without clean intermittent catheterization.

MEDICATION

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Posterior urethral valves (PUVs) initially represent a surgical condition. However, long-term treatment often comprises a combination of medical and surgical treatment, primarily directed at the bladder. The primary medications involved in bladder management are anticholinergic medications used to improve bladder compliance. Other medications that may be needed include prophylactic antibiotics and medications for management of renal insufficiency.

Drug Category: Anticholinergic agents

These agents are used to improve bladder capacity and compliance in the patient with elevated detrusor pressures leading to hydronephrosis, UTI, or incontinence.

Drug Category: Antibiotics

Patients with history of recurrent UTI may benefit from antibiotic prophylaxis, especially in the presence of vesicoureteral reflux. The ideal antibiotic for urinary prophylaxis is safe, effective, inexpensive, and has no adverse effects. Although no antimicrobial is ideal, some are preferred in children. Prophylactic dosage is usually one quarter of the therapeutic dose administered once per day. Too high a dose increases adverse effects (eg, GI upset) and may alter fecal flora. More appropriate antibiotics in children include trimethoprim (TMP), sulfamethoxazole (SMZ), nitrofurantoin, and amoxicillin.

FOLLOW-UP

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Further Outpatient Care

Posterior urethral valves (PUVs) represent a lifelong disorder that can have a profound effect on the entire urinary tract. As such, patients need periodic long-term urologic follow-up care. The status of the kidneys determines the need for additional specialty follow-up care (eg, with a pediatric nephrologist).

• Resolution of obstruction: Relief of bladder outlet obstruction is the first step in treatment. After incision of the valves, a repeat VCUG or repeat cystoscopy 1-3 months later confirms valve resolution and urethral healing. These patients may also be at risk of subsequent urethral stricture formation; repeat these studies at any point in the future if any recurrent bladder outlet obstruction is indicated.
• Urodynamics: Chronic changes, which can lead to elevated intravesical pressures, may occur in the bladder of patients with PUV. This leads to upper tract changes, urinary incontinence, and recurrent UTI. These patients may need periodic urodynamic studies to determine bladder capacity, compliance, and postvoid residual urine volumes. In older children, uroflow and bladder scanning may be a less invasive way to monitor bladder dynamics.
• Upper tract changes: Patients may have baseline renal dysplasia. Elevated bladder pressures and recurrent UTI further may compromise renal function. Obtain periodic renal sonography and serum creatinine levels. Severity of the renal and bladder dysfunction determines the frequency of these studies.
• Urinary incontinence: Approximately one third of patients with PUVs have problems with diurnal enuresis when older than 5 years. Diurnal enuresis may be caused by the bladder changes that lead to elevated storage pressures and poor emptying. Rarely, sphincteric dysfunction secondary to valve ablation can be present. Treatment includes anticholinergic medication, intermittent catheterization, and, in some patients, bladder augmentation.

In/Out Patient Meds

• Because PUV is a lifelong condition due to an anatomic anomaly, medications may be necessary for years to suppress symptoms of infection or enuresis. All of the medications listed above are intended for long-term use.

Transfer

• Newborn care
• • In the newborn with PUV, the first step in treatment is relief of bladder outlet obstruction by placement of a urethral catheter.
  • Cystoscopic valve ablation or vesicostomy can then be performed when the child is stable.
  • Rarely, a urethral catheter cannot be placed because of hypertrophy of the bladder neck (see Media file 1). These patients require cystoscopy under anesthesia for catheter placement, suprapubic tube placement, or primary vesicostomy.
  • Therefore, care of the newborn depends on having adequate instrumentation (eg, pediatric cystoscopic equipment) and expertise (eg, pediatric radiologist, pediatric urologist, pediatric anesthesiologist). If these services are unavailable, place a catheter (if possible) and transfer the child to an appropriate facility.
• Care of the older child
• • Care of the older child also requires adequate equipment and expertise.
  • Periodic radiologic and urodynamic evaluation is important to monitor the upper urinary tract and bladder changes. These evaluations occur over an extended period of time and rarely constitute an emergency.
  • These patients require a timely referral to a center where appropriate services are available.

Deterrence/Prevention

• Because PUV is a congenital anomaly of unknown origin, it is not preventable.
• Subsequent renal deterioration and bladder changes can be treated and minimized with adequate follow-up care.

Complications

• In the newborn
• • Pulmonary hypoplasia secondary to intrauterine renal dysfunction and oligohydramnios is the primary cause of patient death.
  • Other complications of PUV are generally secondary to chronic bladder changes, leading to elevated detrusor pressures.
  • This, in turn, leads to progressive renal damage, infection, and incontinence.
• Renal insufficiency
• • Historically, of those patients with adequate pulmonary function, approximately 25% died of renal insufficiency in the first year of life, 25% died later in childhood, and 50% survived to adulthood with varying degrees of renal function.
  • Today, with the advent of better techniques in the treatment of pediatric renal insufficiency, most of these children can be expected to survive.
  • The goal of treatment is to preserve the maximal obtainable renal function for each patient. This entails aggressive treatment of infections and bladder dysfunction.
• Vesicoureteral reflux
• • Vesicoureteral reflux is commonly associated with PUVs and is present in as many as one third of patients (see Media file 2).
  • Vesicoureteral reflux in most children is believed to be due to an insufficient intravesical ureter.
  • When associated with PUV, reflux is generally secondary to elevated intravesical pressures.
  • Therefore, the treatment of vesicoureteral reflux in patients with PUVs involves treatment of intravesical pressures using anticholinergics, timed voiding, double voiding, intermittent catheterization, and, at times, bladder augmentation.
• Urinary tract infections
• • Recurrent UTIs are common in patients with PUV.
  • Elevated intravesical pressures predispose patients to infection, possibly by altering urothelial blood flow.
  • Additionally, patients with PUV may have elevated postvoid residual urine volumes, leading to stasis of urine.
  • Dilated upper urinary tracts, with or without vesicoureteral reflux, further elevate UTI risk.
  • UTI management is directed at lowering bladder pressures (anticholinergic medication), lowering postvoid residual urine volume (via clean intermittent catheterization), and at times, administering prophylactic antibiotics.
• Urinary incontinence
• • The same factors that lead to vesicoureteral reflux and UTI also lead to urinary incontinence.
  • Correct management of bladder function depends on adequate bladder evaluation with urodynamic studies.
  • Lowering bladder pressure, improving bladder compliance, and minimizing postvoid residual urine volume contribute to attainment of urinary continence.
  • In some, bladder augmentation may be needed.

Prognosis

• The prognosis of children with PUV is continually improving.
• In the past, most children were found to have PUV only after presenting with urosepsis or progressive renal insufficiency. Older series demonstrated mortality rates approaching 50% by late adolescence.
• Today, most individuals with PUV are discovered when prenatal ultrasonography reveals hydronephrosis.
• • Prompt resolution of bladder obstruction, aggressive treatment of bladder dysfunction, and improved surgical techniques have lowered the neonatal mortality rate to less than 3%.
  • Approximately one third of patients progress to renal insufficiency in their lifetimes. Improved dialysis and transplantation techniques have significantly improved not only the mortality rate for these children but also their quality of life.
  • Additionally, medical and surgical management can achieve urinary continence in nearly all patients.
• An interesting group of patients are those with vesicoureteral reflux dysplasia (VURD) syndrome. In these patients, one kidney is hydronephrotic, nonfunctioning, and has high-grade vesicoureteral reflux. The high-grade reflux is thought to act as a pop-off valve, leading to reduced overall bladder pressures and preservation of contralateral renal function. In the past, these patients were thought to have a better outcome due to preserved renal function in one kidney at the sacrifice of the other. More recent data by Narasimhan et al suggests that, although short-term serum creatinine levels may be favorable, these patients may suffer long-term adverse renal function with hypertension, proteinuria, and renal failure.⁷ In the long run, VURD syndrome may not have the favorable outcome it was once thought to have.

Patient Education

• PUV is a lifelong condition that requires continued medical management. Because of this, both the physician and family must understand the potential long-term complication of renal deterioration if bladder function is not adequately treated.
• Patients and families need realistic expectations regarding continence. Although achievable in nearly all patients, continence often depends on adherence to a timed voiding schedule and intermittent catheterization.
• Patients and families must also realize that medications, such as anticholinergics and suppressive antibiotics, are for control of the symptoms of PUV and are not curative.
• For excellent patient education resources, visit eMedicine's Kidneys and Urinary System Center. Also, see eMedicine's patient education article Bladder Control Problems.

MISCELLANEOUS

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Medical/Legal Pitfalls

Several publications have suggested aggressive evaluation of pediatric UTIs.

• Often, a UTI may be the only sign of significant underlying urologic pathology.
• Although most patients with posterior urethral valves (PUVs) are identified because of abnormal prenatal ultrasonography findings, a significant number present later in life with symptoms of UTI or diurnal enuresis recurring or persisting in children older than 5 years. Because of this, the author recommends that any male child older than 5 years with a documented UTI or diurnal enuresis undergo renal and bladder sonography and VCUG.

Special Concerns

• The primary special concerns involved with patients with PUV pertain to the issues of upper urinary tract preservation, UTI, and diurnal urinary incontinence, all of which are secondary to decreased bladder compliance.
• Remember that PUV is a dynamic disease that can have lifelong effects on the bladder. These patients need long-term follow-up care to monitor and treat the effects of altered bladder compliance.

MULTIMEDIA

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Media file 1:  Note hypertrophied bladder neck and dilated posterior urethra proximal to valve narrowing.
	View Full Size Image
Media type:  Radiograph

Media file 2:  Note irregular trabeculated bladder and high-grade vesicoureteral reflux.
	View Full Size Image
Media type:  Radiograph

REFERENCES

Section 11 of 11

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Article Last Updated: Jun 12, 2008