Glossary of Block VIII, Week III

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3 types of cerebral edema?
describe vasogenic cerebral edema
leakage of fluid from damaged microvasculature
describe cytotoxic cerebral edema
cellular injury with cytoplasmic swelling
describe interstitial cerebral edema
ventricular fluid diffuses into brain parenchyma
major clinical complication/manifestation of cerebral edema -"bottom line"?
may cause or contribute to increased intracranial pressure
treatment for increased intracranial pressure?
IV mannitol
herniation may occur as a complication to increased intracranial pressure. order of herniation in top 4 locations?
1. cingulate (under edge of falx)
2. uncal/transtentorial
3. cerebellar tonsillar (through foramen magnum)
4. transcalvarial (through open skull defect)
which vasculature structure is affected in a cingulate herniation?
branches of the anterior cerebral artery (infarction)
structures affected in an uncal/transtentorial herniation?
oculomotor nerve
posterior cerebral a. (infarction)
cerebral peduncle
aqueduct of sylvius (obstruction)
basilar perforating arteries
clinical s/s of oculomotor nv. involvement seen in an uncal herniation?
ipsilateral fixed, dilated pupil
clinical s/s of posterior cerebral a. involvement in an uncal herniation?
cortical blindness
clinical s/s of cerebral peduncle involvement in an uncal herniation?
pathological finding in basilar perforating arteries affected in uncal herniation?
Duret hemorrhages seen in pons
what structure is affected in a cerebellar tonsilar herniation?
medulla, respiratory centers
(see depression of consciousness and respirations)
CSF is produced where and resorbed where?
produced in choroid plexus of lateral, fourth ventricles
resorbed in arachnoid granulations
non-communicating hydrocephalus is usually the result of a blockage where?
aqueduct or interventricular foramina
four mechanisms of non-communicating hydrocephalus
1. congenital (stenosis)
2. neoplasm (ie. choroid plexus adenoma)
3. inflammation (ventriculitis, meningitis)
4. intraventricular hemorrhage
what causes communicating hydrocephalus?
impaired resorption of CSF at the arachnoid granulations (obstructive process involving the meninges)
effects of the mass effect caused by an epidural hematoma?
increased intracranial pressure -> get uncal/transtentorial herniation with associated neurological signs (ipsilateral fixed pupillary dilation)
subdural hematoma is MC seen in what age group?
(cerebral atrophy predisposes to avulsion of bridging veins)
what other group, besides the elderly, are at high risk for subdural hematomas?
chronic alcoholics
how might a subdural hematoma present in an elderly patient?
(DDx: AD, dementia)
clinical s/s of an subarachnoid hemorrhage?
*meningeal irritation (complain of worst H/A ever had)
*no pupillary symptoms (no mass effect)
*may see hyponatremia develop (due to SIADH)
what is the MCC of an subarachnoid hemorrhage?
spontaneous rupture of a berry aneurysm
diffuse axonal injury is due to what mechanism?
rotational/shearing forces within the brain
clinical findings in diffuse axonal injury?
(do see decreased consciousness or coma)
a congenital disorganized cluster of arteries and veins in the brain is called?
arteriovenous malformation (AVM)
are AVMs inherited or sporadic?
clinical implications of an AVM?
may act as a focus for seizures
may have episodic hemorrhage
clinical implications of a cavernous hemangioma?
*most are asymptomatic and incidentally found
clinical implications of capillary angiomas, venous angiomas, telangectasias?
most are asymptomatic, found incidentally
berry aneurysms have an association with what disease?
polycystic kidney disease
what type of hemorrhage does a ruptured berry aneurysm lead to?
subarachnoid hemorrhage
(35% mortality at time of 1st bleed)
most berry aneurysms are found?
in the anterior part of the circle of willis
besides berry aneurysms: what 4 other types of aneurysms are there in the CNS?
1. atherosclerotic
2. hypertensive
3. mycotic
4. traumatic
atherosclerotic aneurysms are MC found in which artery?
(may thrombose but do not rupture)
what is the other name for hypertensive aneurysms?
Charcot-Bouchard (microaneurysms of the arterioles)
rupture of a hypertensive anuerysm results in what type of hemorrhage?
what is a mycotic aneurysm?
infective aneurysm (usually from septic amboli, ie. endocarditis)
a traumatic vertebral artery dissection is also known as?
pathogenesis of amyloid angiopathy
amyloid deposited in small vessel walls, tendency to rupture. NOT DUE TO HTN
three types of neurons that are extremely susceptible to ischemia?
purkinje cells of cerebellum
hippocampal neurons
neurons in basal ganglia
what is the usual cause of small vessel disease leading to a stroke?
chronic HTN
what are some hematologic causes of stroke?
prothrombotic states
(polycythemia vera, sickle cell disease, protein C, S, antithrombin deficiencies, leukemia, DIC)
occlusion of perforating small arteries tends to cause what kind of infarct?
lacunar infarct
(pure motor or sensory deficit)
in regards to ischemia and infarction: a deficit that lasts <24 hrs is called?
transient ischemic attack
(usually lasts 5-30 min)
in regards to ischemia and infarction: a deficit that lasts >24 hrs but <3 wks is called?
reversible ischemic neurologic deficit
in which type of infarct is it advised to "do nothing," as treatment will cause increased injury upon reperfusion?
hemorrhagic infarct
gross manifestations of a cerebral infarction at:
1. 6-12 hrs
2. 48-72 hrs
3. >72 hrs
1. mild softening, blurring of grey-white matter junction
2. marked softening and edema
3. coagulation necrosis, eventual cavitation
micro manifestations of a cerebral infarction at:
1. 12-24 hrs
2. >24 hrs
3. later
1. red dead neurons
2. influx of neutrophils and macrophages
3. peripheral gliosis, central cavitation
describe injury to the peripheral axon
*focal (trauma) or generalized (DM) injury
*wallerian degeneration of axons distal to injury
*may have chromatolysis of neuron cell body
*secondary disintigration of myelin sheath
describe myelin (Schwann cell) injury
*segmental myelin sheath damage, with segmental cells present
*underlying axon intact, potential for remyelination
what is the MCC of peripheral neuropathy worldwide?
is Guillan-Barre more common in males or females?
describe the clinical s/s of guillan-barre
acute onset of rapidly progressing motor, sensory and autonomic disturbances
*LMN disturbances (symmetrical weakness, hyporeflexia)
what is the pathogenesis of guillan-barre?
immune mediated disease
*lymphocytic infiltrates around peripheral nerves
*schwann cell injury, peripheral demyelination
in guillan-barre - approx. 1/3 have a history of illness 2-3 wks prior. what types of illness did they commonly have?
1. upper respiratory infx (ie. mycoplasma)
2. GI (ie. campylobacter jejuni)
*also have been associated with vaccinations, lymphomas, some drugs, pregnancy
CSF studies seen in Guillan-Barre?
elevated protein
clinical course of G-B?
usually self-limited
complete recovery
Tx. is supportive
what is the equivalent of "MS" in the PNS?
chronic inflammatory demyelinating polyradiculoneuropathy
treatment for chronic inflammatory demyelinating polyradiculoneuropathy?
plasma xchange
what are the 3 types of neuropathy seen in DM?
1. diffuse symmetric axonal injury (MC)
2. mononeuropathy or plexopathy
3. autonomic neuropathy (symp/parasymp)
clinical manifestations of autonomic neuropathy seen in DM?
*GI (stomach, bowel motility dysfx)
*GU (bladder, erectile dysfx)
carpal tunnel injury is due to damage to which nerve?
saturday night palsy is due to damage of which nerve?
radial nerve
what is a traumatic neuroma?
disorganized attempt at nerve regeneration, often at sites of major or minor nerve transection, may be painful
histology seen in a traumatic neuroma?
sprouting axons
proliferating schwann cells
clinical s/s of Morton's neuroma?
shooting pain around ball of foot
pain worse with weightbearing
histology seen in Morton's neuroma?
perineural fibrosis
vascular microthrombi
which tumor of the PNS characteristically has palisading nuclei upon histological examination?
where are neurofibromas MC seen?
what do neurofibromas consist of?
disorganized schwann cells
mucous material
what is the plexiform type of neurofibroma and what is significant about it?
involves peripheral nerves
*when present is pathognnomonic for neurofibromatosis type I*
what is the basic difference between a schwannoma and a neurofibroma?
schwannoma - no neural infiltration
neurofibroma - expand whole nerve, within nerve
what are the only two situations in which a malignant peripheral nerve sheath tumor asrises?
1. neurofibromatosis (neurofibroma turned malignant)
2. large nerve trunk
inheritance pattern of neurofibromatosis?
where is the mutation found in neurofibromatosis type I?
chromosome 17
three characteristics of NF type I?
1. cafe-au-lait spots
2. multiple cutaneous neurofibromas
3. Lisch nodules - pigmented iris hamartomas
where is the mutation found in NF type II?
chromosome 22
4 characteristics of NF type II?
1. bilateral acoustic neuromas
2. gliomas
3. meningiomas
4. neurilemmomas
inheritance pattern of tuberous sclerosis?
in relation to tuberous sclerosis - pathologic findings in:
1. brain
2. skin
3. viscera
1. hamartomas
2. ash-leaf patches (hypopigmented areas), angiofibromas of face (adenoma sebaceum)
3. rhabdomyomas of heart, angiomyolipomas of kidney, cysts in liver, kidney, pancreas
transmission of von-hippel lindau syndrome?
where is the mutation found in von-hippel-lindau?
chromosome 3
in relation to von-hippel-lindau syndrome: pathologic features in:
1. brain
2. eyes
3. viscera
1. cerebellar hemangioblastomas
2. retinal angiomas
3. cysts in liver, kidneys, pancreas, angiomas
von-hippel-lindau syndrome is associated with an increased risk of what cancer?
renal cell carcinoma
manifestations of sturge-weber syndrome in the brain?
ipsilateral leptomeningial angiomas with underlying atrophy of cerebral cortex
what is the composition of prions?
just protein
are prions hardy or not?
very hardy
can be exposed to heat, radiationand chemical disinfectants and still survive
prognosis of a prion disease once symptoms appear?
NO remission or recovery
four prion diseases seen in humans?
1. Kuru
2. CJD
3. gerstmann-straussler-scheinker syndrome (GSS)
4. fatal familial insomnia (FFI)
describe the prion hypothesis
PrPsc (prion protein)forms beta sheets and is protease resistant. it serves as a template for converting normal protein into PrPsc. this modification is permanent
why are animal forms of prion diseases inefficiently transmitted to humans?
species barrier
where do prions replicate in the human host?
lymphoid tissues and spleen
what (in regards to the immune system) is required for prions to enter the CNS?
a competent immune system with fully differentiated B cells
characteristic histo findings in spongiform encephalopathies?
*vacuolation of dendritic and axonal processes
*proliferation and hypertrophy of astrocytes
*spongiform gray matter
*amyloid plaques and fibrils
age of onset of CJD?
40-70 yrs
is CJD familial or sporadic?
(most sporadic (85%), some familial)
incubation time of "infectious" CJD?
3-20 yrs
3 MC s/s seen in CJD?
dementia (seen in all)
involuntary mvmts
cerebellar ataxia
inheritance of gerstmann-strassler-scheinker syndrome?
compare the clinical s/s of gerstmann-strassler-scheinker syndrome to CJD
gerstmann-strassler-scheinker syndrome - like CJD, but cerebellar ataxia is dominant feature
inheritance pattern of fatal familial insomnia (FFI)?
what is the predominant clinical feature of FFI?
progressive insomnia
shape of the rabies virus?
bullet shaped
describe the genome of the rabies virus
the rabies virus genome only encodes how many genes?
what is the protein found in the envelope that targets neutralizing antibodies called?
G protein
three hosts of rabies in the US?
transmission of rabies virus?
*virus-containing saliva inoculation through broken skin
*infected aerosols
behavioral patterns seen in animals infected with the rabies virus?
more aggressive
more likely to attack unprovoked
what causes the hydrophobia seen in rabies patients?
spasms of the muscles of deglutition - inability to drink or swallow saliva
what is the mortality rate of rabies once prodromal symptoms have appeared?
diagnosis of rabies?
fluorescent antibody staining of skin biopsy or hair follicles
classic histo of rabies infection?
Negri bodies (eosinophilic inclusions in brain tissue)
how is post-exposure rabies treated?
hyperimmune globulin
brain tumors MC arise from which cell type?
glial cells
are most astrocytomas benign or malignant?
astrocytomas tend to involve which brain locations in:
1. adults
2. children
1. cerebral hemospheres
2. posterior fossa, optic nerve
in a high grade astrocytoma, what is the classic lesion seen on CT
ring-enhancement lesion
pilocytic astrocytomas are MC seen in what age group?
MC location of a pilocytic astrocytoma?
(circumscribed cystic lesion with a mural nodule)
behavior of a pilocytic astrocytoma?
relatively benign
where are oligodendrogliomas MC found?
white matter of cerebral hemispheres
common presentation of pts with oligodendrogliomas?
compare the prognosis of an astrocytoma and an oligodendroglioma?
oligodendroglioma has better prognosis (slower growing)
what is seen upon a CT scan of an oligodendroglioma?
what neoplasm is slow growing, circumscribed, MC seen in children, and MC occurs in the 4th ventricle or spinal cord?
is an ependymoma MC benign or malignant?
where are choroid plexus tumors MC located?
in lateral or 4th ventricles
(where choroid plexus is)
choroid plexus tumors are MC in which age group?
what is the MC type of choroid plexus tumor?
papillomas (benign)
which CNS neoplasm is one of the "small blue cell tumors of childhood" and is commonly located in the cerebellum?
what does the prognosis of a medulloblastoma depend on?
extent of surgical resection
N-myc and C-myc oncogene amplification
C-erb-B2 overexpression
where do medulloblastomas tend to metastasize to?
spinal cord
describe the "character" of a meningioma
indolent, most grow slowly
where are meningiomas MC found
intracranial or spinal location
any connection between meningiomas and pregnancy?
meningiomas may have estrogen receptors, therefore may grow more rapidly in pregnancy
what is the classic growth pattern seen in a meningioma?
whorling growth pattern
(also see psammoma bodies)
where do most acoustic neuromas occur?
bilateral acoustic neuromas should make you think of?
neurofibromatosis type II
where are most cranioparyngiomas located?
suprasellar, in hypothalamic region
germ cell neoplasms MC occur in which sex and age group?
young men
name four germ cell neoplasms commonly seen in the CNS?
embryonal carcinoma
where do CNS hemangiomas MC occur?
cerebellum, spinal cord
syndrome with hereditary form of CNS hemangioma?
von-hippel-lindau syndrome
typical sites of origin of metastatic tumors to the brain?
what are the 3 states of existence (according to the sleep lecturer)?
N-REM sleep
REM sleep
what wave activity is seen in wakefullness?
alpha waves
(restful wakefullness when eyes are closed)
*Alpha for Awake*
describe stage I N-REM sleep
*decreased alpha waves to <50%
*slow rolling eye mvmt
*decreased muscle tone
*THETA waves
describe stage II N-REM sleep
*K complex
*no eye mvmt
what type of waves are seen in stage 3 and 4 N-REM sleep?
delta waves
delta waves signify what kind of sleep?
deep sleep "D for Deep Sleep"
(wake up from this and have foggy haze, poor judgement, poor memory)
in which type of sleep is HR and RR irregular?
in which type of sleep is skeletal muscle tone absent?
in which type of sleep is penile tumescence and vaginal engorgement seen?
in which stage of sleep is poikilothermia observed?
(that's why see sweating and chills in REM sleep)
in what type of sleep do most sleep problems occur?
REM sleep
what are the 3 mechanisms underlying wakefullness and sleep?
1. circadian
2. homeostatic
3. masking
which type of sleep waves are important in cognitive maturation?
delta waves
where in the brain is REM sleep initiated?
when are PGO waves seen?
REM sleep only
which 3 neurotransmitters have been shown to turn off REM?
connection between adenosine and sleep?
adenosine = sleep factor
(caffeine inhibits)
three aspects in the mechanism of N-REM sleep?
1. inhibiting process of cortex and thalamus
2. decreased excitability of cortex and hypothalamus (thalamic gating)
3. dissappearance of FFWs (fast freq. wavelets)
what is thalamic gating?
shutting off of excitability coming from the lower brain centers
describe the effects of N-REM sleep on the following:
1. HR
2. BP
3. cerebral flow, metabolic rate
1. decreases
2. decreases
3. decreases
*remember: N-REM is primarily a PARASYMPATHETIC state*
describe CO early in the morning
(that's why more MIs occur in the morning)
what happens to the upper airway muscles in REM?
this increases airway resistance (see snoring and OSA)
what else relaxes airway muscles?
when are ACTH and cortisol levels highest?
4-8 am
when is GH released?
90 minutes after sleep onset
TSH and Melatonin release are circadian related. what does this mean?
both are released in the evening and levels are lower in the daytime
what is meant when it is said that PRL is sleep related?
levels are increased in sleep, decreased in wakefulness
any connection between gastric secretions and sleep?
increased gastric secretions during sleep
when is brain activity highest?
REM > wake > nREM
what is the correlation between age and quality of sleep?
increase age, increase sleep complaints
define parasomnias
undesirable phsyical or experiential phenomena which occur exclusively during the sleep period or are exacerbated by sleep
top 2 reasons for excessive daytime sleepiness?
1. apnea
2. insufficient sleep
historical term for sleep apnea?
pickwickian syndrome
(70% of pts with OSA are overweight)
symptoms of OSA?
excessive sleepiness
apneic episodes
choking or gasping in sleep
predisposing factors to OSA?
Age (40-60yrs)
anatomical abnormalities
family history
CV complications of OSA?
pulmonary HTN, cor pulmonale
brady or tachycardia
complete heart block
sudden death
possible therapies for OSA?
1. positive airway pressure
2. oral appliances
3. surgery
s/s of narcolepsy
1. excessive daytime sleepiness
2. cataplexy (REM intrusion on the state of wakefullness)
when is cataplexy MC seen?
strong emotion
(bilateral loss of muscle tone provoked by strong emotion)
what are hypagognic hallucinations?
vivid, frightening, dream like experiences that occur in the transition from wakefullness to sleep or vice versa
describe the nocturnal sleep habits of a pt with narcolepsy
disturbed nocturnal sleep
(sleep fragmentation, nightmares, hypnagogic hallucinations, sleep paralysis, sleep apnea)
human narcolepsy shows a loss of what neurgenic substance?
what is the normal requirement for sleep?
ranges from 4-10 hrs
what are some medical conditions that can cause insomnia?
arthritic conditions
renal failure
lung disease
heart failure
hepatic disease
what is psychophysiological insomnia?
conditioned arousal to sleep environment
what is delayed sleep phase syndrome?
can't fall asleep until 2-3 am, wake up at 7 or 8am. whole wake/sleep cycle is shifted
3 MC parasomnias?
1. disorders of arousal
2. nocturnal seizures
3. REM sleep bahavior disorder
3 disorders of arousal?
1. confusional arousals
2. sleepwalking
3. sleep terrors
what are confusional arousals?
confusion following arousal from sleep, disorientation
what is REM sleep behavior disorder?
abnormal intrusion of muscle tone in sleep, can be violent
(dreams acted out)
what is the MC life threatening neurologic disease adn the 3rd leading cause of death in the USA?
what is the difference between cerebral ischemia and a cerebral infarct?
a cerebral infarct is dead neurologic tissue secondary to cerebral ischemia.
how long after lack of blood flow does metabolic failure of cerebral tissue occur?
10 sec
(ie. if sudden anoxia such as choking or heart stops -> 10 sec. until unconscious)
how long after lack of blood flow does irreversible damage of cerebral tissue occur?
4 minutes
infarcted tissue is replaced with cystic areas. this is called?
encephalomalacia (lack of brain tissue)
what is the amount of blood flow to normal brain tissue?
50 mL/100g/min
blood flow in an ischemic penumbra?
<25 mL/100g/min
cell death occurs at what blood flow?
<10 mL/100g/min
84% of all strokes are of this type?
three mechanisms of ischemic stroke?
1. large vessel
2. cardioembolic
3. small vessel
2 mechanisms of hemorrhagic stroke?
1. vascular malformation
2. small vessel
3 vascular malformations that may result in a hemorrhagic stroke?
1. aneurysm
2. AVM
3. cavernous hemangioma
at what size are saccular (berry) aneurysms mor elikely to rupture?
>10 mm
which sex, age is rupture of berry aneurysms MC in?
avg. age of rupture - 50 yrs
rupture of a berry aneurysm results in what type of hemorrhage?
"hypertensive hemorrhage" is due to rupture of?
small vessels
(may cause lobar hemorrhage)
top 3 locations of large vessel disease leading to ischemic stroke?
1. internal carotid
2. vertebral-basilar embolism
3. aortic arch
what is the MCC of cardioembolic stroke?
atrial fibrillation
other causes of cardioembolic stroke?
wall motion abnormalities
valvular disease
paradoxical embolism
what is the spectrum of small vessel ischemic disease?
mild - gliosis, demyelination
moderate - lacunar stroke
severe - hypertensive hemorrhages, lobar hemorrhages
prognosis of lacunar strokes compared to other forms of strokes?
(many recover function)
which type os hemorrhage is caused by arterial degeneration with amyloid deposits in arterial walls?
lobar intracerebral hemorrhage
MC location of lobar intracerebral hemorrhage?
cortical-subcortical junction
some risk factors for ischemic stroke?
family Hx
coronary artery disease
carotid artery disease
smoking, etoh
hematologic and cellular disoroders that predispose to stroke?
sickle cell
cardiolipin antibodies, lupus anticoagulants
protein C,S, antithrombin III deficiency
s/s of an intracerebral hemorrhage?
*acute onset neurologic deficit
*quickly worsening
*H/A, N/V
*altered level of consciousness
*markedly elevated BP
s/s of subarachnoid hemorrhage?
*acute onet of severe H/A ("worst H/A of my life)
*meningeal signs
*confusion, LOC, seizures
*may progress and have focal neurologic signs
describe the level of consciousness in an ischemic stroke
(unless bilateral brainstem reticular activating system is involved)
symptoms of an anterior circulation stroke in the right (non-dominant) side?
*L body weakness, numbness
*visual spacial neglect
*L hemifield loss
*amaurosis fugax (blindness in ipsilateral eye)
symptoms of an anterior circulation stroke in the left (dominant) side?
*R body weakness, numbness
*R hemifield loss
*amaurosis fugax
symptoms of a stroke to the posterior circulation (brainstem)?
dysarthria, dysphagia, diplopia, nystagmus, vertigo, mixed weakness/numbness, N/V, somnolence
symptoms of a stroke to the posterior circulation (cerebellum)?
symptoms of a stroke to the posterior circulation (occipital lobe)?
hemifield visual defect
symptoms of a stroke to the posterior circulation (medial temporal lobe)?
memory loss
give examples of some things that mimic TIAs
episodic vertigo
transient global amnesia
in a young patient with a cryptogenic stroke, what should we be looking for?
vascular abnormality or hypercoagulable state
in which imaging modality (CT or MRI) does stroke show up earliest?
which imaging modality is better to see hemorrhage with?
which imaging modality shows blood flow in vessels?
secondary prevention in a cardioembolic stroke?
secondary prevention in a large vessel stroke?
carotid endarterectomy
secondary prevention in a small vessel stroke?
risk factor management
antiplatelet meds
avoid anticoagulation
a cortical stroke is caused by?
emboli from heart or large vessels
a subcortical stroke is caused by?
small vessel disease
signs of a subcortical (small vessel) stroke?
profound sensory or motor loss without aphasia or neglect
(cortical strokes have aphasia and neglect)
most improvement after a stroke is in which timeframe?
1-3 months afterwards
(then slows down - will see most recovery by 2 yrs)
which has a worse prognosis: intracerebral hemorrhage or subarachnoid hemorrhage?
subarachnoid hemorrhage (mortality near 50%)
acute treatment of ischemic strokes (medications)?
secondary prevention of ischemic strokes?
antiplatelet agent
control of BP, glucose and lipids
carotid endarterectomy
why is reactive HTN allowed to go oup to 220/120 in ischemic stroke?
want to keep penumbra alive
treatment of hemorrhagic stroke?
*correct blood clotting abnormalities
*only allow BP up to 140-180
BP guidelines in a SAH?
keep BP at normotensive range until aneurysm is clipped, then allow HTN and vascular expansion

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