CNS -1 Flashcards
Explain the process following initial injury/stimulus/growth that leads to the clinical manifestations. -sorry didnt know how else to ask this : )
Initial insult –> 1) invasion –> focal deficits & cerebral edema
- -> 2) compression ---> cerebral edema ---> increase ICP
- -> 3) Increased ICP --> leads to clinical manifestations
What 2 mechanisms can cause brain cell death?
1) Anaerobic metabolism (ATP driven ie NaKpump)
2) Deterioration of ion gradients
What are some clinical manifestations of Increase ICP?
Decrease cognitive function --> behavioral changes HA, vomitting, seizures papilledema unsteady gait loss of sphincter control
A direct insult of the initial insult is what type of brain injury?
Primary
Progressive damage resulting from body’s physio response to initial insult is what type of brain injury?
Secondary
What is the critical factor in determining neuronal cell fate after injury?
degree of ATP depletion = decrease cellular function
What is a contributing factor to the primary insult or part of the secondary response?
decrease blood flow = decreased 02 at cellular level & cant wash out metabolites
Under anaerobic metabolism, what is the importance of mitochondrial dysfunction?
Normally under 02 –> Oxidative phosphorylation occurs in mitochondria highly efficient in forming ATP. w/o 02 –> anaerobic glycolysis
Due to mitochondrial dysfunction the anaerobic glycotic pathway is initiated and therefore ____________ is converted to _____________.
pyruvate —> lactate
In the anaerobic metabolism pathway what affects neuronal integrity, the cell membrane?
H ions —> acidosis
How does inadequate ATP, which maintains ion gradients, lead to cell injury and death?
Anoxic depolarization (K leaves, Na Cl Ca enter) w/o functional ATP pump.. tries to equilibrate …H20 follows solute cell swells = death
What excitatory neurotransmitter binds to NMDA receptors?
Glutamate
Where does Glutamate act and what ion influx causes depolarization?
Post synaptically. NMDA ligand gated Ca Channel, Ca influx depolarizes
Normal glutamate is cleared/reuptake by ATP pump, when ATP is depleted what can occur?
failure to remove excessive glutamate (excitotoxin)
Excess glutamate can stimulate nearby neurons to then uptake large amounts of what ions ? and what is the result?
Calcium ions overload injury cytotoxic edema and swelling
NMDA receptor activation stimulates production of what? in turn excess of this can increase production of what?
Nitric Oxide–> reactive Nitrogen species, free radicals damage cell components
How does reperfusion cause cell death?
02 re-enters = produce reactive products behave as free radicals (hydroxyl radicals, superoxide, peroxide)
How does reperfusion (secondary injury) cause injury to the cell membrane therefore not allowing it to act as a barrier?
lipid peroxidation formation of arachidonic acid= more 02 free radicals and mediators of inflammation
What contributes to ability to maintain perfusion, supply of 02 and nutrients, to both sides and remove wastes?
Auto regulation (myogenic reflex)
Metabolic vasodilation is influenced by what 3 factors?
pH, C02, 02 in arterial blood. stimulus to bring in blood flow and wash out metabolites
Interference with vessel dilation leads to ?
ischemia
Impaired vasoconstriction causes what 2 things to occur?
hyperperfusion and edema formation as to not deplete the other side
As ICP increases volume increases and compliance _________?
decreases
The cranium is composted of what 3 elements that are effected by ICP? and what is a normal ICP
brain tissue CSF blood
ICP 0-15
What are some causes of increase ICP related to increase blood volume?
high C02 & acidosis -vasogenic (vessels) metabolite vasodilation to increase flow
increase RAP
dural sinus thrombis
Causes of increased ICP related to CSF?
obstruction and nonobstructive hydrocephalus
excess CSF production
Causes of increased ICP related to brain tissue?
tumor masses lesions hemorrhage infection edema ischemia and necrosis
Clinical manifestation of increased ICP?
HA vomiting altered LOC
blurry vision edema of optic disk (papilledema)
Motor clinical manifestations of increase ICP?
as ICP increase LOC decreases… impaired pupil response to light
altered resp patterns unresponsive to stimuli
unable to move verbalize or open eyes
Order of clinical manifestation with increase ICP?
LOC -> sensory -> motor
Management for herniation?
imagining (CT or MRI) surgical or medical measure ICP and CPP removal lesions or CSF Tx: cerebral oxygentaiton
What is the minimal CPP needed to ensure adequate blood flow to prevent ischemia?
CPP of at least 60
What is the most sensitive indicator of altered brain function?
change in LOC
The state of alertness and attentiveness is dependent on what activity what system?
RAS: reticular activating system
Changes in pupils size, shape and reactivity is an early indicator of what?
ICP and possible herniation
Which maneuver, when assessing oculovestivubular reflex, entails rotating head side to side? what is the normal response?
Doll’s eyes normally turn to opposite direction of head rotation
Which maneuver to inject cold water into ear? what is normal response?
Cold calorics- tonic deviation of both sides toward side irrigated
Absence of blink during assessment of corneal reflex indicates what?
severely impaired brain function
How does hypothermia relate to management of increase ICP?
reduces brain’s metabolism saving 02 decrease work load
What are some factors that can increase brain metabolism thus increasing ICP?
fever seizures agitation pain all should be avoided
What are the three types of primary TBI?
focal- primary
polar- opposite (acceleration and deceleration)
diffuse- global injury
What are the three intracranial hematomas (secondary TBI)?
epidural subdural subarachnoid
Which type of primary TBI is localized to site of impact?
focal (coup)
Which type of primary TBI is d/t acceleration and deceleration movement of the brain within the skull?
Polar injury (coup contracoup) resulting in usually double injury (usually opposite focal injury)
Which type of primary TBI is caused by movement of the brain within the skull resulting in widespread axonal injury?
diffuse injury
What is the criteria for a concussion?
mild TBI alteration in LOC <30min but NO evidence of damage on CT
HA N&V dizziness fatigue blurred vision etc
Which will show injury on CT or MRI… concussion or contusion?
Contusion reveals damage necrosis laceration bruising
What is a localized collection of blood in the cranium called?
intracranial hematoma–> disruption of vasculature can lead to hemorrhage
Which type of hematoma generally involves arterial injury?
Epidural hematoma
Epidural hematoma has a rapid onset, why is that?
arterial injury high pressure
Which type of hematoma has a minor primary injury characterized with lucid intervals of disturbed then normal levels of cognition with a final rapid deterioration?
epidural
Which 2 hematomas generally involve rupture of bridging veins?
subdural and subarachnoid
A chronic subdural hematoma is prone to what?
re-bleeding
Subdural hematoma has a slower onset d/t involvement with veins when might you see symptoms in an acute situation?
within 24 hours
Which hemorrhage is commonly associated with rupture of cerebral aneurysms or AVM (arterial in origin)?
Subarachnoid
What are important treatments in patients with TBI to reduce brain swelling and decrease ICP?
maintain normal body temp or mild hypotherm
normal PaC02
normal glucose
and intravascular volume
What is a sudden onset of neurologic dysfunction d/t vascular disease resulting in an area of brain infarction? which is the most common?
Stroke- ischemic
Ischemic strokes result from sudden occlusion of cerebral artery secondary to thrombus or emboli. Which of the two are associated with atherosclerosis and coaguloaphies?
Thrombotic
Which type of ischemic stroke is associated with cardiac dysfunction or dysrhythmias (afib)
Embolic strokes
What are some clinical manifestations of ischemic strokes?
contralateral hemiplegia
hemisensory loss
contralateral visual field blindness
What is the penumbra?
peripheral to the insult, it’s reversible ischemia
salvaging penumbra is aim of early thrombotic therapy
What type of ischemic stroke has completely resolved neurologic deficits?
TIA symptoms last minutes as long as 24 hours
What is an important warning sign of thrombotic disease and carries a significant risk for subsequent stroke?
TIA
What is the treatment for a TIA?
ASA, CEA, or angioplasty if 70% occluded
What type of stroke usually occurs secondary to severe, chronic hypertension?
Hemorrhagic
Where does a hemorrhagic stroke occure?
in the midbrain (basal ganglia or thalamus)
Which type of stroke has a higher degree of secondary injury and associated morbidity and mortality ?
hemorrhagic
The treatment for hemorrhagic stroke is aimed at minimizing infarct size and preserving neurologic function, what are some of these treatments?
thrombolytics, anticoagulant, antiplatelet, endarterectomy, angioplasty, stents, BP managment (keep mildly HTN at first)
Initial motor deficits occurs as ________ or _________; recovery of motor function occurs with onset of ____________.
Does this occur ipsilateral or contralateral on side brain stroke occurred
flaccidity
paralysis
spasticity
-contralateral
Loss of visual field on the paralyzed side also contributes to?
neglect of movement
what is it called when the same side of the retina in each is is blinded?
homonyzmous hemianopsia
contralateral field blindness
Aphasia occurs with brain damage to which cerebral hemiphere?
dominant
Which aphasia is associated with motor/expressive and consists of poor articulation and sparse vocabulary?
Broca
Which aphasia is associated with sensory, acoustic, receptive, and characterized by impaired auditory comprehension and speech that is fluent but doesn’t make sense ?
Wernicke
What are the most common causes of Subarachnoid hemorrhage?
AVM and cerebral aneurysms
What is characterized as ballooning and dilation of a segment of the vessel?
Cerebral aneurysm
In Marfans an congenital defect in which layer of the artery becomes weakened causing an eventual burst= hemorrhage?
Medial layer (normally has autoregulation to dilate or constrict with changes in pressure) but defected
Where are most cerebral aneurysms found?
Circle of Willis- saccular/berry aneurysms
areas of bifurcation
What are the 3 components of meningismus?
1) photophobia
2) N&V
3) stiff neck
What does a sudden severe HA with meningismus indicate?
cerebral aneurysm rupture
what is the treatment for cerebral aneursym?
arterial clipping
embo
manage vasospasm by keeping blood volume and blood pressure normal to high and Ca Channel blockers
What is the failure of capillary system to develop called?
AVM
Arterial blood shunted to venous system in the case of AVM, how does this result in rupture and hemorrhage?
Vessels englarge=high vasc pressure
How might AVM clinically manifest? treatment?
seizure and neuro dysfunct.
surgical removal, gamma knife/sterotactic radio surgery
irradiation or glue embo
What might dilated vessels on imagining reveal?
AVM
Which two of the three CNS infections we discussed in class are bacterial infections and which is viral?
Bacterial- meningitis and cerebral abscess
encephalitis viral
Risk factors for CNS infections?
immunocompromised
debilitation
poor nutrition (AA needed for immunoglobulins)
radiation, steroid therapy, contact with vectors
Meningitis is most commonly associated with what bacteria?
streptococcus pneumoniae
Which CNS infection is described as hematogenous dissemination of bacteria ?
Meningitis
Where does the bacteria colonize in meningitis?
nasopharynx, enter blood stream, and enter subarch space and CSF
The pathogenesis of meningitis starts with bacterial toxins how does this lead to neuronal necrosis?
Bacterial toxins-> neuronal apoptosis-> BBB damange-> vasc permeability-> edema = increase ICP=decrease CPP–> hypoxia->
neuronal necrosis
In meningitis there is an accumulation of neutrophils which release their contents to destroy bacteria, what is this called?
degranulation- destroys bacteria but also damages normal tissue (brain nerves blood vessels)
The degranulation of neutrophils leads to vasculitis and clotting causing cerebral infarcts, accumulation of inflammatory exudate care result in what?
obstructive hydrocephalus
Diagnose meningitis by lumbar puncture which will show what?
bacterial and increase neutrophils in CSF.
Protein elevated
glucose low d/t high cellular use/function
Meningitis is treated with IV antibiotics and prevention includes vaccinations for what?
Hib and N.meningitis
What CNS infection is characterized by inflammation of brain cause by a virus?
Encephalitis
In encephalitis the virus attacks what membrane ?
arachnoid membrane and CSF
A patient is bitten by an insect, he is likely to have what CNS infection?
Encephalitis
Treatment for encephalitis is supportive with control of symptoms, this includes?
antripyretics, antivirals, steroids, antiseizure, fluid resuscitation
Which CNS infection is characterized by a newly formed cavity filled with pus (pyogenic) ?
Brain Abscess
Treatment for brain abscess includes?
drainage or excision of abscess and IV antibiotics
What makes up the infected core in a brain abscess ?
neutrophils and tissue debris
What surrounds the granulation tissue in a brain abscess? and what occurs there?
perifocal edema- proliferation of astrocytes
Long term chronic phase of a brain abscess would have what two characeristics?
liquefied core and fibrous fliosis- inflamm response - scar tissue
