Nur 211 Cerebral Vascular Disorders Summary

Chapter 67 Management of Patients with Cerebrovascular Disorders
Reading 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