2. Clinical Case
Case of a posterior
Urethral valve in a Viable
Twin Intrauterine
Gestation Of About
23W2D, affecting the
leading Twin in a 23-year-
old woman.
9/11/2013
3. Patient Clinical History
History :
A 23-year-old pregnant woman presented
asymptomatic.
With no clinical signs of oligohydramnios
No complains of lower abdominal pains
First pregnancy and with no history of
abortion.
Normal heart rate of fetus on midwife’s
examination.
Abdomen was normal for GA
Family his. Of twin GA
9/11/2013
5. Department Protocol
Ultrasound Department Manhyia District
Hospital protocol with additional comments
and impression stated in the exams report.
MANHYIA DISTRICT HOSPITAL 2ND AND
3RD.docx
9/11/2013
6. The Examination
Patient in supine position.
Machine Exam preset: Gen. OB
Transducer: curvilinear (2- 5MHZ) Fetal
Trans-abdominal approach
biometry taken (i.e. HC, BPD, AC, FL, EGA and
EFW)
For sex determination patients are asked to
vary their position (in terms of difficulty)
There is variation of protocol and examination
in terms of twin gestation.
9/11/2013
17. Ultrasound findings
Also noted was dilated echogenic
thickened walled urinary
bladder, with a dilated
proximal urethra (keyhole sign)
and bilateral hydronephrosis .
Adequate amniotic fluid was also
note
Differences in GA
9/11/2013
25. Relation of encountered pathology in relation
to patient presentation and our findings.
The presence of intrauterine twin gestation with twin A
not affected with any obstructive uropathy, in this case
is an indication of adequate amniotic fluid noted
around both twins, which ruled out oligohydramnios
associated with PUV. Thus the affected twin only
swallows the amniotic fluid without urinating into it
but the unaffected one swallows and at the same time
urinates into the amnion which keeps the fluid
balanced.
The absence of Oligohydramnios explains the mother’s
condition of showing no signs and symptoms.9/11/2013
26. Dilated urinary bladder with thickened echogenic wall and
dilated proximal urethra (keyhole sign) noted on sonogram
above suggests that there is an obstruction, of lower urinary
tract origin preventing urine from coming out of the urinary
system. This in effect builds up a backwards pressure
(thrust) which pushes urine back to fill the pelvicalyceal
systems which was noted as Bilateral hydronephrosis on
sonogram above.
9/11/2013
27. Conclusions drawn:
After discussing case with my
supervisor we came to a
conclusion that the findings were
consistent with posterior urethral
valve in a twin gestation of about
23w2d affecting twin B.
9/11/2013
28. Ultrasound Exams Final Report
MANHYIA DISTRICT HOSPITAL.pdf
Differentials
Urethral atresia/agenesis
Neurogenic bladder
Prune-belly syndrome
9/11/2013
29. Follow-up
Follow up was done and patients was asked to
come for antenatal care consistently and
routine ultrasound examinations will be done
to monitor the progress of the condition.
If fetus survive up to term, they will deliver
them by appropriate method and will be
handed over to a pediatrician surgeon for
surgical repair of the urethral valve.
9/11/2013
30. Discussion:
Megacystis
In the first trimester, an enlarged bladder >7 mm (megacystis)
should raise the suspicion of either chromosomal abnormalities
or obstructive uropathy. Approximately 20% of fetuses with
megacystis measuring 7–15 mm have an underlying
chromosomal abnormality such as trisomy 13 or 18. If the
bladder measures >15 mm, the risk of an underlying bladder
outlet obstruction (urethral atresia, posterior urethral valves, or
cloacal abnormalities) is very high and is associated with a very
poor prognosis. With megacystis >15 mm, it is sometimes
possible to find echogenic or dysplastic kidneys and reduced
liquor volume in the first trimester.
From: problem-based obstetric ultrasound by Basky
Thilaganathan, Shanthi Sairam, Aris T
Papageorghiou and Amar Bhide.
9/11/2013
31. Discussion:
• Obstruction of the posterior urethra by a congenital valve, a severe
condition often associated with refluxing or obstructive uropathy
and renal dysplasia, mostly seen in baby boys. from Encyclopedia
of Diagnostic Imaging volume 1
• Posterior urethral valves are the most common cause of lower
urinary tract obstruction, followed by urethral atresia or stricture.
Posterior urethral valves are seen exclusively in males and may
cause total, intermittent, or partial obstruction, with variable
prognosis. Most cases are sporadic, occurring in 1 in 5000 male
births; and the recurrence risk is small.
• Back pressure causes a persistently dilated urinary bladder, with
a dilated proximal urethra (keyhole sign). There may be
thickening of the bladder wall (>2 mm) or a severely distended
thin-walled bladder, bilateral tortuous hydroureters, and
hydronephrosis. If the obstruction is severe and of long-standing,
progressive renal parenchymal fibrosis and dysplasia develop,
resulting in severe oligohydramnios, pulmonary hypoplasia, and
compression deformities (Potter’s syndrome). There may be
spontaneous bladder rupture with urinary ascites or a calyceal
rupture with perirenal urinoma. If spontaneous decompression
occurs, this “safety valve” may protect the kidneys from further
prenatal damage and may diminish the degree of
hydronephrosis. Rumack
9/11/2013
32. Discussion: CAUSES
• The etiology is unknown
• Genetics.
• Developmental anomaly in the urethra
• Abnormal embryology and persistent of a fold
which remains and forms flaps or valves in
the urethral passage which Normally forms in
the 4th months of gestation.
• Urethral carcinoid tumors normally occur at
the verumontanum.
9/11/2013
33. Type of
PUV
• Type I - Most common type; due to
anterior fusing of the plicae colliculi,
mucosal fins extending from the bottom
of the verumontanum (SMC) distally
along the prostatic and membranous
urethra
• Type II - Least common variant; vertical
or longitudinal folds between the
verumontanum and proximal prostatic
urethra and bladder neck
• Type III - Less common variant; a disc
of tissue distal to verumontanum, also
theorized to be a developmental
anomaly of congenital urogenital
remnants in the bulbar urethra
From Embryo
and fetal
pathology color
atlas with
ultrasound
correlation by
Enid Gilbert-
Barness and
Diane Debich-
Spicer
9/11/2013
36. Discussion:
Role of Ultrasonography in Diagnosis and
assessment
Ultrasound can accurately detect fetal lower urinary tract Obstruction with a
sensitivity of 95% and a specificity of 80%. The sensitivity of ultrasound screening
for these abnormalities is improved because anomalies of the renal tractand kidneys
are also associated with secondary findings,such as oligohydramnios.
Assessment of the fetal genitourinary tract is a part of all routine ultrasound
examinations. When abnormalities are detected, this should lead to a detailed
assessment focusing on amniotic fluid volume, renal size and parenchyma, the
collecting system, and bladder size. Dilatation of the renal pelvis and fluid-filled
areas as small as 1-2mm may be visualized in utero using high-resolution real-time
ultrasound.
Ultrasonography may allow differentiation of obstructive and non-obstructive
causes of megacystis, with the association of increased echogenicity and
oligohydramnios in the presence of bladder distension being predictive of an
obstructive aetiology. Similarly, in cases of hydronephrosis, Oliveira et al. showed
that oligohydramnios and megacystis were predictive of an obstructive aetiology,
with the sensitivity and specificity of the combination of both variables being 60 and
98% respectively. However, ultrasound
is of limited value in determinng the underlying aetiology causing the LUTO.9/11/2013
37. Treatment/
management
Open fetal surgery
The initial approach adopted involved open hysterotomy.
Harrison et al. performed the first successful in-utero
decompression for hydronephrosis in 1981. The maternal
morbidity associated with open surgery, and associated fetal
risks of preterm labour and neurological sequelae, have led to
the development of alternative minimally invasive techniques.
No new cases of open fetal surgery have been reported since
1988
Vesico-amniotic shunting
Ultrasound-guided percutaneous vesico-amniotic shunting is
the most commonly used method to relieve urinary tract
obstruction. This technique involves the placement of a double
pig-tailed catheter under ultrasound guidance
and local anaesthesia, with the distal end in the fetal
bladder and the proximal end in the amniotic cavity to
allow drainage of fetal urine.
Vesicocentesis
Fine-needle aspiration under ultrasound guidance
9/11/2013
38. References
• Diagnostic Ultrasound, 4th Ed vol 1;
Rumack, Wilson, Charboneau, Levine
• Problem-based obstetric ultrasound by
Basky Thilaganathan, Shanthi Sairam,
Aris T Papageorghiou and Amar Bhide.
• Posterior%20Urethral%20Valves%20Symp
toms%20and%20Treatment.htm
• Fetal lower urinary tract obstruction by
David Lissauer, Rachel K. Morris, Mark D.
Kilby in Seminars in Fetal & Neonatal
Medicine journal (2007)12, 464e470
available at www.sciencedirect.com9/11/2013
