Pathoma CNS Flashcards
how are neural tube defects detected during prenatal care?
alpha-fetal protein levels in the maternal blood and amniotic fluid
what is anencephaly
absence of skull and brain. disruption of the cranial end of the neural tube.
what does the fetus resemble?
has a frog-like appearance.
consequences of anencephaly?
maternal polyhydraminos due to lack of the swallowing centers in the fetus.
what is spina bifida occulta
dimple or patch of hair overlying the vertebral defect. (failure of the posterior arch to close during development disruption of the caudal end of the neural tube).
spina bifida alternative presentation?
meningiocele: protrusion of the meninges through the vertebral defect.
meningomyelocele: protrusion of meninges and the spinal cord through the vertebral defect.
congenital aqueduct stenosis
narrowing the channel that reroutes CSF flow throughout the brain from 3rd ventricle to the fourth. most common cause o hydrocephalus in newborns. presents with enlarging head circumference.
dandy-walker malformation
congenital lack of a cerebella vermis. massively dilated fourth ventricle. often associated with hydrocephalus.
arnold-chiari malformation
congenital downward displacement of the cerebellar vermis and tonsils through the foramen magnum. obstruction of CSF flow results in hydrocephalus. o
what is arnold-chiari associated with (other than hydrocephalus?
meningiocele and syringomyelia.
syringomyelia
cystic degeneration of the spinal cord. trauma or type 1 arnold chiari. usually occurs between C8-T1. gives loss of pain and temperature in the upper extremities, but spares fine touch and position sense. presents as a cape-like lesion. white anterior commissure and spinothalamic tracts are involved.
what happens as the syringomyelia progresses
it expands and takes out the anterior motor tracts muscle atrophy, impaired reflexes as well as horners syndrome when it disrupts the sympathetic tracts.
poliomyelitis
damage to the anterior horn due to infection. presents with lower motor signs.
werdnig-hoffman disease
inherited degeneration of the anterior horn -motor. this is auto recessive.
what happens in werdnig-hoffman?
floppy baby syndrome. eventually death a few years after.
amyotrophic lateral sclerosis
degenerative disorder of the upper and lower motor neurons. anterior horn degen leads to lower motor signs. lateral corticospinal tract degen leads to upper motor neuron signs.
what are the early signs of ALS
atrophy and weakness of the hands.
what distinguishes ALS from sphyngomyelia?
lack of sensory issues
most common age group for ALS?
middle-aged adults.
what are the genetic causes of ALS
zinc-copper super oxide dismutase. leads to free radical injury of the neurons.
Friedrich Ataxia
degeneration of the cerebellum and spinal cord. degeneration of the cerebellum leads to ataxia, degeneration of the spinotracts leads to loss of vibratory sense, proprioception, muscle weakness, loss of tendon reflexes.
what are the genetics of friedrich ataxia?
autosomal recessive, trinucleotide repeat expansion with the frataxin gene.
what does the frataxin gene do?
essential for iron transport into the mitochondria.
who presents with F. Ataxia?
childhood disease. patients wheelchair bound within a few years.
what is F. Ataxia associated with?
hypertrophic cardiomyopathy
meningitis
inflammation of the leptomeninges (pia and arachnoid).
neonate meningitis cause?
group B strep., E. coli, listeria monocytogenes.
children and teenagers meningitis cause?
N. meningitidis
adults and elderly meningitis cause?
strep pneumonia
nonvaccinated infants cause of meningitis
H. flu.
viral meningitis children
coxsackievirus. fecal oral transmission
what is agent of meningitis for immunocompromised patient?
fungi.
what is the classic triad of meningitis
HA, nuchal rigidity and fever. (viral has photophobia) vomiting, altered mental status may also be present.
CSF for bacterial meningitis
neutrophils, low glucose, high protein,
CSF for viral meningitis
lymphocytes, protein, glucose is normal.
CSF for fungal meningitis
lymphocytes, protein, and low glucose.
what is a leukodystrophy?
inherited mutations in enzymes that maintain myelin.
metachromatic leukodystrophy
deficiency of arylsulfatase (autosomal recessive). this is the most common leukodystrophy. sulfatides cannot be broken down and accumulate in lysosomes of oligodendrocytes.
krabbe disease
deficiency of galactocerebroside (autosomal recessive). accumulates in macrophages.
adrenoleukodystrophy
impaired addition of co enzyme A to long chain fatty acids (X-linked defect). accumulation of fatty acids damages adrenal glands and white matter.
multiple sclerosis
autoimmune destruction of the CNS myelin and oligodendrocytes. most common disease of the CNS in young adults 20-30 years.
MS more common in who?
women. more commonly seen in areas away from the equator.
genetic association?
HLA-DR2
what are the clinical features of MS
periods of remission and relapsing including:
- ) blurred vision in one eye
- ) vertigo and scanning speech mimicking alcohol intoxication
- ) internuclear opthalmaplegia
- ) hemparesis or unilateral loss of sensation
- ) loss of sensation of the lower extremities.
- ) bowel, bladder, and sexual dysfunction (autonomic function)
diagnosis of MS
LP: increased lymphocytes, increased Ig with oligoclonal IgG bands and myelin basic protein
subacute sclerosis panencephalitis
progressive, debilitating encephalitis that leads to death. due to measles viral infection infection occurs in infancy. characteristic for viral inclusions within neurons and oligodendrocytes.
progressive multifocal leukoencepholitis
caused by JC virus infection of oligodendrocytes. immunosuppression causes reactivation, presents with rapidly progressing neurological signs leading to death.
central pontine myelinolysis
focal demyelination of the pons due to rapid infusion of hypertonic solution or rapid correction of hyponatremia in alcoholics.
how does central pontine myelinolysis present?
presents as locked-in syndrome or acute bilateral paralysis.
where are childhood primary tumors?
infratentorial
where are adult primary tumors?
supratentorial
where are metastatic tumors likely to be found within the CNS?
at the gray white junction
most common tumors in adults
glioblastoma multiforme, meningioma, schwannoma
childhood tumors?
pilocytic astrocytomas, medulloblastoma, ependymoma
glioblastoma multiforme
malignant high-grade tumor of astrocytes, most common primary tumors, usually arises in the cerebral hemispheres, characteristically crosses the corpus (butterfly tumor), poor prognosis.
characteristic histology of GBM
regions of necrosis surrounded by tumor cells, (pseudopalisading), endothelial cell proliferation.
what are the typical stain for GBM
GFAP +
meningioma
benign tumors of the arachnoid most common tumors of the CNS in adults. more common in women and rare in children. may present as seizures.
do meningiomas invade the parenchyma?
no. they compress, but do not usually invade.
what does imaging reveal for a meningioma?
round tumor attached to the dura.
what does the histology of meningioma show?
whorled pattern with psammoma bodies.
schwannoma
benign tumors of schwann cells. involves cranial and spinal nerves, commonly cranial VIII at the cerebropontine angle.
how do schwannomas present?
they present as decreased hearing and tinnitus.
what is the histology of schwannoma?
stains with s-100
what the genetics of bilateral schwannomas?
NF2.
oligodendrogliomas
malignant tumor oligodendrocytes. may present with seizures.
what lobes do the tumor involve?
usually the fontal lobe.
what is the appearance of schwannoma?
calcified tumor of the white matter, has fried-egg cells
pilocytic astrocytomas
benign tumor of astrocytes, most common tumor in astrocytes, usually in the cerebellum. cystic lesion with a mural nodule.
what are the histology of pilocytic astrocytomas?
rosenthal fibers, which are thick eosinophilic processes of astrocytes with staining GFAP.
medulloblastoma
malignant tumor derived from granular cells of the cerebellum or the neural ectoderm. usually arises in children.
histology of medulloblastoma
small round blue cells, homer-wright rosettes
what is the prognosis of medulloblastoma?
this is an aggressive tumor that spreads throughout the CNS via CSF. commonly mets to the caudal equina through drop mets.
what are drop metastasis?
when medulloblastoma metastasizes to the cauda equina.
ependymoma
malignant tumor of ependymal cells found in children. most common in fourth ventricle and causes hydrocephalus.
what are the characteristic findings of ependymoma?
perivascular pseudorosettes
craniopharyngioma
tumor that comes from epithelial remnants of rathke’s pouch. presents as one of the only supratentorial masses is children and young adults. it can compress the optic nerve giving bitemporal hemianopia. calcifications commonly found.