Cerebrovascular Accident

Cerebrovascular Accident (CVA)

is the sudden death of some brain cells due to lack of oxygen when the blood flow to the brain is impaired by blockage or rupture of an artery to the brain. A CVA is also referred to as a stroke. It is a condition in which neurologic deficits result from decreased blood flow to localized area of the brain. Neurologic deficits are determined by the area of brain involved, size of affected area, length of time blood flow is decreased or stopped. Major loss of blood supply to brain can cause disability or death.

 Classification of CVA o Ischemic stroke Occurs when the blood supply to a part of the brain is interrupted or totally occluded. Commonly due to thrombosis or embolism.  Thrombotic (large vesse)l Stroke The most common cause of ischemic stroke which is cause primarily with atherosclerosis- fatty materials deposit on large vessel walls that eventually causes stenosis of the artery. The blood swirls around the irregular surface of the plagues causing platelets to adhere and vessel becomes obstructed.  Lacunar (small vessel) Stroke Endothelium of smaller vessel is primarily affected due to hypertension leading to arteiosclerosis and stenosis. Infarcts are usually located in the deeper, noncortical parts of the brain or in the brainstem.  Embolic Stroke The occlusion of a cerebral artery by an embolus or moving blood clot which forms outside the brain, detaches and travels through the cerebral circulation where it lodges and causes an obstruction. Other sources of emboli include tumor, fat, bacteria and air.  Hemorrhagic Stroke This results from rupture of a cerebral vessel causing bleeding into the brain tissues. Bleeding results with edema compression of the brain contents or spasm of the adjacent blood vessels. This is often secondary to hypertension and most common after age 50. Other factors includes ruptured intracranial aneurysms, trauma, erosion of blood vessels by tumors, arteriovenous malformations, anticoagulant therapy and blood disorders. This usually produce extensive residual functional loss and slowest recovery.

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Clinical manifestations o Stroke manifestations can be correlated with the cause and with the area of the brain in which perfusion is affected  Manifestations of thrombotic stroke develop over minutes to hours to days (slow onset is related to increasing size of the thrombus)  Embolic strokes occur suddenly and without warning

Hemorrhagic stroke occurs rapidly with manifestations developing over minutes to hours o General findings unrelated to specific vessel sites includes headache, vomiting, seizures and changes in mental status o Early warnings of impending ischemic stroke includes  Transient hemiparesis  Loss of speech  Hemisensory loss 

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Specific deficits after stroke o Motor deficits        

Affects connections involving motor areas of cerebral cortex, basal ganglia, cerebellum, peripheral nerves Produce effects in contralateral side ranging from mild weakness to severe limitation Hemiplegia (paralysis of half of body) Hemiparesis (weakness of half of body) Apraxia (inability to perform a previously learned skilled task in the absence of paralysis) Flaccidity (absence of muscle tone or hypotonia) Spasticity (increased muscle tone usually with some degree of weakness) Muscles of the thorax and abdomen are usually not affected because they are innervated from both cerebral hemispheres

o Communication disorders 

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Aphasia (deficit in the ability to communicate or inability to use or understand language) • Wernicke’s aphasia o Sensory speech problem in which one cannot understand spoken or written word • Broca’s aphasia o Motor speech problem in which client understands what is said but can only respond verbally in short phases or inability to combine sounds into appropriate words and syllables o Ability to write, make signs or speak is lost • Mixed or global aphasia o Affects both speech comprehension and speech production Dysarthria (imperfect articulation that causes difficulty in speaking) • Client understands language but has difficulty pronouncing words

o Sensory-perceptual deficits 

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Visual changes • Parietal and temporal lobe strokes may cause visual acuity impairment Homonymous hemianopia • Visual loss in the same half of the visual field of each eye Agnosia (inability to recognize one or more subjects that were previously familiar through the senses) Hemisensory loss (loss of sensation on one side of the body) Unilateral neglect (inability to respond to stimulus on the contralateral side of the cerebral infarct)

o Elimination disorders 

Partial loss of sensation that triggers bladder and bowel elimination

o Cognitive and behavioral changes   

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Ranges from mild confusion to coma May result from actual tissue damage from stroke, cerebral edema, or increased intracranial pressure May exhibit • Emotional lability: laughing or crying inappropriately • Loss of self-control (i.e. swearing, refusing to cooperate)

Diagnostic tests 

CT scan without contrast: determine hemorrhage, tumors, aneurysms, ischemia, edema, tissue necrosis, shifting in intracranial contents.

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Arteriography of cerebral vessels: reveals abnormal vessel structures, vasospasm, stenosis of arteries

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Magnetic Resonance Imaging (MRI): detect shifting of brain tissues resulting from hemorrhage or edema

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Positron emission tomography (PET), single-photon emission computed tomography (SPECT): examine cerebral blood flow distribution and metabolic activity of brain

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Medical Management and Nursing Care  

Medical management is directed at early diagnosis and early identification Maintain cerebral oxygenation and cerebral blood flow  Maintain patent airway and turn patient to side if unconscious  Elevate head and neck should not be flexed

Hypertension may be reduced with vasodilators and calcium channel blockers  Thrombolytic agents are given to dissolve the clot • Intracerebral hemorrhage should be ruled out first • Must be given within 3 hours of onset of manifestations • E.g. streptokinase, urokinase and tissue plasminogen activator (alteplase)  Antiplatelet and anticoagulants are given to prevent clot formation • Heparin and warfarin • Aspirin, clopidogrel (Plavix), ticlodipine (Ticlid) or dipyridamole (Persantine)  Corticosteroids to treat cerebral edema, diuretics to reduce increased intracranial pressure and anticonvulsants to prevent seizures  Hyperthermia is treated immediately • Temperature elevations lead to increased cerebral metabolic needs which in turn cause cerebral edema which can lead to further ischemia • Antipyretics are used • Causing the client to shiver should be avoided  Aspiration precaution is done • Oral food and fluids are generally withheld for 24-48 hours • Tube feeding is done  Prevent valsalva maneuver • Maneuver increases ICP • Straining stool, excessive coughing, vomiting, lifting and use of the arms to change position should be avoided • Mild laxatives and stool softeners are often prescribed  Compensate for perceptual difficulties  For clients with visual deficits • Approach the client from the unaffected side • Place articles on the unaffected side • Teach client to turn the head from side to side to see entire visual field • Eye patch over one eye in clients with diplopia is helpful  Assist and support client • Prevent injury and falls • Promote self-care and prevent skin breakdown  Prevent complications  Physical therapy to prevent contractures and to improve muscle strength and coordination • Encourage bed exercise • Facilitate ROM and isometric exercises 

o Do not force extremities beyond the point of initiating pain and spasm o Always support the joint and move the extremity smoothly • Allow client to work on balance and proprioception skills  Occupational therapy • Help client relearn ADLs and to use assistive devices that promote independence • Teach client how to use the wheelchair and promote walking with assitance  Speech therapy for clients with impaired verbal communication • Most aphasic clients regain some speech through spontaneous recovery or speech therapy • Speech therapy should be started early • For aphasic clients o Speak at a slower rate o Give client time to respond o Do not shout and always put client at ease o Repeat simple directions until they are understood o Give client practice in repeating words after you o The family should not do all the talking for the client  Provide emotional support and health education to the client and family. Reference: http://www.enotes.com/nursing-encyclopedia/cerebrovascular-accident http://www.medterms.com/script/main/art.asp?articlekey=2676