Congenital malformations - Edocr

CHAPTER 37 OMPHALOCELE 243
TABLE 37-1 Common Congenital
Malformations in Infants with Omphalocele
and a Normal Karyotype
Central nervous system
• Spinal defects
• Anencephaly
• Craniosynostosis
Cardiovascular system
• Ventricular septal defect
• Atrial septal defect
• Tetralogy of Fallot
• Coarctation of aorta
• Persistent pulmonary hypertension of
newborn
Genitourinary system
• Renal agenesis
• Hypospadias
Others
• Skeletal dysplasia
• Arthrogryposis
• Diaphragmatic hernia
• Cystic hygroma
except those directly related to the defect such as
malrotation of the gut, pulmonary hypoplasia. Associated
chromosomal abnormalities are rare in
infants with isolated omphalocele but nearly
half of all omphalocele infants with other structural
anomalies have an associated chromosomal
abnormality. 5,6 The commonly associated
structural anomalies in omphalocele infants with
a normal karyotype are listed in Table 37-1. The
likelihood of associated malformations is higher
in infants with a larger omphalocele.
According to the Online Mendelian Inheritance
in Man (OMIM) database, >50 syndromes
have been described in association with omphalocele.
Chromosomal abnormalities have been
reported in 20–60% of all liveborn infants with
omphalocele. The most frequently associated syndromes
are Beckwith-Wiedemann syndrome and
trisomy 13 and 18. The other commonly associated
syndromes are listed in Table 37-2. Associated
chromosomal abnormalities are more likely
in infants with small omphalocele with intracorporeal
liver. 1
EVALUATION
Prenatal diagnosis of omphalocele is easy and
fairly common. Maternal serum alpha-fetoprotein
(MSAFP) level is elevated in majority of fetuses
with omphalocele and nearly all infants can be diagnosed
on prenatal ultrasound. However, it is
important to remember that the late first trimester
ultrasound can result in an erroneous diagnosis of
abdominal wall defects because of normal physiologic
herniation of bowel into the base of the
umbilical cord. Amniocentesis for karyotype, prenatal
echocardiography, and detailed ultrasonography
evaluation for associated malformations
should be offered as soon as possible after a prenatal
diagnosis of omphalocele is made. All infants
should undergo echocardiography after birth
to exclude any congenital cardiac abnormalities
and karyotype should be obtained if not done
prenatally. The need for a cranial or a renal ultrasound
is less clear in the absence of any associated
malformations on clinical exam and cardiac
echo. Infants with Beckwith-Wiedemann syndrome
should be monitored for ongoing episodes
of hypoglycemia and should have kayotype and
methylation testing of chromosome 11p15.
MANAGEMENT AND PROGNOSIS
In several studies and meta-analyses, the mode of
delivery has not been shown to affect either survival
or morbidity in these infants. 7 All infants with
omphalocele should be carefully examined after
birth for the presence of associated anomalies and
clues to associated syndromes such as Beckwith-
Wiedemann syndrome. Serum blood sugar should
be monitored closely to exclude hypoglycemia
which is commonly seen in infants with Beckwith-
Wiedemann syndrome. These infants should also
be monitored closely after birth for signs of pulmonary
insufficiency and persistent pulmonary
hypertension of newborn. Primary repair and closure
of abdominal wall defect is the procedure of
choice but placement of silo and sequential reductions
are offered to infants with larger defects in
whom primary repair can compromise pulmonary