Intro to Neuropath Flashcards
GFAP stains what cells
astrocytes
selective vulnerability
set of neurons with shared properties in response to insult
when do you see red neurons
12-24 hrs after acute insult; earliest indicator
what is the primary indicator of an axonal reaction
- central chromatolysis (nissl at periphery)
- peripheral displacement of nucleus
what is the intracytoplasmic neuronal inclusion
lipofuscin
when is lipofuscin present
- rabies: negri bodies [esosinophilic]
- AD: neurofibrillary tangles
- parkinson: lewy bodies
- CJD
what are the intranuclear neuronal inclusions
- herpes: cowdry type A bodies [acidophilic]
- CMV (has intranuclear and cytoplasmic) [basophilic]
hypertrophy and hyperplasia of astrocytes; most important indicator of CNS injury
gliosis
astrocytes are metabolic buffers and detoxifiers of brain; foot processes contribute to BBB
describe the appearance of a gemistocyte
large nucleus that is eccentrically located, bright pink cytoplasm
what three diseases have ALZ type 2 astrocyte
hyperammononemia, wilson, hereditary metabolic disorder of the urea cycle
HSP alpha-B crystalline and HSP27
seen in rosenthal fibers
- thick, elongated, brightly eosinophilic
- occur within astrocyte processes
what are the two histo elements of pilocytic astrocytoma
note: both are slow processes
- rosenthal fibers - beaded sausage / corkscrew hyaline bodies; bright pink
- eosinophilic granular bodies - protein droplets, PAS+ ; seen in gangliolioma and pleomorphic xanthoastrocytoma
this leukodystrophy has periventricular, perivascular, and subpial rosenthal fibers
alexander disease
indigestible remnants of astrocyte metabolism, commonly seen in aged brains
PAS+
corpora amylacea
round, faintly basophilic and laminated; subpial and perivascular
corpora amylacea and EGB are both…
PAS+
microglia are derived from
mesoderm
CR3 and CD68 +
microglia
*CD68 stains brown
miroglial response to injury
- microglial nodules : surround small foci of necrosis
- neuronophagia : surround dying neuron
- rod cell w/ elongated nuclei (neurosyhpillis)
what cells are responsible for PML and MSA in response to injury
oligodendrocytes
- progressive multifocal leukoencephalopathy
- multiple system atrophy
PML has…
intranuclear inclusions
MSA has…
alpha-synuclein, a glial cytoplasmic inclusion
what virus damages ependymal cells?
CMV; viral inclusions
disruption of ependymal lining can lead to ependymal granulations
increased EC fluid d/t BBB disruption and increased vascular permeability
vasogenic edema
describe the fluid shift in vasogenic edema
intravascular to intercellular
what impairs resorption of excess extracellular fluid in vasogenic edema?
paucity of lymphatics
vasogenic edema often follows…
ischemic injury
increased intracellular fluid d/t neuronal, glial or endothelial cell membrane injury
cytotoxic edema
cytotoxic edema follows…
generalized hypoxic/ischemic insult or metabolic derangement
gyri flattened, sulci narrowed and ventricles compressed is ecidence of […] which can lead to…
- cerebral edema
2. herniation
results in an increased production of CSF
choroid plexus papilloma
pyogenic meningitis results in suppurative exudate covering the brainstem and cerebellum, resulting in thickened leptomeninges
what is a consequence of this
obstructive hydrocephalus
what two pathogens have a predilection for the base of the brain
TB and neurosyphillis
hypervitaminosis A can lead to…
acquired hydrocephalus
- cranial bones softened; bulging fontanelles, increased ICP, blurred vision
what kind of hydrocephalus does neurosyphillis cause?
communicating
b/c involves leptomeninges, not a single point of obstruction
most common parasitic nervous system disease worldwide, causes 50% of acquired epilepsy cases in developing countries
neurocysticercosis, caused by Taenia solium tapeworm
hydrocephalus ex-vacuo
where do you see atrophy?
what is the CSF pressure?
frontal atrophy, normal CSF
symmetric type of hydrocephalus; develops slowly; dementia-like manifestations
normal pressure hydrocephalus
wacky, wet, wobbly
it is reversible
increased ICP is generally due to
- generalized brain edema
- expanding mass lesion (tumor, abscess, hemorrhage)
- increased CSF volume (rare)
- dilated pupil and impaired eye movement
- CL homonomyous hemianopia
- duret hemorrhage
- IL paralysis
uncal herniation (transtentorial)
- CN3
- PCA
- rupture of paramedian artery; hemorrhagic lesions visible in midbrain and pons
- compression of CL cerebral peduncle
1 + 4 = kernohans phenomenon
respiratory and cardiac compression
tonsillar herniation; cerebellar tonsils displaced through foramen magnum
subfalcine (cingulate) herniation may lead to hydrocephalus due to obstruction of
foramen of monro
signs and symptoms of ICP
- HA, N, V, lethargy, change in behavior
- change in pupil reaction, impaired upward gaze
- false localizing signs (6th nerve palsy; ie kernohan/uncal)
- seizures
- decreased coordination, ataxia
- papilledema
what nerve is affected in kernohans phenomenon
CNVI
what portions of the brain are most sensitive to hypoxia?
- purkinje of cerebellum
2. pyramidal cells of sommer’s sector (CA1 and CA2 of hippocampus)
encephalocele is a diverticulum of disorganized brain tissue extending through a defect in the cranium, most often in the
posterior fossa
name the three consequences of a myelomeningocele
- motor and sensory deficits of LE
- bowel and bladder control dysfxn
- infections
what are the three main causes of microcephaly
- FAS
- HIV-1 acquired in utero
- zika
decreased amount of gyri; smooth or cobblestone surface
lissenencephaly
agyria = no gyri
neronal heterotopias are commonly associated with
epilepsy
- collections of neurons in inappropriate places (ventricular surface)
filamin A protein + DCX (double cortin protein) on X chromosome lead to
males: lissencephaly
females: subcortical band heterotopias
trisomy 13, SHH leads to
holoprosencephaly
- incomplete separation of cerebral hemispheres across midline
- cyclopia, arrhinenceophaly
agenesis of the corpus callosum leads to
mental retardation or normal mentation
batwing lateral bentricles
fairly common
which forebrain anomaly has entrapment of meningeal tissue?
polymicrogyria
genetic is symmetric and BL; could be d/t local tissue injury at end of migration
<4 layers of gray matter
downward extension of the cerebellar vermis into the foramen magnum
Chiari II malformation
Chiari II malformation is usually associated with
hydrocephalus
myelomeningocele
low-lying cerebellar tonsils extend down vertebral canal
Chiari I
symptomatic if impaired CSF flow
enlarged posterior fossa with expanded, roofless fourth ventricle
absent cerebellar vermis replaced by cyst with ependymal lining, which is contagious to leptomeninges
dandy-walker malformation
hypoplasia of vermis, elongation of cerebellar peduncles and altered brainstem shape
molar tooth sign
joubert syndrome
fluid-filled cleft-like cavity in the inner portion of the spinal cord
isolated loss of pain and temperature sensation of the UE
syringomyelia (syrinx)
affects the anterior white commissure
expansion of ependymal-lined central canal of the cord
hydromyelia
hemorrhage seen in the germinal matrix of premature infants
intraparenchymal hemorrhage
where does an intraparenchymal hemorrhage occur?
between thalamus and caudate nucleus
can lead to SAH; hem. is BL and when large enough, ruptures into 3rd and 4th ventricles
