Overview of Common Obstructive
Uropathy in Childhood
DR RM AKUSE
Consultant Paediatric Nephrologist,
Ahmadu Bello University Teaching
Hospital Zaria
DEFINITION
• Obstructive uropathy(OU) is a condition in which
the flow of urine is blocked along the urinary tract.
• The hindrance may be structural or functional.
• if left untreated can lead to injury to kidney(s) and
renal failure.
WHY WORRY?
• Cause of morbidity and mortality in children
– CKD, HYPERTENSION, UTI
• UPTH (1997-2002), 20 CHILDREN

HYPERTENSION- 50%

RENAL FAILURE- 30%

DEATH - 35%
• Accounted for 16.5% of all pediatric renal
transplants in 1997
Potential killer
RENAL FAILURE DUE TO OU
• 30-70% of all End stage renal disease (ESRD)
NIGERIA
• UPTH- 30%
• UBTH - (9.6%)
• CALABAR – 6.7%
• OAUTH- 8%
Types
• Can occur in any part of the urinary system,
• In children often congenital
• Associated congenital abnormalites
CLASSIFICATION
• Congenital/Acquired
• Acute/Chronic
• Anatomical- level of obstruction
• Unilateral/Bilateral
Types
KIDNEY
• Ureteropelvic junction (UPJ) obstruction
URETER
• Intraluminal = kidney stones, blood clots, papillae
sloughing, scarring
• Extraluminal - enlarged lymph nodes,
enlarged uterus (haematocolpos)
cancer/tumors,
strictures,
trauma
Types
BLADDER
• Neurogenic
• Stones
• Tumors or masses around the bladder neck or urethra
• Scarring
• Retroperitoneal fibrosis
URETHRA
• Posterior and anterior urethral valve
• Atresia
• Tumors or masses
• Phimosis
• Meatal Stenosis – post circumcision
Common causes
Congenital
• Posterior Urethral Valve (PUV) obstruction
• Pelvi-Ureteric junction
Acquired
• Calculi
• Post traumatic
• Post inflammatory strictures
• Meatal stenosis
Associated anomalies
• Dysplastic kidneys
• Imperforate anus
• Vertebral malformations
• Prune belly syndrome
Ardissino et al (2003)
• OU cause of ESRD in 27.1% of pediatric patients
COMMONEST TYPES
• Posterior urethral valves (23.8%).
• Ureteropelvic junction (UPJ) obstruction= 3.6%,
• Obstructive megaureter 3.5%,
• some form of urethral hypoplasia/atresia 2.3%,
• ureterocele 1.7%,
• Other complex uropathies accounted for 5.9%.
UPTH – CAUSES OF OU (1997-2002)
(n=20)
• Post urethral Valve -16 (80%),
• bladder calculi -2 (10%),
• bladder rhabdomyosarcoma - 1 (5%)
• urethral stenosis - 1 (5%)
PATHOPHYSIOLOGY
• MECHANICAL DAMAGE
• RELEASE OF BIOCHEMICAL MEDIATORS
• CELLULAR INFILTRATES
• FOETAL URINE FLOW IMPAIRMENT
MECHANICAL DAMAGE
• INCREASED INTRATUBULAR PRESSURE
• LOCAL ISCHEMIA
• SIGNIFICANT LOSS OF FUNCTIONAL RENAL
PARENCHYMA
• SECONDARY REFLUX
• SUPERIMPOSED UTI.
RELEASE OF BIOCHEMICAL MEDIATORS
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prostaglandins,
thromboxane [A.sub.2]),
angiotensin II,
atrial natriuretic peptide,
nitric oxide, endothelin,
platelet activating factor,
nuclear factor kappa B (NF-[kappa]B),
transforming growth factor-beta (TGF-[beta]
CELLULAR INFILTRATES
• Macrophages, T-lymphocytes, and fibroblasts
• glomerular damage,= albuminuria
• tubular damage= elevated microglobulin alpha-1.
• tubulointerstitium, - Most damage - Fiborsis
FOETAL URINE FLOW IMPAIRMENT
• Causes deregulation of renal precursor cell
turnover and expression of growth
factor/survival and transcription factor genes.
• Renal dysplasia
END RESULT
• HYDRONEPHROSIS,
HYDROURETERS,
HYPERTROPHIC BLADDER
• BIOCHEMICAL ABNORMALITIES
sometimes type 1 renal tubular acidosis (reduced distal
hydrogen secretion)
• RENAL DYSPLASIA -undifferentiated and metaplastic
tissues.
• OBSTRUCTIVE NEPHROPATHY – bilateral,
unilateral
Clinical features
Consider OU in patients with any of the following:
•
•
•
•
Diminished or absent urine output
Unexplained renal insufficiency
Pain that suggests distension in the urinary tract
oliguria or anuria alternating with polyuria
Clinical features
• Fever
• Dysuria
• Problems with passing urine – incontinence,
hesitancy, increased frequency
• Poor urinary stream
• Dribbling
• Symptoms associated with primary disease
INVESTIGATIONS
• URINALYSIS
may be normal
Abnormal - casts, WBCs, RBCs, albuminuria
•
•
•
•
Urine MCS
Urea, electrolytes, creatinine
FBC and differential.
IMAGING
Abdominal ultrasonography
• Detection of hydronephrosis.
• Follow up of hydronephrosis
• false-negative resultsif obstruction is early,
if obstruction is mild
if retroperitoneal fibrosis or
tumour encases the
collecting system
preventing dilation
of the ureter.
Voiding cystourethrography (VCUG)
• Displays anatomy of BLADDER NECK and
URETHRA
• Volume of urine left in the bladder after
voiding
• Vesicoureteral reflux,
Voiding
cystourethrogram
•posterior
urethral valves
• associated
reflux (Grade V).
IVU
• USEFUL when CT cannot identify the level of
obstructive uropathy
• when acute obstructive uropathy is thought to be
caused by calculi, sloughed papilla, or a blood clot
• Must have some renal function
• Allergic reactions may occur
• ANTEGRADE OR RETROGRADE PYELOGRAPHY
Antegrade
pyelogram.
stricture of distal
ureter in
patient with
moderate
hydroureteroneph
rosis.
CT SCAN/MRI
• CT SCAN- Used when obstruction cannot be shown by
ultrasonography or IVU.
• NOTE
ultrasonography and CT may not be able to
differentiate hydronephrosis from multiple renal or
parapelvic cysts.
• MRI (with or without contrast).
used when avoiding ionizing radiation is important (eg,
in young children).
as accurate as ultrasonography or CT.
Radionuclide scans
• Don’t use contrast agents
• Can determine perfusion
• Identifies functional renal parenchyma
• BUT cannot detect specific areas of obstruction
• mainly used TOGETHER WITH diuresis renography
to evaluate hydronephrosis without apparent
obstruction.
Diuretic renography
• Frusemide given before i.v injection of
radiopharmaceutical (Tc 99m DPTA or MAG 3) or IVU).
• Note- Must have enough renal function to respond to
the diuretic.
• Rate of washout of radionuclide (or contrast agent) is
measured
• Rapid washout - dilated non-obstructed system.
• Delayed washout - obstructed pattern
• Indeterminate - Washout between 1.5 and 20
minutes
• False-positive and false-negative are common
LEFT: complete obstruction
of one kidney (upper graph)
partial obstruction of other kidney.
RIGHT: Discrepancy in function but no evidence of
obstruction
Foetal urinary electrolytes
• normal foetal kidney makes hypotonic urine
• foetal urinary biochemical markers most useful
after 20 weeks' gestation
• Reliability varies
• foetal urinary sodium <100 mEq/L and
• β-2 microglobulin -more appropriate predictor of
postnatal serum creatinine in the foetus
INTERPRETATION
• A dilated renal collecting system may not mean a
true obstruction.
• HYDRONEPHROSIS
must distinguish whether it secondary to an
ongoing obstruction or secondary to a prior
obstructive event that occurred and resolved
antenatally.
THIS AFFECTS MANAGEMENT
MANAGEMENT
• A challenge for paediatricians and
urologists is to diagnose and intervene
appropriately for problems
without overreacting to variants of
normal.
MANAGEMENT GOALS
• Relieve obstruction – antenatal/Postnatal
• Maximize renal function
• Maintain normal bladder function
• Minimize morbidity
• Prevent iatrogenic problems
COMPLICATIONS
• CHRONIC KIDNEY DISEASE, ESRF
• UTI – Chronic or recurrent
• BLADDER PROBLEMS- incontinence, retention
• CALCULI – Renal or uretal
• Complications due to long-term catheter use
PROGNOSIS
• Duration
• Specific nature of the blockage,
• Other factors
-Financial constraints
- Availability of diagnostic facilities
equipment drugs
Posterior urethral valve (PUV)
• Commonest cause OU in
children
• Occurs sporadically but
familial cases have been
reported
• Cause -obstructing
membrane in lumen of the
posterior (prostatic) urethra.
CLINCAL FEATURES
• broad spectrum of clinical severity
• The most severe forms do not survive in utero,
• Mildest forms may go undetected.
• Antenatally
detected on routine foetal ultrasonography,
– hydronephrosis,
renal parenchymal echogenicity, renal cysts
PRENATAL
ULTRASOUND OF
FETUS WITH PUV
renal dysplasia
Severe hydronephrosis,
parenchymal thinning,
increased echogenecity of
parenchyma.
Sagittal view of upper
pole of kidney with renal
cyst.
Ultrasound of
bladder of patient
with PUV
Full bladder with
thickened wall and
dilated ureters posterior
to the bladder (black
arrows).
Prenatal ultrasound
with dilated posterior
urethra and dilated
bladder (“keyhole” sign).
POSTNATAL
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age at presentation- BIRTH -13 YEARS,
Poor urinary stream.
incontinence
recurrent UTIs.
Urinoma
Urinary ascites
MANAGEMENT - POSTNATALLY
• ASSESS PATIENT
• Treat Acute illness
• Surgery - Ablation of valve
Urinary diversion -vesicostomy, cutaneous
ureterostomy,
augmentation cystoplasty with later
reconstruction.
• Manage CKD
• RENAL TRANSPLANT
• FOLLOW UP - Check for persisting or increasing upper
urinary tract dilatation, increasing serum creatinine,
bladder problems
PRENATAL INTERVENTION
• Uncertain whether antenatal diagnosis or
treatment improves long-term renal outcome
• Identify those who intervention may benefit
using
– gestational age,
– amniotic volume,
– Renal dysplasia - cortical cysts, increased echogenicity.
– renal function - -urinary electrolytes, β-microglobulin
levels
– Karyotype
Foetal surgery
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•
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continues to remain controversial.
normal outcomes can occur without intervention.
Indications
? for the carefully selected patient who has
normal-appearing kidneys and normal urinary
electrolytes with severe oligohydramnios
• Surgery - vesicoamniotic shunts, valve ablation ,
bladder marsupialization
•
COMPLICATIONS
of interventions
• Shunt failure and declining appearance of
fetal lungs kidney.
• Chorioamnionitis,
• Spontaneous ruptures of membrane,
• amniotic fluid leak.
• Premature labor with respiratory failure.
• Fetal mortality rate – 33-43%.
POSTNATALLY
• intervention may not change the prognosis of
renal function
• We must not give families unrealistic expectations
that fetal surgery is the cure for obstructive
uropathy or that the child will not need extensive
follow-up after delivery.
Outcome
• BLADDER DYSFUNCTION
hyperreflexia, hypertonic, small capacity bladder,
sphincter incompetence and/or myogenic failure.
• End-stage renal disease –
• Renal failure - in 19% to 64% diagnosed prenatally
•
in 25% to 40% diagnosed postnatally
•
CONCLUSION:
• Advances in postnatal surgery and medical
management have reduced the mortality in
PUV
• Earlier diagnosis by ultrasound,
• Developments in surgical technique
• Meticulous attention to neonatal care.
UPJ obstruction
• Intrinsic obstruction
hypoplastic adynamic ureteral segment at the UPJ
• Extrinsic causes - aberrant vessels, kinks,
• PAIN - abdominal or flank -worse with diuresis
• hematuria following mild trauma,
• chronic nausea, UTI.
• DIURETIC RENOGRAPHY – may be delayed washout
• Rx – Nil, surgery, Antibiotics
Uretervesical junction (UVJ)
OBSTRUCTION
• hydroureter + HYDRONEPHROSIS
• NORMAL BLADDER
• megaureter. - not necessarily obstructed.
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mainly found incidentally on prenatal sonography,
Usually normal physical exam
UTI, hematuria,
abdominal pain or mass,
uremia.
Management
Depends on
• presence of obstruction
• presence of reflux,
• Continued surveillance
• Patients with nonobstructed system often resolve
spontaneously
• antibiotic prophylaxis is recommended until a
proper diagnosis can be made.
• Surgery -
SURGERY
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increasing hydronephrosis on ultrasound,
decreasing renal function,
Recurrent infections
Persistent symptoms
Calculi
Careful follow up
The Future
• ? Development of molecular markers for diagnosis and
progression
• ? Improve criteria to select patients for treatment
• ? improve prenatal treatment to improve bladder function,
• ? Better imaging techniques
???fetal magnetic resonance imaging to assist in
differentiating PUV from other causes of severe
hydronephrosis, eg, prune belly syndrome,
vesicoureteral reflux
Prevention
• need to improve the country's socioeconomic
conditions
• Need to improve health facilities
• make medical facilities more available to children
• prevent renal diseases that may lead to ESRF
• Education at the community level
CONCLUSION
• OU – IMPORTANT CAUSE OF RENAL
IMPAIRMENT
• ADEQUATE MEASURES NEEDED TO PREVENT OR
TREAT ESRF
• RESOURCE CONSTRAINED COUNTRIES –
SEVERAL CHALLENGES
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REFERENCES
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Anochie I, Eke F.Obstructive uropathy in childhood, as seen in University of Port Harcourt Teaching Hospital, Nigeria.
Niger J Med. 2004 Apr-Jun;13(2):136
Michael IO, Gabriel OE. Pattern of renal diseases in children in midwestern zone of Nigeria. Saudi J Kidney Dis Transpl.
2003 Oct-Dec;14(4):539-44.
Nasir AA, Ameh EA, Abdur-Rahman LO, Adeniran JO, Abraham MK. Posterior urethral valve. World J Pediatr. 2011
Aug;7(3):205-16. Epub 2011 Aug 7.
Etuk IS, Anah MU, Ochighs SO, Eyong M..Pattern of paediatric renal disease in inpatients in Calabar, Nigeria. TropDoct.
2006 Oct;36(4):256.
Eke FU, Eke NN Renal disorders in children: a Nigerian study. PediatrNephrol. 1994 Jun;8(3):383
Woolf AS; Thiruchelvam . Congenital obstructive uropathy: its origin and contribution to end-stage renal disease in
children.Adv Ren Replace Ther. 2001; 8(3):157-63
Obstetric uropathy . Considerations for the nephrology nurse. Nephrology Nursing Journal . March 2004
Ardissino et al 2003).
Nicholas Holmes, Michael R. Harrison, Laurence S. Baskin, Fetal Surgery for Posterior Urethral Valves: Long-Term
Postnatal Outcomes
Obstructive uropathy - Overview http://www.umm.edu/ency/article/000507.htm#ixzz1jdfjZGzr
ROTH Karl S) ; KOO Harry P. ; SPOTTSWOOD Stephanie E. ; CHAN James C. M.Obstructive uropathy: An important cause
of chronic renal failure in children
Congenital obstructive uropathy: its origin and contribution to end-stage renal disease in children. Adv Ren Replace
Ther. 2001; 8(3):157-63
N Eke, SN Elenwo. Obstructiveuropathy in childhood: A review Port Harcourt Medical Journal>Vol 1, No 3 (2007)
Casale AJ Early ureteral surgery for posterior urethral valves.
. Urol Clin North Am. 1990 May;17(2):361-72.
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Anochie I, Eke F.Obstructive uropathy in childhood, as seen in University of Port Harcourt Teaching Hospital, Nigeria. Niger J Med. 2004 AprJun;13(2):136
Michael IO, Gabriel OE. Pattern of renal diseases in children in midwestern zone of Nigeria. Saudi J Kidney Dis Transpl. 2003 Oct-Dec;14(4):539-44.
Nasir AA, Ameh EA, Abdur-Rahman LO, Adeniran JO, Abraham MK. Posterior urethral valve. World J Pediatr. 2011 Aug;7(3):205-16. Epub 2011 Aug
7.
Etuk IS, Anah MU, Ochighs SO, Eyong M..Pattern of paediatric renal disease in inpatients in Calabar, Nigeria. TropDoct. 2006 Oct;36(4):256.
Eke FU, Eke NN Renal disorders in children: a Nigerian study. PediatrNephrol. 1994 Jun;8(3):383
.
Woolf AS; Thiruchelvam . Congenital obstructive uropathy: its origin and contribution to end-stage renal disease in children.Adv Ren Replace
Ther. 2001; 8(3):157-63 (
Obstructive uropathy: considerations for the nephrology nurse. : Nephrology Nursing Journal
Publication Date: 01-MAR-04
Ardissino et al 2003).
Nicholas Holmes, Michael R. Harrison, Laurence S. Baskin,
Fetal Surgery for Posterior Urethral Valves: Long-Term Postnatal Outcomes
Obstructive uropathy - Overview http://www.umm.edu/ency/article/000507.htm#ixzz1jdfjZGzr
THANK YOU!