2. What Is A Stroke?
0 Contributing Author: Guy Slowik FRCS
0 A stroke occurs when the blood flow to a part of the brain is
disrupted. Not enough blood reaches the affected part of the
brain. The cells in the part of the brain affected do not get
enough oxygen and begin to die.
0 Damage to the brain can cause loss of speech, vision, or
movement in an arm or a leg, depending on the part of the
brain that is affected.
3. There are two main types of stroke:
1. Stroke caused by a blockage in the artery supplying blood to a particular region of the brain (called
cerebral infarction). This is the most common type of stroke.
2. Stroke caused by bleeding within the brain (called intracerebral hemorrhage).
In addition, some people experience brief warning signals that a major stroke is going to happen in the
future. The medical term to describe these symptoms is transient ischemic attack or TIA. Sometimes
called "mini-strokes", TIAs are exactly like a stroke, but they last only a few minutes (or sometimes as
long as an hour) and leave no disability.
In many cases, a stroke will affect only one side of the body:
A stroke that damages the right side of the brain will affect the left side of the body.
A stroke that damages the left side of the brain will affect the right side of the body.
4. 1. Stroke Caused By Blocked Blood Flow
About 85 percent of all strokes happen because not enough blood gets to the brain. Blood
flow stops when an artery carrying blood to the brain becomes blocked. The technical
name for this type of brain attack is cerebral infarction. It is also called ischemic stroke.
"Ischemic" refers to a condition caused by a decreased supply of oxygenated blood to a
body part .The blockage can be caused either by a blood clot that forms in an artery in the
brain, or by a blood clot formed elsewhere in the body that travels through the
bloodstream to the brain. If this clot becomes stuck in an artery in the brain, a stroke can
result. Clots are more likely to form in arteries that are damaged by atherosclerosis, also
called "hardening of the arteries," due to the build up of cholesterol and other thick, rough,
fatty deposits in the arteries.
5. The blockage also can be caused by a small piece of tissue, usually a blood clot, that has travelled
through the bloodstream from elsewhere in the body.
In ischemic stroke, one of two major arteries is usually involved:
The carotid artery (most commonly involved site)
The basilar artery
The carotid arteries start at the aorta (just above the heart) and lead up through the neck,
around the windpipe, and into the brain. The basilar artery is formed at the base of the skull
from the arteries that run up along the spine, and branches off in the brain.
6. 2. Stroke Caused By Bleeding In The Brain( intracerebral hemorrhage)
The other 15 percent of strokes happen when an artery carrying blood to the brain
bursts suddenly. The bursting can happen because of a weak spot in the wall of an
artery called an aneurysm. This type of brain attack is called a hemorrhagic stroke.
Two kinds of stroke are caused by bleeding in the brain:
A subarachnoid hemorrhage occurs when a blood vessel on the brain bursts and
bleeds into the fluid-filled space between the brain and the skull. This type of stroke
can happen at any age.
An intracerebral hemorrhage occurs when an artery bursts inside the brain,
flooding the surrounding brain tissue with blood. This type of stroke is often
associated with high blood pressure.
7. What Are "MiniStrokes"?
A "mini-stroke" is exactly
like a stroke, but it lasts only
a short time and leaves no
disability. The term for this
event is transient ischemic
attack or TIA
A TIA happens when a blood clot
clogs an artery temporarily,
cutting off blood flow and,
consequently, the supply of oxygen
to cells. But the difference
between a TIA and a stroke is that,
with TIA, the blood clot dissolves
on its own and blood flow is
restored before permanent
damage to the brain can occur.
8. What Are The Signs Of A Stroke?
The warning signs of stroke are:
Sudden weakness or numbness of the face, arm, and leg on one
side of the body
Sudden loss of vision or dimmed vision, particularly in one eye
Loss of speech, or trouble talking or understanding speech
Sudden, severe headaches with no apparent cause
Unexplained dizziness, unsteadiness, or sudden falls, especially if
accompanied by any of the previous symptoms
Most severe headaches are not a sign of stroke. Migraine, which can
cause quite severe and sometimes alarming headaches, is very
common and affects about one in five people.
9. • Age - The older a person gets, the
The Risk For A
greater the risk of stroke.
Sex - Men are more likely to have
a stroke than women are.
Race - Blacks have a greater risk
of stroke than whites do.
Diabetes- People with diabetes
mellitus are more at risk.
A history of migraine headachesRecent studies indicate that women
who experience migraines are at
higher risk for ischemic stroke
(stroke caused by a blockage in a
A prior stroke -Someone who has
had a stroke has a slightly increased
risk for another.
10. Risk Factors That Can Be Changed With Medical
• High blood pressure- High blood pressure has no warning signs, so regular
blood pressure checks are important. The condition can be easily and
successfully controlled with medication.
• TIAs, or "mini-strokes" - A surprising number of people ignore the
symptoms of TIAs, which are warning signs that a stroke may be about to
happen. But people who have had TIAs can take steps to help prevent a
Berry aneurysms - These are small, sac-like areas within the wall of a
cerebral artery. Some people are born with berry aneurysms. They occur
most often at the junctures of vessels at the base of the brain. Berry
aneurysms may rupture without warning, causing bleeding within the
Cardiovascular disease - Certain disorders of the heart and/or blood
vessels, such as atherosclerosis and atrial fibrillation, can produce blood
clots that may break loose and travel to the brain.
12. 1.Control high blood pressure.
Work closely with your health care provider. Have a healthy
diet, exercise daily, quit smoking, reduce salt intake, and watch
your weight. Check your blood pressure on a normal
13. 2.Control diabetes
Diabetics are at a higher risk of having a stroke. Reduce
your risks of getting diabetes by managing your diet
and exercising regularly to maintain a healthy weight
15. 4.Control high blood cholesterol.
Eat a diet low in saturated fats and cholesterol and high in fiber.
Maintain healthy body weight, and exercise regularly. Have your
cholesterol levels checked every 4-5 years (more often if you know it is
16. 5.Watch the alcohol use.
Overindulgence of alcoholic beverages can increase
the risk of high blood pressure. Drink in moderation
17. 6.Maintain a healthy weight
Eat less, eat healthy foods, and exercise more. If you are
obese or have trouble sticking to a diet, talk to your
doctor. Consult a nutritionist or join a weight loss group
18. 7.Be aware that if you suffer from atrial
(an irregular and rapid heart rhythm) your risk for a stroke
is highly increased. Atrial fibrillation can create clots which
can lead to a stroke. Your doctor can provide you with the
proper care and medication.
19. NICE TO KNOW
Atrial fibrillation is a heart disorder in which the heart beats quickly
and in an irregular manner. As a result, the heart's chambers do not
completely empty themselves of blood. Blood that remains in these
chambers can become stagnant, and clots can form. These clots can
then travel in the bloodstream to the brain and cause a stroke.
Individuals with atrial fibrillation often need to take anticoagulant
drugs ("blood-thinners"). These medications help prevent the
formation of blood clots.
Atherosclerosis is also called "hardening of the arteries." Cholesterol
plaque and other fatty substances build up on the inner walls of
arteries, causing them to narrow. Pieces of plaque from deposits on the
inner walls of arteries can break off and travel throughout the body.
They can cause a stroke if they block blood flow to the brain.
Atherosclerosis can be especially dangerous if it affects the arteries in
the neck, called the carotid arteries, because any clots that might break
off will not have far to travel before reaching the brain.