Stroke Test 3 Flashcards
Cerebrovascular disease and stroke
Stroke ( brain attack)
- sudden or rapid onset of neurologic deficit linked to vascular territory
-disruption of blood supply (oxygen) to part of the brain , in which turn disrupts the body function controlled by that brain area
aka CVA
( lack of oxygen /glucose that leads to disrupted function- very specific damage depending on region affected)
Diff Dx
- seizure
- migraine (with sensory and motor impairments)
- tumor (putting pressure on location of brain)
- peripheral cause of motor impairment/sensory loss
- nerve entrapment
Incidence of Cerebrovascular disease and stroke
- 114 per 100,000 persons
- incidence doubles with every decade after 55 years of age across all ethnicities
- african american males and females have significantly higher incidence
- occur at earlier ages-possible link to sickle cell anemia?
- 50% higher chance of stroke in African american males than Caucasian males
- 130-150% higher chance of stroke in African american males than Caucasian females
- recurrence rates in 1st year and in males
- 75% of strokes are first time-25% recurrent rate
- incidence is higher in spring
- sedentary in winter and start moving again?
Cerebrovascular disease and stroke Prevalance
4 million survivors in US
-3rd leading cause of death in 97
modifable Risk factors
- HTN (>140/90): increased BP increases risk of hemorrhagic type stroke
- increased cholesterol: dyslipidemia, high LDL level
- adult onset diabetes(type 2 non insulin dependent)
- cigarette smoking: increases risk of stoke by 50%, risk increases w/ # of cigs smoked per day
- alcohol and cocaine use
- obesity
- MI: increases risk by 31% in 1st mo. post( due to clot forming in vessel)
- cardiac irregularities: atrial fibrillation-rapid continuous contraction of atrial w/out rest-> pooling/coagulation
- decreased activity
- carotid artery disease: increases risk by 30%
non-modifiable risk factors
- age (greatest risk: 72% occur after 65y/o)
- race (African american)
- gender (males)
early warning signs of stroke
- sudden weakness or numbness of face, arm,leg
- sudden dimness or loss of vision, particularly in on eye
- sudden difficulty speaking or understanding speech ( articulation/expression or receptive)
- sudden severe headache with no know cause ( diff dx -unexplained spike in BP, deprivation of caffeine, migraine)
- unexplained dizziness, unsteadiness or sudden falls ( medication side effect-infection)
Pathophysiology of stroke
- loss of blood supply -> cell paralysis-> loss of function
- cell damage within core area-> cells die and spill contents (excitotoxity)-> increase release of NT-> additional cell death and increased cell swelling)
- result: area of damage-> ischemic prenumbra
Causes of Ischemic stroke (thrombus or embolus)
- atherosclerosis-larger vessel disease
- cerebral or peripheral vasculature
- thrombus : slow occlusion of blood vessel due to clot-coagulation of blood in one area
- embolus: thrombus or other material ( fat, blood clot, tumor) that breaks off and travels/ occludes a vessel
-atherosclerosic plaque may lead to tear in wall & bleed or the decreased lumen could lead to turbulence and increased viscosity pf blood leading to clotting
causes of cerebrovascular disease: cerebral embolism
-emboli can travel from other areas of the body to the brain
-arterial source, fat emboli
-from the heart; most are from here, larger the size the more significant the problem
-atrial fibrillation-clot formation; may have meds or have surgery to increase heart function to decrease clotting
( DVT doesn’t increase risk of stroke bc goes to lungs 1st- PE)
-severity depends on location/distribution of vessel affected
Hemorrhagic stroke
-more sudden onset
-rupture of elastic vessel wall &bleed into surrounding tissue putting pressure on brain through meninges or into parenchyma
Common causes:
-Berry Aneurysm:
-AV Malformation
-Charcot Bouchard Aneurysm
-subdural Hemorrhage
Berry aneurysm
-abnormality in internal elastic lamina of vessel
-similar to a balloon enlarging over time(until point of rupture)
-related to defect in collagen or CT tissue of vessel wall
ruptured berry aneurysm at circle of willis
-major cause of subarchnoid hemorrhage
-may bleed directly into ventricles
AV Malformation
- congenital defect, direct connection b/w veins and arteries w/out a capillary
- high pressure goes directly into low pressure-may result in rupture
- high BP is major cause and increases risk
Charcot Bouchard Aneurysm
clinical picture of events
- person engaged in activity which increases BP significantly: constipation, after sex
- present with extreme headache and change in level of consciousness (rapid)
Subdural Hemorrhage
- TBI
- rupture of veins b/w surfaces of brain and dura-blood increases pressure on brain and deprives brain of blood
Transient Ischemic Attack (TIA)
- resembles a stroke-focal symptoms
- damage to brain non-existent
- individual recovers rapidly w/out permanent deficit
- complete recovery within 24 hours
- majority of TIAs last 5-20 min
- present with sensory/ motor / speech deficits
- multiple TIAs increases risk of stroke
- can not differentiate b/w stroke and TIA until after( txt as stroke until ruled out)
cerebrovascular disease and stroke clinical picture
- clinical picture is correlated with area of CNS damaged
- in general the pt may present with
- Mvmt disorders; mm tone(hypo or hyper) and strength
- Balance deficits
- sensory disturbances
- cognitive impairments; memory, emotion,sppech
Middle Cerebral Artery Syndrome
- MCS supplies the lateral aspect of the frontal, temporal, and parietal lobes and subcortical structures
- most common site of stroke
- contralateral hemiplegia and hemianesthesia
- global aphasia( if dominant hemisphere)
- loss of fluency, ability to name objects, comprehend auditory information or repeat language
Anterior Cerebral Artery Syndrome
- ACA supplies medial aspect of frontal and parietal lobes and subcortical structures
- uncommon area
- collateral blood flow
Posterior Cerebral Artery Syndrome
- PCA supplies occipital lobe, medial and inferior temporal lobe and upper brainstem
- subthalamus, medial thalamus, ipsilateral cerebral peduncle and midbrain
- contralateral ataxia
- homonymous hemianopsia (can see only to one side)
- cortical blindness
- alexia (unable to read)
- agnosia (inability to interpret sensations and recognize things)
- memory deficits
Cerebellar Infarcts
Cerebellum is supplied by 3 pairs of cerebellar arteries from the vertebrobasilar system
- Posterior Inferior Cerebellar A. (PICA)
- Superior Cerebellar A.
- Anterior Inferior Cerebellar A. (AICA)
Lacunar Infacts
- hypertensive pts
- internal capsule: depending on location of infarct-variable presentations
- posterolateral thalamus
diagnosis of stroke
- history of event (timing, pattern of onset, course)
- angiography( depends on pt presentation-done later so doesn’t increase fluid in system)
- CT (fastest to dx)
- MRI
- PET (done later , not acute)
Angiography
- invasive procedure
- inject radio-opaque contrast agent or dye in a vein or artery
- series of x-rays taken
- can help dx obstruction or stenosis in vessels
Clinical Picture: Mvmt problems associated with stroke
- decreased force production
- sensory impairments
- abnormal synergistic organization of movement
- altered sequencing (timing) of mm contractions
- impaired regulation of force control
- delayed responses
- abnormal mm tone (hypo or hyper)
- loss of ROM
- altered biomechanical alignment
Left Stroke ( Right Hemiplegia)
(if in dominant hemisphere)
- speech and language problems: aphasia-receptive &/or expressive
- possible dysphagia
- profits from gestures and non-verbal instructions
- individual aware of problems, often responds w/ anxiety
- repetition is necessary due to impaired ability to retain info
- L/R discrimination may be impaired
- Problems with recognition of objects or word recall
- tends to be slow, cautious and disorganized when approaching unfamiliar tasks
- easily frustrated and angered w/ communication difficulties
- needs time to process information and time to respond either verbally or with gestures
Right Stroke (Left Hemiplegia)
( if in dominant hemisphere)
- difficulty with spatial perceptual tasks
- profits from verbal instructions over gestures
- needs cues to take things one step at a time
- has difficulty assembling or completing tasks such as dressing and other self-care activities. Relearning ADL skills may take longer
- Left sided neglect
- Tends to move impulsively and not follow directions or cues( thinks they can do tasks independently =safety risk)
- overestimates own abilities to perform task
- has increased distractibility
- judgement and consistency are very important
- thinking is disjointed
- safety awareness is diminshed
Medical Mgmt
- Fibrinolytic therapy: attempt to get repurfusion to area by dissolving the clot. may get hemorrhage in addition to thrombotic damage
- tissue plasminogen activator-tPA
- direct administration of anticoagulant at the site of the clot (
Surgical mgmt
- carotid enarterectomy
- if stenosis in carotid > 70% in internal carotid then surg. is warranted
- could be an aboulsion? & destroy material
- increases risk of stroke
- balloon angioplasty-put in catheter and blow up in vessel to flatten plaque against wall
- Aneurysm clip (with wire)
- mechanical thrombolysis
- thread in catheter to vessel and break up thrombus mechanically with vibration
Prognosis
- loss of consciousness -> poorer prognosis
- ischemic stroke( thrombus type) typically has better outcome w/ respect to function vs embolic or hemorrhage
- thrombus takes longer to form and gives more time to text before it becomes too late
- greatest amount of recovery of function occurs in first 3-4 mo.
