Posterior Urethral Valve

Fig. 70.1
a Micturating cystourethrogram showing dilated bladder with no vesicoureteric reflux. Note the dilated posterior urethra indicative of posterior urethral valve. b micturating cystourethrogram showing a dilated posterior urethra indicative of posterior urethral valve
A321246_1_En_70_Fig2_HTML.gif
Fig. 70.2
a and b Micturating cystourethrogram showing dilated posterior urethra indicative of posterior urethral valve. Note the marked right sided and left sided vesicoureteric reflux
  • Visualization of the valve leaflets
  • A thickened trabeculated urinary bladder
  • A dilated or elongated posterior urethra
  • A hypertrophied bladder neck
  • The presence of diverticula, vesicoureteral reflux, and reflux into the ejaculatory ducts
  • Very thickened hypertrophied urinary bladder wall which may lead to secondary ureterovesical junction obstruction
  • Renal scintigraphy
    • Tc-dimercaptosuccinic acid (DMSA) and mercaptoacetyltriglycine (MAG-3) renal scintigraphy provide information about relative renal function and areas of scarring or dysplasia.
    • MAG-3 renal scan with furosemide (Lasix) also provides information about renal drainage and possible obstruction.
  • Urodynamic evaluation:
    • Provides information about bladder storage and emptying.
    • 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 evaluation throughout childhood because bladder compliance may further deteriorate over time.
  • Cystoscopy: serves both diagnostic and therapeutic functions.
    • Diagnostic cystoscopy:
      • ◦ Confirm the diagnosis
    • Therapeutic cystoscopy:
      • ◦ Transurethral incision of the PUV.
      • ◦ Multiple techniques have been described for ablating the valves.
      • ◦ Currently, valves are disrupted under direct vision by cystoscopy using an endoscopic loop, Bugbee electro cauterization, or laser fulguration.
      • ◦ In extremely small infants (< 2000 g), a 2F Fogarty catheter may be passed either under fluoroscopic or under direct vision for valve disruption.
      • ◦ In some patients, the urethra may be too small and a temporary vesicostomy is performed.

      Secondary effects of PUV:

      • Vesicoureteral reflux (Fig. 70.3)
        A321246_1_En_70_Fig3_HTML.jpg
        Fig. 70.3
        Micturating cystourethrogram showing vesicoureteric reflux (left), which is severe in the second picture (right)
        • Vesicoureteral reflux is commonly associated with PUV and is present in as many as one third of patients .
        • When associated with PUV, reflux is generally secondary to elevated intravesical pressures.
        • The treatment of vesicoureteral reflux in patients with PUV involves treatment of intravesical pressures using :
          1.
          Anticholinergics
           
          2.
          Timed voiding
           
          3.
          Double voiding
           
          4.
          Intermittent catheterization
           
          5.
          Bladder augmentation
           
      • UTIs
        • Recurrent UTIs are common in patients with PUV. These are secondary to :
          1.
          Elevated intravesical pressures
           
          2.
          Increased post void residual urine volumes, leading to stasis of urine.
           
          3.
          Dilated upper urinary tracts, with or without vesicoureteral reflux.
           
        • UTI management is directed at:
          1.
          Lowering bladder pressures (anticholinergic medication)
           
          2.
          Lowering post void residual urine volume (via clean intermittent catheterization)
           
          3.
          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.
        • These include:
          1.
          Lowering bladder pressure.
           
          2.
          Improving bladder compliance.
           
          3.
          Minimizing post void residual urine volume.
           
          4.
          In some, bladder augmentation may be needed .
           

      Pathophysiology

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      Mar 8, 2017 | Posted by in PEDIATRICS | Comments Off on Posterior Urethral Valve

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