STROKE; Cerebrovascular Accident (CVA)

A stroke is caused by a disruption in the normal blood supply to the brain. This disruption in blood supply may be in the form of interruption in blood flow to the brain, in which case the stoke is ischemic in origin. The blood supply disruption may also take the form of bleeding within or around the brain. This is called a hemorrhagic stroke. Formerly called cerebrovascular accident (CVA), the National Stroke Association now uses the term brain attack to describe a stroke. A stroke is a medical emergency that strikes suddenly, and it should be treated immediately to prevent neurologic deficit and permanent disability. Stroke is the second most cause of death and major disability worldwide.

Strokes are generally classified as Ischemic and Hemorrhagic. Ischemic strokes are more common than hemorrhagic stroke, but hemorrhagic strokes are more sever and fatal.

ISCHEMIC STROKE:

An ischemic stroke is caused by the occlusion of a cerebral artery by either a thrombus or an embolus. A stroke that is caused by a thrombus is referred to as a thrombotic stroke, whereas a stroke caused by an embolus is referred to as an embolic stroke. About 80% of all strokes are ischemic.

Thrombotic Stroke

Thrombotic stroke account for more than half of all strokes and are commonly associated with the development of atherosclerosis of the blood vessel wall. Atherosclerosis is a complex process that includes altered function of the inner lining of arterial vessels, inflammation, and increase growth of smooth muscle cells. It is the process by which plaques develop on the inner wall of the affected arterial vessel. The bifurcation (point of division) of the common carotid artery and the vertebral arteries at the junction with the basilar artery are the most common sites involved. Because of the gradual occlusion of the arteries, thrombotic strokes tend to have a slow onset.

A lacunar stroke is another type of thrombotic stroke. A lacunar stroke causes a soft area or cavity to develop in the white matter or deep gray matter of the brain. This type of stroke may result in significant neurologic dysfunction if it damages a critical area in the brain.

Embolic Stroke

An embolic stroke is caused by an embolus or a group of emboli (clots) that breaks off from one area of the body and travel to the cerebral arteries via carotid artery and vertebrobasilar system. Te usual source of emboli are cardiac. Emboli can occur in clients with nonvalvular atrial fibrillation, ischemic heart disease, rheumatic heart disease, and mural thrombi following a myocardial infarction (MI) or insertion of prosthetic heart valves. Another source of emboli may be plaques that break off from the carotid sinus or

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internal carotid artery. Emboli tend to be lodge in the smaller cerebral blood vessels at their point of bifurcation or where the lumen narrows. Embolic strokes account for almost half of all strokes.

The middle cerebral artery (MCA) is the most common involved in an embolic stroke. As the emboli occlude the vessel, ischemia develops, and the client experiences the clinical manifestation of the stroke. However, the occlusion may be temporary if the embolus breaks into smaller fragment, enter smaller blood vessels, and is absorbed. For these reasons, embolic strokes are characterized by the sudden development and rapid occurrence of focal neurologic deficits. The symptoms may be resolved over several hours or a few days. A cerebral hemorrhage may result if significant damage to the wall of the involved vessels has occurred. Conversion of an occlusive stroke to a hemorrhage stroke may occur because the arterial vessel wall is also vulnerable to ischemic damage from blood supply interruption. Sudden hemodynamic stress may result in vessel rapture, causing bleeding directly within the brain tissue.

Transient Ischemic Attack (TIA) and Reversible Ischemic Neurologic Deficit (RIND)

TIA and RIND are the preceding signs of Ischemic stroke.TIA is also called “silent stroke”Both cause transient focal neurologic dysfunction resulting from cerebral vasospasm or transient systemic arterial hypertension.The difference between a TIA and an RIND is the length of time the client is symptomatic.TIA last a few minutes to fewer than 24 hours.RIND symptoms last longer than 24 hours, but less than a week.Both may damage brain tissue with repeated insult.

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HEMORRHAGIC STROKE

The second major classification of stroke is hemorrhagic stroke. In this type of stroke vessel integrity is interrupted, and bleeding occurs into the brain tissue or into the spaces surrounding the brain. (ventricular, subdural, subarachnoid). Hemorrhage into the brain generally results from a rapture aneurysm; rapture of an anteriovenous malformation; or, more commonly, sever hypertension.

Aneurism

A ruptured cerebral aneurysm results in hemorrhagic stroke. An aneurism is an abnormal ballooning or blistering on the involved artery. Aneurysm may be congenital or traumatic. In congenital aneurism, there is a weakened vessel wall. Continued force on the weakened vessel wall from elevated blood pressure stretches and thins the vessel wall, causing the innermost vessel layer to protrude. Rapture of the blood vessel can occur during activity. Aneurysms are most often found at the bifurcations of major cerebral arteries.

Aneurysm rapture causes the development of an intracerebral hematoma, bleeding into the subarachnoid space, or bleeding directly into the ventricles. Vasospasm, a sudden and transient constriction of a cerebral artery, often occurs after a cerebral hemorrhage from aneurysm rapture. This occurs because blood is also an irritant to arterial vessels. Blood flow to distal areas of the brain supplied by the artery is markedly diminished, which leads to cerebral ischemia and infarctions and further neurologic dysfunction.

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Anteriovenous Malformation

AVM is a developmental abnormality that occurs during embryonic development. It is a tangled or spaghetti-like mass of malformed, thin-walled dilated vessels. A congenital absence of capillary network forms an abnormal communication between the arterial and venous systems. The vessels may eventually rapture, causing bleeding into the subarachnoid space or into the intracerebral tissue. The risk of rapture and cerebral hemorrhage exist because normally the capillary network, the

thinned wall veins are subjected to arterial pressure.

Hypertension

Although the exact mechanism involved are unknown, it is hypothesized that elevated systolic and diastolic blood pressures cause changes within the arterial wall that leave it susceptible to rapture. An intracerebral hemorrhage when the vessel raptures. Damage to the brain occurs from bleeding, causing distortion or displacement. Brain tissue edema acts as a direct irritant to brain tissue. Hemorrhagic stroke may be more likely with sudden, dramatic blood pressure elevations, such as those seen with cocaine intoxication.

The picture above shows massive hypertensive hemorrhage in the brain.

Common, Etiologic, and Genetic Risk

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HypertensionType II DiabetesHeart DiseaseHypercholesterolemiaHypercoagulable (increase clotting) stateIllicit drugs (especially cocaine)ObesityHeavy alcohol useMigrainesOlder ageMale

Black HeritageSickle cell anemiaSudden discontinuation of antihypertensive medicationsNonvalvular Atrial Fibrilation.Heart mumur or atrial fibrillationMIPrevious stroke or TIAVavular heart DiseaseSmokingSedentary lifestyleOral contraceptive use

Signs and Symptoms of CVA

Signs

Sudden weakness, numbness, or paralysis of the face, arm or leg, on one or both sides of the body.Sudden blurred vision or blindness in one or both eyes.Sudden difficulty speaking, slurring of speech or difficulty understanding.Sudden severe headache with sudden onset that occurs without apparent reasons.Sudden loss of balance, dizziness, or falling without any apparent reason.

Symptoms

Symptoms Depends on what side of the brain is affected.

Feature Left Hemisphere Right HemisphereLanguage Aphasia

Wernicke's aphasia Broca's aphasia Global aphasia

AgraphiaAlexia (word blindness)

Impaired sense of humor

Memory Possible deficit Disorientation to time, place, and person.Inability to recognize faces.

Vision Inability to discriminate words and letters.Reading problemsDeficit in the right visual

Visual spatial deficitsNeglect of the left visual field.Loss of depth perception.

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field.Behavior Slowness

CautiousnessAnxiety when attempting a new task.Depression or a catastrophic response to illness.Sense of guiltFeeling of worthlessness.Worries over future.Quick anger and frustration.Intellectual impairment.

ImpulsiveLack of awareness of neurologic deficits.ConfabulationEuphoriaConstant smilingDenial of illnessPoor judgmentOverestimation of abilities (risk for injuries)

Hearing No deficit Loss of ability to hear tonal variations.

Diagnostic Procedures

Blood Tests - including a complete blood count, blood sugar, cholesterol, fat levels, clotting levels, and a check of other elements in the blood

Electrocardiogram (EKG) – to measure heart rhythm and check for an irregular heart beat

Ultrasound– a test that uses sound waves to help determine if there are blockages in the arteries supplying the brain

MRI Scan – a test that uses magnetic waves to make pictures of structures inside the head

CT Scan – a type of x-ray that uses a computer to make pictures of structures inside the head

Magnetic Resonance Angiography – performed prior to carotid artery surgery to determine how much the artery has narrowed. Gadolinium, a type of dye, may be injected into your vein for this test.

Arteriogram - during a conventional arteriogram, a contrast dye is injected and x-ray images are produced to precisely locate the blockage and to determine how much of the artery is blocked. This test is usually only done to confirm the need for surgery.

Echocardiogram - an ultrasound test that looks for blood clots and valve abnormalities within the heart

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Electroencephalogram (EEG) - a test that can detect seizures by measuring brain waves (used only if a seizure is suspected)

Surgical Management

Endarterectomy – purpose is to remove the atherosclerotic plaque from the inner lining of the carotid artery.Extracranial-Incracranial Bypass – bypasses the blocked artery by making a graft or a bypass from the first artery to the second artery.Management Of Anteriovenous Malformation - is an interventional therapy to occlude abnormal arteries or veins and prevent bleeding from the vascular lesions. Whenever possible the affected vessels are totally removed. The surgeon ligates the vessels and removes the defect.Management of Cerebral Aneurism – Aneurysm may be repaired via craniotomy. Less invasive procedure is interventional RadiologyManagement of Intracranial Bleeding – Blood clots are removed via craniotomy.

Other Medical Management:

Medical Management

a. Steroids/corticosteroids given in full stomach with antacid or H2 receptor antagonists

b. Vitamin B complex – promote restitution of function of neurons which have reversible damage.

c. Cerebral activator/stimulants – stimulate CNS function.

nootrophil- PIRACETAM

encephabol- PYRITINOL HCl

hydergine- CODERGOCRIN

d. Drugs if it is due to thrombus, give ANTI-COAGULANT

heparin- HEPARIN SODIUM

coamadin- WARFARIN SODIUM

e. Drugs if it due to hemorrhage with large hematoma

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Nursing Managements

A. Initial nursing objective is to support life and prevent complications.

B. Maintain patient airway and ventilation--- elevate head of bed 20 degrees unless shock is present.

C. Monitor clinical status to prevent complications.1. Neurological

a. Include assessment of recurrent CVA, increased intracranial pressure, hyperthermia.

b. Continued coma--- negative prognostic’ sign2. Cardiovascular--- shock and arrhythmias, hypertension.3. Lungs--- Pulmonary emboli.

D. Maintain optimal positioning.1. During acute stages, quiet environment and minimal handling to prevent

further bleeding.2. Upper motor lesion--- spastic paralysis, flexion deformities, external rotation

of hip.3. Position schedule--- 2hours on unaffected side, 20minutes on affected side.4. Complications common with hemiplegia--- frozen shoulder, footdrop.

E. Maintain skin integrity: turn and provide skin care.

F. Maintain personal hygiene: encourage self-help.

G. Promote adequate nutrition, fluid, and electrolyte balance.1. Encourage self-feeding.2. Food should be placed in unparalyzed side of mouth.3. Tube feedings or gastrostomy feeding may be necessary.

H. Administer tube feedings.

I. Promote elimination.1. Bladder control may be regained within three to five days.2. Retention catheter may not be part of treatment regimen.3. Offer urinal or bedpan every two hours day and night.

J. Provide emotional support.1. Behavior changes as consciousness is regained--- loss of memory, emotional

liability, confusion, language disorders.2. Reorient, reassure, and establish means of communication.

K. Promote rehabilitation to maximal functioning.

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1. Comprehensive program--- begins during acute phase and follows through convalescence.

2. Guidelines to assist client with lesion left hemisphere.a. Do not underestimate ability to learn.b. Assess ability to understand speech.c. Act out, pantomime communication; use client’s term to

communicate; speak in normal tone of voice.d. Divide tasks into simple terms; give frequent feedback.e.

3. Guidelines to assist client with lesion right hemisphere.a. Do not overestimate abilities.b. Use verbal cues as demonstrations; pantomimes may confuse.c. Use slow, minimal movements and avoid clutter around client.d. Divide tasks into simple steps; elicit return demonstration of skills.e. Promote awareness of body and environment on affected side.

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PATHOPHYSIOLOGY

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Predisposing Factors: Life style (sedentary) Vices (Alcohol, smoke) Age Diet SexHeredity Self-medication

Precipitating Factors: Hypertension Hyperlipidemia Diabetes Mellitus Heart DiseasesAtherosclerosisArteriosclerosisThrombosisSevere dehydration

Ischemic Stroke

Subarachnoid Hemorrhage

Transient Ischemic Attack

Venous Stroke

Large Artery Strokes

Small Artery Stroke

Embolic strokes

VASOCONSTRICTION

Blockage of the blood vessel

Lack of oxygen & nutrients supply

Embolism

Hypoxia

Altered cerebral metabolism

Aneurysm Rupture

Cerebral Ischemia

- Cell death- Decreased Oxygen level

Decreased cerebral perfusion

Intracerebral hemorrhage

Cytotoxic Edema

Local Acidosis

Brain tissue Necrosis

PARALYSIS

D E A T H Severe Cases

High blood pressure, smoking, heart diseases, diabetes, narrowing of arteries supplying the brain, high cholesterol and an unhealthy lifestyle.

High blood pressure, smoking, and a family history of burst aneurysms.

Severe dehydration, severe infection in the sinuses of the head and medical or genetic conditions that increase a person’s tendency to form blood clots.

Hypertension, diabetes, smoking and high cholesterol levels.

Same with Ischemic stroke

Hypertension, diabetes and smoking.

Irregular heart beat (atrial fibrillation), a heart attack (myocardial infarction), heart failure or a small hole in the heart called a PFO (Patent Foramen Ovale).

The Human Brain

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