cerebrovascular accident

CEREBROVASCULAR ACCIDENT (CVA)

cerebrovascular accident

A general overview of CVA

Cerebrovascular accident, also known as stroke, apoplexy, or brain attack is brain damage caused by lack of blood flow to a part or parts of the brain.

In order for the brain to perform its many functions or activities, from walking to seeing, the brain requires a constant supply of energy provided by oxygen and nutrients that are delivered by the flowing blood.

If blood supply is restricted or cut off at any point between the heart and the brain, portions of the brain relying on the blood from the obstructed blood vessel become deprived of oxygen and nutrients which causes the death of brain cells.

CAUSES

  • Cerebral thrombosis (a blood clot within the blood vessels of the brain)
  • Cerebral embolism
  • Ischaemia (decreased blood flow to an area of the brain)
  • Cerebral hemorrhage (rupture of a cerebral blood vessel with bleeding or pressure in the brain)
  • Cerebral infarction

Major Types of Stroke and Their Causes

ISCHEMIC

  • Large artery thrombosis
  • Small artery thrombosis
  • Cardiogenic emboli
  • Cryptogenic (no known cause)

HEMORRHAGIC

  • Intracerebral hemorrhage
  • Subarachnoid hemorrhage
  • Cerebral aneurysm
  • Arteriovenous malformation

PATHOPHYSIOLOGY

The pathophysiology of CVA depends on the type of stroke. There are three types of stroke which are;

  • Transient ischaemic attack (TIA- also known as ministroke).

It occurs as a result of temporal disruption of circulation to parts of the brain due to atherosclerosis, obstruction of cerebral microcirculation by a small embolus, a decrease in cerebral perfusion pressure (CPP), or cardiac dysrhythmias.

It is characterized by sudden loss of motor, sensory or visual function.

Symptoms of TIA typically lasts less than an hour.

  • Ischaemic stroke (brain attack); a sudden loss of function resulting from disruption of the blood supply to a part of the brain due to thrombi formation, atherosclerotic plaques, or unknown causes.

When cerebral blood flow falls to less than 25 mL/100g/min, neurons cannot maintain aerobic respiration. This leads to a wide variety of neurologic deficits depending on the location of the deficit.

Hemorrhagic stroke

when an aneurysm ruptures and bleeds into the subarachnoid space. Normal brain metabolism is disrupted by the brain being exposed to blood, which also leads to increased ICP.

It leads to compression and injury to brain tissue.

There’s also secondary ischemia of the brain resulting from reduced perfusion pressure.

RISK FACTORS

  • High cholesterol intake
  • Hypertension
  • Previous TIA
  • Diabetes mellitus
  • RISK FACTORS CONT’D
  • Obesity
  • Smoking
  • Migraines
  • Increasing age

CLINICAL MANIFESTATIONS

  • Numbness or weakness of the face, arm or leg, esp on one side of the body.
  • Confusion or change in mental status
  • There may be trouble speaking or complete loss of speech (dysarthria-difficulty in speaking; dysphasia/aphasia- defective speech or loss of speech)
  • Loss of consciousness
  • Respirations are usually slow
  • Pulse is full and bounding
  • Temperature is normal initially, but later becomes elevated
  • Hemiplegia (paralysis of half of the body)
  • Hemiparesis (weakness of half of the body)
  • Dizziness
  • Sudden severe headache
  • Visual disturbances
  • Apraxia (inability to perform a previously learned action)
  • Sensory loss- there is the loss of voluntary muscle control, hence incontinence of urine and feces, also slight impairment of touch.
  • Cognitive impairment and psychological effects-

if damage occurs to the frontal lobe, learning capacity, memory or other higher cortical intellectual functions may be impaired.

It may reflect in limited attention span, forgetfulness, difficulties incomprehension and lack of motivation which causes them to become frustrated.

DIAGNOSIS

  • Comprehensive patient history
  • Complete physical and neurologic examination
  • Electrocardiography
  • Transcranial doppler flow studies
  • Carotid ultrasonography
  • Cerebral angiography
  • Non-contrast computed tomography scan
  • Transthoracic/transesophageal echocardiography
  • MRI of the brain and neck
  • Single photon-emission CT
  • A lumbar puncture may be performed

PREVENTION

Identify high-risk persons and educate pts and communities about the recognition and prevention of stroke.

Help patients alter risk factors for stroke such as treating hypertension and hyperglycemia, stopping smoking and living healthy lifestyles ie. Eating a low-fat diet, low cholesterol diet, increasing exercise, eating fish 2 or times a week.

Administration of anticoagulant agents as prescribed. Eg. Aspirin and Warfarin.

MEDICAL MANAGEMENT

Patients with TIA are treated with dose-adjusted warfarin sodium unless it is contraindicated. If contraindicated, aspirin is used.

Thrombolytic agents dissolve blood clot blocking blood flow to the brain.

Recombinant tissue plasminogen activator (recombinant t-PA) is given IV to establish blood flow through a blocked artery to prevent cell death in a patient with acute onset of ischemic stroke. This therapy shd be initiated within three hours after the attack, else will be ineffective.

If a patient does not qualify for t-PA (not all pets are candidates for t-PA), other treatments include anticoagulant administration (iv heparin or low-molecular-weight heparin).

In case of increased intracranial pressure (ICP), administer an osmotic diuretic (eg mannitol), elevate the head of the bed, endotracheal intubation for patent airway, and monitor the BP.

Endarterectomy for the prevention of ischaemic stroke- it is the main surgical procedure for managing TIAs and a small stroke.

It is the removal of atherosclerotic plaque or

thrombus from the carotid artery to prevent stroke. It is indicated in patients with severe carotid artery stenosis or moderate stenosis with significant risk factors.

NURSING MANAGEMENT

  • Reassure pt and family that the client would be handled by competent staff.
  • The patient’s condition should be explained to the patient and family.
  • Place the patient on a low comfortable bed with side rails.
  • Ensure bed rest with sedation to prevent agitation and stress.
  • If the patient is unconscious, a nurse in a lateral position to allow fluid drainage.
  • Suction patient regularly
  • The patient shd be catheterized bcos of urine incontinence.
  • Monitor vital signs (T, P, R, BP) quarterly for an hour, then half-hourly for the next hour, then hourly till the condition stabilizes, then four hourly.
  • Pupils are observed and checked at frequent intervals for size, reaction to light and any changes that might occur. This enables the assessment of the level of consciousness.
  • Monitor intake and output strictly.
  • Observe skin for pressure sores
  • Pass nasogastric tube if pt is unconscious
  • Give pt bedbath taking into consideration care of the perineal area, vulva care, oral care, hair care and care of the nails.
  • Provide pt with pen and book if there is difficulty in speaking and the client is literate.
  • Allow the client to voice out his fears
  • In case of constipation, pt shd be encouraged to increase the intake of roughages and fluid.
  • As patients condition improves, feed pt foods high in calorie, vitamins, and low sodium. If one side of pt is paralyzed, feed pt on the opposite side and meals shd be served in bits.
  • The patient is fitted with elastic compression stockings to prevent deep vein thrombosis, a threat to any pt on bed rest.
  • Invite the physiotherapist to help when necessary, and the speech therapist when needed.

 

REHABILITATION

When a patient is no longer acutely ill after a stroke, the health care staff focuses on maximizing the individual’s functional abilities.

This is most often done in an inpatient rehabilitation hospital or in a special area of a general hospital. Rehabilitation can also take place at a nursing facility.

The rehabilitation process can include some or all of the following :

speech therapy to relearn talking and swallowing;

occupational therapy to regain as much function dexterity in the arms and hands as possible;

physical therapy to improve strength and walking;

family education to orient them in caring for their loved ones at home and the challenges they will face.

The goal for rehabilitation is for the patient to resume as many, if not all, of their pre-stroke activities and functions.

Since a stroke involves the permanent loss of brain cells, a total return to the patient’s pre-stroke status is not necessarily a realistic goal in many cases.

However, many stroke patients can return to vibrant independent lives.

 

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