Posterior urethral valve

An Overview of Posterior Urethral Valve

1. Posterior Urethral Valve Dr. M. YIGAH

2. Introduction It is a congenital condition characterized by the presence of abnormal obstructing urethral membranes in the proximal urethra . Commonest cause of bladder outlet obstruction in infants Abnormal development of the wolffian and müllerian ducts based on an autopsy study The presentation of posterior urethral valves is often antenatal, and pathognomonic findings on postnatal imaging confirm the diagnosis Surgical procedure may be short but the management may be life-long the embryonic insults to the bladder, kidneys and other organs can be life-long

3. Epidemiology In the UK 1 out of every 500 pregnancies has an anomaly of the urinary tract. The incidence of lower urinary tract obstruction (LUTO) in the UK is 2.2 per 10,000 births , Incidence of PUV in the UK is 1.4 per 10,000 births. In the US incidence ranges from 1 per 8000 to 1 per 25,000 live births . In Nigeria There were 3–8 reported cases per annum (Uba et al, 2007) A hospital in Port Harcourt observed that it accounted for 1 in 2,447 children (Jaja et al, 2012) 71% were already in renal failure at presentation ( Odetunde et al, 2012) It affects male babies

4. Hugh Hampton Young Historical Overview Valve-like leaflets was recognized in1769 by Morgagni Post-mortem findings were confirmed by Langenbeck in 1802. Hugh Hampton Young described the first endoscopic diagnosis of a urethral obstruction that was termed posterior urethral valves. Also described the various types of PUV Randall carried out the first endoscopic resection of valves in 1920

5. Gross Anatomy of the Urethra

6. Pathology “ The prostatic urethra is markedly dilated. The vesical neck raised and bladder orifice relaxed. Deep pittings penetrate down into either lateral wall of the prostatic urethra and at the extremity the verumontanum is seen a fine frenulum which extends distally for about 1 cm, and in dividing, forms what is apparently a definite valve on either side of the urethra, rising from the floor to each side wall. Randall carried out the first endoscopic resection of valves in 1920” Randall 1921

7. Pathology Crescentic duplication of the urethral mucosa forming paper-thin valves arise from the verumontanum and extend downward and laterally to the side walls of the urethra at apex of the prostate. There may be no hinderance to retrograde instrumentation but the valves come together to obstruct the flow of urine Prostatic urethra becomes dilated Bladder hypertrophy with trabeculations, sacculations and diverticula Hydroureter and hydronephrosis

8. Type 1 PUV The mucosal folds extending anteroinferiorly from the caudal aspect of the verumontanum often fusing anteriorly at a lower level like the membranous urethra. 95% of PUV

9. Type 2 PUV Bicuspid valves as leaflets radiating from the verumontanum proximally to the bladder neck

10. Type 3 PUV Valves as concentric diaphragms within the prostatic urethra, either above or below the verumontanum (~5% of PUVs)

11. Pathophysiology A vicious cycle of obstructive uropathy and renal dysplasia. Dam of urine in the bladder and upper segments of the urinary tree. Thickened bladder wall with reduced bladder compliance ( remodelling of the bladder) Vesicoureteric reflux Hydroureters and Hydronephrosis Progressive renal calyceal dilatation and renal damage Impairment of concentration of urine by the renal tubules Polyuria Worsening bladder dysfunction - end-stage bladder, or Bladder valve syndrome . Worsening renal function leading to ESKD.

12. Diagnosis Clinical Features Maternal signs of oligohydramnios Physical stigmata of oligohydramnios Potter facies Clubfeet and deformed hands, and poor abdominal muscle tone. Failure pass urine after birth Infant may pass urine with weak stream with intermittency The bladder is distended and the kidneys may be palpable An infant affected by PUV may be affected by comorbidities such as Pulmonary hypoplasia – tachypnoea, poor respiratory effort, cyanosis Urinomas – neonatal ascites, respiratory distress

13. Diagnosis Clinical Features (Delayed Presentation) Recurrent Urinary tract infection (UTI) Diurnal enuresis in boys older than 5 years Secondary diurnal enuresis Voiding pain or dysfunction Abnormal urinary stream Poor growth, hypertension, and lethargy PUVs are sometimes discovered during evaluation of abdominal mass or renal failure

14. Diagnosis Ultrasonography Some of the cardinal features of a LUTO are thickened, dilated bladder along with bilateral hydroureter and pelvocaliectasis Oligohydramnios Dilated posterior urethra displaying the “keyhole sign” Increased renal echogenicity in PUV is an indicator of renal damage. Very difficult to differentiate PUV from other causes of LUTO like urethral atresia or prune-belly syndrome, bilateral primary obstructing megaureters

15. Diagnosis Voiding Cystourethrography Definitive radiologic study in confirming the diagnosis of posterior urethral valves. Visualization of bladder leaflets The bladder often appears thickened and trabeculated with multiple diverticuli. Hypertrophied bladder neck High-grade vesicoureteral reflux may be seen Radionuclide Renal Scan The radionuclide renal scan offers quantification of differential renal function Cortical deficits seen on the study may imply renal dysplasia

16. Voiding Cystourethrography

17. Diagnosis Supportive Investigation BUE and Cr Chest Xray FBC Urine RE and CS

18. Chest Xrays Bronchopulmonary dysplasia Reduced lung volume left upper and lower lobe atelectasis

19. Differential diagnosis Anterior urethral valves Urethral stricture disease Detrusor sphincter dyssynergy Diurnal urinary incontinence Pediatric renal insufficiency Urinary tract infection

20. Treatment The treatment goals are To restore flow of urine through the urethra and enable normal cyclic filling and emptying of the bladder, which is superior to urinary diversion and passive urine drainage. Halt the deterioration of renal function Prevent complications of PUV Improve the quality life

21. Surgical Interventions Cystoscopy with Valve Ablation The preferred initial surgical option in any neonate diagnosed with posterior urethral valves There a various sizes 7.5- or 9-Fr infant cystoscope and can be done in the smallest neonates The cystoscope is assembled with an ablating device which can be a cold knife or an electrocaultery Example; Collins knife working, Bugbee electrode The valves are incised at the ventral 5 and 7 o’clock positions with or without an incision at the dorsal 12 o’clock position Avoid aggressive resection to prevent strictures from developing

22. Before and After Ablation of PUV

23. Cystoscopy with Valve Ablation Cystoscopy with Valve Ablation A urethral catheter is typically placed for at least 24 hours after the procedure. Baby is monitored post-op for improvements in renal parameters or respiratory issues VCUG must be repeated after valve ablation within 1 month to ensure that the valves are no longer visible.

24. Surgical Interventions Vesicostomy very low-birth-weight infant whose urethra cannot accommodate an endoscope Continued impaired renal function, high bladder urine volumes, and upper tract deterioration after valve ablation or urethral catheterization

25. Vesicostomy

26. Vesicostomy

27. Surgical Interventions Upper Tract Diversion Cutaneous ureterostomy or Pyelostomy It was believed direct decompression of the kidneys will produce direct, low-pressure urinary drainage, allowing optimization of renal function. It is complex and not better than the lower urinary diversion. It not just about the diversion but also about the renal dysplasia Circumcision vesicoureteral reflux, incomplete bladder emptying, and severe upper urinary tract dilation predispose to Pyelonrphritis Circumcision reduces that risk of urinary tract infection by 83% to 92%, a reduction to a level of risk similar to that for unaffected boys ( Wiswell et al, 1988; Mukherjee et al, 2009)

28. Antenatal Surgical Interventions Antenatal interventions are considered when Oligohydramnios, Dilated bladder Severe hydroureteronephrosis without renal cortical cystic lesions Normal karyotype. Vesicoamniotic shunting Foetal cystoscopy with valve ablation Cutaneous ureterostomy vesicostomy

29. Prognostic Factors Serum Creatinine at 1 year of life and (1 month post treatment) Cr < 0.8 mg/dL appears to indicate a minimal risk Cr > 1.2 mg/dL higher risk of developing end-stage renal failure Age at diagnosis Renal dysplasia Hyperechogenic kidneys, cystic cortical changes & loss of corticomedullary differentiation Recurrent urinary tract infections Bladder dysfunction.

30. Quality of Life Patients with posterior urethral valve have a lifetime of repercussion. Erectile dysfunction Infertility. Persistence of lower urinary tract symptoms – urgency, frequency, incontinence. Increased risk of UTI. Development of end stage kidney disease. Associated co-morbidities of renal transplantation.

31. References Uba AF, Chirdan LB, Ihezue CH, Ramyil VL, Dakum NK. Posterior urethral valves in chilhood : Experience in a centre with scarce facilities. Afr J Urol. 2007;13:124–31. Jaja T, Anochie IC, Eke FU. Posterior urethral valve in childhood in Port Harcourt, Nigeria. Port Harcourt Med J. 2012;6:10–6. Odetunde OI, Odetunde OA, Ademuyiwa AO, Okafor HU, Ekwochi U, Azubuike JC, et al. Outcome of late presentation of posterior urethral valves in a resource-limited economy: Challenges in management. Int J Nephrol 2012. 2012 345298 Baja Medscape