CEREBROVASCULAR ACCIDENT (CVA)

The Human Brain

CEREBROVASCULAR ACCIDENTS (CVA)•A sudden focal neurological deficit due to cerebral vascular disease; most common cause of brain disturbance. •Characterized by the gradual or rapid, onset of neurologic deficits that fit a known vascular territory and last for at least 24 hours.•Occurs when impaired circulation in the brain disrupts the supply of oxygen.•Recovery from a CVA depends on how quickly and completely circulation is restored. However, almost half of all patients who survive a CVA are permanently disabled and will suffer a recurrent attack.

•Alternate names: Cerebral Infarction, Stroke, Cerebrovascular Disease

Causes of CVA:A cerebrovascular accident results from impaired circulation in one or more of the brain’s blood vessels. Impairments are usually caused by:

1.THROMBUSThe most common cause of CVA, which is usually related to atherosclerosis. Plaque and atheromatous deposits gradually occlude the artery. Occlusion leads to ischemia and infarction of brain tissue, followed by edema and necrosis. It usually occurs in the extracerebral vessels but sometimes occurs in the intracerebral vessels.

1.HEMORRHAGEThe most devastating cause of CVA, hemorrhage occurs when a cerebral vessel ruptures and bleeds into brain tissue or subarachnoid space. Usually results from a rupturing arteriosclerotic vessel caused by exposure to prolonged hypertension, a cerebral aneurysm. Effects may be severe. More than 50% of patients die within the first 3days from brain herniation.

Photographs show acute, massive hypertensive hemorrhages. Note that the blood here is under enough driving pressure to destroy the tissue, rupture through the ependymal lining and fill the ventricle with blood. When massive, these tend to be fatal events.

C. EMBOLISM

Usually, fragments break off from a mural thrombus in the left atrium or ventricles or from bacterial vegetations affecting heart valves. These emboli travel through the carotid artery and typically lodge in the smaller cerebral vessels. It may occur quite suddenly, often followed by necrosis and edema.

B. Risk factors. 1. Atherosclerosis 2. Hypertension 3. Anticoagulation therapy 4. Cardiac vascular disease 5. Synthetic valve and organ displacement 6. Atrial arrhythmias 7. Diabetes

C. Signs and Symptoms.•persistent headache•dizziness or slight headache•altered LOC•blurring of vision one or both eyes•stumbling of speech•bowel or bladder incontinence

D. Interruptions of blood supply to brain via carotid and vertebral-basilar arteries--- causes’ cerebral anoxia.

E. Cerebral anoxia longer than ten minutes to a localized area of brain—causes cerebral infarction (irreversible changes).F. Surrounding edema and congestion causes further dysfunction.

G. Lesion in cerebral hemisphere (motor cortex, internal capsule, basal ganglia)—results in manifestations on the contralateral side.

H. Permanent disability unknown until edema subsides. Order in which function may return: facial, swallowing, lower limbs, speech, arms.

Assessment:

1.Evaluate transient ischemic attack (TIA), a precursor symptom or warning of impending ischemia.

A.Rapid onset and short duration (30 minutes to 24 hours); No permanent neurological deficit.B.Most common symptoms: vision loss, diplopia, contralateral hemiparesis, aphasia, confusion, slurred speech and vertigo.

1.Carotid endartectomy is a surgical procedure for carotid stenosis—often done following TIA or presence of stenosis.

A.Procedure removes atherosclerotic plaque from arterial wall.B.Monitor closely first 24 hours for cerebral ischemia or thrombosis or intolerance from carotid clamping.

2.Observe for generalized signs: headache, hypertension, changes in level of consciousness, convulsions, vomiting, slow bounding pulse, Cheyne-Strokes respirations.

D. Evaluate residual manifestations A. Lesion left hemisphere

1. Behavior is slow, cautious, disorganized.2. Usually dominant, containing speech center, right

hemiplegia, aphasia, expressive and/or receptive.

B. Lesion right hemisphere1. Left hemiplegia; spatial-perceptual deficits.2. Behavior is impulsive, quick; unaware of deficits; poor

judge of abilities, limitations; neglect of paralyzed side.

C. General1. Memory deficits; reduced memory span; emotional

liability.2. Visual deficits such as homonomous hemianopia (loss of

half of each visual field).3. Apraxia (can move but unable to use body part for

specific purpose).

NURSING MANAGEMENTS:•Initial nursing objective is to support life and prevent complications.•Maintain patient airway and ventilation--- elevate head of bed 20 degrees unless shock is present.•Monitor clinical status to prevent complications.

A.Neurological1.Include assessment of recurrent CVA, increased intracranial pressure, hyperthermia.2.Continued coma--- negative prognostic’ sign

•Cardiovascular--- shock and arrythmias, hypertension.•Lungs--- Pulmonary emboli.

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

Upper motor lesion--- spastic paralysis, flexion deformities, external rotation of hip.Position schedule--- 2hours on unaffected side, 20minutes on affected side.

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.

A.Encourage self-feeding.B.Food should be placed in unparalyzed side of mouth.C.Tube feedings or gastrostomy feeding may be necessary.

H. Administer tube feedings.I. Promote elimination.

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

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

J. Provide emotional support.A.Behavior changes as consciousness is regained--- loss of memory, emotional liability, confusion, language disorders.B.Reorient, reassure, and establish means of communication.

K. Promote rehabilitation to maximal functioning.

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

B.Guidelines to assist client with lesion left hemisphere.1.Do not underestimate ability to learn.2.Assess ability to understand speech.3.Act out, pantomime communication; use client’s term to communicate; speak in normal tone of voice.4.Divide tasks into simple terms; give frequent feedback.

C.Guidelines to assist client with lesion right hemisphere.1.Do not overestimate abilities,2.Use verbal cues as demonstrations; pantomimes may confuse.3.Use slow, minimal movements and avoid clutter around client.4.Divide tasks into simple steps; elicit return demonstration of skills.5.Promote awareness of body and environment on affected side.

Medical treatment:

Steroids/corticosteroids given in full stomach with antacid or H2 receptor antagonistsVitamin B complex – promote restitution of function of neurons which have reversible damage.Cerebral activator/stimulants – stimulate CNS function.

nootrophil- PIRACETAMencephabol- PYRITINOL HClhydergine- CODERGOCRIN

Drugs if it is due to thrombus, give ANTI-COAGULANTheparin- HEPARIN SODIUMcoamadin- WARFARIN SODIUMDrugs if it due to hemorrhage with large hematoma•patient may need operative removal of blood clot (craniotomy)

TRANSIENT ISCHEMIC ATTACK (TIA)

•Sudden, brief episodes of neurologic deficits caused by focal cerebral ischemia. It usually lasts 5 to 20 minutes and is followed by a rapid clearing of neurologic deficits (typically within 24 hours). Recurrent attacks are common.

•A brief reversible episode of neurologic dysfunction caused by temporary interruption of blood supply to the brain.

•Also called “intermittent cerebrovascular insufficiency”.

Causes:

Causes of TIAs include:•vascular disorders•blood disorders•cerebrovascular insufficiency

Signs and Symptoms:•sudden loss of consciousness•slurring of speech•drooling of saliva

Blood Supply to the Brain

What increases risk of a TIA?

•High blood pressure. You can lower your risk of TIA by lowering your blood pressure.

•High cholesterol. High cholesterol increases your risk of atherosclerosis, which can lead to blood clots. By lowering your cholesterol, you can lower your chance of having a TIA.

•Smoking. If you stop smoking, you can lower your risk of having a TIA.

Heart disease. The higher your risk of heart attack, the higher your chance of having a TIA. By lowering your risk of heart attack, you also reduce your chance of having a TIA.

Age. Most TIAs occur after the age of 60.

Family and medical history. If one of your family members has had a stroke or TIA or you have had a previous TIA, you are more likely to have a stroke or TIA.

Common Clinical Presentations of TIA

Excessive somnolence This symptom may indicate bilateral hemispheric or brainstem involvement.

Agitation or psychosis Rarely, these symptoms may indicate brainstem ischemia, particularly if they occur in association with cranial nerve or motor dysfunction.

Confusion or memory changes These rarely are isolated symptoms; more frequently, they are associated with language, motor, sensory, or visual changes.

Inattention to surrounding environment, particularly to one side; if severe, patient may deny deficit or even his or her own body parts.

Depending on the severity of neglect, the physician may need to lift the patient's arm to check for strength, rather than rely on the patient to perform this task.

DiagnosisThe doctor will ask about your symptoms and medial history, and perform a physical exam. A primary goal is to determine your stroke risk.

Tests may include:Blood Tests - including a complete blood count, blood sugar, cholesterol, fat levels, clotting levels, and a check of other elements in the bloodElectrocardiogram (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 heartElectroencephalogram (EEG) - a test that can detect seizures by measuring brain waves (used only if a seizure is suspected)Occupational Therapist

Rehabilitation after an injury may help some patients regain lost functions or learn new ways of accomplishing everyday tasks.