Definition of "Stroke"

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Stroke (aka cerebrovascular accident, CVA) is the brain version of a heart attack, and is where there is disturbance in blood supply to an area of the brain.

Patient information

What is a stroke?
It's the brain version of a heart attack. So remember, a heart attack is when there's not enough blood supplying the heart. So for a brain attack, there's not enough blood supplying the brain.

What, that sounds a bit like a TIA, what's the difference?
TIA is a temporary version of stroke. So it's a bit like the angina of stroke. And just like how heart attack causes permanent damage, so does stroke.

Sx
  • Loss of function supplied by the relevant area of the brain, including:
    • Contralateral paralysis (i.e. inability to move limbs)
    • Sudden weakness or numbness
    • Amaurosis fugax (i.e. sudden dimming or loss of vision)
    • Homonymous hemianopia (loss of vision on 1 side)
    • Receptive aphasia (i.e. failure to understand) or expressive aphasia (i.e. failure to express language)
    • Dysarthria (i.e. slurred speech)
    • Vertigo (feeling like the world is spinning)
    • Mental confusion
  • Sx often appear soon after the stroke has occurred
  • If Sx last <2 hours, it is known as TIA (transient ischemic attack)

Patient information

What's going to happen in a stroke then?
Any and everything the brain controls, can be affected. It can be weakness in movement. Loss of vision. Loss of ability to understand, or to speak. Feeling confused.

Pathophysiology

It results in pat of the brain not functioning properly, including:

  • Middle cerebral artery (MCA) is one of the major paired arteries that supply brain to the cerebrum, but not considered apart of the Circle of Willis per se
Classification

Ischemic stroke, where blood supply to part of the brain is decreased, causing dysfunction of brain tissue in that area. This can happen because:

  • Thrombosis (obstruction of a blood vessel by a blood clot forming locally), called thrombotic stroke
  • Embolism (aka embolic stroke), caused by an arterial embolism (i.e. blockage of an artery), by an embolus from elsewhere in the body. This can be caused by:
    • The heart, most commonly, especially in  Fib, including:
      • Atrial fibrillation and paroxysmal atrial fibrillation
      • Rheumatic disease of the mitral or aortic valve disease
      • Artificial heart valves, known as cardiac thrombus of the atrium or ventricle
      • Sick sinus syndrome
      • Sustained atrial flutter
      • Recent MI
      • Chronic myocardial infarction together w/ EF<28%
      • Sx CHF w/ EF<30%
      • Dilated cardiomyopathy
      • Libman-Sacks endocarditis
      • Marantic endocarditis
      • Infective endocarditis
      • Papillary fibroelastoma
      • L atrial myxoma
      • CABG (coronary artery bypas graft) surgery
    • Paradoxical embolism, where a DVT embolizes through an atrial or ventricular septal defect in the heart into the brain
  • Systemic hypoperfusion (general decrease in blood supply, e.g. in shock), called cerebral hypoperfusion
  • Venous thrombosis

Hemorrhagic stroke (i.e. bleeding), caused by bleeding of blood vessels of the brain, either:

  • Directly into brain parenchyma, called intracerebral hemorrhage
  • Into surrounding subarachnoid space (i.e. space surrounding brain tissue)

Silent stroke (see page)

Patient information

What causes not enough brain to get to the brain?
A blood clot, preventing blood from getting to the brain. Or a bleed in the brain, so blood can't get to where it's supposed to, in the brain.

Risk factors
  • Old age
  • Hypertension
  • Previous stroke or TIA
  • Diabetes
  • Hypercholesterolemia
  • Tobacco smoking
  • Atrial fibrillation

Patient information

What makes it more likely for not enough blood getting to the brain?
It's the same stuff that's bad for your heart. So high blood pressure. Diabetes. High cholesterol. Smoking. And of course, a previous episode of stroke.

Tx
  • Stroke rehabilitation, is Tx to recover any lost function, ideally in a stroke unit, involving a team approach, involving speech and language therapy, physiotherapy, and occupational therapy
  • Address risk factors, including controlling:
    • Hypertension
    • Hypercholesterolemia (statins)
  • Specifically for ischemic stroke:
    • Thrombolysis, if detected within 3-4.5 hours
    • Prevention of occurrence may involve administration of:
      • Aspirin
      • Anticoagulants
      • Carotid endarterectomy (i.e. surgery used to remove atherosclerotic material stenosing the carotid artery), even
  • Specifically for hemorrhagic stroke, some may benefit from neurosurgery

Patient information

What can you do if not enough blood is getting to the brain?
For whatever loss of function that there is, you can try to recover as much as you can. You can also address address risk factors, like lowering blood pressure and cholesterol.

What about imemdiately, what can you do immediately?
It depends on if it's caused by a bleed in the brain, or a clot. If there's a bleed in the brain, you need to wait for it to clot, then maybe you can do brain surgery. If there's a clot, you can use a drug to break up the clot, if it's within 4 hours of the stroke. You can also prevent future clots causing problems, by using aspirin, anticoagulants. You can even use surgery to remove atherosclerotic material, wherever it is.

Prognosis
  • Stroke is a medical emergency, that can cause permanent neurological damage, or death
  • It is the second most leading cause of death, after ischemic heart disease
  • 66% occur in those over 65yo
See also
  • TIA (TEMPORARY loss of function)

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Definition of Stroke | Autoprac


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