Neuroscience 210

  1. Scope of the problem of stroke
    • Number one cause of disability
    • number 3 cause of death (1st is heart disease, then cancer)
    • 3 billion dollar a year cost
  2. What does stroke mean
    • apoplexy--struck down with violence
    • 1599--stroke first used to describe apoplective seizures
    • Hippocrates originally described this affliction

    AKA CVA--cerebrovascular accident.
  3. What is a stroke?
    WHO definition--a neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours.
  4. Ischemia vs Hemorrhage
    1. Ischemic--blockage of artery resulting in loss of blod flowby a thrombus (clot) -clot can form and a part can break off and move on to cause another blockage = 80% of strokes

    • 2. Spontaneous intracranial hemorrhage (10-15%)
    • Aneurysmal subarachnoid hemorrhage (5-10%)

    strokes visualized with CT scans --hemmorrhage look like bright spots on the scan
  5. Symptoms of stroke
    • vision
    • headache
    • weakness
    • trouble speaking
    • diziness
  6. Signs of stroke
    • sudden onset of:
    • unilateral weakness or numbness
    • difficulty speaking/understanding
    • loss or change in vision
    • severe and unusual headache (can indicate subarachnoid hemorrhage)
    • loss of balance or dizziness
  7. Neuroanatomy
    • stroke symptoms are dependent on the area of brain affected by ischemia or hemorrhage
    • on the motor strip, legs are usually the first to be distrupted, they are in the fold between the two hemispheres.
  8. Dysphasia/Aphasia
    Broca's= non fluent--slow halting, effortful speech, frustrated, relatively good comprehension

    Wernike's=fluent= empty speech, word salad, poor comprehension

    Dysarthria--slurring of speech
  9. Neglect/hemi inattention
    • usually from right parietal lobe damage
    • inattention to the left side of speace and even their own body
    • very disabling as patients lack insight into deficits
  10. sub cortical anatomy (white matter)
    • contains the internal capsule--info from cortex to spinal cord, damage causes contralateral weakness
    • white matter is the brain's wiring
  11. arterial supply of the brain
    vertebral artery==two arteries come together to form one--posterior

    internal carotid artery-- supplies anterior 2/3 of cerebral hemisphere

    • anterior circulation of the brain done by the anterior cerebral artery and the middle cerebral artery--branches of the internal carotid artery
    • posterior circulation of the brain by posterior cerebral artery, basilar artery, vertebral artery

    circle of Willis-- structure at base of brain that is formed by the joining of carotid and basilar arteries, has redundancies so if one part is blocked blood can still flow
  12. middle cerebral artery
    supplies lateral surface of hemisphere and deep structures like the basal ganglia and subcortical white matter

    • blockages affect contralateral face and arm areas, causes weakeness
    • causes dysphasia (left hemisphere) and neglect (right hemisphere)
  13. Anterior cerebral artery
    • supplies medial surface of hemisphere
    • causes contralateral leg weakeness/numbness
  14. Large artery/cortical stroke
    • contralateral weakness
    • neglect (if in right )
    • aphasia, dysphagia
    • contralateral visual loss
  15. subcortical/lacunar
    affects the internal capsule--contralateral weakness--affects face, arm and legs, even small strokes can be debilitating
  16. Posterior circulation
    vertebral and basilar arteries supply posterior and medial regions of hemispheres, brainstem, diencephalon and cerebellum

    posterior cerebral artery and cerebellar arteries--3 branches
  17. brainstem stroke
    • lacunar syndrome--weak and ataxic on the contralateral side
    • brainstem contains wiring downstream for the internal capsule
  18. Posterior cerebral artery stroke
    contralateral hemianopsia (blind on one side of visual space)
  19. Pons: locked in syndrome
    pons--entire brainstem stroke at the pons, afferents are spared, can feel but completely paralysed.

    only stroke with bilateral symptoms
  20. Transient ischemic attack (TIA)
    symptoms of stroke that resolve within 24 hours of onset

    • WARNING sign for major stroke
    • ~50% of all TIA are associated with permanent damage, particularly if symptoms last > 1 hour
  21. Risk factors for stroke
    • age
    • hyptertension (high blood pressure)
    • smoking--chemicals entering bloodstream
    • diabetes
    • irregular heartbeat (atrial fibrillation)--blood will pool because it is not being moved, clots form and might get out of the heart and move until it gets to artery it cant fit through and cause a blockage.
  22. Sources of emboli (clots) that cause stroke
    • the heart
    • arteries in the neck
    • arteries in the brain
  23. carotid artery atherosclerosis
    plaques can form (often at intersections of arteries) and pieces can break off and go on to cause a stroke or cause platelets to stick to it and cause a blockage
  24. Cerebral Ischemia
    • Insufficiency of blood supply and oxygen and glucose to meet the metabolic demands of the brain
    • critical thing is that ATP stops being made . ATP keeps potassium out, and water out. if there is no ATP water can move in the cell (imaging measures water, shows the core region of damage)

    • 65 mL/100g/min is regular CBF
    • once it drops to between 20-10 the tissue is electrically silent--penumbral tissue that is functionally inactive but structurally fine

    at 10 there is K release and cell death
  25. treating ischemic stroke
    Thrombolysis--tPA--busts the clot and restores blood flow to the brain, helps to save the penumbra regions
  26. Hemorrhagic stroke
    • 2nd most common stroke type
    • higher rates in Asians and Africans--higher blood pressure rates

    subarachnoid hemorrhage is 3rd most common

    • size of the stroke matters--initial levels of consciousness and hematoma volume prodiects death
    • if they are alert and have a hematoma <30 ml, 17% mortality rate
    • if they are drowsy/in a coma with a hematoma there is a 91% mortality rate

    amyloid proteins deposited in the vessles makes them more brittle and prone to rupture
  27. treating hematoma
    • hemostatic drugs--to speed clotting
    • acute blood pressure reduction--reducing the pressure
  28. Developmental aneurysms
    weakness in vessel wall, if it is in a focal area, and aneurysm is caused, and rupture causes a subarachnoid hemorage

    risk factors are hypertension, smoking, and genetics
  29. subarachnoid hemorrhage
    rupture of aneurysm, treated by surgical clip or endovascular coil which causes it to clot
  30. treating stroke
    • treatment varies with type of stroke, can't tell difference without imaging , requires brain scan
    • time is brain!

    • ischemia--tPA
    • hemorrhage--no proven therapy
    • aneurysm--clip/coil

    can be prevented with high BP treatment(lower blood pressure=lower stroke), stopping smoking, taking low doses of asprin (stops platelets from becoming active and spiny and sticking to each other) Warfarin (rat posion) for patients with atrial fibrilation--blood thinner, prevents clotting in heart
Card Set
Neuroscience 210
stroke lecture