eMedicine Specialties > Pediatrics: Surgery > Urology

Posterior Urethral Valves: Treatment & Medication

Author: Martin David Bomalaski, MD, FAAP, Pediatric Urologist, Alaska Southcentral Urology Specialists
Contributor Information and Disclosures

Updated: Jun 12, 2008

Treatment

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

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.

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.

Oxybutynin chloride (Ditropan)

Inexpensive and effective, oxybutynin chloride long has been the first-line anticholinergic. By inhibiting muscarinic action of acetylcholine on smooth muscle, exerts antispasmodic effect on bladder muscle. Its nonselective anticholinergic action increases adverse effects; however, it may produce fewer adverse effects if dosing is gradually increased over >2 wk. Available in both 5-mg tab and 5-mg/5-mL elixir. A long-acting 10-mg tab with once-a-day dosing was recently introduced but is expensive and has been approved only for adults.

Hyoscyamine sulfate (Levbid, Levsin)

Works by inhibiting postganglionic cholinergic receptors on smooth muscle cells. Rapidly absorbed and distributed throughout body, including across blood-brain barrier. Half-life is 3.5 h; excreted unchanged in urine.
Available in PO, IV, and SL forms; tab generally used for treatment of PUV. Time-release formulation available. Elixir and drops available.

Tolterodine (Detrol)

A new antimuscarinic drug with more selective receptor profile targeted for detrusor smooth muscle. Used extensively in adults but not approved by FDA for children. In adults, demonstrated equal in efficacy to oxybutynin chloride with significantly fewer adverse effects. Available in 1- and 2-mg tab.

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.

Trimethoprim and sulfamethoxazole (Bactrim, Septra, Cotrim)

Inhibits bacterial growth by inhibiting synthesis of dihydrofolic acid. TMP alone or in combination with SMZ is the most commonly used antibiotic for both treatment and prophylaxis of UTI. Inexpensive and has minimal adverse effects on bowel and vaginal flora because excreted and concentrated in urine. Pediatric susp (40 mg TMP and 200 mg SMZ per 5 mL) available.

Nitrofurantoin (Furadantin, Macrodantin, Macrobid)

Synthetic nitrofuran that interferes with bacterial carbohydrate metabolism by inhibiting acetylcoenzyme A. Bacteriostatic at low concentrations (5-10 mcg/mL) and bactericidal at higher concentrations.
Another common prophylactic antimicrobial agent, which is also excreted in urine, allowing urinary levels to be high while having few effects on fecal flora. Inexpensive and comes in both liquid and tab preparations. Rarely, associated with peripheral neuropathy and pulmonary hypersensitivity. SR formulation available; liquid susp (25 mg/5 mL) also available.

Amoxicillin (Trimox, Amoxil)

Interferes with synthesis of cell wall mucopeptides during active multiplication, resulting in bactericidal activity against susceptible bacteria. Used as prophylaxis in certain PO, GI, or genitourinary procedures.

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