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Nur 211 Cerebral Vascular Disorders Summary
This is a comprehensive and detailed summary on Chapter 67;Cerebral Vascular Disorders.
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Chapter 67 Management of Patients with Cerebrovascular DisordersReading Notes
Vocabulary:
Agnosia: loss of ability to recognize objects through a particular sensory system, may be visual, auditory, or tactile
Aneurysm: a weakening or bulge in an arterial wall
Aphasia: inability to express self or understand language
Apraxia: inability to preform previously learned purposeful motor acts on a voluntary basis
Dysarthria: defects of articulation due to neurologic causes
Dysphagia: difficulty swallowing
Expressive Aphasia: inability to express oneself; often associated with damage to left frontal lobe
Hemianopsia: blindness in half of the field of vision in one or both eyes
Hemiparesis: weakness of one side of the body
Hemiplegia: paralysis of one side of body
Infarction: tissue necrosis in an area deprived of blood supply
Penumbra region: area of low cerebral flow
Receptive Aphasia: inability to understand what someone is saying; often associated with damage to the temporal lobe
Reading Notes:
Introduction
Cerebrovascular disorders is an umbrella term used to describe functional abnormalities of the CNS that occurs when blood
supply to the brain is interrupted -> stroke is primary one
Most strokes are ischemic in nature (87%) others are hemorrhagic in nature (13%)
Look at chart 67-1 pg. 2010 for comparison of two types of strokes
Ischemic Stroke
“Brain attack” is a sudden loss of function resulting from disruption of the blood supply to part of the brain
Early treatment w/ thrombolytic agents results in fewer symptoms and less loss of function
Treatment window of 3 hours after onset of stroke and up to 4.5 hours
5 different types:
o Large artery thrombotic (20%)
o Small penetrating artery thrombotic (25%)
o Cardiogenic embolic stroke (20%)
o Cryptogenic stoke (30%)
o Other (5%)
Large artery strokes are caused by atherosclerotic plaque build up in the large vessels of the brain -> occlusions results in
ischemia and infarction
Small penetrating artery thrombotic strokes affect one or more vessels and are common
o Also called lacunar strokes -> cavity created after death of infracted brain tissue
Cardiogenic embolic stroke are associated with cardiac dysrhythmias -> atrial fibrillation
o Embolic stroke can be associated with valvular heart disease and thrombi in the left ventricle
o These strokes can be prevented with anticoagulant therapy
o Most commonly affects the left middle cerebral artery
2 types of ischemic strokes: cryptogenic stroke (no known cause) are strokes from other causes like drug use ex. cocaine
Pathophysiology
Disruption of blood flow due to obstruction of blood vessels -> causes the ischemic cascade
This cascade begins when cerebral blood decreases to less than 25 mL/100 g of blood per minute
Neurons at this point are unable to maintain aerobic respirations -> less effective production of ATP -> less electrolyte balance
and the cell ceases to function
Mitochondria must switch to anaerobic respirations -> lactic acid formation -> change in pH
Area of low cerebral flow is penumbra region and this exists early on around the site of infraction
o Can be salvages with timely interventions
o This area in threatened because less depolarization means build up a Ca and glutamate -> vasoconstriction and
release of free radicals
Brain can age 3.6 years each hour without treatment
Penumbra area may be revitalized by administration of tissue plasminogen activator (t-PA)
, Chapter 67 Management of Patients with Cerebrovascular Disorders
Reading Notes
Medications that protect the brain from secondary injury are known as nuero-protectants
Clinical Manifestations
Depends on which type of vessel is obstructed, size of the area with less perfusion, and amount of secondary or accessory blood
flow
S/S:
o Numbness or weakness in arms, face, leg usually on one side of body
o Confusion or change in mental status
o Trouble speaking or understanding speech
o Visual disturbances
o Difficulty walking, dizziness, or loss of balance and coordination
o Sudden and severe headache
Look at table 67-3 for R vs. L hemisphere stroke
Motor Loss
Hemiplegia caused by lesion of the opposite side of the brain
Hemiparesis or weakness is another sign
Flaccid paralysis and decrease in deep tendon reflexes -> when these reflexes reappear (48 hours later) increased tone and
spasticity of the extremity on the affected side is noticed
Communication Loss
Most common cause of aphasia
o Expressive aphasia inability to express oneself
o Receptive aphasia inability to understand language
o Or a mix of both -> global
Dysarthria difficulty speaking or dysphagia (impaired speech) caused by paralysis of muscles
Apraxia inability to preform a previously learned action, shown as the patient making verbal substitutions for desired words or
syllables
Perceptual Disturbance
Visual-perceptual disturbances are caused by disruptions in the primary sensory pathway between the eye and visual cortex
Hemianopsia may occur from stroke and can be temporary or permanent -> affected side corresponds with paralyzed side of
body
Disturbances in visual-spatial relations are seen in right sided hemisphere damage (perceiving the relationship of two or more
objects in spatial areas)
Sensory Loss
Can be mild or severe
Agnosia may be visual, auditory, or tactile
Cognitive Impairment and Psychological Effects
If the stroke occurs in the frontal lobe -> memory and learning capacity may be impaired
Limited attention span, difficulty in comprehension, forgetfulness, lack of motivation -> easily frustrated during rehabilitation
Depression is common and emotional liability, hostility, frustration, resentment, lack of cooperation mat occur
Assessment and Diagnostic Findings
Rapid focused physical and neurological assessment
Initially we focus on airway patency (loss of gag or could reflex) and altered respiratory pattern, cardiovascular status
(including bp, rate and rhythm, carotid bruit, and gross neurological deficits
TIA manifests by a sudden loss of motor, sensory, or visual function
o Typically last 1-2 hours
o Result from temporary ischemia to a specific region of the brain -> not shown on brain imagery
o May be a sign of a impending stroke
Non-contrast CT is the diagnostic test for a stroke -> should be done within 25 minutes of presentation to see what type of
stroke it is and to guide treatment
Identify the source of the thrombi or emboli
A 12 lead ECG and carotid ultrasound are standard tests
Other studies include: CT angiography, CT perfusion, MRI, magnetic resonance angiography, transcranial Doppler flow studies,
echocardiogram, single photon emission CT scan
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