Lower Urinary Tract Obstruction - Networks
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Lower Urinary Tract Obstruction ‘LUTO’ or Bladder Outlet
Obstruction ‘BOO’Miss Harriet Corbett Consultant Paediatric
Urologist
Aims
• the anomalies we encounter
• how to manage them
• Commonest cause of LUTO in children
• Males only
• Associations – Trisomy 21 (not in all series)
– Kupferman 1996 Paediatr nephrol (find association), Qureshi 2000
Fetal Diagn (do not)
– UDT in up to 12-17%
Posterior Urethral Valves
Posterior Urethral Valves
Obliquely orientated membrane (not actually valves) From region of
veru through external sphincter to anterior urethral wall a very
wide spectrum (veru)
Posterior Urethral Valves
• Young’s classification - no longer considered valid: Type I –
pair of oblique postero-anterior folds directed distally from veru
(95%) veru enlarged ?in fact a single membrane, bicuspid due to
catheters Type II – folds between veru and bladder neck *?if these
exist - considered to be non-obstructing Type III –
membrane/diaphragm distal to veru (5%)
• Dewan et al. 1990s – If perform cystoscopy before catheter, find
Type III – Catheter converts it to Type I – Proposed new
terminology: COPUM Congenital Obstructing Posterior Urethral
Membrane A membrane rather than valve leaflets
• Embryology - theories
• e.g. abnormal integration of Wolffian ducts into the urethral
wall, abnormal cloacal membrane
• Krishnan et al. J Urol 2006:
• persistent urogenital membrane
Posterior Urethral Valves
Pathophysiology
• Urinary tract obstruction – May be evident as early as 14 weeks –
reduced liquor volume
– reduced volume of urine passed – consequences on fatal lung – and
posture
– abnormal bladder wall – chronic raised intravesical
pressure
– abnormal proximal urinary tract – dilated ureters, abnormal
kidneys
Uterus
• Commonest cause of BOO/LUTO in childhood
• Commonest cause of childhood renal failure – Approx 25%
ESRF
• Bladder dysfunction – In 25-30%
Presentation of PUV
1. Antenatal
• must be considered in any baby (boy) with bilateral AN hydro or
abnormal bladder
2. Early postnatal
3. Infants
4. Childhood
5. Later
Antenatal USS
• Urinary tract = commonest system to find anomalies – Mild
dilatation of renal pelvis in 1:100 pregnancies – Significant
problems 1:500
• 70% of anomalies are detected at 20 weeks
• BUT: 80% of antenatal findings are non specific
Aetiology & incidence of antenatal hydronephrosis
Transient hydronephrosis 41–88%
Vesicoureteric reflux 10–20%
megaureters 5–10%
Posterior Urethral Valves/urethral atresia 1–2%
Nguyen HT et al. The Society for Fetal Urology consensus statement
on the evaluation and management of antenatal hydronephrosis. J
Pediatr Urol 2010:6:212-31
Which ones to worry about
• OLIGOHYDRAMNIOS – risk of pulmonary hypoplasia
• Anything BILATERAL – Ureters or kidneys
• Anything that includes bladder abnormality – Especially the
‘Keyhole’ sign
• Abnormal solitary kidneys
• 55% suspected at 20wks • Further 20-30% detected later • Bad
signs
Detect <24wks (later = better) Oligohydramnios ‘Bright’
kidneys
....Consider TOP if v.early/severe oligo....
Refs: Sarhan, 2008 & BAPS CASS survey 2018
PLUTO
• Percutaneous shunting for Lower Urinary Tract Obstruction – LUTO
: 60% PUV, 21% other, 5% c’some etc – Metanalysis of literature to
date suggests a benefit from shunting
in utero – ANY fetus with LUTO where it is uncertain if shunting
will help to
be randomised to shunt/no shunt – Needed 200 patients to show 20%
difference in mortality – Didn’t recruit enough
What to do with a baby with antenatal urological abnormality
Ultrasound Scan • Timing depends upon antenatal scan so it does
matter what the antenatal scan showed afterall! • Urgent postnatal
ultrasound at 24-72 hour old, if:
• oligohydramnios / lung abnormality • bilateral dilation OR
unilateral with bladder
abnormality • solitary abnormal kidney • if normal :repeat 3 to 7
days later • if still normal repeat at 6 weeks • if still normal,
no follow up required
Urgent postnatal ultrasound
MAG3
3months
URGENT
REFERAL
Antibiotics
Referral
Paeds/nephrology/urology
Referral Urology
Protocol 1 1. Renal dilation with oligohydramnios or lung
abnormality 2. Bilateral renal dilation 3. Unilateral renal
dilation with ureteric dilation or bladder abnormality or
contralateral kidney abnormal
‘False Alarm’ - bilat hydro due to VUR
PUV case 1: baby AT
• Bilateral hydronephrosis & oligohydramnios on 34 week
scan
• Elective CS delivery at 36 weeks
• Ventilated for respiratory distress – Pneumothorax – O2
requirement
• Creatinine 147 on D3
Beware the early USS
• This baby had normal kidneys on a Day 1 USS
– But they looked like this on day 13
PUV case 2: Stoke baby
• Antenatal diagnosis of bilateral hydronephrosis and dilated
bladder
• Catheterised after birth, transferred to AH
• USS = gross bladder wall thickening & significant bilateral
hydro
• MCUG = poor bladder with PUV
18 months post treatment
• Beware v. thick bladder wall obstructing VUJ
– SPC difficult due to thick wall • Alternatives: vesicostomy,
ureterostomy(ies),
nephrostomy(ies)
• Monitor U&E – Nephrology input – Allow stabilisation before
anything else
Micturating CystoUrethroGram
• +/- circumcision
• urosepsis
• clinical LUTO = big bladder, big kidneys, big abdomen (urinary
ascites)
3. Infants
4. Childhood
5. Later
• Presented at 6 weeks of age with frank haematuria
• likely UTI (>1000 WCC, but mixed growth)
• terrible USS
• urosepsis - often very unwell
• clinical LUTO = big bladder, big kidneys, big abdomen (urinary
ascites)
4. Childhood
5. Later
Renal failure
• First ever urinary tract symptom
• Though imperfect bladder function likely overlooked in view of
T21
• Trisomy 21
Long term: rule of thirds
BLADDER: • normal • poor .... Late potty training, wetting • bad
.... Overactive/poor compliance/myogenic failure
with time - may need ISC/surgery etc
KIDNEYS • normal • marginal • poor progressing to CRF / transplant
• ***↑nadir creatinine and bladder dysfunction are risk
factors for ESRF (DeFoor 2008 J Urol)
Long term....
•Obstructing ureteroceles
•Anterior urethral valves, Cobbs collar, Congenital urethral
stricture, Polyps
Obstructing Ureteroceles
• (single system ureteroceles often innocent)
Duplex systems: plenty of scope for abnormality but… both moieties
may be normal
Duplex systems: if abnormal: lower moiety - ureter inserts lateral
and above medial ureter, may be ‘too lateral’ - likely to have
VUR
Duplex systems: if abnormal: upper moiety - ureter inserts medially
and below, often ectopic, may have ureterocele The Weigert-Meyer
rule states that the upper pole ureter is the ectopic ureter and
its orifice inserts inferomedially in the bladder in relationship
to the lower pole normal ureter.
» Ureteroceles
» if not causing other problem then nil to do
» BUT
» OR get infected above…
» vagina
» urethra
• Well at birth
• Initial early scan ‘not bad’ – but repeated according to
protocol
• Repeat scan ~1 week later – quite abnormal
Urethral Atresia
Potters syndrome equivalent
Summary
Urologists happy to advise