Ischemic Stroke

Ischemic Stroke

1. General Manifestations (Zomorodi, 2014).

   • Impaired mobility
   • Impaired respiratory function
   • Impaired swallowing & speech
   • Impaired gag reflex
   • Impaired self-care abilities
   • Akinesia, impairment in the control over volentary movements
   • Alterations in muscle tone
   • Alteration in reflexes

2. Classifications of Ischemic Stroke (Zomorodi, 2014).

   • Thrombotic
     • Plaque lines the arteries and causes a clot to form. The clot blocks the passage of blood from flowing through the artery (Zomorodi, 2014).
       • 2/3 of thrombotic stroke is associated with diabetes mellitus or hypertension (Zomorodi, 2014).
       • 30-50% have experienced a Transient Ischemic Attack (TIA) before their ischemic stroke (Zomorodi, 2014).
   • Embolic
     • A blood clot or other debris that circulates the blood reaches an artery in the brain that is too narrow to pass through. The blockage becomes lodged and prevents the flow of blood (Zomorodi, 2014).
       • Rapid occurrence of severe clinical symptoms (Zomorodi, 2014).
       • Second most common cause of stroke (Zomorodi, 2014).

3. Treatment & Management

   • Medications (Zomorodi, 2014).
     • Recominant tissue plasminogen (tPa)
       • Re-establishes blood flow to prevent cell death by breaking up blood clots (Zomorodi, 2014).
       • Extensive screening to rule out hemorrhagic stroke, blood disorders, recent history of GI bleeding, head trauma in the last 3 months, and major surgery in last 2 weeks (Zomorodi, 2014).
     • Anticoagulants or lately inhibitors help prevent further clot formation
       • Aspirin (325mg) administered 24-48 hours after onset of ischemic stroke, unless contraindicated (Zomorodi, 2014).
     • Blood pressure lowering medications (beta blocker, ACE inhibitors, ARBs, Calcium Channel Blockers, etc)
   • Acute Stroke Interventions
     • In order to treat a stroke, diagnostic testing must occur to determine what type of stroke is occurring. A CT or MRI will indicate the size and location of the legion as well as determine what type of stroke (Zomorodi, 2014.
       • Intravenous thrombolysis is the mainstay of acute ischemic stroke management for any patient with disabling deficits presenting within 4.5 hours of symptom onset (Prabhakaran, & Ruff, 2015).
       • Mechanical thrombectomy has demonstrated substantial rates of partial or complete arterial recanalization and improved outcomes(Bernstein (Prabhakaran, & Ruff, 2015).
       • See "Diagnostic" section
     • Managing circulation, airway and breathing. Oxygen administration, artificial airway insertion, intubation, and mechanical ventilation may be required (Zomorodi, 2014.
     • Pain management (Zomorodi, 2014.
     • FAST Assessment to determine stroke (Heart and Stroke, 2018)

4. Diagnostic (Zomorodi, 2014).

   • MRI
   • CT angiography
     • CT scan with contrast (Zomorodi, 2014).
   • Ceberal Angiography
     • An X-ray of the brain with contrast (Zomorodi, 2014).
   • Transcraniel Doppler Ultrasonography
     • Ultrasound used to examine the blood circulation within the brain (Zomorodi, 2014).
   • Lumbar Puncture
     • Done to look for evidence of red blood cells in cerebral spinal fluid (Zomorodi, 2014).
   • Digital Subtraction Angiography
     • Multiple X-rays with contrast of the brain to better visualsze any problems with blood flow (Zomorodi, 2014).
   • LICOX System
     • A system that monitors the brains oxygen perfusion, tempurature and intracranial pressure (Zomorodi, 2014).
   • Blood work
     • CBC, platelet count, PT/PTT, fasting blood glucose, and lipid profile (Zomorodi, 2014).

5. Client-Centered Collaborative Care (Health Monitor, 2019)

   • Primary Care Physician
   • Neurologist
   • Nurse Practitioner
   • Physical Therapist
   • Occupational Therapist
   • Speech and Language Pathologist
   • Dietition or Nutritionist
   • Nurses
   • Personal Support Workers
   • Physiatrist (rehabilitation specialist)
   • Psychologist/Psychiatrist/Therapist
   • Pharmacist
   • Social Worker
   • Neurosurgeon or Vascular Surgeon

6. Prevention (Zomorodi, 2014).

   • Healthy Diet
     • Reduce sodium intake to keep blood pressure low (Zomorodi, 2014).
   • Regular Exercise
   • Limit Alcohol intake
   • Smoking Cessation
   • Routine Health Assessments
   • Close Management of
     • Hypertension
     • High serum lipids
     • Diabetes Mellistus and prediabetes, have been found to cause an increased risk in reaccurence of stroke and TIA. Thus close management and prevention of onset of diebetes is crutial for prevention of ischemic stroke (Pan, Chen, and Wang, 2019).
     • Cardiac Dysfunction
   • Medications
     • Anticoagulants, inhibit coagulation of blood (Zomorodi, 2014).
     • Antiplatelets, inhibit thrombus formations (Zomorodi, 2014).
   • Surgical interventions (Zomorodi, 2014).
     • transluminal angioplasty, a procudure to open up blocked vesseles or arteries. by using a small catheter with a ballon at its end. This is used to inflate the vessle of artery and rstore normal blood flow (Zomorodi, 2014).
     • carotid endarterectomy reduces risk of stroke by correcting stenosis in the common and internal carotid arteries (Zomorodi, 2014).
     • Extracranial-intracranial bypass, a surgical procedure that is performed to increase ceribral blood flow. by connecting a branchof the external caratid to a branch of the internal caratid artery (Zomorodi, 2014).
     • Surgical interventions for aneurysms at risk of bleeding (Zomorodi, 2014).
     • Stenting of carotid artery

7. Risk Factors

   • Modifiable (Zomorodi, 2014).
     • Illicit drugs/Alcohol Abuse
       • Increases risk of heart disease, increasing risk of stroke (Heart and Stroke, 2018)
       • Stroke can occur hours after taking drugs (Heart and Stroke, 2018).
     • Stress
       • Increases blood pressure (Heart and Stroke, 2018).
     • Heart disease
       • Several heart diseases increase risk of stroke (Heart and Stroke, 2018)
     • Diabetes mellitus
       • Three times more likely to have a stroke. (Health Monitor, 2019)
     • Hypercoagulability
       • Increased tendency towards blood clotting, increasing risk of stroke. (Health Monitor, 2019)
     • Asystomatic carotid stenosis
       • Atherosclerosis causes narrowed arteries, reducing blood flow to the brain (Ringer, 2018).
     • Dyslipidemia
       • Elevated cholesterol increases risk of ischemic stroke (Athyros, Karagiannis, Mikhailidis, & Tziomalos, 2009).
     • Hypertension
       • High blood pressure, specifically over 160mmHg systolic, drastically increases stroke over prolonged periods. The higher the systolic BP, the worse the functional outcome is (Kang, Kim, Han, & Bae, 2019).
       • High blood pressure may contribute to cerebral atherosclerosis, which accounts for 70% of strokes (Kang, Kim, Han, & Bae, 2019).
     • Obesity & body fat distribution
       • Over 60% of Canadian adults are overweight or obese (Heart and Stroke, 2018).
       • Obesity leads to high blood pressure, and atherosclerosis. Both drastically increase risk of stroke (Heart and Stroke, 2018)
     • Oral contraceptive use
       • Medications with estrogen increase risk of stroke (Heart and Stroke, 2018).
     • Physical inactivity
       • Leads to obesity and high cholesterol. This increases blood pressure, and creates plaque build-up in arteries (Heart and Stroke, 2018).
     • Sickle Cell disease
       • The sickled red blood cells are rigid and tend to clump along the walls of larger arteries that go to the brain. This damages the vessels walls, exposing more tissue that gathers more sickle cells and further narrows the vessels (Stroke Centre, 2019).
       • Children have a 67% risk of recurrence with strokes recurring up to nine months apart (Stroke Centre, 2019).
     • Sleep apnea
       • Causes low oxygen levels and high blood pressure, increasing stroke risk (American Sleep Apnea Association, 2019).
     • Smoking
       • Triples risk of stroke for middle-aged adults (Heart and Stroke, 2018).
   • Non-Modifiable (Zomorodi, 2014).
     • Age
       • risk increases with age (Zomorodi, 2014).
       • Risk doubles every decade after 55 years of age (Zomorodi, 2014).
     • Gender
       • More common in men (Zomorodi, 2014).
       • Higher risk of mortality for women (Zomorodi, 2014).
     • Race/Ethnicity
       • African Americans have almost twice as many strokes as white Americans, they are also more likely to die from stroke. (Health Monitor, 2019)
     • Family History
       • One may inherit conditions that put you at risk for stroke, i.e. high blood pressure (Health Monitor, 2019).
       • Lifestyle behaviours such as smoking or overeating increase stroke risk (Health Monitor, 2019).
     • Low birth weight
       • Associated with high triglyceride and cholesterol levels, increasing stroke risk (West Virginia University, 2019)

8. Right-brain Damage Effects (Zomorodi, 2014).

   • left-sided paralysis
   • Spatial-perceptual deficits (Zomorodi, 2014).
     • altered perception of self and illness
     • Altered perception of self in space
     • Aprioxia, the inability to preform previously learned sequential movements, such as throwing a ball
     • Agnosia, an inability of pt to identify or recognize objects via sight, touch and or hearing
   • Left-sided neglect
   • Tends to deny or minimize problems
   • Rapid performance, short attention span
   • Impulsive
   • Impaired judgment
   • Impaired time concepts

9. Left-brain Damage (Zomorodi, 2014).

   • Right-sided paralysis (hemiplegia)
   • Impaired right-left discrimination
   • Slow performance (cautious)
   • Depression/anxiety due to deficits
     • Depression and feelings associated with changes in body image and loss of function can make this worse (Zomorodi, 2014).
   • Impaired comprehension and speech/language
     • The left hemisphere is dominant for language skills in right-handed, and most left-handed persons (Zomorodi, 2014).
     • Aphasia (total loss of comprehension and use of language or total inability to communicate), dysphagia (impaired ability to communicate), as well as dysarthria (disturbance in the muscular control of speech) (Zomorodi, 2014).
   • Difficulty controlling emotions. May be exaggerated or unpredictable.
   • More likely to result in memory problems related to language

10. Pathophysiology

    • Inadequate blood flow in a single brain artery is usually compensated by the remaining network of arteries that make up the circle of Willis (Giraldo, 2017)
      • Normal variations, atherosclerosis and other arterial lesions can inhibit the remaining structures ability to compensate which increased the chance that a blockage of one artery will cause brain ischemia (Giraldo, 2017)
        • The extent of the damage depends on the severity of the ischemia. If it is mild the damage proceeds slowly, taking hours for brain tissue to die. For severe ischemia brain tissue can begin to die after as little as 15 minutes (Giraldo, 2017)
          • Damage occurs more rapidly during hyperthermia and more slowly during hypothermia (Giraldo, 2017)
            • If tissue is ischemic but not irreversibly damaged, prompt treatment to restore blood flow may reduce or even reverse the injury (Giraldo, 2017)
    • Mechanisms of Ischemic Injury (Giraldo, 2017)
      • Edema
        • If edema is extensive, it can increase intracranial pressure (Giraldo, 2017).
      • Microvascular thrombosis
      • Apoptosis (Programmed cell death)
      • Infarction with cell necrosis

11. Definition: Strokes that result from inadequate blood flow to the brain from partial or complete occlusion of an artery (Zomorodi, 2014).

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