Gastroschisis Versus Omphalocele / Exomphalos

8/13/2019 Gastroschisis Versus Omphalocele / Exomphalos

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Gastroschisis Versus Omphalocele / Exomphalos

Author: Junise Swanson RNJonathan Weeks, M.D.

Objectives: Upon the completion of this CME article, the reader wille ale to!. E"plain the importance of makin# a distinction etween a

dia#nosis of #astroschisis $ersus omphalocele.

%. Descrie the associated anomalies that can e seen with

#astroschisis and omphalocele.

&. Discuss the o$erall pro#nosis and mana#ement of #astroschisis

and omphalocele.

Introduction'here are two main t(pes of $entral adominal wall defects seen

at the le$el of the umilicus that are detectale ( perinatal

ultrasound. 'hese are #astroschisis and omphalocele ) e"omphalos.

'he identification of these two anomalies ( ultrasound alon# with

ein# ale to differentiate etween them is essential for prenatal

dia#nosis, ostetrical mana#ement, and assessin# pro#nosis.

Definition and Incidence


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*astroschisis is a malformation of the adominal wall that

presents as a protrusion of $iscera throu#h a paraumilical defect.

'his condition has no known #enetic association. 'he defect usuall(

occurs to the ri#ht of the umilicus ut the umilicus is intact.

*astroschisis in$ol$es all the la(ers of the adominal wall. +s a result,

the small owel almost alwa(s e$iscerates throu#h the defect and

floats freel( in the amniotic fluid. 'here is no memranous co$erin#. t

is also unusual for the li$er, spleen, or ladder to herniate throu#h the

defect. 'he incidence of #astroschisis worldwide is aout ! per !-,---

li$e irths. owe$er, isolated cases of #astroschisis can occur at a rate

of aout / per !-,--- li$e irths in mothers under the a#e of %-.

0mphalocele 1E"omphalos2 is a midline defect where the

adominal contents herniate throu#h the ase of the umilicus. 'he

herniated adominal contents usuall( include the owel and stomach,

and often a portion of the li$er. 'hese contents are co$ered with a

translucent, a$ascular memrane, consistin# of peritoneum on the

inside and amniotic memrane on the outside, separated ( Wharton3s

4ell(. 'he incidence of omphalocele in li$e irths worldwide is aout %

per !-,--- and increases with maternal a#e.

Pathoenesis*astroschisis is a defect resultin# from a $ascular compromise of

either the ri#ht umilical $ein or the omphalomesenteric arter(.

Disappearance of the ri#ht umilical $ein 1prior to %56&% da(s after

conception2 ma( lead to ischemia and result in mesodermal and

ectodermal dama#e. +nother possiilit( is a $ascular accident

in$ol$in# the omphalomesenteric arter( that leads to a disruption of

the umilical rin# and hence, herniation of the adominal contents.


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'he patho#enesis of 0mphalocele ) E"omphalos is completel(

different. Durin# the de$elopment of the emr(o, four areas of tissue

con$er#e to complete the closin# of the adominal wall. 'hese are the

caudal 1lower2, cephalic 1upper2, and two lateral 1side2 folds. f the

caudal 1lower2 fold fails to fuse, it results in cloacal e"troph( of the

ladder. f the cephalic 1upper2 fold fails to fuse the result is

omphalocele with ectopia cordis 1the fetal heart outside the chest2

alon# with sternal and ) or diaphra#matic malformations 1often called

7entalo#( of Cantrell2. When the lateral 1side2 folds fail to fuse, this

results in isolated omphalocele producin# the herniation of owel and

usuall( li$er, stomach, and sometimes spleen dependin# on the si8e of

the defect. 'his herniation is contained within a memranous sac into

which the umilical cord inserts.

Associated Anomalies+ppro"imatel( 5-9 of #astroschisis cases are isolated

occurrences, ut !-9 to &-9 are associated with other malformations.

ntestinal tract complications are the most common and include

malrotation, atresia, stenosis, chemical irritation and thickenin# 1due to

direct e"posure with the amniotic fluid2, ischemia of owel sections

1due to kinkin#2, and owel ostruction. 0ther defects or

complications that ha$e een reported are con#enital heart defects,

h(drocephalus, pol(h(dramnios, oli#oh(dramnios, #enitourinar( tract

anormalities, and prune ell( s(ndrome.


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:or omphalocele ) e"omphalos, appro"imatel( ;-9 to /-9 are

associated with other serious anomalies. Chromosome anormalities

are seen in aout ;-9 of the fetuses with omphalocele. 1'o riefl(

re$iew, the normal #enetic makeup of an indi$idual should consist of

%% pairs of chromosomes, which are numered ! throu#h %%, with a

pair of se" chromosomes, for a total of %& pairs or chromosome ?

most often >A2, and triploid( 1which is an indi$idual with a

complete set of %& e"tra chromosomes ? such as =B >>>2. 0ther

sporadic disorders that ma( include omphalocele as a component are

7entalo#( of Cantrell 1as descried ao$e2 and eckwith6Wiedemann

s(ndrome 1which is a disorder of macrosomia in con4unction with an

enlar#ed li$er and kidne(s and a lar#e protuerant ton#ue ?

macro#lossia2. +ssociated cardiac defects are also common 1such as

$entricular septal defect and tetralo#( of :allot2 as are neural tuedefects, a two6$essel umilical cord, diaphra#matic hernias,

arterio$enous 1+2 malformations, low irth wei#ht, and a hi#her

incidence of preterm deli$er(.

!ltrasound "indins and Prenatal Dianosis


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:or #astroschisis, multiple echo#enic free6floatin# owel loops

near the anterior adominal wall can e $isuali8ed durin# an

ultrasound e$aluation. + memranous co$erin# or sac will not e

seen. 'here will also e an intact umilical cord insertion site seen to

the left of the defect. 7ol(h(dramnios or oli#oh(dramnios can also e

present. 'hese findin#s can e identified on a routine ultrasound

howe$er, a tar#eted scan should e done to e$aluate the fetal

anatom( for other possile anomalies. Earl( detection of additional

anomalies mi#ht affect pro#nosis. :actors that can sometimes make it

difficult to identif( #astroschisis are a low amount of amniotic fluid

1oli#oh(dramnios2, the si8e of the defect, the fetal si8e and #estational

a#e, and the fetal position. Detection efore !% weeks #estation can

e difficult due to the normal mi#ration of the fetal #astrointestinal

tract. 'he emr(onic owel normall( protrudes into the ase of the

umilical cord durin# the first trimester of pre#nanc(. 'he owel later

mi#rates ack into the adominal ca$it(. 'his process occurs etween

the 5thand !%thweek of #estation. 'herefore, it is important not to

make an incorrect dia#nosis of a fetal anomal( at this earl( #estational

a#e for a findin# that is a normal anatomical process.'he maternal serum alpha6fetoprotein 1MS+:72 is a screenin#

#enetic lood test that can e performed durin# pre#nanc(. alues are

recorded as anormall( low, normal, or anormall( hi#h. :or

#astroschisis, the MS+:7 le$el is anormall( ele$ated in B59 of the

cases. f an amniocentesis is performed, the amniotic fluid +:7 le$el is

also ele$ated. +cet(lcholinesterase 1+CE2 is another sustance that

can e tested for in amniotic fluid. Under normal circumstances, +CE

should not e detected in the amniotic fluid. owe$er, for

#astroschisis, +CE is detected in the amniotic fluid. f (ou comine

MS+:7 screenin# with a positi$e identification ( ultrasound, most

cases of #astroschisis can e dia#nosed prenatall( 1fi#ures ! F %2.


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:or omphalocele ) e"omphalos, a solid appearin#, round,

echo#enic mass ad4acent to the anterior adominal wall is seen on

ultrasound. 'he herniation is in the midline within a sac or memrane

and the umilical cord inserts into this mass. +mniotic fluid +:7 le$els

are also usuall( si#nificantl( ele$ated 1similar to #astroschisis2. +s

with #astroschisis, ( cominin# +:7 screenin# with a positi$e

identification ( ultrasound, a dia#nosis of omphalocele can usuall( e

made. With this dia#nosis, howe$er, a tar#eted scan for other

anormalities is $er( important due to the hi#h rate of associated

anomalies 1fi#ures & F


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:or omphalocele ) e"omphalos, serial ultrasound e$aluations are

indicated to follow fetal #rowth. ntrauterine #rowth restriction is also

common with this disorder, alon# with pol(h(dramnios and preterm

laor. Rupture of the memrane co$erin# is rare 1ut can occur2

howe$er, owel atresias are uncommon. @ar(ot(pin# 1throu#h #enetic

amniocentesis2 is usuall( recommended, especiall( in the presence of

other anomalies ecause of the hi#h rate of chromosomal

anormalities seen with omphalocele. +n omphalocele ( itself is not

an indication for cesarean section. :or a lar#e omphalocele containin#

li$er, the fear of in4ur( to the li$er with $a#inal deli$er( is a concern

and therefore, cesarean section is often recommended. Stillirths are

common amon# fetuses with omphalocele, especiall( in the presence

of other anomalies or chromosomal defects. Death durin# the

neonatal period depends on the other anomalies that ma( e seen in

addition to the omphalocele. Se$ere associated anomalies are

responsile for 5-9 to !--9 of the reported deaths. Sepsis and

complications from sur#ical repairs are responsile for less than !-9 of

the deaths. +ppro"imatel(, ;-9 of fetuses dia#nosed with

omphalocele will not sur$i$e 1a#ain, this is usuall( due to the otherassociated anormalities2. n the asence of other anomalies, the

outcome for a fetus with omphalocele is #ood. Sur#ical repairs can e

comple" and sta#ed closures are usuall( dependent upon the si8e of

the defect. 0mphaloceles are usuall( repaired within %< to


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'hou#h somewhat similar in their presentation 1an adominal

wall defect with an ele$ated maternal serum +:7 le$el2, #astroschisis

and omphalocele are distinctl( different. 'he( ha$e a dissimilar

patho#enesis and can carr( a different pro#nosis dependin# on the

associated anomalies, if present. t is important for ultrasono#raphers

to understand these differences when dealin# with a patient who is

carr(in# a fetus with one of these con#enital defects.

"iures! F % *astroschisis ? free6floatin# owel loops with no memrane

co$erin#.

& F < 0mphalocele ? mass ad4acent to the fetal anterioradominal wall with a memrane co$erin#.

&eferences or $uested &eadin:!. Creas( R@ and Resnik R. Maternal6:etal Medicine. 7rinciples and

7ractice. 7hiladelphiaG Saunders !BB


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5. Cher$enak :+, saacson *C, and Campell S. Ultrasound in

0stetrics and *(necolo#(, olume % US+G al !BB&.

B. Jones @H. Reco#ni8ale 7atterns of uman Malformation.

7hiladelphiaG Saunders !BB/.

!-. 7etriko$sk( M. :etal Disorders, Dia#nosis and Mana#ement.

New AorkG Wile(6Hiss !BBB.

!!. :leischer +C, Romero R, Mannin# :+, et al. 'he 7rinciples and

7ractice of Ultrasono#raph( in 0stetrics and *(necolo#(.

ConnecticutG +ppleton F Han#e !B5;.

About the Author

Junise Swanson recei$ed her achelors de#ree from theUni$ersit( of @entuck( in Nursin# in !B/=. She also conducted further

post6#raduate studies in iolo#( in !B5/ from the Uni$ersit( of

Houis$ille. She was a neonatal nurse for !< (ears in the Neonatal

ntensi$e Care Unit at the Uni$ersit( of Houis$ille ospital. :or the last

/ (ears she has een a 7erinatal Ultrasono#rapher at the Maternal

:etal Medicine Center at the Uni$ersit( of Houis$ille ospital, Norton

ealthcare3s Reproducti$e 'estin# Center, and 'he Maternal :etal

Medicine Center of the Norton Suuran ospital.

Jonathan Weeks, M.D. is a oard certified 0stetrician )

*(necolo#ist and 7erinatolo#ist. e is currentl( director of the

Maternal :etal Medicine Center at Norton Suuran ospital. Dr.

Weeks has se$eral pulications in peer6re$iew medical 4ournals and has

lectured at numerous meetin#s across the countr(.

Examination:!. *astroschisis is a malformation of the adominal wall that

+. is commonl( associated man( different #enetic disorders.. usuall( occurs to the left of the umilicus ut the umilicus

is intact.C. onl( in$ol$es a few la(ers of the adominal wall.D. has no memranous co$erin#.


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E. allows adominal contents to herniate throu#h the ase ofthe umilicus.

%. 'he incidence of #astroschisis worldwide is aout+. ! per !-,--- li$e irths.

. % per !-,--- li$e irths.C. & per !-,--- li$e irths.D. < per !-,--- li$e irths.E. ; per !-,--- li$e irths.

&. 0mphalocele 1E"omphalos2 is a midline defect+. where the adominal contents herniate to the ri#ht side of

the umilicus.. that rarel( contains the li$er, owel, and stomach.C. that allows adominal contents to herniate throu#h the

ase of the umilicus.

D. that has no memrane co$erin#.E. where the adominal contents herniate to the left side of

the umilicus.


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C. #astroschisisD. 7entalo#( of CantrellE. ectopia cordis

5. 'he most common associated anomal(1s2 seen with #astroschisis

is 1are2+. prune ell( s(ndrome. #enitourinar( tract anormalitiesC. con#enital heart defectsD. intestinal tract complicationsE. h(drocephalus

B. +ssociated anomalies seen with #astroschisis include all of thefollowin# e"cept

+. intestinal tract complications such as malrotation, atresia,and stenosis.

. ischemia of owel sections due to kinkin#, and ostruction.C. con#enital heart defectsD. #enitourinar( tract anormalitiesE. trisom( !5.

!-. n re#ard to omphalocele ) e"omphalos, chromosomeanormalities are seen in aout IIIIIII of fetuses.+. !-9.. ;-9C. %;9D. /;9

E. B-9

!!. 0mphalocele can e seen with numerous different chromosomeanormalities includin# triploid(, which is a fetus with+. .


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!&. 'he ultrasound findin#s for #astroschisis ma( include all of thefollowin# e"cept

+. multiple echo#enic free floatin# owel loops near theanterior adominal wall

. no e$idence of a memranous co$erin# or sac

C. pol(h(dramniosD. oli#oh(dramniosE. an umilical cord that inserts into the mass

!


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C. kar(ot(pin# 1#enetic amniocentesis2 should alwa(s erecommended ecause most cases of #astroschisis areassociated with chromosome anormalities.

D. the patient should deli$er ( cesarean sectionE. if the case is an isolated #astroschisis the o$erall pro#nosis

is $er( poor with a sur$i$al rate of less than !-9.

!5. Re#ardin# a potential dia#nosis of #astroschisis, one potentialconcern that ma( result in some prenatal testin# centers offerin#further #enetic testin#, such as amniocentesis, is+. the issue that an omphalocele ma( ha$e ruptured throu#h

its memrane co$erin#, mimickin# the appearance of a#astroschisis.

. the presence of owel ischemia due to kinkin#.C. the presence of oli#oh(dramnios.D. the presence of an ele$ated maternal serum alpha6

fetoprotein.E. the presence of owel thickenin# due to prolon#ed

e"posure to amniotic fluid.

!B. With a dia#nosis of omphalocele ) e"omphalos,+. serial ultrasound e$aluations are indicated to watch for

macrosomia ecause it is common with this disorder.. rupture of the memrane co$erin# is $er( common findin#.C. kar(ot(pin# 1#enetic amniocentesis2 is usuall(

recommended, especiall( in the presence of otheranomalies.

D. if the defect is lar#e containin# the li$er, the patient shoulde informed that it is less traumatic to the li$er to deli$er$a#inall(.

E. the risk of stillirth is rare ecause omphalocele is usuall(not associated with other anomalies or chromosomaldefects.

%-. ecause of the other associated anormalities, appro"imatel(IIIIII of fetuses dia#nosed with omphalocele will not sur$i$e.+. !-9. %;9

C. &;9D. ;-9E. /;9

Documents

Gastroschisis Versus Omphalocele / Exomphalos