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Download Esophagus Stomach Duodenum Small intestine Large bowel
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Ugochi Akoma, MD
Fellow, Maternal Fetal Medicine
Esophagus
Stomach
Duodenum
Small intestine
Large bowel
Esophagus and trachea originate from the
median ventral diverticulum of the forgut,
separated
p
by
y esophago-tracheal
p g
septum
p
TEF: esophageal and trachea fail to separate
during division of the endoderm
Esophageal atresia: tracheal structure is
composed of mostly of the endoderm
Describe anomalies of the fetal GI system
à Esophagus
à Stomach
à Small and large intestine
Identify fetal GI anomalies associated with
an increased risk of chromosomal
abnormalities
Explain fetal GI anomalies with associated
amniotic fluid abnormalities
Usually
y collapsed
p
in fetal life
Imaged only as two to four echogenic lines
representing the anterior and posterior walls
Nonlinear and all regions can not be imaged
simultaneously under normal conditions
Visualization of fetal swallowing has been
described in late gestation
(A) The laryngotracheal diverticulum
forms as a ventral outpouching from the
caudal part of the primitive pharynx.
(B) Longitudinal tracheoesophageal folds
begin to fuse toward the midline to
eventually form the tracheoesophageal
septum.
(C) The tracheoesophageal septum has
completely formed.
(D) If the tracheoesophageal septum
deviates posteriorly, esophageal atresia
with a tracheoesophageal fistula develops
*MID PORTION OF ESOPHAGUS
DOES NOT DEVELOP*
1
Incidence is between 1:3,570 -4,500.
Fetal gender: Males > Female
30-50%: congenital anomalies (35% cardiac; 30%
musculoskeletal)
20-30%: premature
VACTERL syndrome:
85%
Most common
Small Stomach
2%
Proximal TEF
No distal fistula
Absent stomach
Gasless abdomen
Often has a long
gap between the
Esophageal ends
Polyhydramnios
Vertebral anomalies:
Anal: imperforate anus, duodenal atresia
Cardiac: VSD, PDA, TOF, coarction of aorta, ASD
Trachea: TEF
Esophageal: EA
Renal: renal agenesis,ureteral abnormalities, hypospadias
Limb: polydactyly, vertebral, radial), wrist/knee anomalies
6%
Atresia alone,
no fistula
Absent stomach
Gasless abdomen
Usually has a long
gap between the
esophageal ends
Polyhydramnios
l%
Proximal and
distal fistulas
("double fistula")
Small stomach
Polyhydramnios
2
System affected
Musculoskeletal
Musculoskeletal
6%
No atresia of
p g
the esophagus
Fistula only
Normal stomach and
Amniotic fluid
Gastrointestinal
Cardiac
Genitourinary
Antenatal Diagnosis
Polyhydramnios
Small or absent stomach
Distended upper esophageal pouch
Abnormal swallowing
Potential anomalies
Hemivertebrae, radial dysplasia or
amelia, polydactyly, syndactyly, rib
malformations, scoliosis, lower limb
defects
Imperforate anus, duodenal atresia,
malrotation, intestinal
malformations,
Meckel s
alformations Meckel's
diverticulum, annular pancreas
Ventricular septal defect, patent
ductus arteriosus, tetralogy of Fallot,
atrial septal defect, single umbilical
artery, rightright-sided aortic arch
Renal agenesis or dysplasia,
horseshoe kidney, polycystic kidney,
ureteral and urethral malformations,
hypospadias
Is it visible?
Is it too small?
Is it in the proper location?
Is it too large?
Diagnostic suspicion is increased when
abnormalities known to be associated with
esophageal atresia are identified
Can Confirm with MRI
From www.ob-ultrasound.net
3
Defect in the developing diaphragm of the fetus
leading to…
1 in 2000 to 5000 live births
Hernation of abdominal contents occurs through
Herniation of abdominal viscera into the thorax
Significant pulmonary, cardiac, and gastrointestinal
sequelae
*Posterolateral defect (foramen of Bochdalek) in ~ 95%
Retrosternal herniation (foramen of Morgagni) in ~ 5%
Location
Left-sided CDH are more common (80%)
Right-sided CDH are less common (20%)
Rarely bilateral
%
Associated with g
genetic anomalies: 10-20%
Smith—Lemli Opitz syndrome
DiGeorge syndrome
Chromosome 15,18,13 and 21 anomalies
*Survival depends on degree of pulmonary
hypoplasia*
4
60% antenatal detection rate
Usually seen initially at prenatal anatomy
ultrasound
High-Resolution
g
ultrasound in the 1st/2nd trimester
can visualize the diaphragm
*Can be missed even on early 2nd trimester U/S
Polyhydramnios
Intrathoracic stomach or liver
Observe for other anomalies
Fetal echo is recommended
à Incidence of associated cardiac anomalies up to 25%
If ultrasound is positive, consider MRI
Recently fetal MRI and fetal echocardiography,
helpful to determine degree of pulmonary
hypoplasia.
Amniocentesis is recommended to provide
information regarding possible chromosomal
abnormalities
Stomach
“Double bubble” sign
Duodenum
5
Not usually diagnosed prior to 24 weeks of
gestation
“Double bubble” sign common
Trisomy
risomy 21 present in 30%
Congenital heart disease present in 30%
Other associated GI anomalies are common
No fetal sex differentiation
Association with anomalies of the VACTERL
spectrum
Incidence--11 in 5,000 -10,000 live births
Incidence-75% of stenoses and 40% of atresias are found
in Duodenum
Multiple atresias in 15% of cases
50% pts are LBW and premature
Polyhydramnios in 75%
Caused by failure of recanalization of the
bowel lumen
Doesn’t change from solid Æ tube structure
6
Jejunal is most common
1 per 2,000 live births
Atresia due to inin-utero occlusion of all or
part off the
h blood
bl d supply
l to the
h b
bowell
Classification-Classification
--Types
Types II--IV
*Duodenal= Failure of canalization
*Distal bowel = Ischemic process
Defect in ventral abdominal wall
Defect covered by peritoneum
Umbilical cord inserts into this membrane
High incidence of chromosomal anomalies
Omphalocele
Higher if liver NOT in sac
Higher with smaller defect
Gastroschisis
7
Full-thickness defect in abdominal wall
Usually to right of umbilical ring
Not associated with increased risk of
chromosomal anomalies
Not associated with extra-gastrointestinal
extra gastrointestinal
abnormalities
Other GI anomalies occur in 20-40%
Volvulus
Malrotation
Infarction
IUGR occurs in up to 75%
From www.obgyn.net
8
Bowel echogenicity comparable to bone in 2nd
trimester
Increased incidence of Down syndrome
Rarely an isolated finding in Down syndrome
Likelihood ratio = 12.7-21.9
??What else can this be??
Normal
Cystic Fibrosis
Viral infection
Swallowed blood
The double bubble sign represents duodenal
atresia and an increased risk of chromosomal
anomalies
Omphalocele,
O
h l l but
b t nott gastroschisis,
t
hi i represents
t
an increased risk of chromosomal anomalies
The End
Echogenic bowel in the 2nd trimester is a
genetic marker for chromosomal anomalies
9
