Stroke

第三章 Stroke

What is stroke

A brain attack

• A sudden interruption of continuous blood flow to the brain
• __A stroke occurs when a blood vessel in the brain becomes blocked or narrowed, or when blood vessel bursts and spills blood into the brain
  $\Downarrow$
• Cells die, because they stop getting the oxygen and nutrients they need
• Damaged by sudden bleeding in or around the brain

Symptoms

• Summerize them as BEFAST

  • Balance

    • Sudden trouble walking, dizziness, loss of balance or coordination

  • Eyes

    • Sudden trouble seeing in one or both eyes

  • Face Arm

    • Sudden numbness or weakness of face, arm or leg, especially on one side of the body

  • Speech time

    • Sudden confusion, trouble speaking, or understanding

Effects

• The effect of stroke may range from mild to severe disabilities depending on the type, severity, and location of the stroke

• Problems with Muscle Movement (motor sensory impairment)

  • Weakness (paresis) or paralysis (plegia)
  • Affect only the face, leg, arm or affect one entire side of the body and face

• **Problems with Cognition, Thinking or Memory

  • Permanent decline in cognitive function known as vascular cognitive impairement(VCI)

• Problems with Speaking or Understanding Speech

• Problems with Emotion

  • Diffculty in controling their emotions
  • Post-stroke depression
  • $\Downarrow$
  • Hemper recovery and rehabilitation
  • Even lead to suicide

Types of stroke

Ischemic stroke (Most common type)

• Occur when the supply of blood to the brain is suddenly cut off or interrupted

  • Thrombosis(thrombi)
    • A clot develops and grows large enough to impair blood flow
  • embolism(emboli)
    • A clot moves from another part of the body into a narrower artery in the neck or brain
  • Stenosis
    • An artery in the brain or neck arrows
    • Atherosclerosis - The most common cause of stenosis
      • Deposits of plaque build along the inside of arteries
        • Thickening
        • Hardening
        • Loss of elasticity

Hemorrhagic stroke

• An arteries in the brain bursts

  • Blood gushed into or around the brain, damaging the surrounding tissue

• Two main types

  • Subarachnoid hemorrage
    • Rupure of a vessel on the surface of the brain and bleeding into the space between the brain and arachnoid layer
  • Intracerebral hemorrage
    • Bleeding directly into the brain tissue

What cause blood vessels to burst?

• Aneurysm
  • A weak or thin spot on an artery wall $\rightarrow$ Weak spots stretch or ballon out $\rightarrow$ Aneurysms can rupture, causing blood to gush ionto the brain, and raise the intracranial pressure
• Arteriovenous malformations (AVMs)
  • An abnormal tangle of defective blood vessels $\rightarrow$ Multiple irregular connections between the arteries and veins $\rightarrow$ Arterial blood travels directly to veins $\rightarrow$ The blood flow is extremely high $\rightarrow$ Cause the vessels to rupture

Risk factors

Unmodifiable

• Those that can’t be changed
  • Gender
  • Family history
  • Age
  • Prior stroke of heart attack

Modifiable

• Those that can be changed or controlled

  • Cholesterol - Produced by the liver, is a vital body product

    • Production of hormones
    • Part of cell membrane
    • Most is
      • Excessive LDL $\rightarrow$ Cholesterol builds up in the vessels $\rightarrow$ Stenosis and atherosclerosis

  • Hypertension - Number one risk factor for stroke

    • Promotes atherosclerosis
      • Atherosclerosis is the major cause of blood vessel narrowing
    • Damage to blood vessels

$$antihypertensives\begin{cases}Relaxing&the&blood&vessels\\ Decreasing&blood&volume\end{cases}$$

- Diabetes

	- Glucose builds up $\rightarrow$ Damage the blood vessels in the brain


- Smoking

$$Smoking\begin{cases}Promotes&atherosclerosis&and&aneurysm\\Stimulates&blood&clotting&factors\end{cases}$$

	- The risk decreases significantly 2 years after quitting smoking
	- By 5 years, the risk dereases even further to the level of nonsmokers

- Heart disease
- Atrial fibrillation $\rightarrow$ Atria no longer beat $\rightarrow$ Muscular walls wiggle $\rightarrow$ Atria don't push blood out $\rightarrow$ Blood stagnation $\rightarrow$ Blood clots form $\rightarrow$ Can loosen and leave the heart $\rightarrow$ Ischemic stroke

Treatment

Emergency medical or surgical care given immediately after a stroke

• Minimize the extent of injury

Treatment to prevent a second or recurrent stroke

Rehabilitation to improve disabilities that result from stroke

• Physical therapy

  • Relearn simple motor activities

• Occupational therapy

  • Relearn the skills needed to perform everyday activities

• Speech therapy

  • Relearn language and speaking skills

• Vocational therapy

  • Helps people return to the workfore

• Psychological theragy

  • Helps people recuperate

Ischemic stroke treatments

• Antithrombotics
  • Anticoagulants $\rightarrow$ Reducing the clotting property of the blood
• Carotid Endarterectomy (CEA)
  • For patient with cerebrovascular atherosclerotic disease $\downarrow$
  • Surgical removal of obstructing plaque from the inside of a carotid artery
• Stenting
  • Inserting a catheter with a wire inside into the diseased artery $\downarrow$
  • Passing a tube-shaped device made of a mesh-like material $\downarrow$
  • Expanding the stent to widen the artery and flatten the plaque

Hemorrhagic stroke treatments

• Clipping For subarachnoid hemorrhage
  • An operation during which an experienced neurosurgeon places a clamp on the aneurysm neck to prevent the chance that it will burst
• Endovascular coiling To treat high-risk cerbral aneurysm
  • Coil is inserted through an artery in the thigh and threaded though the vessel $\downarrow$
  • It is released into the aneurysm $\downarrow$
  • It triggers clotting and an immune respone $\downarrow$
  • It strengthens the artery walls and reduces the risk of rupture