ischaemic stroke

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					Ischaemic Stroke
           Ischemic Stroke
• Synonyms : brain attack, cerebrovascular
  accident

• It is a sudden loss of function resulting
  from disruption of the blood supply to a
  part of the brain.

• Result of long-standing cerebrovascular
  disease.
Ischaemic strokes divided into five
  different types according to their cause :
Large artery thrombosis :

Atherosclerotic plaques in the large blood
 vessels of the brain.

Thrombus formation and occlusion at the
 site of the atherosclerosis

Ischaemia and infarction
Small penetrating artery thrombosis :

One or more vessels are affected

Most common.

Cavity is created when the infarcted brain
 tissue disintegrates

Hence called lacunar strokes
Cardiogenic embolic stroke

Associated with cardiac arrhythmias
e.g. atrial fibrillation.

Emboli may be prevented by the use of
 anticoagulation therapy
Cryptogenic and others




             No known cause
    Major Types of Stroke and Their Causes
      CLASSIFICATION                CAUSES
Ischemic                Large artery thrombosis
                        Small penetrating artery
.                       thrombosis
                        Cardiogenic embolic
                        Cryptogenic (no known cause)
                        others

Hemorrhagic             Intracerebral haemorrhage
                        Subarachnoid haemorrhage
                        Cerebral aneurysm
                        Arteriovenous malformation
              Pathophysiology
• In ischemic brain attack : disruption of blood flow due
  to obstruction of a blood vessel  ischaemic cascade

• Early in the cascade, an area of low cerebral blood
  flow, referred to as the Penumbra region exists
  around the area of infarction

• Timely intervention may prevent infarction from
  spreading into the penumbra region
       Clinical Manifestations
• Sudden severe headache
• Confusion or change in mental status
• Visual disturbances
• Trouble speaking or understanding speech
• Numbness or weakness of the face, arm, or leg,
  especially on one side of the body
• Difficulty walking, dizziness, or loss of balance
  or coordination
• Motor, sensory, cranial nerve, cognitive, and
  other functions may be disrupted
• Neurological deficits
• Motor loss : hemiplegia or hemiparesis
• Communication loss : dysarthria, dysphasia or aphasia
  expressive or receptive or global (mixed) aphasia
• Apraxia : inability to perform a previously learned
  action - combing using fork
• Perceptual disturbances : homonymous hemianopsia –
  same side as paralysis
• Sensory loss : touch sensation; proprioception, visual,
  tactile, and auditory stimuli
• Cognitive impairment and psychological effects:
  frontal lobe damage : learning capacit, memory, or other
  higher cortical intellectual functions may be impaired.
  Memory affected.
  Inattention +, lack of motivation, depression, emotional
  lability, hostility, frustation, resentment, lack of
  cooperation
      Assessment And Diagnostic
              Findings
• History and neurological examination
• Transient ischaemic attack
• Reversible ischemic neurologic deficit
• Stroke in evolution
• Completed stroke
• Initially non-contrast CT brain – ischaemic or
  haemorrhagic
• ECG, carotid ultrasound cerebral angiography,
  transcranial doppler flow studies, transthoracicor
  transesophageal echocardiography, manetic resonance
  imaging of the brain or neck, xenon CT, single photon
  emission CT. , digital subtraction angiography for
  carotid artery
An ischemic stroke occurs when an artery in the
            brain becomes blocked.
A major ischemic stroke
The motor nerve pathways : upper and lower motor neurones
  The path of the
motor neurones and
their decussation at
medulla oblongata
Ischemic
  Stroke
Haemorr
 hagic
 stroke
 CT angiogram
of the neck with
arrow pointing
 to blockage in
   the internal
 carotid artery)
 Carotid
endarterec
  tomy
Carotid stenting
Ischemic stroke
• Acute care:
• Thrombolysis to dissolve the clot causing
  an acute stroke
• Within three hours.
• Long term care:
  Carotid endarterectomy
              Prevention
• Treat hypertension
• Treat hyperglycemia
• Stop smoking
• Reduce high cholesterol
• Reduce obesity
• Low cholesterol low fat diet
• exercise
              Medical treatment
• Warfarin or aspirin or clopidogrel (antiplatelet
  regimen)
• Administration of t-PA – loading dose and then
  infusion
• Low molecular weight heparin – dalteparin
• If ICT is increased – mannitol, maintaining PaCO2
  within the range of 30 – 35 mmHg. , positioning to
  avoid hypoxia
• Elevation of head end
• Intubation if needed
• Bp within 180/100 mmHg
        Nursing interventions
• Improving mobility and preventing joint
  deformities
• Preventing shoulder adduction
• Positioning the hand and fingers
• Changing positions
• Establishing an exercising program
• Preparing for ambulation
• Preventing shoulder pain
• Enhancing self care
• Managing dyphagia
• Managing tube feeding
     Nursing interventions (contd)
• Attaining bladder and bowel control
• Improving thought processes
• Improving communication
• Maintaining skin integrity
• Improving family coping
• Helping the patient cope with sexual
  dysfunction
• Teaching self care and continuing care
                       Glossary
• Agnosia : failure to recognize familiar objects perceived
  by the senses
• Aneurysm : a weakening or bulge in an arterial wall
• Aphasia : inability to express oneself or to understand
  language
• Apraxia : inability to perform previously learned
  purposeful motor acts on a voluntary basis
• Ataxia : impaired ability to coordinate movement, often
  seen as a staggering gait or postural imbalance
• Dysarthria : difficulty in articulation due to neurologic
  causes
• Expressive aphasia : inability to express oneself often
  associated with damage to th left frontal lobe area
• Hemianopsia : blindness of half of the field of vision on
  one or both eyes

				
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posted:4/13/2011
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