Nervous System Pathology Flashcards
Define Leptomeningitis
an inflammatory process that is localized to the interfacing surfaces of the pia and arachnoid, where CSF flows
Which type of meningitis is more common and related to bacteria?
leptomeningitis
Define pachymeningitis
inflammation of the dura, usually a consequence of contiguous infection, such as chronic sinusitis or mastoiditis.
What is the dura?
a barrier to infection
What kind of organism is usually responsible for bacterial meningitis in neonates?
e. coli and GBS
What kind of organism is usually responsible for bacterial meningitis in infants?
H. influenza
What kind of organism is usually responsible for bacterial meningitis in adults?
strep. pneumococcus
gram + diplococcus
What kind of organism is usually responsible for bacterial meningitis in military barracks?
neisseria meningitidis
Cerebritis
bacterial infection around the brain
encephalitis
viral infection inside of the brain
What is the definitive dx index of meningitis?
PMNs in the CSF
What is the hallmark of meningitis caused by TB, viral meningitides, and chronic fungal infections
lymphocytes
The ….. although delicate, is an effective barrier against the spread of infection and generally prevents involvement of the underlying brain
pia
common sxs of bacterial meningitis??
H/A, vomiting, and fever, convulsions frequently occur in children.
cervical rigidity, head retraction, +Kernig, +brudzinski
What is Parkinson’s disease?
neurologic disorder characterized by the loss of neurons in the Substantia Nigra (strips in midbrain)
tremors at rest, muscular rigidity, expressionless face and emotional lability
When do sxs of Parkinson’s disease usually appear?
6th-8th decade
Cause of early onset parkinson disease?
due to point mutation of chromosome 4
Main cause of parkinson disease?
idiopathic
What is found on gross pathologic association of parkinson disease? microscopic?
loss of pigmentation in the Substantia Nigra and Locus Ceruleus
pigmented neurons are scarce with small extracellular deposits of melanin, from necrotic neurons
What are Lewy bodies?
residual atrophic nerve cells that contain spherical, granular, eosinophilic cytoplasmic inclusions
What type of dementia has visual hallucinations?
Lewy body dementia
Pill rolling tremor?
seen in Parkinson disease
present at rest and disappears with voluntary movement
Parkinson disease pts have increase risk of….
depression and dementia
Therapy for early parkinson disease?
Levodopa, does not rectify underlying disorder and becomes ineffective
Other causes of Parkinson like sxs?
- Drugs: Phenothiazines and Haldol
- CO or Manganese poisoning
- Bilateral infarcts of Basal Ganglia
- Hydrocephalus
- Tumors near the Basal Ganglia
- Cerebral Trauma
Define Alzheimer
An insidious and progressive neurological disorder characterized by loss of memory, cognitive impairment, and eventual dementia
How can we dx Alzheimer?
definitive- autopsy
but can be pretty accurately dx with radiograph + clinical presentation
Most common cause of dementia?
Alzheimer
Are women and men affected with Alzheimer’s the same?
women 2x more than men
Cause of alzheimer’s disease
not fully known but thought to relate to beta-protein amyloid deposition in senile plaques
What occurs grossly in the brain of a pts with Alzheimer’s?
loss of neurons and neuritic processes, the gyri narrow, the sulci widen, and bilateral cortical atrophy becomes apparent in the frontal, temporal,parietal and hippocampal cortices
Alzheimers is a …..disease
cortical
microscopic pathology of Alzheimer’s disease?
- Senile (neuritic) Plaques
- Neurofibrillary tangles
- Amyloid angiopathy
What are senile plaques? Where are they found?
discrete spherical masses of silver-staining neuritic processes surrounding a central amyloid core.
Found predominantly in the hippocampus and amygdala, as well as the cortex
What are neurofibrillary tangles? Where are they found?
bundles of paired, helical filaments in the cytoplasm of cortical neurons or hippocampal pyramidal cells that displace or encircle the nucleus (flame cells)
cortex, hippocampus and amygdala
Where is amyloid angiopathy found?
within cerebral blood vessels seen with congo red stains
Terminal stages of Alzheimer’s disease?
incontinent and bedridden
Usual cause of death of alzheimer’s disease?
terminal bronchopneumonia
What is Multiple Sclerosis?
chronic, demyelinating disease of the CNS in which there are numerous patches of demyelination throughout the white matter.
What is the most common demyelinating disorder?
MS
1/1000
What does MS affect?
both sensory and motor functions
Mean age of MS onset?
30
more common in women
Etiology of MS?
unknown
possible: genetic, immune, infectious
Hallmark of MS?
plaque
variable size with smooth rounded contour
usually situated in white matter
(has preference for optic nerves and chiasm, can also involve cerebellum, brain stem and spinal cord)
how is seen MS histologically?
selective loss of myelin in a region of axonal preservation
perivascular inflammation of lymphocytes and macrophages with focal edema
Course of MS?
usually onsets of 3rd/4th decades with periods of exacerbation and remissions
Initial sxs of MS?
typically begins with symptoms related to lesions of the optic nerves, brainstem or spinal cord.
- Blurred vision, or the loss of vision in one eye, is often the presenting complaint. - When the initial lesion is in the brainstem, the most troubling early symptoms are double vision and vertigo.
Prognosis of MS?
pts usually survive 20-30 yrs after the onset
How do MS pts typically die?
respiratory paralysis or UTIs in terminal coma
Cause of berry aneurysms?
arterial defects that originate during embryonic development, when the bifurcation of an artery creates a Y-shaped configuration
The circumferential muscular layer of the parent vessel, may fail to interdigitate to the two branches, creating a point of congenital muscular weakness, bridged only by endothelium, the internal elastic lamina, and the slender adventitia
Etiology of berry aneurysm?
congenital- embryological malformation
Rupture of berry aneurysm causes…
life threatening subarachnoid hemorrhage
initial sxs of ruptured berry aneurysm
sudden severe HA = onset of SAH, may be followed by coma
Sxs of pts who survive 3-4 days after ruptured berry aneurysm
progressive decline in consciousness due to arterial spasm and cerebral ischemia/infarction
What can HTN causes in the brain?
HTN associated aneurysms
Charcot-Bouchard aneurysms, small fusiform dilatations located on the trunk of a vessel
What causes Charcot-Bouchard aneurysms?
HTN compromises cerebral arterioles by depositing lipid and hyaline in the walls
What happens when Charcot-Bouchard aneurysms rupture?
hypertensive cerebral hemorrhage
Where do hypertensive intracerebral hemorrhages occur?
basal ganglia-thalmus
the pons
the cerebellum (retractable n/v)
Sxs Hypertensive Intracerebral Hemorrhage
abrupt onset sxs, weakness is most prominent, ataxia, occipital HA, vomiting
when hemorrhage is progressive (which it usually is) death occurs within hrs to days
Causes of cerebral infarction
Atherosclerosis predisposes to vascular thrombosis > embolic events > ischemia > cerebral infarction
What types of cerebral infarcts are more likely to be “bland?”
those initiated by thrombotic occlusion are largely ischemic
Which cerebral infarcts are more likely “hemorrhagic”?
those caused by embolism
an embolus occludes vascular flow abruptly and then ischemic region undergoes necrosis
What happens within months are a cerebral infarction?
the necrotic area is excavated by phagocytosis and a permanent cyst is formed
Where do primary brain tumors usually metastasis?
they stay in the brain and spinal cord!
all tumors….
increase ICP and chance of seizures
Brain tumors in adults are…
usually in the front
Brain tumors in kids are…
usually in occiput and cerebellum
benign meningioma v. astrocytoma
can be just as deadly
GBM
result in rapid growth and are fatal in a short time
What are astrocytomas?
glial neoplasms derived from astrocytes
What are astrocytes?
star shaped cells distributed throughout the nervous system, support neurons and respond to tissue injury
Where are astrocytomas usually found? In what pt population?
in cerebral hemispheres in adults and cerebellum and pons in kids
usually see in late middle age or older
Describe grade I astrocytoma
Composes 20% of primary intracranial neoplasms
poorly demarcated and infiltrates the cortex with an indistinct margin
Life expectancy for pt with grade I astrocytoma?
~5 yrs
Describe anaplastic (Grade II) astrocytoma
greater cellularity, cellular pleomorphism and anaplasia than well differentiated astrocytoma
rapid tumor growth
Life expectancy for grade II astrocytoma?
~3 yrs
Life expectancy for pt with glioblastoma multiforme? (GBM)
~18 months
Describe GBM
infiltrates extensively in the cortex, freq. crossing the corpus callosum with bi extension into the white matter of both hemispheres with red (recent) and yellow (remote) hemorrhage that looks like a butterfly on gross examination
Where do oligodendrogliomas from?
in the white matter, predominately in the cerebral hemispheres in adults
Describe oligodendrogliomas
Well circumscribed gelatinous grey masses, often with cysts, focal hemorrhage and calcifications
slow growing = better prognosis
Why oligodendrogliomas grow slowly?
due to absence of mitotic figures and necrosis
sxs of oligodendrogliomas
several yrs of neurologic complaints, including seizures
What is an ependymoma?
glial tumor most common in the fourth ventricle, producing obstruction and resulting in hydrocephalus
Most common location for ependymoma’s in adults? kids?
spinal cord
near 4th ventricle
Ependymoma prognosis
tumor generally grows slowly, but can seed the subarachnoid space with CSF dissemination
avg 4 yr survival after surgery and radiotherapy
Where do medulloblastomas arise from?
exclusively from the cerebellum
What are the small, round, blue cell tumors of childhood?
medulloblastoma, neuroblastoma, Ewing’s sarcoma, PNET, Burkitts lymphoma and rhabdomyosarcoma
Describe medulloblastoma
tumor infiltrates the vermis of the cerebellum aggressively and frequently disseminates through the CSF
tumor is well circumscribed, gray and friable
How do children with medulloblastoma present?
cerebellar dysfunction (ataxia) or hydrocephalus
prognosis for Medulloblastoma
highly malignant tumor but extremely radiosensitive if dx early
with total excision and radiation, 10 yr survival rate is 50%
What is a meningioma
Intracranial tumors that arise from the arachnoid villi and produce symptoms by compressing brain tissue
When are meningiomas most commonly seen?
4th and 5th decades
majority arise sporadically and exhibit either a deletion or mutation of chromosome 22
How do meningiomas appear grossly?
well circumscribed, firm, bosselated masses of variable size
Sxs of meningiomas
tumors in olfactory groove: anosmia
suprasellar region: visual defects, HAs
seizures
What happens if you partially excise a meningioma?
they recur!!
they typically double in size every 2 yrs
What is an acoustic neuroma?
intracranial schwannoma restricted to the 8th CN, found in the cerebral pontine angle
What sxs do acoustic neuromas cause?
tinnitus, deafness, can also compress other CN depending on its size
malignant change is rare
How do metastatic tumors reach the brain?
through the blood stream
Where do most metastatic tumors live in the brain?
in the gray-white junction
