Available via license: CC BY 4.0
Content may be subject to copyright.
diagnosis
of
early
papilledema
is
often
difficult,
especially
in
small
children,
even
for
the
experienced
pediatric
neurologist.
Ophthalmologists
may
negate
the
neurologist's
suspicions, but
CT
scan
is
nonetheless
advis¬
able
if
the
clinical
picture
suggests
a
space-occupying
lesion.
CONGENITAL
MALFORMATIONS
NEURAL
TUBE
DEFECTS
In
an
overview
of
neural
tube
defects
(NTD's),
Dr
RJ
Lemire
of
the
Dept
Pediatrics,
Univ
of
Washington
and
Children's
Hospital,
Seattle,
WA,
divides
them
into
two
major
groups:
(1)
neurulation
and
(2)
postneurulation
defects.
Neurulation
defects
arising
between
the
17th
and
30th
day
after
fertiliza¬
tion
are
caused
by
nonclosure
of
the
neural
tube,
leaving
nervous
tissue
exposed,
whereas
postneurulation
NTD's
are
covered
by
skin.
Three
general
categories
of
neurulation
defects
are
described:
(1)
craniorachischis
(total
dysraphism),
(2)
anencephaly,
and
(3)
meningomyelocele.
Environmental
terato¬
genic
factors
implicated
in
neurulation
defects
include
valproate
sodium
and
nutritional
and
vitamin
deficiencies
(see
Ped
Neur
Briefs
1987;1:15).
Pre¬
natal
diagnosis
is
made
by
screening
for
maternal
serum
a-fetoprotein(AFP)
levels
during
the
16th-18th
week
of
pregnancy
with
follow-up
ultrasound
and
amniocentesis
when AFP
is
elevated.
Elevated
amniotic
fluid
acetylcholines¬
terase levels
are
confirmatory
of
open
NTD
and
eliminate
possible
false-posi¬
tive
results
of
AFP
tests.
The
population
incidence
of
open
NTD's
is
about
2/1000
births
but the
chance
of
recurrence
is
1/20.
Postneurulation
or
closed
NTD's
arising
after
the
30th
day
of
fetal
life
include
hydrocephalus,
encephalocele,
and
lumbosacral
lesions.
The
causes
of
hydrocephalus
and
associated
abnormalities
are
listed
as
follows:
Arnold-
Chiari
malformation
with
meningomyelocele,
tumors
and
cysts,
aqueductal
steno¬
sis,
achondroplasia, tuberous
sclerosis,
Dandy-Walker
syndrome,
chromosome
trisomy
13
and
18
anomalies,
prenatal
infection,
and
aneurysm
of
the
vein
of
Galen.
Comprehensive
lists
of
lumbosacral
NTD's
and
encephalocele
syndromes
are
provided.
Early
resection
of
caudal
NTD's
is
advised
when
practical.
(Lemire
RJ.
Neural
tube
defects.
JAMA
Jan
22/29
1988;
259:558-562).
COMMENT.
As
an
encouraging
postscript
to
this
depressing
subject,
the
author
notes
a
declining
incidence
of
NID's
in
several
areas
of
the
world,
including
the
U.S.,
related
in
part
to
prenatal
diagnosis, genetic
counsel¬
ling
and
nutritional
supplementation.
Folate
treatment
before
and
at
the
time
of
conception
prevent
recurrence
of
spina
bifida.
Exposure
to
spermi¬
cide
contraceptives
is
not
a
risk
factor.
(See
Ped
Neur
Briefs
Aug
1987;
1^(3):15).
A
late
occurring
intrauterine
cause
of
hydrocephalus
is
reported
in
the
following
paper.
CONGENITAL
HYDROCEPHALUS
Intrauterine
intraventricular
hemorrhage
occurring
about
2
weeks
or
more
prior
to
birth
was
the
cause
of
congenital
hydrocephalus
in
4
newborn
infants
reported
from
the
Abteilung
Neonatologie,
Universitats-Kinderklinik,
Rumelin-
strasse
23;
D-7400
Tubingen,
FR
Germany.
Multiple
pregnancy
was
an
associated
risk
factor
in
2
cases
and
a
hemorrhagic
diathesis
was
present
or
suspected
in
2.
Intrauterine
diagnosis
of
subependynal/intraventricular
hemorrhage
may
be
made
by
sonography
of
the
fetal
brain
when
indicated,
especially
in
multiple
pregnancy,
hemorrhagic
diathesis
by
history,
fetal
growth
retardation,
and
signs
of distress.
Postnatally,
cerebral
ultrasound,
CT
and
examination
of
the
CSF
for
siderophages
may
be
confirmatory.
(Leidig
E
et
al.
Intrauterine
development
of
posthemorrhagic
hydrocephalus.
Eur
J
Pediat
Jan
1988;
147:
26-29).
-
12
-