Posterior Urethral Valves Treatment & Management
- Author: Martin David Bomalaski, MD, FAAP; Chief Editor: Marc Cendron, MD more...
In newborns with posterior urethral valves (PUVs), the first step in treatment is to relieve bladder outlet obstruction by placing a urethral catheter. Cystoscopic valve ablation or vesicostomy can then be performed when the child is stable. in rare cases, a urethral catheter cannot be placed, because of hypertrophy of the bladder neck. 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.
Medical management of PUVs relates to treatment of the secondary effects of the valves. Adequate care involves a team approach that includes a neonatologist, a general pediatrician, a pediatric urologist, and a pediatric nephrologist. Short-term goals involve treatment of pulmonary distress, immediate relief of urethral obstruction (placement of a 5-French 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.
Few patients present with bilateral renal dysplasia at birth. In the past, if patients did not die of associated pulmonary insufficiency, they died of progressive renal insufficiency. Advances in peritoneal dialysis have made it possible for some to may be treated successfully from birth. If growth is adequate, renal transplantation is often possible after the first year of life.
Approximately one third of patients with PUVs eventually progress to end-stage renal disease (ESRD) and will require dialysis or transplantation. Progression of ESRD is accelerated at the time of puberty as a consequence of 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.
All male children with antenatal hydronephrosis should undergo voiding cystourethrography (VCUG) shortly after birth to exclude PUV. While awaiting the study results, place a 5- or 8-French 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 uncommon.
Later in childhood, 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 of the patient with PUV varies according to age, bladder status, and renal status. Antenatal 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 antenatal ultrasonography, the hope was that earlier intervention with vesicoamniotic shunting would improve postnatal renal function. However, identification of those patients who may benefit from early intervention remains elusive. To date, improvement in renal function has been difficult to demonstrate, and antenatal intervention remains experimental.
Urinary drainage may be accomplished by means of postnatal primary valve ablation, vesicostomy, or cutaneous ureterostomies.
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 8 French and smaller sizes. The valves can be incised at the 12-, 5-, and 7-o'clock positions, with either a cold knife or an 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 the posterior urethral diameter with anterior urethral diameter can provide an objective measure of valve ablation. In most patients, the posterior urethra is markedly dilated. Postincision diameter should decrease if the incision is successful. 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. One third of patients require a second incision to achieve this level of posterior urethral reduction.
Because approximately one third of patients will require a second valve incision, some authors recommend routine surveillance cystoscopy 1-2 months after the initial incision to evaluate and treat any residual valvular obstruction.
In a study by Shirazi et al, factors significantly associated with a higher incidence of obstructive remnant leaflets after valve ablation for PUV included the following :
Younger age at the time of surgery
Hyperechogenicity of renal parenchyma
Presence of vesicoureteral reflux (VUR)
Grade 4 or 5 reflux preoperatively
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- to 20-French stoma is created approximately midway between the pubis and the 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. Formation of too small a stoma results in stomal stenosis and inadequate bladder emptying; formation of too large a stoma allows for bladder prolapse. Vesicostomy use has decreased because most patients can be safely drained and can undergo valve ablation.
Bilateral cutaneous ureterostomies can also be placed to provide for urinary drainage. Techniques for cutaneous ureterostomy include the following:
End stomal ureterostomy
Y-ureterostomy (in which the ureter is divided and one end is brought to the skin and the other is reanastomosed in a ureteroureterostomy)
Potential complications of cutaneous ureterostomies, all of which are rare, include the following:
Secondary bladder surgery
Secondary bladder surgery takes the form of augmentation cytoplasty or continent appendicovesicostomy.
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, the large bowel, stomach, and ureter are also used, depending on clinical conditions and surgeon preference.
Before an augmentation procedure is undertaken, 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 the following:
Bladder rupture (~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
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. Augmentation cytoplasty does not appear to have an adverse effect on overall renal outcome in PUV patients who undergo kidney transplantation, though it is associated with a higher incidence of recurrent urinary tract infection (UTI).
Despite these risks, augmentation can significantly improve patient lifestyle in those who have intractable incontinence as a consequence of poor compliance and bladder overactivity. By lowering intravesical pressures, the upper urinary tract may also be protected.
Also called the Mitrofanoff technique, continent appendicovesicostomy involves placing 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 highly dilated proximal urethra that 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.
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.
Historically, of 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.
Certain risk factors for progression of PUV have been identified. Elevated nadir creatinine defined as greater than 1 mg/dL measured during the first year of life has been identified as a risk factor for development of future renal insufficiency. Additionally, bladder dysfunction with poor compliance, elevated leak point pressures, and the need for clean intermittent catheterization have been identified as predictive of eventual renal deterioration.
VUR (see the image below) is commonly associated with PUVs and is present in as many as one third of patients. In most children, VUR is believed to be due to an abnormal insertion of the ureter into the bladder. When associated with PUV, reflux is generally secondary to elevated intravesical pressures. Therefore, the treatment of VUR 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 PUVs. 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 VUR, 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.
The same factors that lead to VUR 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.
Dietary restrictions depend on renal status. Avoiding the 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.
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.
Because PUV is a congenital anomaly of unknown origin, it is not preventable. Urinary organogenesis occurs around week 8 of gestation, long before imaging can accurately assess anatomy. Urinary tract dilation is generally not detectable until approximately week 18 of gestation.
Subsequent renal deterioration and bladder changes can be treated and minimized with adequate follow-up care.
The child with PUV is best cared for by employing a team approach.
Pediatrician and neonatologist
The most life-threatening problem in the newborn period is the potential pulmonary hypoplasia related to renal dysfunction in utero. 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.
Establishing the diagnosis is a priority in the newborn period. Obtain VCUG with proper views of the posterior urethra. Other required studies include renal ultrasonography and, at times, renal scintigraphy.
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. 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 by 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.
Should the child display evidence of renal failure, input from a nephrologist is helpful in managing electrolyte imbalances, acidosis, and diet. In more severe cases, the nephrologist addresses dialysis issues and coordinates a possible renal transplantation.
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). Medications may be necessary for years to suppress symptoms of infection or enuresis. All of the medications listed in the Medication section are intended for long-term use.
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 symptoms are reported.
Long-term 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 (cystometrography).
In older children, uroflow and bladder scanning may be a less invasive way to monitor bladder dynamics. Noninvasive monitoring with voiding diary, uroflowmetry, ultrasonographic evaluation of residual urine, and serum creatinine measurement is acceptable, with more invasive cystometry and pressure/flow studies being reserved for those patients who manifest progressive deterioration.
Upper tract changes
Patients may have baseline renal dysplasia. Elevated bladder pressures and recurrent UTI further may compromise renal function. Obtain periodic renal sonograms and serum creatinine levels. The frequency of these studies is determined by the severity of the renal and bladder dysfunction.
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.
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