Anorectal Atresia

6
39 5 Anorectal Atresia: Prenatal Sonographic Diagnosis Robert D. Hams1 To determine the prenatal sonographic findings of a no re ctal a tre sia (AR A), we retro- David A. Nyberg spectively review ed 12 proven cases. Sonography showed abnormally dilated bowel Laurence A. Mack  9ment5 in five cases (42 ), four of which w ere ide ntified prosp ective ly ; at a uto ps y, E dw ard W ein ber” er  other cases showed m ild colon dilatation not evident on sonograms. Bowel dilatation  w as n ot associated with the location of atresia or the presence of a fistula, but was possibly related to menstrual age. E le v e n fetuses (92 ) had significant other anomalies prim arily related to the VACTERL syndrom e (vertebral defects, anal atresia, tracheo- esophageal fietula with esophageal atresia, radial and ren al d y sp la s ia , and l im b m a lf or - mations) and/or the caudal regression syndrom e; of these, sonography identified one or more concurrent anom alies in seven cases. In tw o c ses, bowel dilatation was the prim ary s o n og ra p hic fin din g. D eath in nine cases resulted from te rm in atio n of p re gn an cy (fo ur c a se s ) o r perinatal d em is e (five cases); three patients ar e s t il l alive. W e conclude that some cas s of ARA can be suspected on prenatal sonograms b y demonstration of dilated colon, and that the sensitivity of this finding m ay be related to menstrual age at the tim e of the examination. Distinguishing ARA from other causes of fetal-bowel dilatation is important because of the frequency of concurrent anomalies associated with ARA. Anorectal atresia (ARA) is a major congenital malformation that occurs in about one of 5000 live births [1]. Recogni ion of ARA is important not only because surgical correction is required after delivery but also because it is frequently associated with other anomalies [2-7]. An association between v erte bral, a n a l, cardiovascular, tracheoesophageal, renal, and lim b m alformations has b en rec- ognized and termed the VACTERL syndrome [2-7]. Anorectal anomalies are also found frequently in association with sacral agenesis and lower lim b hypoplasia as part of the caudal regression syndrome [8]. Prenatal detection of ARA has been reported infrequently. Two previously published case reports suggest that dilated fetal bowel seen on prenatal sonogra- phy may result f om ARA as well as from other causes of bowel obstruction [9, 10]. Recently, we also encountered several cases of ARA that presented with abnormally dilated fetal bowel segments. However, the frequency and significance of this observation and its association ith other sonographic findings remain unknown. Furthermore, quantitative comparison with normal bowel measurements has not been studied previously. To determine the usual sonographic findings in fetuses with ARA, we undertook the present study of 1 2 proved cases. R ece ive d F eb ru ary 4 1987; accepted after re- v is io n A pril 7 , 1 98 7. I A l l a u th o rs : Department of R ad io lo gy . S B -0 5, Matenals and Met ods  Our review of clinical and pathologic records covering a 5-year period (i9 8i -1 98 6) y ie ld ed berg. 1 2 fetuses with ARA for whom a prenatal sonogram was available for e va lu atIo n. A no re ct a l  R 149:395-400, August 1987 m alform ations that w ere considered a part of ARA included im perforate anus, anal agenesis, 0361-803X/87/1492-0395 anorectal agenesis, and rectal atresia. Indications for sonography included size less than 0 American Roentgen Ray Society dates (four cases), determination of menstrual age (three cases), premature la or (three

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39 5

A n o re c ta l A tre s ia :

Prenat a l

S o n o g ra p h ic D ia g n o s is

R o b e rt D . H a m s 1 T o d e te rm in e th e p re n a ta l s onogr aph ic fin d in g s o f

a no re cta l a tre sia

(A R A), w e re tro -

D a v id A . N y b erg spec t ive ly re v ie w ed 1 2 p ro v e n c a s es . S o n o g ra p h y s h o w e d a b n o rm ally d ila ted b o w el

Lau rence A . M ack  9 m e n t5 in fiv e c as e s (4 2 ) , fo u r o f w h ic h w ere ide ntified p rosp ec tive ly ; a t a uto ps y,

E dw ard W ein ber” er   o th e r c a s e s s h o w ed m ild c o lo n d ila ta tio n n o t e v id e n t o n s o n o g r a m s . B o w e l dila tation

  w as n ot a s s o c ia te d

with

th e lo c a tio n o f a tre s ia o r th e

presence

o f a fis tu la , b u t w as

poss ib ly re la ted to m enstru a l age . E leven fe tu ses (92 ) h ad s ign ifican t o th e r a nom alies

prim arily re la te d

to th e V A C T E R L s y n d ro m e (v e rte b ra l d e fe c ts , a n a l a tre s ia , t racheo-

es op ha g ea l fie tu la w ith e so p h a g e a l a tre s ia , ra d ia l a n d ren al dy sp las ia , an d l im b m a lf or -

ma t io n s ) and /o r th e c a u d a l re g re s s io n s y n d ro m e; o f th e s e , s o n o g ra p h y id e n tifie d o n e

o r m o re c o n c u rren t a n o m alie s in s e v e n c a s e s . In

tw o

c a s e s , b o w e l d ila ta tio n w a s th e

p rim ary s o n og ra p hic fin din g. D ea th in n in e c a s e s re s u lte d f rom te rm in atio n o f p re gn an cy

(fo ur ca ses ) o r per ina ta l d em is e (f iv e c a s e s ); th ree pa t ien ts ar e s t il l a li ve .

W e

conc lude

th a t s o m e ca s e s o f A R A

ca n b e su sp ec te d o n p re na ta l s on og ra m s

b y

d e mo n s t ra t i o n

o f d ila te d c o lo n , a n d th a t th e s e n s it iv ity o f th is fin d in g m ay b e re la te d to

mens trua l

a g e a t th e tim e o f th e e x a m in a tio n . D is tin g u is h in g A R A fro m o th e r c a u s e s o f

f e ta l - bowe l d i la ta t ion is im p o rta n t b e c a u se o f th e freq u e n c y o f

concu r ren t

a n o ma l ie s

ass oc ia te d w ith A R A .

A no recta l a tre s ia (A R A ) is a m a jo r co nge n ita l m a lfo rm a tion th a t occu rs in a bou t

one o f 50 00 live b irths [1 ]. R e cog n it ion o f A R A is im po rtan t no t on ly because

s u rg ica l co rre c tio n is re q u ire d a fte r d e live ry b u t a lso b e c a u se it is fre q u e n tly

a s so c ia te d w ith o th e r a n o m a lies [2 -7 ]. A n a ss o c ia tio n b e tw ee n

v erte bra l, ana l,

ca rd iovascu la r , tracheo esoph age a l, ren a l, and lim b m alfo rm a tion s ha s be e n re c-

ogn ized an d te rm ed th e V A C T E R L synd rom e [2 -7 ]. A no rec ta l a nom a lies a re a lso

fo un d fre q u e n tly in a ss o c ia tio n w ith sa cra l a g e n e s is a n d lo w e r lim b h yp o p la s ia a s

p a rt o f th e c a ud a l re g re ss io n s yn d ro m e [8 ].

P re n a ta l d e te c tio n of A R A h a s b e e n re po rte d in frequ en tly . T w o pre v io us ly

p ub lish ed ca se rep o rts sugg est tha t d ila ted fe ta l b ow e l se en o n pren a ta l son ogra -

p h y m a y re s u lt fro m A R A a s w e ll as fro m o th e r c au s e s o f b o w el o b s tru c tio n [9 ,

1 0 ]. R e ce n tly , w e a lso e n co u n te re d se v e ra l ca s e s o f A R A th a t p re s e n te d w ith

a b n o rm a lly d ila te d fe ta l b o w e l se g m e n ts . H o w e ve r, the fre q u en c y a n d s ig n ifica n c e

o f th is o b s e rva tio n a n d its a s so c ia tio n w ith o th e r s o n o g ra p h ic fin d in g s re m a in

u n k n o w n . F u rth e rm o re , q u a n tita tive c o m pa ris o n w ith no rm a l b o w e l m e a su re m e n ts

h a s n o t b e e n

s tud ied p rev iou s ly . T o de te rm ine the usu a l so nogra ph ic fin d in gs in

fe tuses w ith A R A , w e un derto ok the p re sen t s tu dy o f 1 2 p roved ca ses .

R ece ive d F eb ru ary 4 19 87 ; a cce p te d a fte r re -

v is io n A pril 7 , 1 98 7.

I

A l l a u th o rs : Depar tmen t o f R ad io lo gy . S B -0 5, M a te n a ls a n d M e th o d s

  O ur re v ie w o f c lin ic a l a nd p a th o log ic re co rds co ve ring a 5 -y ea r pe rio d

( i9 8i -1 98 6) y ie ld ed

b erg . 1

2 fe tu s e s w ith A R A fo r w h o m a p re n a ta l s o n o g ra m w a s a v a ila b le fo r

e va lu atIo n. A no re cta l

  R

14 9 :3 95 -4 00 , A u gu st 1 98 7 m alform atio n s th at w ere co n s id e re d a p a rt o f A R A in c lu d e d im pe rfo ra te a n us , a n a l a g e n es is ,

0 3 61 -80 3 X /87 /14 9 2-0 3 95 a n ore c ta l ag e ne s is , a n d re c ta l a tre s ia . In d ica tion s fo r so n og ra ph y in c lu d ed s ize less th an

0 A m e ric an R o e n tg en R ay S oc ie ty d a te s (fou r ca se s ), d e te rm in a tion o f m e ns tru a l ag e (th ree c ase s ), p rem atu re la bo r (th ree

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C a s e

N o.

A ge

(w e e k s )

Sonogr aph ic F in d ing s P a th o lo g ic an d S u rg ica l

Find ings

C o lo n

D ia me te r

( m m )

O th e r

F e ta l

O u tc o me

Loca t ion

o f A RA

Fis tu la

O th er A n om a lie s

2 2 2 N o tse e n

3 2 4 N o tse e n

V T O P N A Y e s

O m ph alo ce le , m en in go my elo -

ce le

A n h y d ra m n io s h yd ro ce p h a lu s V T O P

A nh yd ram n ios , ren a l a ge ne s is V T O P

M ulticys tic dy sp la s tic k id ne y

Al ive

5 3 0 i 3 (re tro s p e c- H y d ro ce p h a lu s , a n h yd ra m - D e a th

tiv e ) n ios , ren a l ag en es is , sa cra l

agenes is

6 2 9 20 P o ly h yd ram n io s , fe ta l a s c ite s D ea th

7 35 22

8 2 6 2 0

9 2 6 N o ts e e n

io 1 9 N o ts e e n

ii 2 7 N o ts e e n

i2 2 i N o ts e e n

A nh yd ram n ios D ea th

Al ive

Al ive

N o t e . - V TO P

= v ol un ta ry t er m in a ti on

o f p re gn a nc y ; N A

= in fo rm atio n no t a va ilab le fro m p ath olo gy

repo r t .

39 6

H A R R IS E T A L .

c ase s ), m a te rn a l d ia be tes (on e ca se ), a n d su spe c te d a b sen t fe ta l

h ea rt to nes b y D op p le r (o n e ca se ).

A ll

so n o g ra m s w ere O bta in ed with c o mme rc ia l l y

a va lla bl e r ea l- ti me

so no gra ph ic eq u ip m e n t. T he pro sp ect ive so nog ra ph ic f in d ing s w ere

n o te d , an d e a c h sonogram w as a ls o rev iew ed re tro sp e ct ive ly b y tw o

sonographers

fo r th e p re s e n ce , s ize , a n d

loca t ion

o f fe ta l b ow e l

s e g m en ts . W he n d isc re te c o lo n se g m en ts w e re id e n tifie d , th e d ia m -

e te r w a s m ea s u re d fro m th e in n e r b o w e l w all. T h e s e re s u lts w ere

c o m p a r e d

w ith c o lo n d ia m e te r m e a s u re m e n ts m a d e fro m 1 20 ra n -

A JR :1 49 , A ug us t 1 98 7

dom ly se le c te d n orm al fe tuses see n be tw e en 20 to 4 0 m enstru a l

w e ek s w h o h a d n o rm al

c lin ic a l e va lua tio ns a fte r b irth .

F e ta l o u tco m e fo r th e i 2 fe tu se s w ith A R A in c lu d e d te rm in a tio n o f

pre g na nc y (fou r c a se s), p e n n a ta l d e m ise (five c a se s), o r s u rv iva l

beyond th e n e o n a ta l p e rio d (th re e ca se s ). A ll p a tie n ts w e re p rov e d

to ha ve A R A b y su rg e ry (th re e ca se s ) o r au top sy (n in e ca se s ). T he

lo c a tio n o f a tre s ia w as ca tego r ized a s e ith e r h ig h (a b ov e th e le va to r

s lin g ) or lo w (b e lo w th e lev a to r s lin g ). T h e p re se n ce of a n a ss o c ia te d

d is ta l co lo n ic fis tu la w a s a lso n o te d , w h e n kn o w n . T h e p re se n c e o f

T A B L E 1 : S on og ra ph ic , C lin ic al, an d P ath o lo g ic F in d in gs In A no re c ta l A tre s ia (A RA )

i i8 N o tse en

4 2 3 N o ts e e n

27 9

33

27

A n h y d ra mn io s D ie d i w e ek

a ft er b ir th

D e a th

H yd roc ep ha lu s, m en in go my e-

V T O P

l oc al e, s co li os is

O lig oh yd ra mn io s (p re ma tu re

ru ptu re o f m em bra ne s)

O mph a loc e le , sm all-

b o w e l

a tr es ia , s ac ra l

agenes is , me n in g o -

mye loce lc

H igh N o S ire n om e lia , re na l a g en -

e s is , r ad ia l d y s pl as ia ,

hyd rocepha lus

H igh Y es S ire nom e lia , ab se n t

g en it ali a, r en al

a g e n e -

s is , m ild ly d ila te d d is -

t al c olo n

H igh N o S m a ll-bo w e l as tre s ia ,

a nn ula r p an cr ea s,

re na l d ys pla sia , sa c-

r a l a g en e si s

H ig h N o S iren om e lia , re n a l ag e n-

e sis , r ad ia l d ys pla sia ,

a tna l se pta l d efe ct,

h yd roc ep ha lu s , d i-

la te d d is ta l c olo n

H ig h Y es E so p ha ge a l a tres ia w ith

t racheoesophagea l

fis tu la , ve rte bra l m al-

fo rm atio ns , re n a l dys -

p la s ia , d ila te d d is ta l

co lon

H ig h N o E s op ha gea l a tre s ia w ith

t r ac heoes ophagea l

fis tu la ; a bse nt g en i-

ta lia ; r ig ht c ys tic d ys-

p la stic k id ne y, le ft

r en al a ge ne sis ; te tra l-

og y o f F allo t; s ho rt

ex tre m it ies , ro ck e r-

bo t tom f ee t; d il at ed

co lo n fille d w ith

m e-

con ium

H ig h Y e s tke th ra l a tre s ia , m e n in -

goc e le , a m b ig u o u s

g en it al ia , m i ld ly d i-

la te d c olo n

L o w Y e s A m b ig u o u s g e n ita lia , d i-

l a t ed co lon / i leum,

c lu b fo o t

H ig h N o H yd roce p ha lu s , m en in -

g o m ye lo ce le , sco -

Iiosis

H igh N o T e tra log y o f F a llo t,

c ryp to rch id ism

L o w N A N o n e

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22 2 4 26 28 3 3 2 34 36 38 4 42

M E N S T R U A L A G E (w e e k s )

F ig 3 .-C o lo n d ia m e te rs from

fou r fe tu se s w ith a n o re c ta l

a tr es ia ( do ts )

co m pa red w ith va lu es ob ta in ed fro m 120 n orm a l fe tu se s (m ea n ± 2 S D ).

O n e c ase (cas e 4 ) s howed p ro gre ss ive (a rro w) co lo n d Ila ta tiO n fro m 2 7 to

33 w e e k s .

F ig . 1 .-Case

7.

C o ro na l s on og ra m

at 3 5 w e ek s

sho ws s eg me nt

o f

d ila ted co lo n (C ) in fe ta l pe lv is

m e as uring 2 2 m m In d iam ete r. N o te V co n fig u ra -

ho n o f d il at e d b ow el se gm en t

F ig . 2 .- C as e 6.

A S a gf tt al s on og ra m

at 29

w e ek s s ho w s p o ly hy d ra m n io s . C = fe ta l cran iu m .

B Ad jacen t sonogram s h o w s d ila ted s eg m e n t o f b ow el (B ) in fe ta l pe lv is a n d a sc ite s (a r ro w s) . A t

bir th, in fant w as

found

to h av e

m u lt ip le a no m ali es

inc lud ing bo th

a no re ct al a tr es ia

a nd e so ph ag ea l

a tr es ia w i th t ra c he o es o ph a ge a l fis tu la . T he in fan t d ied 1 w e ek afte r de l ive ry .

A JR :i 49 A ug us t 1 98 7

A N O R E C T A L A T R E S IA

39 7

c onc u r r en t anoma l ies

w as d e te rm in e d b y c lin ic a l, s u rg ic a l, a n d a u -

t op sy e xa m in at io n.

R e s u f ts

Sonograph ic

f in d in g s a re c o m p a re d w ith p a th o lo g ic a n d

c l in ica l resu lts in T a b le 1

.

O f the 1 2 fe tu se s s tud ied , five

sh ow ed a t le as t o ne segm en t o f ab norm ally d ila te d fe ta l bow e l

(F igs . 1 a n d 2 ). In fo u r o f th e se ca se s , th e ab n o rm a lity w a s

p ro s p e ctiv e ly re c o g n iz ed a t th e tim e o f th e in it ia l so n o g ra m ;

in one o th e r case , it w as

s e e n

on re tro spe ctive re v ie w . In

e a c h c a s e , th e

loca tio n and ap pea rance o f th e bow el segm en t

su gge ste d tha t it re p resen ted co lon . C o lon d iam e te rs fo r

these

f iv e ca s e s w e re g re a te r th a n 2 S D a b o v e n o rm a l c o lo n

d iam e te rs , as d e te rm in ed from 1 20 n orm a l cases (F ig . 3 ). In

th e o the r seve n ca se s, d isc re te bow e l segm en ts w e re n o t

id en tifie d e ith er p ro sp ec tiv ely o r re tro sp ec tiv ely .

O f the five cases w ith so nog raph ica lly de tectab le bow e l

d ila ta tio n , fou r show ed a n an echo ic seg m en t o f bo w e l lo ca ted

in th e pe lv is o r low e r a bdo m en , and th ree d em o nstra ted a V

o r U c o n fig u ra tio n (F ig s . 1 a n d 2 ). In o n e c a s e , a lo n g s e g m e n t

o f d ila ted co lon , f illed w ith e cho gen ic m e co n iu m , w as im age d

around th e p e r ip h e ry o f th e a b d o m e n (F ig . 4 ). T h is c a s e a ls o

d e m on s tra te d a c tiv e c o lo n p e ris ta ls is , n o te d p ro s p e c tive ly o n

r ea l-tim e s on og ra ph y.

T h e p re s e n c e o f c o lo n d ila ta tio n s e e n b y s o n o g ra p h a n d /

or a t a u top sy a ppe ared to b e re la ted to m ens trua l age . C o lon

d ila ta tio n w as no t seen so nog ra ph ica lly in an y o f the fou r

ca se s e x a m in e d a t o r b e fo re 2 2 w e e k s , w h e re a s a ll th re e

cases se en

a fte r 2 7 w e e k s d e m o n s tra te d d ila te d c o lo n . B e -

tw ee n 23 and 27 w ee ks , one o f five cases had son ogra ph ica lly

de tec tab le co lon d ila ta tio n , and tw o o th e r ca s e s h a d d ila te d

co lon s o n pa tho lo g ic exa m in a tions . T he ea rlie s t tha t co lo n

d ila ta tio n w a s d e te c te d b y s o n o g ra p h y w a s 26 w e e k s , a l-

thou gh m ild co lon d ila ta t ion w as fo und pa tho log ica lly as ea rly

a s 2 4 w e e ks . O n e c a se w ith m in im a l co lo n d ila ta tion (9 m m )

a t 2 7 w e e ks e n la rg e d s ig n ific a n tly to 2 7 m m b y 3 3 w e e ks

(F ig . 4 ).

N o c o rre la tio n w a s o b s erve d b e tw e e n c o lo n d ila ta tio n a n d

the s ite o f a tres ia o r the p re se nce o f a fis tu la . T h e lo ca tion o f

A R A w a s re p o rte d b y s u rg ic a l o r a u to p s y fin d in g s a s h ig h

(s u pra le v a to r) in n in e c a se s , lo w (in fra le va to r) in tw o

cases,

and no t rep o rte d in on e ca se . A fis tu la w a s iden tified in five

ca se s ; tw o o f th e se sh o w e d bo w e l d ila ta tio n .

E leven ca se s (92 ) had co ncu rren t m alfo rm a tion s in a dd i-

tion to A R A (T a b le 1 ); o f these , se ven h ad th ree o r m ore

ca rd ina l fea tu re s of th e V A C T E R L sy n d ro m e (ca s es 1 -7 ) a n d

fo u r h a d tw o fea tu re s (c a se s 8 -1 1). F iv e fe tu s e s (c a se s 1 -5 )

a lso h a d ch a ra c te ris tic fe a tu re s o f th e c au d a l re g res s io n

syn d ro m e , in c lu d in g s a cra l a g e n e s is (tw o ca s e s) or s ire n o -

C O L O N

D I A M E T E R

( m m )

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39 8

H A R R IS E T A L .

A JR :14 9, A ug us t 1 98 7

F ig . 5 .- Ca se 3.

A S o n o g r a m at 2 4 w ee ks s h o w s anhyd ramn ios

a n d r e na l a g e ne s is , c on sis te nt w ith P o t t er ’ s d i s ea s e .

Sp = s p ine .

B Pho tog raph o f fe tu s a fte r te rm in a tio n o f p reg -

n a n c y

s ho ws s ire nO m ella

w ith fu sed low er e xtre mi-

tie s. A no re cta l a tre sia w as a lso presen t

m elia (th ree cases) (F igs . 5 a nd 6). A t au to psy , the m os t

c o m m o n c o nc u rre n t a n o m a lie s in c lu d e d s a cra l a g e n e s is (tw o

c a se s), s ire n o m e lia (th re e ca se s ) (F ig s . 5 a n d 6 ), re n a l a g e n -

e s is (th re e cases b ila te ra l, o ne case un ila te ra l) (F ig . 5 ), c ys t ic

d y sp la s tic k id n e y (th re e ca s e s), e s o p ha g e a l a tre s ia w ith tra -

ch e oe so ph a ge a l fis tu la ( tw o ca se s ) (F ig . 2 ), h yd ro ce p h a lu s

(th ree case s), and m en in gom ye loce le (th ree case s).

S o nog ra phy ide n tif ied on e ab norm a lity o r m ore in seven

fe tu se s , in c lu d in g fo u r w ith h yd ro ce p h a lu s (F ig . 6 ) a n d /o r a

m e n in g o m ye lo ce le . O f th e five re m a in in g ca se s , th re e h a d

se ve re o ligoh yd ra m nios tha t lim ited so nog raph ic eva lu a tio n .

O f the s ix ca se s w ith o lig ohyd ram nio s, five w ere asso c ia ted

w ith re n a l a n om a lie s a n d o n e h a d p re m atu re rup tu re o f m e m -

b ra n e s . T h e o n ly ca s e w ith p o lyh yd ra m nio s h a d e so p h a g e a l

a tre s ia w ith tra ch e o e so p h a g e a l fis tu la (F ig . 2 ).

D is c u s s io n

T h e c las s ifica tio n o f a n o re c ta l m a lfo rm a tio n is va r ia b le ,

re fle c tin g th e com p lex ity o f m a lfo rm a tion s in vo lv in g the c lo a ca

a n d h in d g u t [7 ]. W e h a v e in c lu d e d u n d e r A R A a sp e c tru m o f

m a lfo rm a tio n s in c lu d in g im pe rfo ra te a n u s , a n a l a g e n e s is , a n -

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A JR :i4 9 , A ug u s t 1 98 7 A N O R E C T A L A T R E S IA

39 9

o re cta l a ge ne sis ,

a n d re c ta l a tre s ia [7 ]. A n y o f th e s e le s io n s

m ay a lso ha ve an assoc ia ted fis tu la . F o r s im p lif ica tion , A R A

ca n be d iv ide d in to tw o g ro up s : h igh (su p ra le v ato r) le s io n s

tha t te rm ina te a bove the leva to r s ling an d lo w (in fra leva to r)

les io n s th a t te rm in a te b e lo w th e le v a to r s lin g . H ig h les io n s

a re th e m o s t c o m m o n ty p e o f A R A a n d a re a s s o c ia te d m o re

o fte n w ith fis tu la s an d gen itou rina ry m alfo rm ation s [7 ].

O u r p re s e n t s tu d y c o n firm s p re v io u s o b s e rv a tio n s [9 , 1 0 ],

su gge stin g th a t d ila ted fe ta l bo w e l m ay re su lt fro m A R A (F igs .

1 a n d 2 ) in a d d itio n to m o re co m m o n ly re co g n iz ed ca u se s o f

fe ta l b o w e l o b s tru c tio n (F ig s . 1 a n d 2 ). A U - o r V -s h a p e d

se gm e n t o f d ila ted bow e l in th e low er a bdo m e n or pe lv is is

pa rt icu la rly su gge stive o f A R A and w as se en in th ree o f o u r

c a s e s . B e a n e t a l. [9 ] s h o w e d n e a rly id e n tic a l s o n o g ra p h ic

fea tu re s in a fe tus w ith A R A scann ed a t 34 w ee ks . S im ila rly ,

B a rs s e t a l. [1 0 ] s u s p ec te d d ila te d b o w e l a t 2 8 .5 w e e k s in

an o the r fe tus w ith im pe rfo ra te a nus . S onog raph ic and pa th -

o lo g ic fin d in g s s u g g es t th a t s u c h b o w e l s e g m e n ts re p re s e n t

d is ta l c olo n.

F o u r o f fiv e fe tu se s w ith v is ib ly d ila te d b o w e l w ere

recog -

n ize d p ro s p e c tiv e ly in o u r p re s e n t s e rie s , in d ic a tin g th a t e x -

perienced

s on og ra ph ers c an id en tify p a th o log ic bo w e l s eg -

m ents in the fe tu s . H ow ever, d is t ingu ish in g a bno rm ally d ila te d

c o lo n fro m n o rm a l c o lo n o c c a s io n a lly m a y b e d iff ic u lt s in c e

n o rm a l fe ta l co lon p ro g re s s iv e ly e n la rg es d u rin g p re g n a n cy

a nd can ap proa ch 2 cm in d iam e te r tow a rd te rm [1 1 -1 3 ]. In

q ues tio nab le o r bo rd e rline cases o f co lo n d ila ta tion , com par-

ison w ith a ge -a d jus ted norm al m easure m en ts m ay be he lp fu l

(F ig . 3 ).

W hile th e num be r o f p a tien ts s tud ied w as re la tive ly sm a ll,

o u r re s u lts s u g ge s t th a t c o lo n d ila ta tio n is p ro b a b ly re la te d to

m e n s tru a l a g e . T he e a rlies t c a se d e te c te d in th e p re s e n t

se rie s w a s a t 2 6 m e n stru a l w e e k s a n d th e e a rlie s t p re v io us ly

repo rted case o f A R A w as a t 28 .5 w eeks [1 0 ]. O ne case in

o u r s e rie s sh o w e d m in im a lly d ila te d b o w e l a t 27 w e e ks th a t

prog re ssed s ign ifican tly by 33 w ee ks (F ig . 4 ). A lso , th e ca se

d e scr ib e d b y B e a n e t a l. [9 ] s h o w e d n o rm a l fin d in g s a t 2 4

w ee k s b u t d ila te d b ow e l a t 3 4 w e e k s . P a th o lo g ica lly , m ild

co lo n d ila ta tio n w a s fo u n d a s e a rly a s 2 4 w e e ks b u t w a s n o t

s e e n in an y o f fou r ca ses exam ined be fo re 2 2 w e eks. T he se

re s u lts a re c o n s is te n t w ith kn o w n fo rm a tio n o f m ec o n iu m ,

s in ce m ec on iu m

n o rm a lly d o e s n o t a c cu m u la te in th e co lo n

b e fo re 2 0 w e e ks [1 1 , 1 2 ].

T h e re a s on th a t so m e fe tu se s w ith A R A d e m o n stra te co lo n

d ila ta tio n is u n c le a r a n d is a q u e s tio n th a t h a s n o t b e e n

a d d re s se d p re v io u s ly . A s m e c on iu m n o rm a lly d o e s n o t p a ss

th rou g h th e a n u s in u n co m p lica te d p re g n a n c ie s [1 1 ], in o rd e r

fo r co lo n d ila ta tio n to o ccu r fro m a d is ta l o b s truc tio n , o ne

m u st p os tu la te a n in cre as e d a m o u n t o f in g e s ted a m n io tic

flu id , a d e cre a se d a b so rp tio n o f flu id , o r a n in cre a se d p ro d u c-

tio n o f m e co n iu m . A R A co u ld a lso b e a ss o c ia te d w ith se g -

m e n ta l a g a n g lio n o s is , p e rm ittin g co lo n d is te n s io n to o ccu r,

a lth o u g h th is h a s n o t b e e n s tu d ie d s p e c ifica lly . In ca se s o f

A R A in w h ich co lo n d ila ta tio n is a b s e nt, a p o s s ib le e xp la n a tio n

is tha t a d is ta l co lo re cta l fis tu la d eco m pre sses the o bs truc ted

b o w e l. H o w e ve r, w h ile th e n u m b e r o f c a se s in o u r s tu d y w a s

sm a ll, no d ire c t c o rre la tio n w a s o b s e rv e d b etw e e n th e p re s-

e n c e o r a b se n ce o f a fis tu la a n d co lo n d ila ta tio n .

In add itio n to co lon d ila ta tion , o th e r b ow e l ab norm alit ies

o c ca s io n a lly m a y b e d e m o n stra te d in A R A . C o lon p e ris ta ls is

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40 0

H A R R IS E T A L .

A JR :1 49 , A ug us t 1 98 7

w a s o b s e rv e d o n rea l-t im e s o n o g ra p h y in o n e A R A c a s e in

o u r s tu d y b u t w a s n o t o b s e rv e d in a n y o f 1 20 n o rm a l fe tu s e s .

In tra lum ina l m eco n iu m ca lc ifica tio n has b e e n n o te d in so m e

c a s e s o f A R A [1 4 ], in c lu d in g o n e c a se d e tec te d in u te ro [1 5 ],

a lth o u g h it w a s no t o b se rve d in a n y c a se in o u r p re s en t

se ries . T h e e tio log y o f ca lc ifica tio n in these ca ses is u nce rta in ,

bu t som e au th o rs p ropo se th a t a lka line u rin e from an asso -

c ia te d b la d d e r fis tu la m ay b e c o n trib u to ry [1 4 ].

C on curre n t an om a lie s o ften a re asso c ia ted w ith A R A . A d-

d itio n a l a n o m a lie s w e re p re se n t in 9 2 o f c a se s in o u r p re s en t

s tu d y a n d h a ve

b e e n re po rte d in u p to 7 2 o f cases in

neona ta l

se ries [1 6 , 17 ]. T he assoc ia tion be tw e en A R A and

o th e r type s o f a nom a lies led to de sc rip tion o f the V A T E R

(ve r teb ra l de fe cts , ana l a tres ia , trach eoe sop hag ea l fis tu la w ith

e s o p h a g e a l a tre s ia , ra d ia l a n d ren a l d y s p la s ia ) a c ro n y m [2 ],

w h ic h w as s u b s e q u e n tly m od ified to th e V A C T E R L (v e rte b ra l,

an a l, ca rd iova scu la r, tra che oesoph age a l, re na l, and lim b) syn -

d ro m e [3 ]. O th e r a u th o rs h a v e e m p h a s ize d a b ro a d o v e rla p

b e tw ee n th e V A C T E R L s yn d ro m e a n d th e ca u d a l re g re s s io n

s y n d ro m e [8 , 1 8], w h ic h m a y in clu d e A R A , s a cra l a g e n e sis ,

lo w e r lim b h y p o p la s ia , re n a l a g e n e s is o r d y s p la s ia , a n d its

m o st seve re fo rm , s iren om e lia [1 9 , 20 ].

O n th e bas is o f ou r expe rience , w e sugg est tha t w hen fe ta l

b o we l d ila ta tio n is ide n tifie d a n d A R A is su s p e c te d , a sp e c ific

s e a rc h s h o u ld b e c o n d u c te d fo r c o n c u rre n t a n o m a lie s . A s -

so c ia te d a b n o rm a litie s , e x c lu d in g o lig o h y d ra m n io s , w e re p ro -

spective ly

id e n tifie d b y so n o g ra p h y in se ve n (6 4 ) o f th e 1 1

fe tuses w ith co ncu rren t a nom alies . In o ne case , po lyhyd ram -

n ios w a s the on ly c lue to the p re sen ce o f eso pha gea l a tres ia

w ith tracheo esopha gea l fis tu la (F ig . 2 ). C e n tra l ne rvou s sys-

te m a n o m a lie s in c lu d in g h y d ro c e ph a lu s a n d /o r m e n in g o m ye -

lo ce le w ere co rrectly iden tifie d in fou r o f five ca ses and ha ve

also

b e e n a s s o c ia te d w ith A R A [1 6 , 1 7]. In tw o

cases , ho w -

e ve r, d ila ted fe ta l bow e l w as the p rim ary so nog raph ic ev i-

d e n c e fo r A R A a n d th e V A C T E R L sy n d ro m e (ca s e s 7 a n d 8 ).

In co n tra s t to A R A , o th e r c a us e s o f fe ta l b o w e l o b s truc tio n

a re u s u a lly a n is o la te d a b n o rm a lity n o t as s o c ia te d w ith c o n -

cu rre n t a nom a lies . O the r cau ses o f fe ta l co lo n d ila ta tion in -

d u d e th e m ec o n iu m -p lu g s y n d ro m e [2 1

]

a nd H ir sc hs pr un g’s

d isease [2 2 ], w h ile sm a ll-bo w e l d ila ta tion m a y b e from sm a ll-

b o w e l a tre s ia , v o lv u lu s , L a d d ’s b a n d s , m ec o n iu m ile u s [2 3 ],

or H irschsp run g ’s d isea se [2 4 ]. Iden tifica t ion o f a dd ition a l

m a lfo rm a tion s m a y in fluen ce the obs te tric m ana gem en t o f

fe tu ses fou nd to ha ve bo w e l d ila ta t ion be cau se o f the h igh

m orta lity and m o rb id ity assoc ia te d w ith A R A .

In su m m a ry , th e d ia g n os is o f A R A sh o u ld b e co n s id e re d

w h e n d ila te d fe ta l b o w e l is d ete c ted b y p re n a ta l s o n o g ra p h y ,

p a rticu la r ly w h e n it in vo lve s th e d is ta l co lon . T h is fin d in g

sh o u ld a le rt th e so n o g ra p h e r to p o s s ib le co n cu rren t m a lfo r-

m a tio n s a ss o c ia te d w ith th e V A C T E R L or ca u d a l re gre ss io n

s y n d ro me .

R E F E R E N C E S

1

.

Murken JO , A lbe rt A . G ene tic cou ns e lin g in c ase s o f an a l an d rec ta l a tre s ia .

Prog Ped ia t r Su rg 1 97 6;9 : 1 15 -1 18

2 . Q u an L , S m ith O W .

Th e

V A TE R a ss oc ia tio n: v erte bra ld efe cts , a na l a tre sia ,

tra ch eo es op ha ge al fis tu la w ith e so ph ag ea l a tre sia , ra dia l d ys pla sia . Bir th

De fec t s 1972;8 2 :75-78

3 . N ora R H, N ora JJ . A sy nd ro me o f m ultip le co nge nita l a nom alie s a sso cia te d

w ith t er ato ge nic e xp os ur e. A rc h E nv ir on Hea l t h 1 97 5;8 5: 1 7-2 1

4 . T em tam y S A , M ille r JO . E xten d in g th e s cop e o f the V AT E R as so cia tio n:

d efin it io n o f th e V A TE R s yn dro me .

J P e di at r

1974 ;85 :345 -349

5 . B a rn es JC , S m ith W L. T he V A T E R as so c ia tion . R ad io logy 1978 ; 126 :

445-449

6 . L ud d W E, G ros s R F. C ong en ita l m alfo rm atio n s o f the an us an d rec tum :

rep o rt o f 1 62 c ase s. A m J S urg 1 937 ;2 3 : 16 7 -1 8 3

7 . S tep he ns F D , S m ith E D . A no r e c ta l m alfo rm atio ns in ch ild ren . Ch ic ago :

Y ea r B o ok , 1 97 1: 21 2- 25 6

8 . O uha m e l B . F rom the m erm a id to an a l im pe rfo ra tion . T he sy nd rom e o f

c au d al r eg re ss io n . A rch D is C hild 1 961 ;36 : 1 52 -1 5 5

9 . B ea n W J , C a lo ng e

M A, A p rill C N, G esh n er J . A na l a tre s ia : a p re n a ta l

u l t rasound d iagnos is . JC U 1978; 6 : 111 - 112

1 0.

B ars s V A , B en ac er ra f B R , F rig olo tto F O . A nte na ta l s on og ra ph ic

d iagnos is

o f fe ta l g as tro in te stin al m alfo rm atio n. Ped ia t r i c s

1985 ;76 :445 -449

1 1

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W in dle W F. P hy s io log y o f th e f e tus Spr ing f ie ld , IL : T ho ma s, 1 97 1:9 4-1 00

1 2 . G re lin E S.

F unc tio na lan ato my o f th e n ew bo rn .

N e w H a ve n: Y a le U n iv er si ty ,

1973 :54 - 60

1 3 . N yb erg D A , M ack L A , P atton B M,

C yr D R. F e ta l bo we l: no rm al son og rap hic

f ind ings . J U ltras oun d M ed 1987 :6 :3 -6

1 4 . B e rd on W E, B ake r O H , W igg e s H J , e t a l.

C alc ifie d in tra lu min al m eco niu m

in n ew bo rn m ale s w ith im pe rfo ra te a nu s. AJ R 1975 :125 :449 -455

15 . S h a le v E , W ein e r E , Z u cke rm a n H . P re na ta l U S d iag no s is o f in tes tin a l

ca lc if ic a tio n s w ith im pe rfo ra te a nu s . A cta O b ste t G yn ec o l S can d

1 9 8 3 ;6 2 :9 5 -9 6

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an u s : a sso c ia ted an o m alie s e nc ou n te re d in a se rie s o f 1 2 0 ca se s .

Su rg

G yn ec ol O bs te t 1952 ;95 :281 - 288

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1 8 . K h oury M J , C o rd e ro JF , G reen be rg F , Ja m e s IM , E ric kso n JO . A po pu la t ion

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Pediatr ics i9 83 ;7 1 :8 15 -8 20

1 9 . K a llen B , W inbe rg J . C a ud a l m es ode rm a l pa tte rn o f a nom a lies : from ren a l

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20 . B eam JG . T he a sso c ia tion

o f s ir e no m e li a

w ith P otte r’s s yn dro me .

Ar c h

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1987 :6 :257 -260

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