POSTERIOR URETHRAL VALVE DR. Hamdan H. Alhazmi MD,SBU,ABU pediatric urologist King Khalid University Hospital

INCIDENCE ETIOLOGY ANATOMY OF MALE URETHRA EMBRYOLOGY CLASSIFICATION PATHOPYSIOLOGY CLINICAL PRESENTATION PROGNOSTIC FACTORS DIAGNOSIS

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

ETIOLOGY Not clear Genetic factor are poorly undrerstood

ANATOMY OF MALE UTETHRA ANTERIOR - Penile - Bulbar POSTERIOR - Prostatic - Membranous

EMPRYOLOGY

CLASSIFICATION Young classification 1919

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

Pathopysiology Primitive tissues mature in an abnormal environment of high intraluminal pressures and organ distention UNIVERSAL INJURY IN THE URINARY TRACT

RENAL DYSPLASIA RENAL FUNCTION RENAL TUBULAR FUNCTION HYDRONEPHROSIS VUR VESICAL DYSFUNCTION VALVE BLADDER

1-Renal Dysplassia Defined as a congenital defect of tissue development without premalignant potential Histological diagnosis Cause ? 1- high pelvic pressure during nephrogenesis 2- primary embryologic abnormality from abnormal position of uteteric bud

Commonly associated with PUV Severity well determine ultimate renal function

2-Renal Function Children with PUV may demonstrate gradual loss of renal function over time Cause: 1- Renal parenchymal dysplasia 2- Incomplete relief of obstruction 3-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

3-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 vesical pressure

4-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

5-Vesicoureteral Reflux 50% VUR at time of diagnosis Primary or Secondary

6-Vesical 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 as urinary incontinence (20%) Bladder dysfunction persist in 75 % after valve ablation

- Myogenic failure and overflow incontinence (40%) 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%)

7-VALVE BLADDER Even after relief of obstruction a significant number of patient will continue to have hpertonia and detrusor hyperreflexia and low compliance Physiological obstruction of the ureter associated with bladder filling  persistence hydronephrosis and/or urinary incontinence

PROGNOSTIC FACTOR Good Factors Nadir creatinine < 0.8 mg/dl S. creatinine < 1 mg/dl Pop-off mechanism - VURD - Ascitis - 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

Clinical presentation Variable Age dependent = Prenatally : 70% of PUV by ltrasound = Newborn: - Abdominal mass - Ascites - Respiratory distress - Urosepsis - Delayed viding or poor stream

= Infant: - Urinary dribbling. - Enuresis = Infant: - Urinary dribbling - Enuresis - Failure to thrive/ renal failure - Urosepsis = Toddlers: -UTI - Voiding dysfunction = School-age boy: - Urinary incontinence

Diagnosis

Prenatal Ultrasound Change the the incidence of PUV Prepare physician for immediate postnatal management Finding: -bilateral hydroureteronephrosis -distended, thick wall bladder -+/- oligohydramnios The earlier PUV detected the poorer the diagnosis

Postnatal Ultrasound To evaluate the effect of PUV on the urinary tract rather than to diagnose PUV Typical finding: wide prostatic urethra,thick-walled bladder,and upper tract dilatation Assessment of renal parenchyma

MCUG Gold standard for diagnosing PUV Typically showed :

VUR in 50% of patients with PUV Normal MCUG exclude PUV

Functional assessment Diuretic Radioisotope Scan - DTPA OR MAG-3 - with urethral catheter in place -Exclude obstruction and assess split renal function Serum Creatinine -Immediately after birth reflect maternal createnin

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