DEVELOPMENTAL DISEASES Flashcards
the conjunction of cardiac, limb, gut, and bladder abnormalities with a
neurologic disorder indicates the time at which the insult
takes place: cardiac abnormalities occur between the __________
fifth
and sixth week
Insult to the CNS timing:
meningomyelocele, before ____ days;
anencephaly, before 28 days;
cleft lip, before ______ days;
syndactyly, cyclopia, and holoprosencephaly, before ___
28
36
23 days
defects caused by chromosomal
abnormalities occur in approximately ______percent of live births, but such defects are found in more than ___
of spontaneous abortuses at 5 to 12 weeks gestational age
0.6
5 percent
_________ defined as hydrocephalus and
destruction or failure of development of parts of the cerebrum, is often associated with enlargement of the skull
Hydranencephaly,
causes of hydranencephaly
It can be caused by
cerebral infarction from intrauterine vascular occlusion
or by diseases such as toxoplasmosis and cytomegalovirus
(CMV) disease, which destroy parts of each cerebral
hemisphere.
This type of destruction
of the cerebral mantle in the embryonal period may
lead to the formation of huge brain defects with apposition
of ventricular and pial surfaces
(porencephaly)
result of a focal developmental defect in
the wall of the cerebral mantle
failure of evagination
schizencephaly
_____________, a
common congenital defect, may be associated with macrocephaly
and varying degrees of mental impairment, optic
defects, and seizures.
Agenesis of the corpus callosum
Imaging of agenesis of corpus callosum
“bat-wing” deformity of the ventricles
Agenesis of the corpus callosum is also part of the
_________and the ______________ and it has been noted, without explanation, in
some cases of nonketotic hyperglycinemia
Aicardi syndrome
Andermann
syndrome,
This term refers to a marked
enlargement of one cerebral hemisphere as a result of a
developmental abnormality.
megalencephaly
In megalencephaly, embryogenesis has been deranged at the stage
of ______
neuroblast formation
The growth
of the cranium is inhibited in a direction_______
to the involved suture(s), creating a compensatory
enlargement in other dimensions as allowed by the
patent sutures.
perpendicular
When only the sagittal suture i s involved, the head is
long and narrow _______ and the closed suture
projects, keel-like, in the midline
(scaphocephalic)
With premature closure
of the coronal suture, the head is excessively wide and
short _________
(brachycephalic) .
Approximately one-quarter of affected children with
craniostenoses will be found to have a single gene or
chromosomal abnormality, most commonly in the ____
FGFR3
gene.
When, for any reason, an infant lies with the head
turned constantly to one side (because of a shortened
sternomastoid muscle or hemianopia, for example), the
occiput on that side, over time, becomes flattened, as does
the opposite frontal bone
plagiocephaly, or wry head
During the
_________ postmitotic neurons that will ultimately
reside in the cortex arise in the ventricular zone adjacent
to the ventricles
first trimester,
the emergence
of two separate cerebral hemispheres may not
occur
holoprosenceph
One type of focal band-shaped subcortical
heterotopia is termed __________
“double cortex.
______________
refers to an excessive number of abnormally small gyri.
It is expressed by a syndrome of mental retardation, seizures,
delayed speech, and motor abnormalities
Polymicrogyria
These migrational disorders, particularly heterotopias, are
now being recognized more often by MRI and are found to
have a functional significance in epilepsy but also possibly
in such states as nonspecific ________ and _______
developmental delay, and
dyslexia
there is a failure of differentiation of intraand
intercortical and interhemispheral connections, the
most obvious one being _______
agenesis of the corpus callosum.
All that remains is a hemorrhagic
nubbin of nerve, glial, and connective tissue.
Brainstem, cerebellum, and spinal cord are present but
often, they too are malformed, as are the heart and other
organs (15 to 40 percent of cases).
Anencephaly