Term
| define neural tube defect |
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Definition
| reopening or failure to close the neural tube |
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Term
| explain normal neural tube development and differentiation |
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Definition
neural plate invaginates forming 2 neural crests which grow cranial to caudal
neural crest becomes PNS
neural tube wall becomes CNS
neural tube lumen becomes ventricles and spinal canal |
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Term
| 3 risk factors for neural tube defects |
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Definition
folate deficiency during initial gestation
A-fetoprotein in amniotic fluid signals a neural tube problem
4-5% reoccurrence in subsequent pregnancies |
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Term
| what are the two categories of neural tube defects, which is the most common |
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Definition
caudal (spinal cord) malformations - most common
rostral (brain) malformations |
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Term
| what are the 3 caudal malformations and their categories |
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Definition
spina bifidia occulta
spina bifidia: meningocele, myelomeningocele |
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Term
| spina bifidia occulta: cause, 2 signs |
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Definition
vertebral arch defecit (cord and meninges in tact)
patch of hair or dimple over area |
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Term
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Definition
| vertebral arch defect, meninges protrusion |
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Term
| cause of myelomeningocele |
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Definition
| vertebral arch defect, meninges protrusion, spinal cord protrusion |
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Term
| 2 complications of myelomeningocele |
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Definition
lower limb and sensory issues: loss of bowel and bladder control
infection risk: thin ulcerated overlying skin |
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Term
| what are the two rostral malformations |
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Definition
anencephaly
enecephalocele |
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Term
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Definition
| absence of brain and calvarium development |
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Term
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Definition
maternal polyhydraminos: no brain so CNS controlled swallowing stops and amniotic fluid increases
eyes protrude above top of head due to lack of brain and calvarium (frog fetus) |
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Term
| enecephalocele: cause, location |
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Definition
diverticulum of malformed CNS tissue extending through cranium
posterior more common than anterior |
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Term
| forebrain malformations 6 |
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Definition
microcephaly
lissencephaly
pachygyria
polymicrogyria
holoproencephaly
dysplastic cortex |
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Term
| causes of microencephaly 3 |
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Definition
chromosome abnormalities
fetal alcohol syndrome
in utero HIV |
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Term
| why does microcephaly occur |
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Definition
there needs to be a balance between progenitor cells proliferating in subependymal zone and the backup progenitor cell population
if too many cells leave the back up pool premaurley then it causes decreased generation of mature neurons and a small brain |
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Term
| lissencephaly: define, cause, sign |
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Definition
agyria or smooth brain
disrupts neuonal migration and differentiation due to defect in genes controlling neuron migration
cortex is abnormally thick and only 4 layers |
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Term
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Definition
| less wide spread form of lissencephaly |
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Term
| polymicrogyria: define, signs |
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Definition
increases and irregular gyri form cobblestone surface in focal or widespread area
altered cortical architecture (fusion of superificial molecular layer) |
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Term
| holoproencephaly: cause, difference in signs between severities |
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Definition
disruption in normal midline patterning due to SHH mutation
mild: olfactory bulbs (arrhinecephaly)
severe: brain may not have lobes or hemispheres, one large ventricle, mimdline facial defects |
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Term
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Definition
focal disortion of cortex
neurons stranded beneath cortex in nodules and bands |
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Term
| what are the 3 posterior fossal malformations, which is most common |
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Definition
arnold chiari- most common
dandy walker malformation
robert syndrome |
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Term
| arnold chiari type i: symptoms, cause |
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Definition
NO SYMPTOMS- headache and CN defects may arise as adult
low lying cerebellar tonsils extend through foramen magnum obstructing CSF flow and compressing medulla |
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Term
| arnold chiari type 2: symptoms and cause |
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Definition
SYMPTOMATIC- hydrocephalus
small posterior fossa causes misshaped cerebellum whose vermis extends through the foramen magnum causing obstruction of flow |
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Term
| what condition is arnold chiari type 2 associated with 2 |
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Definition
lumbar myelomeningocele
syringomyelgia |
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Term
| dandy walker malformation: cause 2, effect |
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Definition
enlarged posterior fossa with absent or rudimentary cerebellar vermis
large midline cyst (4th ventricle dilation): lined with ependymal cells and contigous with leptomeninges
causes dysplasia of brainstem nuclei and hydrocephalus |
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Term
| robert syndrome: cause, signs |
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Definition
AR lesionsin primary cilium
looks like dandy walker without brainstem or vermis issies
extra structures in space leads to eye and respiratory problems |
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Term
| where are spinal cord malformations usually located |
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Definition
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Term
| what is the pathological processes normally causing spinal cord malformations |
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Definition
| destruction of gray and white matter causing reactive gliosis |
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Term
| what are the 2 spinal cord formations |
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Definition
hydromyelia
syringomyelia (syrinx) |
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Term
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Definition
| expansion of the central canal |
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Term
| 2 causes of syringomyelia and how, cellular changes, symptoms and why |
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Definition
arnold chiara malformation or trauma damages anterior white comissure C8-T1 causing a fluid filled cavity in inner portion of spinal cord surrounded by reactive GLIOSIS AND ROSENTHAL FIBERS
comissure and spinothalamic tracts cross over before they take pain/temp to the thalamus so they get loss of pain and temp in the UPPER LIMBS |
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Term
| if a syringomyelia expands, where does it expand to 2, what symptoms for each |
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Definition
anterior horns: carry motor to muscles: muscle weakness and atrophy, impaired tone, decreased reflexes
lateral horns: carry sympathetic info to the face: horner syndrom |
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Term
| 3 signs of horner syndrome |
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Definition
ptosis
miosis
anhydrosis on half of face |
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Term
| what are the 4 types of parenchymal injury |
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Definition
contusion
concussion
coup injury
diffuse axonal injury |
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Term
| contusion: two types, define |
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Definition
contusion
penetration
brain impacts side of skull |
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Term
| contusion: cause, 4 effects |
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Definition
| rapid tissue displacement, disruption of vessels, hemorrhages, tissue injury, edema |
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Term
| penetration: cause, 3 effects |
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Definition
object/skull fragment causes laceration
tissue tearing
vascular disruption
hemorrhage
linear path |
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Term
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Definition
| reversible altered conciousness from head injury in absence of contision |
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Term
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Definition
transient neurological dysfunction: LOC, temp respiratory arrest, loss of reflexes
complete neurological recovery: amnesia of event |
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Term
| 3 common locations of parenchymal injury |
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Definition
orbital gyri of frontal lobe
temporal lobe esp tips
crests of gyri |
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Term
| parenchymal injury: what does a new and old one look like, what cells |
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Definition
new: wedge shaped wide at point of impact, effects superificial layers first
old: depressed, retracted, yellow brown, mostly on gyri crest
24h: nuclear pyknosis, eosinophils, cellular degeneration |
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Term
| what is a complication of parenchymal injury what does it look like |
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Definition
| extensive hemorrhaging: cavity lesions, like infarct |
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Term
| cause of diffuse axonal injury |
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Definition
movement of one region of the brain relative to another, twisting and breaking axons
angular acceleration without impact |
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Term
| location of diffuse axonal injury 2 |
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Definition
angle of lateral ventricles or brain stem
asymmetric |
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Term
| effect of diffuse axonal injury 3 |
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Definition
axon dysruption and hemorrhage
50% get coma |
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Term
| 2 types of traumatic vessel injury |
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Definition
epidural hematoma
subdural hematoma |
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Term
| epidural hematoma: cause, effect, location, presentation, progression |
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Definition
trauma causes little vessels that run through bone (ESP MIDDLE MENINGEAL A) to rip and bleed into SUBDURAL SPACE
this causes DURA TO SEPERATE making SMOOTH CONTOUR STOPPING AT SUTURE LINES
as it spreads it compresses brain and causes death WITHIN HOURS |
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Term
| signs of epidural hematoma |
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Definition
| patient is lucid for hours then rapidly develops neurological signs leading to death |
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Term
| subdural hematoma: cause, progression, effect |
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Definition
trauma, retraction of brain (atrophy in elderly) or fragile vessels (babies) causes tearing of BRIDGING VEINS running through subdural space into dural sinuses
beacause this is NOT LIMITED BY SUTURES it can spead laterally over the hemisphers as blood builds up (10% become bilateral) |
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Term
| signs of subdural hematoma |
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Definition
| 48h: headache, confusion, some localizing signs, neurological deterioration |
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Term
| prognosis of subdural hematoma |
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Definition
| bleed is usually self limited but frequently re-bleeds (chronic subdural hematoma) |
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Term
| morphology of subdural hematoma in 1wk, 2wk, 1-3mo |
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Definition
1wk: lysis of clot
2wk: growth of granulation tissue from dura
1-3mo: fibrosis |
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Term
| 3 types of perinatal brain injuries, which is most common |
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Definition
cerebral palsy
intraparenchymal hemorrhage and infarct - most common
preiventricular lekomalaca |
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Term
| cerebral palsy: cause, 5 signs |
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Definition
prenatal and perinatal brain injury causes non-progressive neurological motor disorder
spasticity, dystonia, ataxia, athhetosis, paresis |
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Term
| intraparenchymal hemorrhage and infarct: cause, 1 sign |
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Definition
germinal matrix of premature infants extends into ventricles and subarachnoid
hydrocephalus |
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Term
| periventricular leukemia: cause, 1 sign |
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Definition
infarct in supratentoral periventricular white matter (esp when premature)develops large cystic lesion in gray matter (multicystic encephalopathy)
cysts: large, chalky plaque in white matter with calcifications |
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