Chapter 24: Fetal Head and Brain - pathology
vein of galen aneurysm
CF: CHF SF: anechoic mass within midline of brain that contains turbulent arterial and venous flow when interrogated with pulsed and color doppler, fetal hydrops, cardiomegaly (caused by cardiac overload)
acrania (anencephaly)
CF: elevated MSAFP SF: absent cranial vault, some cerebral tissue, "froglike" facies or bulging eyes
arnold-chiari II malformation
CF: elevated MSAFP SF: lemon sign, banana sign*, obliterated cisterna magna, colpocephaly, enlarged massa intermedia, hydrocephalus, open spinal defect
cephalocele
CF: possible elevation of MSAFP SF: open cranial defect (typically posterior in location), small or obliterated cisterna magna, complex or simple appearing mass protruding from the cranium
occipital region
Most common location for cephalocele
choroid plexus cysts
SF: anechoic, round, smooth-walled cyst located within the choroid plexus of the lateral ventricle
aqueductal stenosis
SF: atrium of lateral ventricle > 10 mm, atrial measurement > 15 mm considered moderate to marked, dangling choroid sign (echogenic choroid plexus, hanging limp, surrounded by CSF), dilation of lateral ventricles and third ventricle (fourth ventricle is normal)
ventriculomegaly
SF: atrium of lateral ventricle > 10 mm, atrial measurement > 15 mm considered moderate to marked, dangling choroid sign* (echogenic choroid plexus, hanging limp, surrounded by CSF), dilation of any part of system
dandy-walker malformation (DWM)
SF: enlargement of cisterna magna > 10 mm in AP, communication of enlarged cisterna magna with dilated fourth ventricle, agenesis or hypoplasia of the cerebellar vermis, varying degrees of ventriculomegaly
mega cisterna magna
SF: enlargement of cisterna magna > 10 mm in AP, normal cerebellum and fourth ventricle
schizencephaly
SF: fluid-filled clefts within the cerebrum, agenesis of CSP and corpus callosum (50% of time), ventriculomegaly
hydraencephaly
SF: fluid-filled cranium, absent or partial absence of the falx cerebri, maintained brain stem, basal ganglia, and thalamus, no identifiable cerebral cortex
alobar holoprosencephaly
SF: horseshoe-shaped monoventricle, fused echogenic thalami; absence of CSP, interhemispheric fissure, falx cerebri, corpus callosum, third ventricle; normal cerebellum and brain stem
porencephaly
SF: image B (bottom), cystic mass that communicates with lateral ventricle, most often unilateral, confused with arachnoid cysts (image A) which will not communicate with lateral ventricle
lissencephaly
SF: lack of sulci and gyri within the cerebrum
agenesis of corpus callosum and CSP
SF: partial or complete absence of the corpus callosum and absence of CSP (after 18 weeks), "sunburst" sign* (radial arrangement of the sulci which produces a "spoke wheel" pattern), colpocephaly (small frontal horns and enlarged occipital horns - teardrop shaped lateral ventricles). elevated and dilated third ventricle
development of fluid-filled clefts within cerebrum
Schizencephaly
the cortex can have 3 shapes (pancake, cup, or ball), often results in neonatal death
alobar holoprosencephaly
most common cause of hydrocephalus in utero
aqueductal stenosis
banana sign
banana-shaped cerebellum
protrusions of intracranial contents through a defect in the skull
cephalocele
typically regress by end of 3rd trimester, associated with trisomy 18
choroid plexus cysts
found within choroid plexus, produce increased CSF, leading to ventriculomegaly
choroid plexus papillomas
obstruction lies outside the ventricular system
communicating hydrocephalus
apert syndrome, holoprosencephaly, DWM, aqueductal stenosis, trisomy 18, trisomy 8, trisomy 13
conditions linked with agenesis of corpus callosum and CSP
severe mental retardation, trisomy 13, patau syndrome
conditions linked with lobar holoprosencephaly
maternal diabetes, use of valproic acid (seizure medication), chromosomal anomalies (Edwards and Patau syndrome), triploidy
conditions linked with neural tube defects
hydraencephaly will not have cerebral mantle present, whereas the other two will have a rim of cerebral tissue maintained
difference between hydraencephaly and severe ventriculomegaly and holoprosencephaly
high impedance with continuous forward flow, effective at evaluating potential hypoxia in fetuses SFD, resistance pattern should be greater than umbilical artery
doppler of middle cerebral artery
omphalocele, gastroschisis, multiple gestations, fetal demise, incorrect gestational dating
elevated levels of AFP linked with
mass of brain tissue
encephalocele
cyclopia, proboscis, anopthalmia, hypotelorism, median cleft lip, cebocephaly
facial anomalies linked with holoprosencephaly
fatal condition which cerebrum is replaced by large sac containing CSF
hydraencephaly
dilation of ventricular system caused by an increased volume of CSF, resulting in increased intraventricular pressure
hydrocephalus
lemon sign
lemon-shaped cranium with flattened frontal bones
encephalomeningocele
mass of meninges and brain tissue
encephalomeningocystocele
mass of meninges, brain tissue, and lateral ventricle
mass of meninges
meningocele
teratoma
most common intracranial tumor found in utero
distal lumbosacral region
most common location of spina bifida
germinal matrix
most common origin of intracranial hemorrhage
the obstruction level is located within the ventricular system
noncommunicating hydrocephalus
> 1.0
normal MCA/umbilical artery ratio
starts in germinal matrix, may spread to lateral ventricle, often leading to a noncommunicating hydrocephalus (because clot obstructs flow of CSF), could lead to formation of cystic cavities within cerebral hemispheres
process of intracranial hemorrhage
maternal platelet disorders
risk for fetal intrauterine intracranial hemorrhage
maternal use of cocaine, trauma, history of amniocentesis
risks for fetal intracranial hemorrhage
mass (myelomeningocele or meningocele) that protrudes from the spine
spina bifida
cephaloceles, spinal dysraphisms, anencephaly, and spina bifida
types of neural tube defects
0.4 mg of folic acid
what supplement can reduce the likelihood of her fetus developing a neural tube defect?
