CSF and Blood Supply Flashcards
where is CSF formed?
in the ventricles
where does CSF circulate?
through the ventricles and subarchnoid space
the CSF is absorbed into ____
lymph
what are the roles of CSF?
regulates extracellular environment (aiming to optimize neural fxn)
protect the CNS
removes metabolites/waste from the brain (glymphatic system-glia and lymphatic system)
what is CSF made of?
water, amino acids, vitamins, proteins, and specific ions
what is the pathway of CSF circulation?
lateral ventricle–>3rd ventricle-> 4th ventricle–>subarachnoid space–>venous system
what are common causes of disorders of CSF?
obstruction or increased volume
what causes increased volume of CSF?
overproduction of CSF or introduction of blood to the CSF
what are communicating CSF disorders?
caused by blockage outside of the ventricular system
what are non-communicating CSF disorders?
caused by blockage within the ventricular system
where is the most common place to have CSF blockage?
in the cerebral aqueduct
what are common disorders of CSF?
hydrocephalus
epidural and subdural hematomas
Chairi malformation
Dandy Walker malformation/cyst
what is usually the cause of epidural and subdural hematomas?
brain trauma
what are the 2 causes of obstruction of CSF?
Chairi malformation
Dandy Walker malformation/cyst
what are the s/s of hydrocephalus in infants?
poor feeding, fussy babies, irritable, chronic headache
low activity
disproportionately large head size pressing on the optic nerve=downward gaze of the eyes
enlarged ventricule puts pressure on white matter
what are common causes of hydrocephalus in infants/fetus?
failure of the 4th ventricle to open and form, Dandy Walker, Chiari
what are the s/s of hydrocephalus in older children/adults?
W triad: Wet (incontinence), Wobbly (gait disturbance), and Wacky (confusion, mild dementia)
are the s/s of hydrocephalus worse or better in adults? why?
worse bc the skull can’t expand
what are common causes of hydrocephalus in adults?
TBI, intraventricular hemmorrhages, subarachnoid hemorrhages
if hydrocephalus is not resolved quickly in infants, what may result?
learning disabilities and cognitive issues
how is hydrocephalus managed?
shunt system
what is a VP (ventriculoperitoneal) shunt?
a shunt from the ventricle to the peritoneum
what is the most frequently used shunt for hydrocephalus?
VP shunt
what is a VA (ventriculoarterial) shunt?
shunt from ventrical to arterial system
what is a ventriculopleural shunt?
shunt from ventricles to pleural space
what is meningitis?
inflammation of the meninges
what are the causes of meningitis?
bacteria, fungus, virus, or parasite infection reaching the brain or SC
what are the s/s of meningitis?
similar to a cold or flu (fever, headache, vomiting, sleepiness, difficulty walking, irritable)
neck stiffness (nuchal rigidity)
photophobia (sensitivity to light)
confusion/altered mental status, seizure
what areas does the MCA supply?
globus pallidus, putamen, most of the lat hemisphere, part of internal capsule and caudate
what areas does the PCA supply?
midbrain, occipital lobe, and inferomedial temporal lobe
what areas does the ACA supply?
med frontal and parietal lobes
what do the superficial cerebral veins drain?
the cortex and adjacent white matter to the sup sagittal sinus, or one of the sinuses around the inferior cerebrum
what do the deep cerebral veins drain?
the basal ganglia, diencephalon (thalamus, hypothalamus, epithalamus) and nearby white matter to the straight sinus
where do both the superficial and deep cerebral veins eventually drain to?
the dural sinuses and then the internal jugular vein
what is a stroke?
loss of blood supply in a specific area that correlates w/a specific loss of fxn
strokes are categorized according to both ___ and ____
pattern and cause
what is a TIA?
focal ischemia w/clinical symptoms lasting <24 hrs with no s/s after
what is a reversible ischemic neurologic deficit (RIND)?
clinical symptoms of stroke last bw a day and 3 wks
t/f: multiple focal lesions in the brain lead to greater loss of fxn in stroke?
true
t/f: TIAs are predictive of future strokes
true
what is the ABCD2?
guidelines for high stroke risk factors following TIA
Age >60
BP (>140 SBP or >90 DBP)
Clinical feature (unilateral weakness or speech disturbance)
Duration >60 min
Diabetes
over 5 points=very high risk for a subsequent stroke following a TIA
what are the 2 types of stroke?
ischemic (infarction) and hemorrhagic
is hemorrhagic or ischemic (infarction) stroke more common?
ischemic (infarction)
do hemorrhagic or ischemic (infarction) stroke tend to have more devastating s/s?
hemorrhagic
what is a brain infarct (ischemic stroke)?
an embolus/thrombus lodges in a vessel, obstructing blood flow
what artery is usually affected in ischemic stroke?
MCA
how are ischemic strokes usually diagnosed?
CT scan (perfusion)
MRI (avoid radiation)
transcranial and carotid doppler (flow of major brain arteries)
cerebral angiography (injection of dye into vessels for series of radiographs usually b4 surgery)
PET (cerebral metabolism-used a lot post stroke)
what is a hemorrhagic stroke?
weakness vessel ruptures, bleeding into the surrounding brain (due to aneurysm or trauma)
intracranial hemorrhage
subarachnoid hemorrhage
t/f: hemorrhagic stroke have high risk for re-hemorrhage
true
what are the s/s of hemorrhagic stroke?
severe acute onset headache, change in alertness, vomiting
what is the medical management for ischemic stroke?
IV recombinant tissue plasminogen activator (tPA) within 4 1/2 hours of onset of stroke
endovascular procedure to place a device in the blocked vessel (performed ASAP)
what is the gold standard for ischemic stroke medical management?
tPA
what is the medical management for hemorrhagic stroke?
control bleeding and reduce pressure in the brain
BP controlling meds
taken off any anticoagulants
what is a common area for stroke?
watershed area
what is an ACA stroke?
stroke affecting the frontal lobe leads to personality changes and cognitive changes (divergent thinking and declarative memory)
contra hemiplegia and hemisensory deficits
loss of fine touch but no other somatosensations
LE>UE
gait apraxia
incontinence
putamen and internal capsule
how is gait apraxia in ACA stroke different from PD gait?
there is no UE involvement, there is normal arm swing, and there is normal standing posture
what is the somatosensory loss associated with ACA stroke?
contra loss of fine touch sensation in LE
what is the motor loss associated with ACA stroke?
hemiplegia (LE>UE)
gait apraxia
are there special sensory and autonomic losses with ACA stroke?
nope
what are the emotional and behavioral changes associated with ACA stroke?
flat affect
impulsive
perseveration
confusion
motor inactivity
what are the cognitive, language, and memory changes associated with ACA stroke?
difficulty w/divergent thinking
what is a MCA stroke of the cortical branch?
optic radiation lesion causes contralateral homonymous hemianopsia
loss in lateral parts of sensorimotor cortex leads to contra hemiplegia and sensory deficits in UE and face
UE and face>LE
if there is a L hemisphere lesion in MCA stroke, what is the impairment?
aphasia (inefficient communication)
if there is a R hemisphere lesion in MCA stroke, what is the impairment?
poor spatial awareness, neglect, poor nonverbal communication
what is the somatosensory loss associated with MCA stroke of the cortical branch?
hemisensory loss face and UE>LE
what is the motor loss associated with MCA stroke of the cortical branch?
face and UE>LE
hemiplegia
what is the special sensory and autonomic losses associated with MCA stroke in the cortical branch?
homonymous hemianopsia
what are the emotional and behavioral changes associated with MCA stroke of the cortical branch?
if R: easily distracted, poor judgement, impulsiveness
if L: apraxia, compulsiveness, and overly cautious
what is a MCA stroke of the deep branch?
striate arteries most commonly affected
supply to striatum and internal capsule cut off leads to loss of motor fxns
contra hemiplegia or UE, LE, and face
stereotypic standing posture : flexion synergies of UE, extension synergies of LE
no sensory deficits
what are the somatosensory losses associated with MCA stroke of the deep branch?
none
what are the motor losses associated with MCA stroke of the deep branch?
contra hemiplegia of UE, LE, and face
flexion synergies of UE
extension synergies of LE
what is a PCA stroke of the midbrain braches?
damage to the oculomotor nuclei, nerve, and or descending neurons from cortical eye movement centers
what is a PCA stroke of the branches of the visual cortices?
calcarine (visual) cortex) affected: cortical blindness of the contra visual field; normal pupillary light reflexes
secondary visual field: visual agnosia (inability to recognize objects by sight despite intact vision)
what are the impairments associated with a PCA stroke of the midbrain branches?
impaired eye movements, not a lot of contra hemiplegia
what is a PCA stroke of the deep branches?
supplies the diencephalon and hippocampus
LMN signs
thalamic syndrome (sever p!, contra hemisensory loss, flaccid hemiparesis)
poor declarative memory
what is an anterior choroidal artery stroke?
affects the posterior internal capsule
control hemiplegia
hemisensory loss
contra homonymous hemianopsia
what is the watershed area?
site of anastomoses of the distal branches of cerebral arteries
vulnerable to ischemia
often cuases UE paresis and paresthesia
what is a stroke affecting the BS/cerebellum?
vertebrobasilar artery ischemia
what are the most common signs of vertebrobasilar artery ischemia?
gait and limb ataxia
limb weakness
oculomotor palsy
oropharyngeal dysfxn
loss of vision
double vision
numbness
dizziness
headache
vomiting
why are the vertebral arteries susceptible to shear forces at the AA jt?
bc they run through the transverse foramen of the cervical vertebrae
what is the CC of vertebral artery disorders?
pain usually in the posterior neck/occiput, spreading to the shoulders
what are the results of an emboli in the vertebral arteries?
dizziness, inability to sit upright, gait impairments, nausea, vomiting, dysarthria, headache
what does a complete occlusion of the basilar arteries result in?
death (bc of the vital fxns of the BS)
what does partial occlusion of the basilar arteries result in?
tetraplegia, loss of sensation, coma, CN signs
what does severe partial occlusion of the basilar arteries result in?
locked-in syndrome
what is an arteriovenous malformation (AVM)?
developmental abnormality
abnormal connection of arteries to veins
no s/s until rupture
upon rupture: subdural hematoma and/or intracerebral hemorrhage
what is an aneurysm?
looks like a protruding sac from the blood vessels
what is the CC in an aneurysm?
“the worst headache I had in my life”
what is the most common type of aneurysm?
saccular aneurysm
where does a saccular aneurysm usually occur?
in the circle of Willis
t/f: hemorrhage from an aneurysm rupture may be massive, causing sudden death, or a wide variety of s/s
true
what causes acquired aneurysms?
HTN, smoking, substance abuse
what is the blood brain barrier?
specialized permeable barrier bw the capillary endothelium of the CNS and extracellular space (tight junction bw capillary endothelial cells and pericyte and astrocyte)
prevents pathogens from entering the CNS
prevents certain drugs and protein antibodies from accessing the brain (dopamine)
where is the blood brain barrier absent?
in areas that directly sample content of the blood/secrete into the blood
parts of the hypothalamus, 3rd ventricle, 4th ventricle
is the cerebrum more or less vulnerable to hypoxia? why?
more bc of it increased consumption of oxygen
in a vegetative state, why is the brain still functioning?
bc the BS is still functioning but not the cerebrum
t/f: the cerebral arteries can autoregulate local blood low by dilating if BP/O2 is inadequate or constrict if reversed
true
what is cerebral edema?
excessive accumulation of fluid in the brain
what are the causes of cerebral edema?
trauma/concussion
cardiac arrest
high altitude
how does trauma/concusssion cause cerebral edema?
fluid leaking from the damaged capillaries
what is high altitude cerebral edema (HACE)?
fatal altitude sickness
progressive
what are the s/s of HACE?
headache, weakness, disorientation, memory loss, hallucinations, psychotic behavior, coma, ataxia (less frequent)
what elieviates cerebral edema?
shunting, meds, moving to lower altitudes
what is ICP?
pressure within the skull
t/f: ICP can produce brain herniation
true
what are the causes of ICP?
cerebral edema, hydrocephalus, tumors, bleeding
what are the s/s of ICP?
nausea, vomiting, headache, drowsiness, frontal lobe gait ataxia, and visual/eye movement problems
what are the causes of brain herniation?
TBI
intracranial hemorrhage
tumor
what is a cingulate herniation?
mass on one hemisphere that displaces the cingulate cortex under the falx cerebri (fold of dura matter)
may compress the ACA (contra motor loss in LE)
may not have s/s
what is an uncal herniation?
space-occupying lesion in temporal lobe
displaces the uncus medially
compresses the midbrain
dysfxn of the oculomotor nerve and ARAS
