Obstructive uropathy (UTP) in children can arise from various causes, presenting either acutely or chronically and necessitating careful diagnosis and management. Key clinical features include renal dysfunction, abdominal pain, and urinary flow issues, with posterior urethral valves being a common cause. Effective management involves both emergency interventions and long-term strategies to prevent kidney failure and ensure the child's well-being.

1. Obstructive uropathy in children
Dr. Abiodun MT

2. Outline
• Overview
• Selected causes in children
• Pathophysiology
• Clinical features
– Fetal/neonatal
– Older children
• Diagnosis/Differential diagnosis
• Management
• Outcome

3. OVERVIEW
• Obstructive uropathy or Urinary tract
obstruction (UTO) is a potentially reversible
urological disorder.
• Obstruction to urinary flow may be
– acute or chronic,
– partial or complete,
– unilateral or bilateral, and
– may occur at any site in the urinary tract,
especially at PUJ, Uretero-vesical jx & pelvic rim

4. UTO in children
• Typical causes of
obstructive uropathy in
children include:
– Posterior urethra valve
– Primary mega-ureter
– PUJ obstruction
– Others: urethral stricture

5. Clinical manifestations of UTO
• Normal/increased urine (partial obstruction)
• Anuria (very suggestive of UTO)
• Abdominal Pain (often absent in chronic UTO)
• Abdominal /flank mass
• Post-obstructive diuresis follows the release of
bilateral UTO,
• Signs of volume depletion:
– hypotension, decreased skin turgor, elevated urea
• AKI / CKD and associated symptoms

6. Emergency care of UTO
• Resuscitate (if indicated)
• Catheterize patient (diagnostic & therapeutic)
– No urine output = investigate upper tract
• Baseline investigations: Ultrasound scan,
electrolytes & Urea, creatinine, etc.
• Treat potentially life-threatening complications
– Pulmonary edema
– Hypovolemia
– Urosepsis
– Hyperkalemia
• Consult to nephrologist/ urologist

7. Radiographic evaluation of UTO
• Renal ultrasonography (USS) is the
radiographic test of choice
• Plain abdominal x-ray (KUB)
• CT scanning if ultrasound results are equivocal
• Micturating/voiding cystourethrogram
(VCUG/ MCUG)
• Intravenous urography (IVU),
• Radio-isotope studies (if indicated)

8. Postnatal evaluation of severe bilateral
prenatal hydronephrosis
.

9. Renal dysfunction in UTO
• Reduced glomerular filtration rate (GFR)
• Reduced renal blood flow (after initial rise)
• Impaired renal concentrating ability
• Impaired distal tubular function
– Nephrogenic diabetes insipidus
– Renal salt wasting
– Renal tubular acidosis (RTA)
– Impaired potassium concentration
• Post-obstructive diuresis

10. Post-obstructive diuresis
• Occurs in BUO or obstruction in a solitary kidney
• Physiologic: caused by retained urea, Na and H2O
• Pathologic: impaired concentrating ability or Na
reabsorption
• Iatrogenic: due to high-volume glucose containing
fluid replacement
• Common chronic obstruction, edema, CHF, uremia
• BUN, Creatinine returns to normal in 24-48 hours
• If persistent diuresis, and elevated creatinine
remains
– IVF (5% dextrose in 0.45% saline)infusion
– Na-wasting nephropathy

11. Obstructive nephropathy
• Damage to the renal parenchyma due to UTO
– Increased intratubular pressure
– renal vasoconstriction, reduced renal blood flow.
– Ischemia and an influx of inflammatory cells
– cytokines, proteases and oxygen free radicals

12. Prognosis of UTO
• Functional recovery ≤10 days following relief
of obstruction;
• Permanent kidney damage can occur:
– Tubulointerstitial fibrosis
– Tubular atrophy and apoptosis
– Interstitial inflammation
• Prognostic factors include:
– Severity &/or duration of obstruction
– Hypertension,
– Infection
– Preexisting renal disease

13. POSTERIOR URETHRAL VALVES (PUV)
• PUVs are obstructing membranous folds in
the posterior urethra
• Incidence: 1 in 5000 to 8000 pregnancies
• Most common cause of LUTO in male
newborn;
• Most common cause of CKD due to LUTO.

14. Pathogenesis of PUV
• Disruption of male urethral development
between 9 and 14 week of gestation:
– Persistence of the urogenital membrane with
abnormal canalization of the urethra.
– Overgrowth of urethrovaginal folds.
– Abnormal integration of the Wolffian duct into
the posterior urethra.

15. .
• .
An oblique membrane associated with the verumontanum, the congenital obstructive
posterior urethral membrane (COPUM), appears to be the cause of PUV

16. Classification of PUV
• Type 1 valve: The most common; a ridge from verumontanum
divides into two leaflets, attaches to anterior urethra
• Type 2 valve: from the verumontanum towards the internal
sphincter and bladder neck (?dissection artifact)
• Type 3 valve: a diaphragm distal to the verumontanum with a
central perforation (? Due to urethral catheterization).
New Classification:
• COPUM :congenital obstructive posterior urethral membrane,
related to verumontanum
• Cobb's collar: congenital urethral stricture caused by a
transverse membrane in the posterior urethra, not related to
verumontanum

17. Clinical Manifestations of PUV 1
• Prenatal: ultrasonographic findings:
– bilateral hydronephrosis,
– dilated bladder,
– dilated posterior urethra (keyhole sign),
– bladder wall thickened
• severe obstruction:
– oligohydramnios,
– urinary ascites
– perinephric urinoma,
– bladder diverticula /patent urachus,
– increased renal echogenicity/cortical cysts (renal dysplasia)

18. Clinical Manifestations of PUV 2
• Neonatal period:
– Respiratory distress due to lung hypoplasia (amniotic
fluid required for canalicular phase of lung devt 16
and 28 weeks GA)
– Abdominal distension (bladder or urinary ascites)
– Poor urinary stream or difficulty with voiding;
• Infancy
– Failure to thrive, Urosepsis,
– Poor urinary stream or straining while voiding;
• Older children
– Urinary tract infections,
– day time and nocturnal incontinence (enuresis),
– voiding dysfx (freq., straining, poor urinary stream)

19. Diagnosis
• Clinical history and examination findings
suggestive of LUTO;
• Diagnosis: Micturating cystourethrogram
(MCUG)
– hallmark is dilated, elongated posterior urethra
with a thin linear defect during the voiding phase;
• Confirmed diagnosis: cystoscopy.

20. .
• .
Voiding cystourethrogram of patient with PUV noted by white arrows with dilated
posterior urethra. Small capacity bladder with VUR (black arrows).
Courtesy of Nicholas Holmes, MD.

21. Radionuclide studies
• DMSA scan: Dimercaptosuccinic acid (DMSA)
detects focal renal parenchymal lesion and assess
the function of each kidney (static scan);
• Technetium 99-DTPA scan: Diethylenetriamine
pentaacetic acid (DTPA) scan assesses renal
excretory function (dynamic scans)

22. Laboratory studies
• Electrolytes, Urea & creatinine
• ESRD may occur early in infancy, and these
infants may require renal replacement
therapy, in addition to medical management
of the complications of renal failure.

23. Prenatal Management
• Prenatal surgery (vesicoamniotic shunt
placement):
– prevent lung hypoplasia
– reduce back pressure and nephron loss,
– improve neonatal survival.
– may reduce ESRD postnatally
• Fetal surgery for PUV is associated with a risk of
fetal and maternal morbidity without proven
benefit for long-term renal outcome.

24. Postnatal Management
• Stabilize the patient
– Correct electrolyte imbalance, treat respiratory distress,
– Treat urosepsis
– Monitor renal function
• Urinary tract drainage : a soft NG tube (size ≥8 French)
– NG tube has a large internal diameter, &inflated balloon of
the Foley catheter may occlude the ureteral orifices.
• Primary ablation during cystoscopy (preferred)
– Feasible in term and preterm infants.
• Vesicostomy (an alternative in very preterm infants )

25. Post-procedure Management
• Detect and treat bladder dysfunction:
– Evaluate with imaging/ urodynamic studies
– anticholinergic drugs lowers bladder pressures
– persistent hydronephrosis suggest abnormal
bladder function.
• Monitor renal function,
• Manage CKD, if present.

26. Outcome of PUV
• Chronic kidney disease (CKD)
• Despite early treatment, a significant
proportion of PUV patients develop ESRD

27. Differential diagnosis of PUV
• Agenesis or stricture/stenosis of the urethra
• Megalourethra
• Megacystis
• Micro-colon syndrome
• These causes are differentiated from PUV by
VCUG and cystoscopy.

28. PELVIC-URETERIC JUNCTION
OBSTRUCTION
• Pelvic-ureteric junction (PUJ) or ureteropelvic
junction (UPJ) obstruction is a partial or total
blockage of the flow of urine that occurs
where the ureter enters the kidney, and
results in hydronephrosis;
• Incidence of up to 1 in 500 fetuses;
• Most common cause of hydronephrosis in the
newborn

29. PUJ obstruction
.

30. Causes of UPJ obstruction
• Both congenital and acquired causes occur,
– congenital causes are more common.
• Congenital UPJ obstruction:
– intrinsic stenosis of the proximal ureter (common)
– extrinsic compression of the UPJ by an aberrant or
accessory renal artery (less common)
– intraluminal fold (rare).

31. Clinical features of PUJ
Antenatal hydronephrosis
Infancy:
• an abdominal mass (enlarged obstructed kidney),
• urinary tract infection,
• hematuria,
• failure to thrive.
Older children:
• intermittent flank and abdominal pain
• renal injury following minor trauma,
• hematuria,
• renal calculi,
• Hypertension (rare)

32. Diagnosis of PUJ obstruction
• Ultrasonography, shows hydronephrosis.
• The diagnosis is confirmed by intravenous
urography (IVU)
• IVU, serial USS, and voiding cystourethrogram
(VCUG) differentiate PUJ from other causes of
hydronephrosis,

33. Treatment of PUJ
• Prenatal intervention in unilateral UPJ obstruction
not recommended;
• Observation & monitoring with serial USS and IVU:
– asymptomatic patients with unilateral UPJ obstruction
– split renal function > 40 % of the affected kidney,
• Surgical intervention, Indications:
– increasing hydronephrosis and
split renal function < 40%
– serial loss >10% in subsequent studies,
– Presence of symptoms,
– massive hydronephrosis with
a renal pelvic diameter >50 mm,

34. Outcome of PUJ obstruction
• Stable or improved renal function, decreased
hydronephrosis, and lack of symptoms in most
patients following surgical correction
• Recurrent obstruction in 5%.
• Uncertain long-term outcome of patients
managed by observation alone

35. Differential diagnosis of PUJ
• Vesicoureteral reflux (VUR),
• Transient and functional hydronephrosis,
• Posterior urethral valves,
• Congenital megaureter,
• Ureterocele, and
• Multicystic dysplastic kidney

36. PRIMARY MEGAURETER
• Megaureter is a ureter that exceeds the upper
limits of normal size or , >7 mm in diameter in
children;
• Primary megaureter is due to a functional or
anatomical abnormality of the ureterovesical
junction;
• Secondary megaureter is due to bladder or
urethra disorders;

37. Incidence and Pathogenesis
• Incidence of primary megaureter is 0.36 per
1000 live births;
– Second most common cause of hydronephrosis in
the newborn (20% of cases )with an estimated;
• Pathogenesis: It is due to an abnormal or
delayed development of the muscle in the
distal ureter at 20 weeks gestation.

38. Clinical features and diagnosis
Clinical features of primary megaureter:
• Abdominal pain,
• Abdominal mass,
• UTI
• hematuria
• Uremia
Diagnosis: USS findings of both hydronephrosis and
a dilated ureter (antenatal / post-natal).

39. Investigation and treatment
MCUG: detects VUR
IVU: isotope clearance, delayed in urinary obstruction.
Treatments
• No prenatal intervention
• Non-surgical management
– In asymptomatic patients with nonrefluxing, non-
obstructed megaureters
– Monitoring with ultrasounds yearly
– Prophylactic antibiotics until the patient is toilet trained.
• Surgical intervention in symptomatic patients
– Relieve the obstruction

40. .
• .
Natural course of megaureter: Series of imaging studies that demonstrate
spontaneous resolution of a left megaureter without surgical intervention.
Courtesy of Dr. Laurence Baskin.

41. URETHRAL STRICTURE
• Stricture associated with urethral
catheterization occurs almost exclusively in
male patients
• Repeated urethral trauma from intermittent
catheterization can cause urethral stricture
formation, which in turn increases the
likelihood of traumatic catheterization.
• The incidence of urethral stricture increases
with duration of chronic catheterization;

42. CONCLUSION
• Obstructive uropathy is a major clinical
morbidity in children;
• Prompt diagnosis and management is
necessary to avoid kidney failure.

43. References
• Principles and practice of pediatric nephrology;
• LUTO. CME, ADC 2016;
• www.uptodate.com
• Urinary tract obstruction, ppt. Victor Federico
B. Acepcion, MD, FPUA

44. .
• Thank you