Etiopathogenesis, Evaluation & Management of Posterior Urethral Valve
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Transcript of Etiopathogenesis, Evaluation & Management of Posterior Urethral Valve
Etiopathogenesis, evaluation & Mx of PUV
Dr. Shubham Lavania
20/05/2016
Introduction
• A congenital obstruction of the posterior urethra ascribed to valvelike leaflets
– 1769 by Morgagni
– Langenbeck in 1802
– Hugh Hampton Young coined “posterior urethral valve”(1919)
– Randall carried out the first endoscopic resection of valves in 1920
Incidence
• The most common structural cause of urinary
outflow obstruction in pediatric practice
• The most common type of obstructive uropathy
leading to childhood renal failure
• 1 of every 5000 to 8000 male births
• 10% of prenatally diagnosed hydronephrosis
• 1 PUV in 1250 fetal ultrasound
CLASSIFICATION
• Young classification 1919
PUV Defined
• Type I– Obstructing membrane that extends distally from each
side of the verumontanum towards the membranous urethra where they fuse anteriorly
• Type II– Described as folds extending cephalad from the
verumontanum to the bladder neck
• Type III– Represent a diaphragm or ring-like membrane with a
central aperture just distal to the verumontanum– Thought to represent incomplete dissolution of the
urogenital membrane
95% 5%
more serious
Type 1 PUV
• Develop when the mesonephric ducts enter the cloaca more anteriorly than normal.
Type 3 PUV
• Incomplete dissolution of the urogenital membrane
Pathophysiology
Primitive tissues mature in an abnormal environment of high intraluminal pressures and organ distention
• UNIVERSAL INJURY
IN THE URINARY
TRACT
Renal Dysplasia
• Defined as a congenital defect of tissue development without premalignant potential
• Histological diagnosis
• Cause ? 1- high pelvic pressure during
nephrogenesis2- primary embryologic abnormality
from abnormal position of uteteric bud
Renal Function
• Children with PUV may demonstrate gradual loss of renal function over time
• Cause:1- Renal parenchymal dysplasia2- Incomplete relief of obstruction3-parenchymal injury from :* UTI*HTN*Progressive glomerulosclerosis
from hyperfiltration* Obstruction
• ESRD
-Occurs in 25% - 40%
-1/3 soon after birth
-2/3 during late teenager
Renal Tubular Function
• 50% of patients with PUV have impairment concentration ability
• Persistently high urinary flow rate regardless of fluid intake or state of hydration
• severe dehydration and electrolyte imbalance
• ureteral dilatation and high resting vesicalpressure
Hydronephrosis
• Significant urethral obstruction variable degree of ureteral dilatation
• After relief of obstruction : gradual but substantial reduction of hydronephrosis
• If not reduced we have to role out:1- High intravesical pressure 2- ureteral muscle weakness 3- UVJ obstruction
Vesicoureteral Reflux
• Present in 33 - 50%
• Usually Secondary
– High intravesical pressures
• 33% resolve spontaneously when obstruction treated
• 33% do well on prophylactic antibiotics
BLADDER DYSFUNCTION
• Commonly presented in patient with PUV
• Usually primary, secondary to irreversible
change in organization and function of the
smooth muscle from outlet obstruction
• Present as urinary incontinence (20%)
• Bladder dysfunction persist in 75 % after valve
ablation
• May cause deterioration of renal function
• Three groups of dysfunction were described
- Detrusor –hyperreflexia (29%)
- Hypertonic and poor compliant bladder
(31%)
- Myogenic failure and overflow
incontinence (40%)
Valve Bladder Syndrome
• The term valve bladder syndrome was coined by Mitchell in 1982
• Factors responsible for devolution of a bladder into a valve bladder
(1) polyuria.
(2) poor bladder compliance with high-pressure voiding and elevated wall tension bladder, and
(3) residual urine volume.
Clinical Presentation
• Varies by degree of obstruction
– Symptoms vary by age of presentation
• Antenatal
– Bilateral hydronephrosis
– Distended and thickened bladder
– Dilated prostatic urethra
– Oligohydramnios - accounts for co-presentation of pulmonary hypoplasia.
Clinical Presentation
• Newborn– Palpable abdominal mass
• Distended bladder, hydronephrotic kidney• Bladder may feel like a small walnut in the suprapubic area
– Ascites• 40% of time due to obstructive uropathy
– History of Oligohydramnios– Respiratory distress from pulmonary hypoplasia
• Severity often does not correlate with degree obstruction• Primary cause of death in newborns
Clinical Presentation
• Early Infancy– Dribbling / poor urinary stream– Urosepsis– Dehydration– Electrolyte abnormalities– Uremia– Failure to thrive; due to renal insufficiency
• Toddlers– Better renal function (less obstruction)– Febrile UTI– Voiding dysfunction – incontinence– Daytime incontinence may be the only symptom in boys with
less severe obstruction
Diagnosis
Ultrasonography
• 1 in 1250 ultrasound screenings
• pathognomonic u/s findings:
– thickened, dilated bladder along with bilateral
hydroureter and pelvocaliectasis
– Oligohydramnios
– dilated posterior urethra
Antenatal U/S
Voiding Cystourethrography• Gold standard for diagnosing PUV
• Typically showed :
• VUR in 50% of patients with PUV
• Normal MCUG exclude PUV
Functional assessment
• Radionuclide Renal Scan
– quantification of differential renal function, and cortical deficits
– DTPA OR MAG-3
– with urethral catheter in place Exclude obstruction and assess split renal
function
• Serum Creatinine
– After 48 hours the infant's baseline laboratory values may be monitored.
– nadir creatinine value at 1 year of age is considered an important diagnostic tool
Initial Management
• Bladder Drainage– A 5 or 8 Fr pediatric feeding tube is ideal
– A Foley catheter should not be used, due to the tendency of the balloon to occlude the ureteral orifice and cause a bladder spasm.• Secondary obstruction
– Broad spectrum antibiotic coverage
– Metabolic panel• Assess renal function and metabolic abnormalities
• Acidosis, hyperkalemia common problems
Surgical Intervention
• Valve ablation
• Vesicostomy
• Upper tract diversion
• Circumcision
• Nephroureterectomy
• Transurethral Valve Ablation
– Incise at 5, 7 & 12 o’clock positions via Pediatric resectoscope
• Avoid urethral sphincter
• Catheter drainage for 1-2 days
• VCUG at 2 months to ensure destruction of valves
• Regular U/S to evaluate resolution of hydronephrosis
• Transurethral Valve Ablation– Alternatively, 8F cystoscope with a Bugbee
electrode adjacent
– Insulated crochet hook (“Whitaker hook”)• When urethra too small to accommodate
cystoscope/Bugbee
Antegrade valve ablation
• Zaontz and Firlit
• advantage of avoidance of instrumentation to the small male distal urethra
Vesicostomy
• reserved for
– the very lowbirth-weight infant
– continued impaired renal function,
– high bladder urine volumes,
– and upper tract deterioration after valve ablation or urethral catheterization.
•key operative step in creation of the vesicostomy is to
ensure that the posterior wall of the bladder is taut
•accomplished by bringing the dome of the bladder to the
skin
Upper tract diversion
Circumcision
• Risk of UTI in children with PUV is 50% to 60%
• UTI can quickly progress to pyelonephritis and sepsis
• Circumcision reduces that risk of UTI by 83% to 92%,
• Strongly recommended as a prophylactic measure for any boy diagnosed with posterior urethral valves
Antenatal m/m
• Intervention when antenatal sonography detects evidence of
– oligohydramnios,
– a dilated bladder, and
– severe hydroureteronephrosis—without renal cortical cystic lesions—in a fetus with a normal karyotype
• Vesicoamniotic shunting to treat oligohydramnios offers potential ameliorative effects on pulmonary function
PROGNOSTIC FACTOR
• Good Factors
• Nadir creatinine < 0.8 mg/dl
• S. creatinine < 1 mg/dl
• Pop-off mechanism
• - massive unilateral reflux
• -Urinary Ascitis (urinoma)
• - Large bladder diverticulum
Bad Factors• Age• Delayed correction• GFR < 50 % of normal in infancy• VUR- Bil -----> 57 % mortality- Uni. -----> 17 %- Non -----> 9 %• Loss of cortico medullary junction• delayed incontinence beyond 5 years
Transplantation in PUV Patients
• The prevalence of end-stage renal disease in PUV- up to 50%
• Obstructive uropathy as the second most common cause for transplantation
• Mixed outcome after transplantation
• Transplantation into a valve-affected bladder may carry a higher risk of ureteral obstruction
• However, there is no increased risk of graft loss compared to controls
Quality of Life with PUV
• have lifetime repercussions
• long-term risk factors
– valve bladder
– erectile dysfunction and infertility
– Risk of urinary tract infections
– associated comorbidities of renal transplantation
• counseling, preparing, and treating valve patients as they reach adulthood
Conclusions:Posterior Urethral Valves
• Two PUV types, Type I the most common, Type III with a worse prognosis
• Prognosis improved with improved symptoms within 1 month of therapy or the presence of a “Pop-off” valve
• Drainage, antibiotics and correction of metabolic disturbances key to initial care
• VCUG, U/S and renal nuclear scan to evaluate• Majority managed by valve ablation• Long-term sequelae significant, primarily renal
disease