Stroke 1.0 - Types of Stroke (Introduction & Ischemic Stroke)


Types of stroke

1. Ischemic stroke; 2. Hemorrhagic stroke

1. Ischemic stroke (occlusive stroke) [Prevalence: 80%]

Occurs when an artery is blocked and part of the brain loses its blood supply

-   Deprived of blood

 

Further classified into: **

A. Thrombotic       B. Embolic

A. Thrombotic stroke 

  • Cause: Artery occluded by a plug of material accumulating at a fixed location
  • Common at inter­nal carotid arteries, the vertebral arteries, and the basilar artery

Mechanism:

  • Typically begins in an area of increased turbulence 
  • Debris in the bloodstream tends to accumulate, narrowing the artery, increasing blood velocity → roughen the lining of the artery
  • Plaques form on roughened areas
  • Narrowed artery, reduces blood flow, causes stroke 

Progression:

  • Irregular, stepwise manner, sometimes preceded by transient periods of ischemia.

  B. Embolic Stroke

-   Caused by a fragment of material that travels through the circulatory system until it reaches an artery smaller than its own diameter, occluding the artery.

 

Possible material in the embolus:

-   Blood clot that has broken loose from its original location 

-   Fragment of arterial lining

-   Piece of atherosclerotic plaque

-   Tissue from a tumor

-   A clump of bacteria

-   Other solids that may move through the arteries

 

Progression:

-   Maximally expressed within a few minutes.


** NB. Classifying Ischemic stroke into Thrombotic and Embolic is just the GENERAL Classification. Clinically, MD follows TOAST Classification. 

References:
Brookshire, R.H. (2007). Introduction to neurogenic communication disorders (7th Ed). St. Louis: Mosby. (page 36- 50)