mately 2 to 3 in 10,000 births.2Jejunoileal atresia usu-
ally occurs more frequently than duodenal atresia. Mul-
tiple atresias are found in 7 to 20% of cases.1,3A few
cases of intestinal atresia with detailed descriptions of
prenatal sonographic findings have been reported.4-9
We present a case of isolated ileal atresia suggested by
results of prenatal sonography and confirmed by
postnatal radiographs with successful surgery. We also
discuss the clinical significance by reviewing recent re-
ports in the literature.
tresias are the most common congenital anoma-
lies of the midgut.1The incidence is approxi-
A23-year-old primigravida at 36 4/7 weeks of ges-
tation was referred with suggestion of fetal anomalies.
Prenatal sonography (Acuson, Aspen, CA, USA) re-
vealed a relatively enlarged fetal abdomen caused by
multiple markedly dilated fluid-filled loops with active
peristaltic movements (Fig. 1). The maximal diameter
obvious signs of dilated rectum or colon were identified.
Distal small intestine obstruction was suggested. No
other anomalies were found, including polyhydramnios,
organs (heart, kidney, liver, head and bones). Color
Doppler showed normal umbilical artery and ductus
venosus flow. After counseling, a 2964-g male infant
was delivered by cesarean section due to malpresentation
2 days after sonography. Apgar scores were 7 and 8 at 1
and 5 minutes, respectively. The chromosomal study
showed 46, XY. Abdominal distension was noted and
greenish bile-like materials were sucked fromthe stom-
ach. Oral contrast radiographs demonstrated distended
bowels, which suggested obstruction at the ileal level
(Fig. 2). Exploratory laparotomy on the third day
postpartum revealed an isolated ileal atresia, about 45
cm proximal to the ileocecal valve (Fig. 3). After cut-
ting 2 blind ends (about 20 cm in length) and tapering
the proximal dilated ileum, end-to-end primary anasto-
mosis was performed. Meconium and contrast medium
were passed on the second post-operative day. The in-
J Chin Med Assoc
1Department of Obstetrics and
Gynecology, Department of Radiology,
2Division of Pediatric Surgery, Veterans
General Hospital-Kaohsiung, Kaohsiung,
isolated ileal atresia;
Prenatal Sonographic Findings in a Fetus
with Congenital Isolated Ileal Atresia
Most cases of isolated nonduodenal bowel atresia are thought to be due to ischemic
events from hypotension, vascular accident, volvulus, intussusception and cocaine.
We present a case of isolated ileal atresia suggested using results of prenatal
sonography which showed multiple markedly dilated fluid-filled intestinal loops
with changeable shapes and positions secondary to active peristalsis. Postnatal oral
contrast radiography demonstrated obstruction located at the ileal level. Exploratory
laparotomy confirmed isolated ileal atresia. Primary end-to-end anastomosis was
ways havefatal prognosis, evenafter surgery. Casesof isolatedintestinalatresiausu-
ally have better prognosis and deserve more attention. Early diagnosis and early in-
tervention are both important for good outcomes.
Received: August 18, 2003.
Accepted: December 18, 2003.
Correspondence to: Fu-Nan Cho, MD, Department of Obstetrics and Gynecology, Veterans General
Hospital-Kaohsiung, 386, Ta-Chung 1st Road, Kaohsiung 813, Taiwan.
Fax: +886-7-346-0284; E-mail: firstname.lastname@example.org
fant endured the procedure well and was discharged 2
weeks after surgery.
The embryonic origins are different for duodenal
atresia and jejunoileal atresia. Duodenal atresia results
from failure of recanalization of lumen before the 10th
gestational week.1,10Some genetically determined fac-
tors may act to induce the transition from solid stage to
hollow stage. Autosomal recessive gene and trisomy 21
are partially responsible for the duodenal atresia.2,10
Most cases of isolated nonduodenal bowel atresia are
thought to be due to ischemic events from hypotension
(due to “brain-sparing” effect in the fetus), vascular ac-
cident, volvulus, intussusception and cocaine.2The
events resulting in ischemic necrosis of a segment of
the intestine may develop after the onset of fetal swal-
lowing, so that meconium may be present in the distal
bowel beyond the atresia.1Hereditory multiple intesti-
nal atresia has been associated with autosomal reces-
sive genetic syndromes including cystic fibrosis.2,4-6,11
Intestinal atresia can be classified into 4 types.12Type I
atresia is caused by a luminal diaphragm with continu-
ing outer muscular layer. In type II, the 2 blind ends of
the bowel are attached by a fibrous cord. Type III
Prenatal Sonographic Findings in Isolated Ileal Atresia
Fig. 1. Multiple dilated fluid-filled intestinal loops (I) pre-
sented with changeable shapes and positions secondary to
active peristalsis. (A) transverse view, (B) longitudinal
view. L = liver, H = heart.
Fig. 2. Oral contrast radiograph showed the markedly di-
lated small intestine (arrows) at the ileal level.
Fig. 3. Intraoperative photograph showed isolated type III
atresia with complete defect (arrow head) between the di-
lated proximal ileum (large arrow) and the small distal il-
eum (small arrow).
atresia is complete separation of the bowel ends. Type
fect. Type IIIb atresia is referred to apple-peel atresia.
Multiple atresia is classified as type IV. Our case was
Differential diagnosis of fetal abdominal cysts
should include origins from the ovary, urinary organ,
hepatic-biliary organ and intestine. Multiple cysts with
obvious peristalsis inclined the consideration of intesti-
nal lesions. More loops dilated usually means more dis-
tal obstruction and less severity of the polyhydramnios.
Absent signs of dilated rectum or colon in our case ex-
cluded the possibility of imperforate anus. Intestinal
volvulus often presents as a whorl-like cystic mass and
fixed dilated loops arranged in 2 to 3 parallel seg-
ments.13Isolated ileal atresia in our case showed multi-
ple markedly dilated fluid-filled loops with active peri-
staltic movements. The loops were shown communicat-
ing after careful tracing of the course of the dilated
loops using real-time ultrasound. Previous report has
mentioned the possibility that torsion of dilated bowel
may occur.7Congenital isolated ileal atresia has been
reported as a single cyst-like lesion due to the incom-
plete torsion of the dilated proximal small bowel.8Late
detection may lead to intestinal necrosis, resulting in
meconium peritonitis. However, the findings in our
case were different.
Patients with multiple intestinal atresia always
have poor prognoses, even after surgery.6,11Cases with
prenatally closed gastroschisis always suffer from ex-
tended intestinal atresia from the jejunum to the proxi-
mal transverse colon and lead to death.14Those with
especially when located at more distal portion, diag-
nosed prenatally and managed prior to the development
of severe distention or perforations of bowels. Accord-
ingly, isolated intestinal atresia deserves more atten-
tion. The favorable prognosis in our case resulted from
the absence of meconium peritonitis, meconium ileus,
malrotation, polyhydramnios, abnormal chromosome
and other congenital anomalies. Early obstetric inter-
vention, successful pediatric surgery and meticulously
intensive care of the newborn also helped achieve the
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Fu-Nan Cho et al.Journal of the Chinese Medical Association Vol. 67, No. 7