cerebrovascular accident (cva) [email protected]
TRANSCRIPT
Cerebrovascular Accident (CVA)
Definition
Ischemia is inadequate blood flow
Brain attack (Stroke) occurs when there is ischemia to a part of the brain that results in death of brain cells
Incidence
3rd Cause of death in US and Canada Statistics
2/3 in people >65 = in men and women Higher incidence and death rates
among African-Americans, Hispanics, Native-American, Asian Americans
Risk Factors
Non Modifiable Age Gender Race Heredity
Risk Factors
Modifiable Obesity HTN Smoking Heavy alcohol
consumption Hypercoagulability Hyperlipidemia
Asymptomatic carotid stenosis
Diabetes mellitus Heart disease,
atrial fibrillation Oral
contraceptives Physical inactivity Sickle cell disease
Review of Cerebral Circulation
Blood supply by arteries
Blood is supplied to the brain by two major pairs of arteries Internal carotid arteries Vertebral arteries
Blood supply by arteries
Carotid arteries branch to supply most of the Frontal, parietal, and temporal lobes Basal ganglia Part of the diencephalon
Thalamus Hypothalamus
Blood supply by arteries
Vertebral arteries join to form the basilar artery, which supply the Middle and lower temporal lobes Occipital lobes Cerebellum Brainstem Part of the diencephalon
“Brain Attack” means:
Blood flow to the brain is totally interrupted
Etiology
Atherosclerosis – Disease of the arteries; hardening and thickening of the arterial wall because of soft deposits of intraarterial fat and fibrin that harden over time.
Common sites for the development of Atherosclerosis
Transient Ischemic Attack (TIA)
Transient ischemic attack (TIA) is a temporary focal loss of neurologic function caused by ischemia
Most TIAs resolve within 3 hours TIAs are a warning sign of
progressive cerebrovascular disease
Types of Stroke
Strokes are classified based on the underlying pathophysiologic findings
Ischemic Hemorrhagic
Ischemic vs. Hemorrhagic
Ischemic Stroke
Ischemic strokes result from inadequate blood flow to the brain from partial or complete occlusion of an artery
85% of all strokes are ischemic strokes
Ischemic Stroke
Thrombotic or Embolic
Most patients with ischemic Most patients with ischemic stroke do not have a stroke do not have a decreased level of decreased level of consciousness in the first 24 consciousness in the first 24 hourshoursMay progress in the first 72 May progress in the first 72 hourshours
Thrombotic stroke
Thrombosis occurs in relation to injury to a blood vessel wall and formation of a blood clot
Result of thrombosis or narrowing of the blood vessel
Most common cause of stroke
Embolic stroke
Occur when an embolus lodges in and occludes a cerebral artery
Results in infarction and edema of the area supplied by the involved vessel
Second most common cause of stroke
Embolic stroke Majority of emboli originate in the
inside layer of the heart, with plaque breaking off from the endocardium and entering the circulation
Patient with an embolic stroke commonly has a rapid occurrence of severe clinical symptoms
Hemorrhagic Stroke
Account for approximately 15% of all strokes
Result from bleeding into the brain tissue itself or into the subarachnoid space or ventricles
Hemorrhagic Stroke Intracerebral hemorrhage
Bleeding within the brain caused by a rupture of a vessel
Hypertension is the most important cause
Hemorrhage commonly occurs during periods of activity
Hemorrhagic Stroke Intracerebral hemorrhage
Manifestations include neurologic deficits, headache, nausea, vomiting, decreased levels of consciousness, and hypertension
Hemorrhagic Stroke Subarachnoid hemorrhage
Occurs when there is intracranial bleeding into cerebrospinal fluid-filled space between the arachnoid and pia mater
Commonly caused by rupture of a cerebral aneurysm
Clinical Manifestations Affects many body functions
Motor activity Elimination Intellectual function Spatial-perceptual alterations Personality Affect Sensation Communication
Clinical Manifestations
Brain attack Term increasingly being used to
describe stroke and communicate urgency of recognizing stroke symptoms and treating their onset as a medical emergency
Clinical ManifestationsMotor Function
Most obvious effect of stroke Include impairment of
Mobility Respiratory function Swallowing and speech Gag reflex Self-care abilities
Clinical ManifestationsMotor Function
An initial period of flaccidity may last from days to several weeks and is related to nerve damage
Spasticity of the muscles follows the flaccid stage and is related to interruption of upper motor neuron influence
Clinical ManifestationsCommunication
Patient may experience aphasia when a stroke damages the dominant hemisphere of the brain Aphasia is a total loss of
comprehension and use of language
Diagnostic Studies
When symptoms of a stroke occur, diagnostic studies are done to Confirm that it is a stroke Identify the likely cause of the stroke
CT is the primary diagnostic test used after a stroke
Diagnostic Studies
Additional studies Complete blood count Platelets, prothrombin time, activated
partial thromboplastin time Electrolytes, blood glucose Renal and hepatic studies Lipid profile
Collaborative CarePrevention
Goals of stroke prevention include Health management for the well
individual Education and management of
modifiable risk factors to prevent a stroke
Collaborative CarePrevention
Antiplatelet drugs are usually the chosen treatment to prevent further stroke in patients who have had a TIA
Aspirin is the most frequently used antiplatelet drug
Collaborative CarePrevention
Surgical interventions for the patient with TIAs from carotid disease include Carotid endarterectomy Transluminal angioplasty Stenting Extracranial-intracranial bypass
Collaborative CareAcute Care
Interventions – Initial Ensure patient airway Remove dentures Perform pulse oximetry Maintain adequate oxygenation IV access with normal saline Maintain BP according to guidelines
Collaborative CareAcute Care
Interventions – Initial Remove clothing Obtain CT scan immediately Perform baseline laboratory tests Position head midline Elevate head of bed 30 degrees if no
symptoms of shock or injury
Collaborative CareAcute Care
Interventions – Ongoing Monitor vital signs and neurologic
status Level of consciousness Motor and sensory function Pupil size and reactivity O2 saturation Cardiac rhythm
Collaborative CareAcute Care
Recombinant tissue plasminogen activator (tPA) is used to Reestablish blood flow through a
blocked artery to prevent cell death in patients with acute onset of ischemic stroke symptoms
Collaborative CareAcute Care
Thrombolytic therapy given within 3 hours of the onset of symptoms ↓ disability But at the expense of ↑ in deaths
within the first 7 to 10 days and ↑ in intracranial hemorrhage
Collaborative CareAcute Care
Surgical interventions for stroke include immediate evacuation of Aneurysm-induced hematomas Cerebellar hematomas (>3 cm)
Collaborative CareRehabilitation Care
After the stroke has stabilized for 12-24 hours, collaborative care shifts from preserving life to lessening disability and attaining optimal functioning
Patient may be transferred to a rehabilitation unit