Week 9 - Cerebral Vascular Disorders Flashcards
what is a cerebral vascular accident? what is another name?
- stroke
- localized infarction (tissue death) of brain tissue resulting from lack of blood flow
at what length of time of ischemia will result in permanent neural damage
- 5 min or less can result in permanent damage
what happens to the tossue during a CVA
- get a central area of necrosis
- surrounded by an area of inflammation & cerebral edema
- eventually, the tissue ilquefies & leaves a cavity in thr brain
what can cause global cerebral ischemia (2)
- circulatory shock
- cardiac arrest
what occurs during global cerebral ischemia (3)
- generalized cerebral edema
- excitoxicity
- liquefaction necrosis
list 9 risk factors for CVA
- HTN
- DM
- hyperlipidemia
- cigarette smoking
- cardiac disease
- substance abuse (alcohol, drugs)
- AIDS
- FHx
- previous history of stroke or TIA
what types of cardiac diseases are risks for CVA(3)
- pervious MI
- valve disease
- atrial fibrillation
what is a transient ischemic attack (TIA)
“mini stroke”
- neuro deficit lasting less than 24 hrs
- due to focal cerebral or retinal ischmia
- and without evidence of cerebral infarction (too short to cause cell death)
the majority of TIAs resolve in how long?
- 30-60 min
list symptoms of a TIA (7)
- hemiparesis
- loss of balance
- hemiparesthesia
- dysarthria
- dysphagia
- diplopia
- monocular blindness contralateral to the effected limbs (bc it is effected the retina where there is no cross over yet)
what is hemiparesis; what side of the body will these symptoms occur in
- weakness of one side of the body
- on the opposite side of the effected brain area
what is hemiparesthesia
- numbness to one side of the body
what is dysarthria
- lack of artciulation
- slurred words
what is dysphagia
- difficulty swallowing
what is diplopia
- double vision
- see two images of the same object
what is the most common cause of TIAs
- cerebral embolism
why are symptoms of a TIA transient (short)
- rapid fibrinolysis of the embolism
what are cardiac causes of embolism (5)
- valve disease
- arrythmia
- endocarditis
- MI
- mural thrombi
what is another major source of an embolus
- rupture of fissure of an athersclerotic plaque in the carotid arteries
list 4 less common causes of an embolism
- polycythemia
- sickle cell disease
- anemia
- systemic inflammatory diseases
describe the prognosis of a TIA
following a TIA:
- 5% of pts will have a CVA within 2 days
- 10% within 90 days
the risk of a TIA causing a CVA is increased with… (3)
- advancing age
- diabetes
- if symptoms lasted longer than 10 mins & involved weakness or speech impairment
what else is there an increased risk of following a TIA
- cardiac event
list 4 treatments for a TIA
- aspirin or other antiplt meds
- anticoagulation w warfarin
- carotid endarterectomy
- reduction of CVS risk factors
who is treatment of TIA with warfarin especially used for
- pts with afib
what is a carotid endarterectomy
- surgery used to treat carotid artery disease
- removal of plaque that builds up inside the carotid artery to restore blood flow to the brain
what cvs risks can be reduced as treatment for a TIA (6)
- HTN
- hyperlipidemia
- smoking
- physical inactivity
- excessive alcohol consumption
- obesity
are all stroke preceded by a TIA
- nooo
what are 3 types of strokes
- thrombotic stroke
- embolic stroke
- hemorrhagic stroke
what is a thrombotic stroke
- the process of clot formation (thrombosis) results in a narrowing of the lumen = blocks the passage of blood thru the artery
what often causes a thrombotic stroke
- when an atheroma (atherosclerotic plaque) in a cerebral artery or carotid artery destabilizes, or ruptures
- ruptures = very stick & causes platelets to stick & a blood clot to form on top of them
what is an embolus
- a blood clot or other debris circulating in the blood
what is an embolic stroke
- when an embolus reaches an artery in the brain that is too narrow to pass through = lodges there & blocks blood flow
- and rapid fibronolysis does not occur
emboli can be… (2)
- cardiogenic (from the heart)
- arteriogenic (from an artery)
what is the difference between an embolic stroke & TIA
- both causes by embolism
- but in a TIA, our body is successful in breaking down that clot before necrosis occurs
what is an ischemic stroke? how prevalent is it
- stroke that occurs from an atheroma or emboli
~80%
what is a hemorrhagic stroke
- stroke due to a burst in a blood vessel
- causes blood to seep into & damage brain tissues & also prevent blood from getting to where it needs to go
- occurs until clotting shuts off the leak
what often causes a hemorrhagic stroke (3)
- intracranial hemorrhage
- prolonged & severe HTN
- cerebral aneurysm
which is more severe; an ischemic or hemorrhagic stroke? why?
- hemorrhagic
- more severe & destructive
- increases ICP to a greater degree
what are the secondary effects of a hemorrhagic stroke (4)
- cerebral edema
- vasospasm
- acidosis
- electrolyte imblances
hemorrhagic strokes can be… (2)
- intracerebral bleeds (cerebral artery)
- subarachnoid bleeds (circle of williss)
what do manifestations of a stroke depend on (3)
- the location of obstruction
- size of the involved artery (bigger artery = more territory = more symptoms)
- functional area affected
what does obstruction of small arteries cause
- may not lead to any obvious signs or symptoms
what is cerebral collateral circulation? what are two types?
- system of blood supply in the brain, which is designed to preserve cerebral blood flow when primary routes fail
1. circle of williss
2. increased capillarization due to progressive, long term atherosclerosis
what is the benefit of collateral circulation during a stroke (2)
- may diminish the size of the affected region
- reduce the amt of neuro impairment
when do symptoms of functional impairment increase during a stroke? subside? why?
- increase during the first 48 hrs, as inflammation & cerebral edema progress
- following this, symptoms subside as neurons surrounding the infarcted area recover
what can inflammation of the brain tissue during a stroke cause
- seizure
what motor impairment initially occurs with a stroke? what is a sign of recovery?
- intially = flaccid paralysis
- after several weeks = spastic paralysis = sign of recovery
what does occlusion of large arteries or hemorrhage during a stroke cause? (3)
widespread effects:
- loss of consciousness
- coma
- death
what are two examples of large arteries that can be blocked during a stroke
- internal carotid
- middle cerebral
what is the onset of a thrombotic stroke? embolic? hemorrhagic?
- thrombotic = gradual & may be preceded by TIA –> may occur at risk
- embolic = sudden
- hemorrhagic = sudden –> may occur w activity
describe the effect of each type of stroke on ICP
- thrombotic = minimal increase
- embolic = minimal increase
- hemorrhagic = high increase
describe the effects of each type of stroke localized or generalized?
- thrombotic = localized
- embolic = localized unless there are multiple emboli
- hemorrhagic = widespread & severe, often fatal
list the effect of right brain damage on intellectual ability (7)
- spatial-perceptual deficits
- deny or minimize problems
- rapid performance
- short attention span
- impulsive; safety problems
- impaired judgement
- impaired time concepts
list the effects of right brain damage on motor function & awareness
- paralyzed left side
- left-sided neglect (impaired awareness to left side)
what is hemiplegia
paralysis on 1 side
list the effects of left brain damage on intellectual & speech ability (9)
- slowed performance
- cautious
- aware of deficits
- depression, anxiety
- impaired comprehension to language
- impaired speech
- impaired comprehension of math
- impaired right-left discrimination
what effect does a left-brain damage have on motor function
- causes paralyzed right side
what does emergent treatment of ischemic stroke require (3)
- angioplasty
- thrombolectomy/embolectomy
- rapid fibrinolysis
which all restore blood flow
what is an angioplasty
- a procedure used to restore blood flow thru an artery
how does angioplasty work
- involves a thin tube being threaded thru a blood vessel
- the tube has a tiny balloon on the end & when it’s in place the balloon is inflated to push the plaque against the wall of the artery
what is a thrombectomy
- type of surgery to remove a blood clot inside an artery or vein
what is an embolectomy
- surgical removal of emboli
what is alteplase
- tPA
- a thombolytic medication that activates plasmin to digest fibrin within the clot
when is tPA effective
- only within 3 hrs of the onset of symptoms
what is important to rule out before treating an ischemic stroke
- rule out hemorrhagic stroke before administration of thrombolytics
what are 2 other treatments for stroke
- investigate & treat the underlying cause
- eliminate CVS risk factors
what % of people suffering from ischemic stroke have had a previous TIA
- 30%
what does the outcome of a stroke depend on (4)
- causative factors
- size of the artery affected
- area of cerebral infarction
- health status of the individual
how common is recovery? what is the mortality of stroke?
- recovery = rare
- mortatility rate of stroke is 20% within the first few days
describe the damage of neurons post-stroke
- loss of neurons is permanent along w the loss of function of the affected areas
- in time, synaptic plasticity & dendrtitic growth = formation of new neural pathways & some funtions can be partially recovered
