Neuropathology Flashcards
what do glial cells do
regulate homeostasis
provide support and protection to neurons
what does an astrocyte do
maintain blood barrier
what does an oligodendrocyte do
myeline CNS axons
what does a microglial cell do
act as a phagocyte
what do ependymal cells do
produce CSF
what are the 5 changes seen in acute neural injury (red neurons)
1.) shrinkage of cell body
2.) pyknosis of nucleus
3.) lack of nucleolus
4.) loss of Nissl substance
5.) eosinophilia of cytoplasm
what is the best indicator of neuronal injury
reactive glial cell changes
what is the most important histopathologic marker of CNS injury
gliosis
what is gliosis
injury of astrocytes that leads to hypertrophy and hyperplasia
what are the two hallmarks of gliosis
Rosenthal fibers and corpora amylacea
what is corpora amylacea
brain sand - polyglucosan aggregates from waste products
what are the 4 steps of microglia response to injury
1.) proliferate
2.) formation of elongated nuclei (rods)
3.) formation of aggregates around tissue necrosis
4.) congregation around cell bodies of dying neurons
what can be seen histologically in oligodendrocyte injury
nuclear viral inclusions or cytoplasmic inclusions
what are ependymal granulations
small irregularities on the ventricular surfaces caused by astrocyte proliferation
which condition can cause ependymal injury with viral inclusions
cytomegalovirus (CMV)
what are the three main causes of increased intracranial pressure
1.) brain edema
2.) hydrocephalus (increased CSF)
3.) expanding masses
what are the two types of cerebral edema
1.) vasogenic edema
2.) cytotoxic edema
what is vasogenic edema
blood brain barrier disruption causes increase in extracellular fluid
only affects white matter
what is cytotoxic edema
injury to cells causes secondary increase in intraceullar fluid
common in cases of obesity and diabetes
affects white and gray matter
what are the three changes associated with generalized cerebral edema
1.) flattening of gyri
2.) narrowing of sulci
3.) compression of ventricles
what is the main change associated with interstitial cerebral edema
lateral ventricle compression
which structure generates the CSF
choroid plexus
what is hydrocephalus
accumulation of successive CSF in the ventricular system of the brain
most commonly cause by impaired flow and resorption of CSF
what is hydrocephalus ex vacuo
compensatory increase in ventricular volume secondary to loss of brain parenchyma
ex. Alzheimer’s
what is a subfalcine herniation
asymmetric expansion of cerebral hemisphere that displaces the cingulate gyrus under the falx
can cause compression of anterior cerebral artery
what causes a red neuron
lack of oxygen (hypoxia)
what is a transtentorial herniation
compression of medial temporal lobe against free margin of tentorium
can cause compression of third cranial nerve (oculomotor) or the posterior cerebral artery which would affect the eyes
what is a tonsillar herniation
displacement of cerebellar tonsils through the foramen magnum
can cause brainstem compression - most deadly
what are duret hemorrhages
secondary hemorrhagic lesions in the midbrain and pons due to progression herniation
what is the most common form of CNS malformation
neural tube defects
the most common neural tube defect involves what
the spinal cord
what is a well-known risk factor for a neural tube defect
folate deficiency
what is the most common type of neural tube defect
spina bifida occulta
what is a meningoencephalocele
neural tube defect where a large portion of the occipitoparietal brain tissue protrudes through the posterior fontanel
a meningoencephalocele is associated with which condition
Meckel-Gruber syndrome
what is iniencephaly
lack of occipital bone and cervicothoracic spinal fusion
what is anencephaly
absence of scalp, cranium, and most of brain
what is craniorachischisis
combination of ancenphaly and boney spinal defect
what are the three main causes of macrocephaly and microcephaly
1.) chromosome abnormalities
2.) fetal alcohol syndrome
3.) HIV infection in utero
what is the main consequence of agenesis of the corpus callousum
prevents both sides of brain from communicating
which three malformations are associated with posterior fossa anomalies (malformations of brainstem and cerebellum)
1.) Arnold-Chiari
2.) Chiari Type 1
3.) Dandy-Walker
what is Arnold-Chiari (type 2) malformation
abnormally small posterior fossa and misshapen midline extensions of vermis through foramen magnum
causes hydrocephalus and lumbar myelomeningocele
Arnold-Chiari (type 2) malformation is associated with what
spina bifida
what is Chiari type 1 malformation
low-lying cerebellar tonsils that extent into the vertebral canal
what is Dandy-Walker malformation
enlargement of posterior fossa leads to absence of cerebellar vermis and replacement by midline cyst
what Cerebral Palsy
neurologic motor deficit due to injury in prenatal and perinatal periods of development
what three things can be seen in Cerebral Palsy
1.) hemorrhage
2.) periventricular leukomalacia
3.) multi cystic encephalopathy
what is periventricular leukomalacia
infarcts in the periventricular white matter seen in Cerebral Palsy
what is multicystic encephalopathy
large, destructive cystic lesions in the brain caused by ischemic damage
seen in Cerebral Palsy
what is a displaced skull fracture
one that extends beyond the thickness of the cranium
conscious falls tend to affect which area of the skull
occipital fractures
unconscious falls tend to affect which area of the skull
frontal fractures
what is a diastatic fracture
skull fracture whose line transverses one or more suture of the skull and lead to its widening
most common in infants an young children
contusions and lacerations of the brain are most common in which two regions
1.) frontal
2.) temporal
what is a plaque jaune
remote contusion of the brain which is a yellow color
what is an epidural hematoma
pooling of arterial blood between the dura and periosteum
what is a subdural hematoma
pooling of venous blood between the dura and brain parenchyma
what is the gross appearance of an acute subdural hematoma
collection of freshly clotted blood along the brain’s surface that doesn’t go down into the sulci
what are the three steps to the breakdown of a subdural hematoma
1.) lysis of clot (1 week)
2.) growth of fibroblasts into hematoma (2 weeks)
3.) development of hyalinized connective tissue (1-3 months)
cord injury at and below the level of the thoracic vertebrae often causes what
paraplegia
cord injury at the level of the cervical vertebrae often causes what
quadriplegia
cervical lesions above C4 can often causes what
respiratory compromise and paralysis of the diaphragm
what is a stroke and what are the two types
sudden interruption of blood flow to the brain
types: ischemic and hemorrhagic
what is an ischemic stroke
hypoxia, ischemia, and infarction caused by impairment of blood supply
what is the most common cause of an ischemic stroke
embolism
which two things can cause a hemorrhagic stroke
1.) hypertension
2.) vascular anomalies like aneurysms
what is a hemorrhagic stroke
rupture of blood vessel leads to hemorrhage
the brain receives about ____% of the body’s resting cardiac output
15%
what are the three survival factors in regards to a cerebrovascular brain injury
1.) collateral circulation
2.) duration of ischemia
3.) magnitude of event and timeliness of onset
what is global cerebral ischemia (diffuse ischemic/hypoxic encephalopathy)
reduction of cerebral perfusion caused by cardiac arrest, shock, or severe hypotension
which brain cell, neurons or glial cells, are most sensitive to hypoxia
neurons
which three types of neurons are most sensitive to hypoxia
1.) pyramidal cells of hippocampus
2.) purkinje cells of cerebral cortex
3.) pyramidal neurons in cerebral cortex
which area of the brain is at most risk for watershed infarct
area between anterior and middle cerebral artery
what is the border (watershed) zone
regions of brain/spinal cord most distal to the anterior blood supply
damage here produces sickle-shaped band of necrosis
the major source of collateral flow in the brain is what
the circle of Willis
which three locations have the least amount of collateral flow within the brain
1.) thalamus
2.) basal ganglia
3.) deep white matter
which artery is most at risk for a cerebral infarct caused by embolus
middle cerebral artery
what are the three main causes of a paradoxical emboli
1.) cardiac anomalies in children
2.) cardiac surgery
3.) tumor, fat, or air
fat embolism syndrome is a common occurrence after what
after fractures and trauma to the bone marrow
what are the three most common locations of a cerebral infarct caused by thrombus
1.) bifurcation of carotid arteries
2.) origin of middle cerebral artery
3.) end of basilar artery
cerebral infarct caused by thrombus is often associated with which two conditions
1.) hypertension
2.) diabetes
what are the two main causes of a cerebral infarct caused by inflammation of blood vessels
1.) infectious vasculitis
2.) non-infectious vasculitis
what are the two main causes of infectious vasculitis
1.) syphilis
2.) TB
what are the three main causes of non-infectious vasculitis
1.) polyarteritis nodosa
2.) primary angitis of the CNS
3.) granulomatous angitis
what are three causes of cerebral infarcts caused by “other” things
1.) hypercoagulation states
2.) dissecting aneurysm of arteries in the neck
3.) drug abuse
which two conditions can cause lacunar infarcts
1.) diabetes
2.) hypertension
what is seen histologically in the beginning stages of acute ischemic injury of the brain
diffuse eosinophilia of shrinking neurons
what is seen histologically 10 days after an acute cerebral infarct
foamy macrophages and reactive gliosis with neovascularization
what are Charcot-Bouchard microaneurysms
minute aneurysms seen in an intracranial hemorrhage
what is the most common cause of a subarachnoid hemorrhage
rupture of a berry aneurysm in a cerebral artery
what is the most common type of intracranial aneurysm
saccular
what is the most common location for a saccular aneurysms
anterior communication artery
which two things increase your risk for a saccular aneurysms
1.) smoking
2.) hypertension
what are the four main types of vascular malformations
1.) arteriovenous
2.) cavernous
3.) capillary telangiectasias
4.) venous angiomas
what is an arteriovenous malformation
tangled network of vasculature with arteriovenous shunting
what is the most common type of significant venous malformation
arteriovenous
what is the most common site of an arterivenous malformation
middle cerebral artery
what is a cavernous malformation
tightly packed, low flow vessels not associated with arteriovenous shunting
what are the three most common locations for a cavernous malformation
1.) cerebellum
2.) pons
3.) subcortical region
what is capillary telangiectasis
microscopic dilated, thin walled vascular channels within normal brain parenchyma
what is the most common location for capillary telangiectasis
pons
what is the most common spread type of a CNS infection
hematogenous
what are the four spread pathways of CNS infections
1.) hematogenous
2.) retrograde venous
3.) direct implantation
4.) local extension
what is retrograde venous spread
spread via anastomoses with veins of the face
what is direct implantation spread
microorganisms gain access through traumatic opening or congenital malformation
what causes acute pyogenic meningitis
bacterial infection
what cases aseptic meningitis
viral infection
what causes chronic meningitis
TB, spirochete, or cryptococcal infections
what will an aseptic meningitis spinal tap reveal
high lymphocyte count
protein elevation
normal glucose
which two organisms most commonly cause acute pyogenic meningitis in neonates
1.) E. coli
2.) group B strep
which organism most commonly causes acute pyogenic meningitis in adolescents and young adults
neisseria
which two organisms most commonly cause acute pyogenic meningitis in older adults
1.) strep. pneumo
2.) listeria
which vaccine can lower the risk of acquiring acute pyogenic meningitis
flu vaccine
what are the 5 main symptoms of acute pyogenic meningitis
1.) headache
2.) fever
3.) photophobia
4.) neck stiffness
5.) irritability
which syndrome is associated with acute pyogenic meningitis
Waterhouse-Friderichsen syndrome
what are the two most common organisms to cause acute focal suppurative infections (brain abscesses)
strep and staph
what usually causes a subdural empyema
bacterial infections of skull or air sinuses like sinusitis or osteomyelitis
an extradural abscess is most commonly associated with which condition
osteomyelitis
which three organisms most commonly cause chronic bacterial meningoencephalitis
1.) TB
2.) syphilis (treponema)
3.) borrelia (Lyme disease)
what is the most frequent clinical presentation of meningovascular syphilis
stroke
what is Heubner arteritis
thickening and lymphocytic infiltration of intima seen in neurosyphilis
how is an aseptic case of meningitis diagnosed
through absence of bacteria in culture
what will a bacterial meningitis spinal tap reveal
high neutrophil count
high protein
low glucose
what are the two main things seen histologically in aseptic meningitis
1.) perivascular cuffs of lymphocytes
2.) microglial nodules
what is arthropod-borne viral meningoencephalitis
viral infections that have animal hosts and insect vectors (mosquitos and ticks)
ex. West Nile encephalitis
which regions of the brain are most affected by HSV-1
inferior and medial regions of temporal lobes
orbital gyri of frontal lobes
HSV-2 causes what in adults
meningitis
HSV-2 causes what in neonates
severe encephalitis
who is most affected by cytomegalovirus (CMV)
immunosuppressed individuals (HIV) and fetuses
15% of those with CMV develop what
hearing loss
CMV affects the brain in which three ways
1.) periventricular necrosis
2.) microcephaly
3.) periventricular calcification
what is poliomyelitis
nervous system involvement due to infection with the poliovirus
what are pathognomonic to rabies
Negri bodies - inclusions found in pyramidal neurons of hippocampus and Purkinje cells of cerebellum
what are the three neuropathologic effects seen in HIV with antiviral therapy
1.) aseptic meningitis
2.) mild lymphocytic meningitis
3.) HIV encephalitis
which two things are common to see histologically in HIV cases
1.) microglial nodule
2.) multinucleated giant cell
what causes progressive multifocal leukoencephalopathy encephalitis
JC polyomavirus
what is progressive multifocal leukoencephalopathy encephalitis
JC polyomavirus infection of oligodendrocytes causes demyelination
which fungal infection is common in those with AIDS
cryptofoccus neoformans
fungal infections most often cause which three forms of CNS injury
1.) chronic meningitis
2.) vasculitis
3.) parenchymal invasion
what are two examples of protozoal diseases that can affect the nervous system
1.) malaria
2.) toxoplasmosis
what are two examples of Rickettsial infections that can affect the nervous system
1.) typhus
2.) Rocky Mountain spotted fever
what are two examples of Metazoal disease that can affect the nervous system
1.) cysticercosis
2.) echinococcosis
which four types of pathologic processes can result in loss of myelin
1.) immune-mediated
2.) viral
3.) drug
4.) inherited disorders
what is the most common demyelinating disorder
multiple sclerosis
what is multiple sclerosis
autoimmune demyelinating disorder that mostly affects the myelin sheath and white matter
CSF tap of multiple sclerosis would show which two things
1.) mildly elevated protein
2.) elevated IgG levels
which stain is used to diagnose multiple sclerosis
Luxol fast blue periodic acid-Schiff stain
what is the pathologic process of neurodegenerative diseases
accumulation of protein aggregates (proteinopathy)
what is a prion
type of abnormally formed cellular protein that can trigged normal proteins in the brain to fold abnormally
what is the most common prion disease
Creutzfeldt-Jakob disease (CJD)
what is seen histologically in someone with Creutzfeldt-Jakob disease (CJD)
Kuru plaques (deposits of abnormal PrP)
may have halo of spongiform change in mad cow disease variant
what is the most common cause of dementia in older adults
Alzheimer disease
what are the two key features of Alzheimer’s
accumulation of Amyloid beta and tau proteins
what is seen grossly in an Alzheimer brain
cortical atrophy of frontal, temporal, and parietal lobes
what are the two key microscopic features of Alzheimer’s
1.) neuritic (senile) amyloid plaques
2.) neurofibrillary tangles (contain Tau)
what is the main cause of Parkinson disease
loss of dopaminergic neurons from the substantia nigra
what is the histologic hallmark of Parkinson disease
alpha-synuclein that forms Lewy bodies and Lewy inclusions
what is the main cause of Huntington disease
degeneration of striatal neurons in basal ganglia
what is seen grossly in someone with Huntington disease
atrophy of caudate nucleus and putamen
what is the most common form of motor neuron disease
amyotrophic lateral sclerosis (ALS)
what is amyotrophic lateral sclerosis (ALS)
loss of upper and lower motor neurons with evidence of toxic protein accumulation
what is seen grossly in the brain of someone with chronic carbon monoxide poisoning
ischemic or hemorrhage necrosis in globus pallidus
demyelination in white matter that doesn’t affect arcuate fibers
what is seen grossly in the brain of someone with ethanol poisoning (chronic alcoholism)
1.) cerebral dysfunction
2.) atrophy and loss of granule cells in vermis
what is the most important factor in the outcome of a patient with a CNS tumor
location of tumor
which lobe of the brain is most commonly affect by tumor
frontal
what is the most common type of primary brain tumor in adults
grade 4 glioblastoma multiforme
what is the most common primary glioma
astrocytoma
what are the two main types of astrocytomas
1.) diffusely infiltrating
2.) localized
what is the most common type of localized astrocytoma
pilocytic
what is the most common location of a diffusely infiltrating astrocytoma
cerebral hemispheres
which types of glial tumor has the best prognosis
oligodendroglioma
what is the gross appearance of an oligodendroglioma
gelatinous with cysts, focal hemorrhage, and calcification
what is the histologic appearance of an oligodendroglioma
anastomosing capillaries resembling chicken wire and granular chromatin
chicken wire appearance is associated with which condition
oligodendroglioma
what are the three main histologic features of a pilocytic astrocytoma
1.) hairlike processes
2.) Rosenthal fibers
3.) mulberry like granular bodies
which stain is used for the hairlike processes seen in a pilocytic astrocytoma
GFAP+
what is the microscopic feature of an ependymoma
perivascular pseudorosettes
what is the most common type of embryonal neoplasm of the brain
medulloblastoma within the cerebellum
what is the most common neoplasm in immunocompromised patients
primary CNS lymphoma
what is seen histologically in primary CNS lymphoma
malignant cells around vessels and necrosis
what is a risk factor for the development of a meningioma
radiation therapy to head and neck
what is the most common genetic abnormality to cause a meningioma
loss of chromosome 22
what is the gross appearance of a meningioma
rubbery and bosselated
what is seen histologically in a meningioma
psammoma bodies
what are the 5 most common primary metastasis sites of brain tumors
1.) lung
2.) breast
3.) skin
4.) kidney
5.) GI
