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Stroke: Symptoms, Types and Causes
Seabrookers, especially older ones are concerned about stroke since the risk of having a stroke increases directly with age. Also, South Carolina has one of the highest rates per population for stroke and Seabrookers are obviously not immune from this devastaing state health problem. Stroke can be defined as an irriversible injury to the brain.  The brain is, of course, important to us since it is where we process information, decide on actions, remember facts, have our emotions and even the residency of our most fundamental control over our bodies such as breathing.  Seabrookers, however, know that having an intact brain or central nervous system allows us to enjoy life, interact socially with each other and function independently.

When the brain does not get adequate oxygen delivered to it by the heart and blood vessels, then the brain tissues becomes ischemic and ceases to function.  If the brain is sufficiently long without oxygen (usually a few minutes) then the cells in the brain die and never are replaced.  If enough cells are lost in this way, the brain cannot function normally.  When this happens the patient has had a stroke.

   

Types and Causes of Stroke
There are two major types of stroke according to the cause.  One is when blood supply to the brain is interrupted and the other is when hemorrage occurs which injures the brain tissue.  The most common cause of obstruction of blood flow is by the formation of a clot in an artery to the brain, but an embolus breaking free from the heart or major blood vessels can also impede blood supply to the brain.  These strokes are termed embolic or thrombotic strokes.  Thrombotic strokes account for 70 - 80 percent of all strokes whereas an embolus only accounts for 5 to 15 percent of strokes.  The site of obstruction of flow is usually associated with atherosclerosis, much as coronary atherosclerosis leads to a heart attack.  It is correct to think of a stroke as a brain attack just as one thinks of a coronary thrombosis as a heart attack.

Bleeding either into the brain or in the thin layer of tissue that overlies the brain (subarachnoid lining) can both cause damage to the nearby brain either by direct compression which reduces blood flow or by increasing the pressure around the brain to a degree that blood cannot flow to the brain.  Roughly 10 percent of all strokes are the result of hemorrhage.  When bleeding occurs within the brain it is called intracerebral hemorrhage and is often the result of a ruptured brain blood vessel.  This can either be a vessel which was congenitally dilated (aneurysm) or one that became weak over time in patients with hypertension and or atherosclerosis.  If blood vessels which course along the surface of the brain leak or hemorrhage, then a subarachnoid hemorrhage is the result.  Patients who survive hemorrahgic strokes have a slightly better overall recovery of function than those who have embolic or thrombotic strokes.     
   
Signs and Symptoms of Stroke
The patient symptoms are a direct result of where the brain is injured.  Different regions of the brain are responsible for different functions.  Likewise, one side of the brain is usually responsible for functions of the opposite side of the body.  The signs and symptoms of a stroke are dependent on the region of the brain which is injured.  The table lists the warning signs of a stroke as published by the American Heart Association. A developing stroke can cause difficulty in movement of arms or legs, face or mouth and tongue.  Speech can be impaired as well as thought processes and level of consciousness.  Headache often accompanies intracerebral hemorrahge, but is often absent with thrombotic strokes. 

If you notice in yourself or in a fellow Seabrooker the signs listed in the table, it is important to see a physician immediately.  As with the onset of a heart attack the beginning of a stroke requires prompt medical attention.  At Seabrook the fastest way to receive this is to dial 911. 

We will devote two more columns to stroke because it is so important.  In the ensuing issues of the Seabrooker we will address risk factors and prevention as well as  treatment. 

WARNING SIGNS OF STROKE*
 -  Sudden weakness or numbness of the face, arm or leg on one side of the body.
-  Sudden dimness or loss of vision, particularly in only one eye.
-  Loss of speech, or trouble talking or understanding speech.
-  Sudden, severe headaches with no known cause.
-  Unexplained dizziness, unsteadiness or sudden falls, especially along with any of the previous symptomes. 
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*  Published by the American Heart Association

MUSCHealth.com Online Health Library Related Links:
Stroke

Other Online Resources Related to Stroke:
Medline plus Information on Stroke
American Stroke Association
 
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