fetal face and neck and neural axis 2 Flashcards

Cerebrospinal fluid
Terms Definitions
a defect that may have varying degrees of severity; abnormality of ventricular system because of a posterior fossa cyst
dandy walker malformation
it manifests with agenesis of hypoplasia of the cerebellar vermis with resulting dilation on the fourth ventricle and therefore dilation of the third and lateral ventricle; occurs in two forms
dandy walker malformation
the mildest form of dandy walker malformation with dilation of the fourth ventricle only
dandy walker variant
assoc. with hydrocephalus, agenesis of the corpus callosum, aqueductal stenosis, microcephaly or macrocephaly, encephalocele, chromosomal anomalies 13, 18, 21, and meckel-gruber syndrome; prognosis depends on the presence or absence of assoc. anomalies.
dandy-walker malformation
sono appearance: posterior fossa cyst that can vary considerably in size; splaying of the cerebellar hemispheres as a result of the complete or partial agenesis of the cerebellar vermis; an enlarged cisterna magna caused by the cerebellar vermis anomaly;
dandy walker malformation
encompasses a range of abnormalities resulting from abnormal cleavage of the prosencephalon (forebrain); falx not there to separate the two brain hemispheres
causes are usually sporadic, with a slight recurrence risk, but also genetic, teratogenic, and chromosomal assoc (13); prognosis is uniformly poor but depends on type
what are the three types of holoprosencephaly (determined on amount of division)
alobar (severe), semilobar (intermediate), lobar (mildest)
characterized by a mono-ventricle, brain tissue that is small and may have a cup, ball, or pancake configuration, fusion of the thalamus, and absence of the interhemispheric fissure, cavum septum pellucidum, corpus callosum, optic tracts, and olfactory bu
alobar holoprosencephaly
presents with a singular ventricular cavity with parital formation of the occipital horns, partial or complete fusion of the thalamus, a rudimentary falx and interhemispheric fissure, and absent corpus callosum, cavum septum pellucidum, and optic tracts a
semilobar holoprosencephaly
almost complete division of the ventricles with a corpus callosum that may be normal, hypoplastic, or absent, although the cavum septum pellucidum will be absent; almost complete hemispheric division
lobar holoprosencephaly
sono appearance: a common c-shaped ventricle may or may not be enlarged is seen; brain tissue with a horseshoe shape as it surrounds the mono-ventricle; fusion of the thalamus with the sbsence of the third ventricle; absence of IHF; a dorsal sac with exp
develops from 12-20 weeks so diagnose until after 20 weeks
often assoc with facial abnormalities, especially in the severe forms; cyclopia, hypotelorism, an absent nose, flattened nose with single nostril, and a proboscis; facial cleft may be present with median or bilateral clefting most commonly observed; also
assoc. with renal cysts or dysplasia, omphalocele, cardiac defects, spina bifida, talipes, and GI anomalies
describes a range of complete to partial absence of the callosal fibers that cross the midline, forming a connection between the two hemispheres; can't be diagnosed until after 20 weeks
agenesis or dysgenesis of the corpus callosum
the etiology is somewhat unclear but is thought to involve a vascular disruption or inflammatory lesion before 12 weeks; may be assoc with CNS malformations, and autosomal dominant, autosomal recessive,a nd x-linked syndromes, trisomy 13 and 18; prognosis
agenesis or dygenesis of corpus callosum
as an isolated event may be asymptomatic or associated with mental retardation and/or seizures
agenesis or dysgenesis or corpus callosum
sono appearance: absence of the corpus callosum, dilation of the third ventricle, widely separated ventricular frontal horns with medial indentation of the medial walls; dilated occipital horns (colpocephaly), givign the lateral ventricles a teardrop shap
agenesis or dysgenesis or corpus callosum
associated with holoprosencephaly, DWM, arnold-chiari malformation, hydrocephaly, encephalocele, porencephaly, and microcephaly; in addition cardiac malformations, diaphragmatic hernia, lung agenesis or dysplasia, and absent or dysplastic kidneys may be s
agenesis or dysgenesis of corpus callosum
results from the obstruction, atresia, or stenosis of the aqueduct of sylvius causing ventriculomegaly; the fourth ventricle, cisterna magna, and cerebellum appear normal but 3rd ventricle and everything prox. to it is dilated
aqueductal stenosis (cerebral aqueduct between the third and fourth ventricle)
usually a sporadic anomaly but also may result from TORCH; cranial masses and ventricular hemorrhage are also contributing factors or aquired obstruction; usually x-linked and has an autosomal-recessive inheritance
aqueductal stenosis
more common in male fetuses; the prognosis is considered poor and varies with assoc. anomalies; mental retardation are seen with x-linked disorders
aqueductal stenosis
sono appearance: ventricular enlargement of the lateral ventricles and third ventricular dilation; flexion and adduction of the thumb are seen in the x-linked form
aqueductal stenosis
an aneurysm of the vein of galen (brain is fed by circle of willis and drained by vein of galen); a rare arteriovenous malformation; the vein is enlarged and communicates with normal-appearing arteries
vein of galen cyst/malformation
is considered sporadic and has male predominance; usually don't see it until the third trimester; usually and isolted anomaly, although it has been assoc. with congenital heart defects, cystic hygromas, and hydrops
vein galen cyst/malformation
prognosis is generally poor, especially when assoc with hydrops and/or cardiac failure
vein galen cyst/aneurysm/malformation
sono appearance: cystic space that may be irregular in shape and is located midline and posterosuperior to the third ventricle; turbulent flow with doppler; cardiomegaly, nonimmune hydrops, ventriculomegaly with resultant macrocephaly also may develop; ma
vein of galen cyst/malformation
round or ovoid anechoic structures found within the choroid plexus; more commonly seen between 13-24 weeks adn then goes away; if it doesn't go away it might be linked to chromosomal problem; contain CSF adn usually an isolated finding without assoc. with
choroid plexus cyst
have been associated with aneuploidy, most commonly trisomy 18 and 21; sonographically is appears as a cyst within choroid plexus in size from 0.3-2 cm; completely round or oval; may be uni or bilateral; soliary or multiple, uni or multilocular, enlargeme
choroid plexus cyst
cysts filled with CSF that communicate with the ventricular system or subarachnoid space; form when there is degeneration of brain tissue usually next to and communicating with lateral ventricles; may result in hemorrhage, infarction, delivery trauma, or
porencephalic cyst
the affected brain parenchyma undergoes necrosis, brain tissue is resorbed, and a cystic lesion remains; there is no known assoc. anomalies with this anomaly
porencephalic cyst
sono appearance: cyst within the brain parenchyma wihtout mass effect; dilation of ventricle; communication of the cyst with the ventricle or subarachnoid space; if it doesn't communicate with lateral ventricle then can't be this; may be confused with ara
porencephalic cyst
a rare disorder characterized by clefts in the cerebral cortex; seen in parietal or temporal lobe; clefts may be uni or bilateral, open-lip (extends to lateral ventricles) or closed lip defects (in cortex only); result from abnormal migration of neurons
schizencephaly cyst
these clefts can extend from the outer surface to the ventricles of the brain and are lined with abnormal gray matter; the etiology remains unclear, although it has been linked with multiple assaults during pregnancy; assoc with congenital infections, dru
schizencephaly cyst
the prognosis varies, with mild to severe outcomes; closed lip might be repairable. open lip repairs often don't work; open lip lesions carry a worse prosnosis; hydrocephalus may be progressive and require shunt replacement
schizencephaly cyst
sono appearance: fluid-filled cleft in the cerebral cortex extending from the calvarium to the ventricular system; ventriculomegaly may be observed; also assoc with absence of septum pellucidum, microcephaly, and corpus callosum
schizencephaly cyst
destruction of the cerebral hemispheres by occlusion of the internal carotid arteries resulting in ischemia of the frontal lobe making water head
brian parenchyma is destroyed and is replaced by CSF; because the posterior communicating arteries are preserved, the midbrain and cerebellum are present, and the basal ganglia, choroid plexus, and thalamus may be spared, but everything anterior is gone
may be assoc with polydramnios, holoprosencephaly, and hydrocephaly; the etiology usually involved congenital infection or ischemia such as TORCH, maternal hypotension, twin-to-twin embolization, or vascular agenesis which can all occlude ICA
may occur later in pregnancy (late second or early third) and that brain structures intially may be normal
sono appearance: absence of normal brain tissue with almost complete replacement by CSF; an absent or partially absent falx, presence of the midbrain, basal ganglia, and cerebellum seen, and the choroid plexus may be identified; macrocephaly may occur; ma
dilation of ventricles in the brain; most common cranial abnormality; occurs when ventriculomegaly is coupled with enlargement of the fetal head
enlargement of the ventricles and thus hydrocephalus occurs with obstruction of cerebral spinal fluid. what are the three types of obstruction
non-communicating, communicating, mass effect
hydrocephalus: type that occurs within the choroid plexus such as a papilloma that caused CSF to overproduce is ___. type that occurs outside the ventricular system is called ___. the type that is caused by aqueductal stenosis or foramen of monroe is __
mass, communicating, non-communicating
physiologically when an obstruction occurs the ventricles dilate as the flow of CSF is blocked; this increases the pressure within the ventricular system, which leads to ventricular expansion; enlarged ventricles may exert pressure on the brain tissue, en
may be assoc with an anomaly or the cause may remain unknown; aqueductal stenosis, arachnoid cysts, vein of Galen aneurysms, spina bifida, encephaloceles, dandy-walker malformation, agenesis of the corpus callosum, schizencephaly, and holoprosencephaly ca
ventriculomegaly is diagnosed when the lateral ventricles are greater than __ mm
complete dilation of the ventricular system typically progresses from the __ horns into the temporal and then to the frontal venticular horns; the mortality rate is high with the outcome depending largely on the presence and severity of assoc anomalies;
sono appearance: lateral ventricular enlargement greater than ten mm; a "dangling choroid sign" as the gravity-dependent choroid plexus fall into the increased ventricular space; possible dilation of third and fourth ventricles; fetal head enlargement; as
an abnormally small head that falls 2 standard deviations (2 weeks) below the mean; it occurs because the brain is reduced in size; all parameters (HC, BPD, FL, AC) should always fall within two weeks of each other
may result from inheritance of either an autosomal-recessive or dominant pattern; if it's genetic link then prognosis is fine. bad prognosis occurs when teratogen-induced, congenital infections, maternal alcohol abuse, heroin addiction, mercury poisoning
sono appearance: small BPD and HC in comparison to other parameters; abnormal hc/ac and/or hc/fl ratios; disorganized brain tissue and ventriculomegaly, encephalocele, porencephaly, agenesis fo the corpus callosum, craniosynostosis (clover-leaf), holopros
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