Omphalocele

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Copyright, 1996 © Dale Carnegie & Associates, Inc.

Omphalocele

Origin from the Greek word

“Omphalos” meaning “center of the

world”

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Introduction

Abdominal Wall defects 3 subtypes

Gastroschisis Omphalocele Hernia of the umbilical cord

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Introduction

Integrity of the fetal abdominal wall

development depends on

appropriate craniocaudal and

lateral infolding of the embryonic

disk.

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Introduction

The migration and fusion of the

cranial, caudal and lateral folds

normally result in an intact

umbilical ring by 5 weeks

gestation.

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Introduction

Partial or complete arrest of this

process is believed to result in

omphalocele.

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Introduction

Failure of migration and fusion of the lateral abdominal folds is associated with the formation of a central abdominal omphalocele with insertion of the umbilical cord onto the central omphalocele sac with a surrounding fascial defect.

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Omphalocele

Defect is covered by a surrounding membrane (peritoneum and amnion)

Umbilical cord inserts into the sac Typically contain bowel and/or

liver, stomach and spleen

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Types of Omphalocele

Central - failure of fusion of lateral

folds

Epigastric - failure of fusion of

lateral and cephalic folds

Hypogastric - failure of fusion of

caudal and cephalic folds

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Omphalocele

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California Birth Defects Monitoring Program

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Comparison

OMPHALOCELE 1:4,000 to 10,000 Covering sac present Cord onto sac Herniated bowel

normal NEC if sac ruptured Failure of migration

and fusion of folds wk 3 to 5

Anomalies 45 to 55 % Survival 20%/70%

GASTROSCHISIS 1:20,000 to 30,000 Covering sac absent Cord onto abdominal

wall Bowel edematous,

matted NEC 18% Failure of return of

midgut to abdomen by wk 10

Anomalies 10 to 15% Survival 70-90%

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Omphalocele

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Gastroschisis

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Associated GI Anomalies Midgut volvulus Meckel diverticulum Intestinal atresia Intestinal duplication Malrotation

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Giant Omphalocele

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Chromosomal Anomalies Amniocentesis is indicated when

an omphalocele is identified in a fetus, because approximately 30 percent of fetuses with an omphalocele have a chromosome abnormality.

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Chromosomal Anomalies The most common chromosomal

abnormalities are Trisomy 18 Trisomy 13 Trisomy 21 Turner syndrome (45, X) Triploidy

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Chromosomal Anomalies Fibrochondrogenesis Amnion rupture sequence Carpenter syndrome CHARGE association Duplication 3q syndrome Fryns syndrome Hydrolethalus syndrome Killian/Teschler-Nicola syndrome Marshall-Smith, Meckel-Gruber, Melnick-

Needles, Miller-Dieker, Oto-Palato-Digital II.

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Associated Anomalies

Another syndrome that may be

associated with an omphalocele is

Beckwith-Wiedemann syndrome.

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Beckwith Wiedemann Syndrome

The cardinal features of this disorder are Exomphalos, Macroglossia, and Gigantism in the neonate.

This was the origin of the initialism EMG syndrome, used earlier as the preferred designation.

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Beckwith Wiedemann Syndrome Associated features - gigantism,

macroglossia, visceromegaly. Developmental abnormalities - Wilms tumor,

congenital heart defects, hemihypertrophy Inheritance - may be AD but expressed only

in individuals who inherit it from their mother. Caused by mutation at 11p15.5

Pathogenesis of the disease - involves deregulation of imprinted genes in the region

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Genetics of BWS

Expression of an allele depends on its parental origin.

Disease can occur if the normally expressed allele is absent or mutated: Deletion Uniparental disomy Chromosome rearrangement Mutation which leads to loss of

expression

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Beckwith-Wiedemann Syndrome Macrosomia, large muscle mass, accelerated

bony maturation Macroglossia, prominent eyes, large fontanels,

prominent occiput Linear fissures lobule of external ear,

indentations on posterior rim of helix Large kidneys, medullary dysplasia Pancreatic hyperplasia with excess of islets Focal adrenocortical cytomegaly Polycythemia, hypoglycemia, cryptorchidism,

isolated cardiomegaly, diaphragmatic eventration

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6 month old infant

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Beckwith-Wiedemann Syndrome Hepatomegaly, hemihypertrophy Adrenal carcinoma, Wilm’s tumor Gonadoblastoma, hepatoblastoma,

large ovaries, hyperplastic uterus and bladder, bicornuate uterus, hypospadias

Immunodeficiency Cardiac hamartoma, focal

cardiomyopathy

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Exstrophy of Cloaca Sequence Incomplete closure of caudal and

lateral folds Cloacal or bladder exstrophy Hypogastric omphalocele Vesicointestinal fissure,

imperforate anus, colonic agenesis

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???

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Omphalocele

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Associated Anomalies

Pentalogy of Cantrell Failure of closure of lateral and

cephalic folds Sternal defect (cleft sternum) Diaphragmatic defect (anterior

midline) Pericardial defect (absence) Abdominal wall defect (omphalocele) Cardiac anomaly (ectopia cordis)

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Associated Anomalies

Other anomalies are identified in

approximately 67 to 88 percent of

fetuses with an omphalocele.

The prognosis of the fetus often

depends on the presence of

associated anomalies.

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Gastroschisis

Small abdominal wall defect, lateral to the umbilicus

Umbilical cord attached to abdominal wall to the left of defect

No limiting sac, viscera often limited to small intestine and ascending colon

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Gastroschisis

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Gastroschisis

Ischemic compromise due to compression of mesenteric blood vessels when defect is small

Serositis and serosal peel result from amniotic fluid exposure

Ischemic changes and atresia are late events related to mesenteric constriction

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Hernia of the Umbilical Cord Occurs later in gestation At 8 to 11 weeks, normal

contracture of the umbilical ring occurs

Accompanied by return of the midgut to the abdominal cavity

Failure of umbilical ring contracture

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Hernia of the Umbilical Cord

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Hernia of the Umbilical Cord Small fascial defect, less than 4 cm An intact umbilical ring Generally, only small intestinal

herniation

Low cord clamping can cause

intestinal injury (small defect, failure

to appreciate herniated intestine)

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Management Advances in obstetric ultrasound have

allowed the diagnosis of abdominal wall defects in utero

Karyotype analysis when appropriate A large omphalocele, a syndrome- associated

omphalocele, Trisomy syndromes, or severe associated anomalies allows counseling for termination of pregnancy

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Management

In addition, prenatal diagnosis

improves management by allowing

maternal transport for labor and

delivery at a tertiary center

PLAN AHEAD

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Management

These infants have excessive heat, fluid and protein losses which must be replaced

Increased risk of contamination because of the absence of a protective barrier

Complete physical examination Attention to euglycemia Call the friendly neighborhood

surgeons

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Management Primary repair of ventral wall defect

with complete reduction Staged reduction of herniated viscera

large defects containing liver and intestine

Skin-flap closure without ventral wall repair multiple complex congenital anomalies

Nonsurgical methods uncorrectable congenital anomalies

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Umbilical scar after repair of Omphalocele