Hydrocephalus in Achondroplasia

PAGE 6
Thefollox'ing article ln'aswrittenfor the Little Peopleof
British Columbia Associatiortb)' Dr. Paul Steinbok HB
,FRCS (C), an associateof Dr. Judith G. Hall's ar Children's
Hospital in Vancouver,B.C. Dr. Steinbok has trealed
and hascortmany membersof LPBC for hydrocephalus
ductedstudiesaccordingly.He comeshighll' recontmended
bv Dr. Hall.
[v[uriel Reid, President,LPBC.
Sincerel.t,,
Hydrocephalusin Achondroplasia
C hildr enr v it h ac ho n d ro p l a s i a re k n o rv nto h a v e enl arged
h eadsu' hic h in m os t i n s ta n c e si s re l a te dto th e t' a c tthat the
. ne of the
fl ui d c av it iesin t he bra i n (r e n tri c l e s) a re e n l a rg e dO
a
maj o r c aus esof v ent r i c u l a re n l a rg e me nits h 1 ' d ro c ephal us.
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si tu at ion
th an n or m al. H1. ' dr o c e p h a l uosfts -nma n i fe s tsi ts e l f e:rrl 1 i n
l i fe * 'it h inc r eas inghe a d s i z e .a n d l a te r i n l i t' e* i th probl cms
such a s headac hesr.o m i ti n g . a n d o b v i o u se r i d e n c c' ofbrai n
d i sfunc t ion.I n c hildr e nrr i th a c h o n d ro p l a s i a
th e re h as been
much c ont r ov er s vab o u t th e s i g n i fi c a n c eo f th e v entri cul ar
bec aus em o s t c h i l d re nd o n o t e x h i b i th eadaches.
e nl a rg em ent
vomi ting.let har gl. an d o th e rs )' mp to msu h i c ho n e a ssoci ates
u i th h1' dr oc ephalu sF. u rth e rm o re .i t h a s b e e n fe h thar i n
chi l dr en s , it h ac hon d ro p l a s i ath
. e v e n tri c u l a re n l a rgement
r
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it
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t
im
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an
d
stabi l iz es
d o e sn o t l e a dto s i g n i ti c a npt robl ems.
We hav e been c on c e rn e da b o u t th i s a p p ro a c hto chi l dren
*'i th ac hondr oplas ia
b e c a u s ei t i s k n o w n fro m o th e rsi tuati ons
i n rvhic ht y dr oc epha l u se x i s ts .th a t i t i s p o s s i b l eto h avemore
chro nichy ' dr oc epha l urv
s h i c hc a n re s u l ti n a b n o rm a lfuncti on
of th e br ain. ev iden c e do n l l ' b y a d e c re a s ei n th e l evel of
i ntel l igenc eand f unc ti o n i n ga t s c h o o l .o rb y mi l d i n te rmi trent
h eadac hes .I t r v as o u r fe e l i n g a t rh e B ri ri s h C ol umbi a
C hi l dr en' sHos pit al t h a t i f h y ' d ro c e p h a l uasc u ta l l ydi d e.ri st
i n a ch ondr oplas ia.an d i f rh e p re s s u rerv i th i nth e r, entri cl es
uas h igJ r ert han it s h o u l d b e . th e n th e re mi g h r b e p ersi stent
chro nicdam ageoc c u ri n gro th e b ra i n .a n d th a t th i s rv oul dnot
be a n ideals it uat ionf o r a n 1 ,o n eBe
. c a u s eo f th i s c o n cern.w e
stu di e d a num ber o f a c h o n d ro p l a s ti cc h i l d re n rvi th bi g
ve ntri c lc s . F ir s t ly ' . w e m e a s u re dth e p re s s u rew ithi n the
ve ntri c lesby put t inga s ma l l tu b e i n to th e b ra i n a n d hooki ng
that up t o a m onit or in gd e v i c e .We rv e rea b l e to s h o rvi n fi ve
ch i l dr en in whom t h i s rv a s d o n e . th a t th e p re s surew as
el e va t ed.W hile t he t u b ew a s s ti l l i n p l a c e .w e to o k the opportuni ty t o injec t a d1' e -l i k em a te ri a l(c o n rra s r).a n d a l so some
ra di o ac t iv em at er ialin to th e v e n tri c l e sto s c ei f th e rew as any
b l o ckaget o t he f lou o f s p i n a lfl u i d rv i th i nth e b ra i nth at mi ght
accountf or t he big v e n tri c l e sa n d h y d ro c e p h a l u sWi
. th thi s
test.we r v er eable t o s h o rvth a t th e re w a s n o b l o c k a ge.Thi s
i ndi cat edt o us t har t. he p ro b l c mc a u s i n gth e h 1d ro c cphal usi n
a ch ondr oplas t ic
c hild rc nm i g h t b c re l a te dto a d c c rc asci n rhe
a bso r pt ionols pinal f l u i d . S p i n a l fl u i d i s n o rm a l l y absorbcd
ove r the t op olt he br a i n i n to th e b i g v e i n sth a t d ra i n t hc brai n.
It rva spos t ulat edr hat p c rh a p sth c p re s s u rei n th c s c bi g vci ns
was too high. and t ha t th i s rv a si n h i b i ti n gth e a b s o rpti onol '
sp i n al f luid. I t was t h o u g h tth a t th i s h i g h p re s s u recr> ul dbe
p ro duc eCbi, a bloc ka g cro th c l l o w o f v c n o u :jb l < lodat thc
baseof t hc s k ull, u hic h i s k n o u ,nto b e v c ry s ma l l i n chi l drcn
LPA TODAY
w i th achondropl asi a.B y putti ng smal l ca t het er sint o t he
venoussystemvi a the groi n. and i nj ecti ngdye int o jugular
veni s rvhi ch drai n the brai n. w e have sho wn t hat t her e is
narrorvi ngof the vei nsat the baseof the skull wher et he skull
meetsthe neck.We have also beenableto shorvthat this does
not causean i ncreasei n the pressurei n the veinsdr ainingt he
brai n. In tw o chi l dren.i t appearedal so that t her e m ight be a
constrictionor narrorvingof the jugular vein as it u'ent lrom
the neck i nto the chest.w hi ch i s al so smal l in childr en wit h
achondroplasia.
B ased on the above studi es.u,e have concludedt hat in
childrenwith achondroplasia.
hydrocephalusis quite common.
and is likely relatedto obstructionto the florvolvenous blood
from the brai n.W e bel i evethat thi s i s a si gn if icantpr oblcm .
and have attemptedto treat thi s b1,shunti ngt luid f r om t hc.
ventri cl esto the peri tonealcavi tf i n the abdom cn.I n t his r vav
* e hal ' e attemptedto reduccthe pressurerr it hin t hc br ain t t 'r
normal . and thus preventtLnher damageti om occur r ingt t 'r
the brai n. Our i ni ti al resul tshave been encour aginu.
W e bel i eve that i t i s i mportant that a ll childr en r vit h
achondropl asi abe l bl l o* ' ed by mcasurem ent sot 't he head
ci rcumference.
Those chi l drenu' hoseheadsar e par t icular lv
Iargeare more l i kel y'to have h1' drocephalus.
and ar e m or e
l i kel l ' to benefi t l rom any type ol shunt pr occdur c. N'lor e
i mportantl l ' perhaps. i s the approach to nnvbor ns uit h
achondropl asi a.becausethese chi l dren mav be bor n *'it h
normalventri cl esand may devel oph1' drocephalus
onll' lat c'r
on i n the fi rst year 61 t\\' o o[ l i fe. It i s easl' t o f ollor v t hcsc
nervbornsrvi threpeatedul trasoundsof the br aint o lor r kat t hc
si zeol the ventri cl es.and i fthe ventri cl esstan t o incr easein
si ze.i t mav be usel ulto consi dcrtreatmcntea r lierr at hcrt han
l ater.
P aul St eit r boA',ill. D.
4180 Oak Street, l'ancou't'er,BC, V6II 3l/1
( 604) 875- 2094
NO it isn't Christmas in June but it is thcJirst tirttcspacc was
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