Brain Strokes

What is a brain stroke ?

How does it happen ?

And why ?

Here are some information i collected for you from different source .

Stroke is a disease that affects the blood vessels that supply blood to the brain.
What causes a stroke?


A stroke occurs when a blood vessel that brings oxygen and nutrients to the brain either bursts (hemorrhagic stroke) or is clogged by a blood clot or some other mass (ischemic stroke). When a rupture or blockage occurs, parts of the brain don't get the blood and oxygen they need. Without oxygen, nerve cells in the affected area of the brain can't work properly, and die within minutes (usually 3 to 4 minutes). And when nerve cells can't work, the part of the body they control can't work either. The devastating effects of a severe stroke are often permanent because dead brain cells aren't replaced.


Types of Stroke?
There are two main types of stroke. One (ischemic stroke) is caused by blockage of a blood vessel; the other (hemorrhagic stroke) is caused by bleeding.
Bleeding strokes have a much higher death rate than strokes caused by clots.



What is ischemic stroke?
Ischemic stroke is the most common type. It accounts for about 87 percent of all strokes. It occurs when a blood clot (thrombus) forms and blocks blood flow in an artery bringing blood to part of the brain. Blood clots usually form in arteries damaged by fatty buildups, called atherosclerosis.
When the blood clot forms within an artery of the brain, it's called a thrombotic stroke. These often occur at night or first thing in the morning. Another distinguishing feature is that very often they're preceded by a transient ischemic attack. This is also called a TIA or "warning stroke." TIAs have the same symptoms of stroke but only last a few minutes; stroke symptoms last much longer and are often permanent. If someones experiences a TIA, they should urgent medical care immediately.
What is a cerebral embolism?
A wandering clot (an embolus) or some other particle that forms away from the brain, usually in the heart, may also cause an ischemic stroke. This is called cerebral embolism. The clot is carried by the bloodstream until it lodges in an artery leading to or in the brain, blocking the flow of blood.
The most common cause of these emboli is blood clots that form during atrial fibrillation (AF). AF is a disorder found in about 2.2 million Americans. It's responsible for 15–20 percent of all strokes. In AF, the heart's two small upper chambers (the atria) quiver like a bowl of jello instead of beating strongly and effectively. Some blood isn't pumped completely out of them when the heart beats, so it pools and clots can form. When a blood clot enters the circulation and lodges in a narrowed artery of the brain, a stroke occurs. This is called a cardioembolic stroke, or a stroke that occurs because of a heart problem.
What is hemorrhagic stroke?
There are two types of cerebral hemorrhages, subarachnoid hemorrhage and intracerebral hemorrhage. A subarachnoid hemorrhage occurs when a blood vessel on the brain's surface ruptures and bleeds into the space between the brain and the skull (but not into the brain itself).
A cerebral hemorrhage occurs when a diseased artery (usually a very small one) in the brain bursts, flooding the surrounding tissue with blood.
Hemorrhage (or bleeding) from an artery in the brain can be caused by the bursting of a small blood vessel or a ruptured aneurysm. Aneurysms are blood-filled pouches that balloon out from weak spots in the artery wall. They're often caused or made worse by high blood pressure. Aneurysms aren't always dangerous, but if one bursts in the brain, they cause a hemorrhagic stroke.
When an intracerebral hemorrhage occurs, the loss of a constant blood supply means some brain cells no longer can work. Accumulated blood from the burst artery also may put pressure on surrounding brain tissue and interfere with how the brain works. Severe or mild symptoms can result, depending on the amount of pressure.
The amount of bleeding determines the severity of intracerebral hemorrhages. In many cases, people with intracerebral hemorrhages die of increased pressure on their brains. But those who live tend to recover much more than people who've had strokes caused by a clot. That's because when a blood vessel is blocked, part of the brain dies — and the brain doesn't regenerate itself; in other words, brain cells can't be replaced. But when a blood vessel in the brain bursts, pressure from the blood compresses part of the brain. If the person survives, gradually the pressure goes away. Then the brain may regain some of its former function.

What are stroke symptoms?

When brain cells are deprived of oxygen, they cease to perform their usual tasks. The symptoms that follow a stroke depend on the area of the brain that has been affected and the amount of brain tissue damage.
Small strokes may not cause any symptoms, but can still damage brain tissue. These strokes that do not cause symptoms are referred to as silent strokes. According to The U.S. National Institute of Neurological Disorders and Stroke (NINDS), these are the five major signs of stroke:

1. Sudden numbness or weakness of the face, arm or leg, especially on one side of the body. The loss of voluntary movement and/or sensation may be complete or partial. There may also be an associated tingling sensation in the affected area.
2. Sudden confusion or trouble speaking or understanding. Sometimes weakness in the muscles of the face can cause drooling.
3. Sudden trouble seeing in one or both eyes
4. Sudden trouble walking, dizziness, loss of balance or coordination
5. Sudden, severe headache with no known cause

10 Risk Factors for Stroke

Ten simple and modifiable risk factors for stroke, including high blood pressure and smoking,comprise 90% of a person's risk, a study shows.

The findings from the INTERSTROKE study are published in The Lancet.

High blood pressure was the leading risk factor for all types of stroke, the study shows.
"Our findings suggest that ten simple risk factors are associated with the 90% of the risk of ischemic and intracerebreal hemorrhagic stroke worldwide," the study researchers conclude."Targeted interventions that reduce blood pressure and smoking, and promote physical activityand a healthy heart, could substantially reduce the global burden of stroke."
There are two main types of stroke: an ischemic stroke occurs when blood flow to the brain is blocked; a hemorrhagic or bleeding stroke occurs when a diseased artery within the brain bursts, allowing blood to leak into the brain.
The new study compared risk factors among 3,000 people who had a stroke to those of 3,000 age- and sex-matched individuals who did not have a stroke. Study participants came from 22 countries.
The 10 risk factors that account for 90% of stroke risk are:

• History of high blood pressure
• Current Smoking
• Abdominal obesity
• Diabetes
• Lack of physical activity
• Poor diet
• More than 30 drinks per month or binge drinking
• Ratio of blood fats known as apolipoprotein B (apo B) to apolipoprotein AI (apo AI)
• Heart disease
• Psychosocial stress/depression

While all of these risk factors were associated with an increased risk for ischemic stroke, just high blood pressure, smoking, abdominal obesity and diet increased the risk of hemorrhagic stroke, the study shows. Nine of these risk factors were also associated with heart attack in a related study on heart risks.
In an accompanying editorial, Jack V Tu, MD, PhD, of the Sunnybrook Schulich Heart Centre at the University of Toronto, writes that these important findings should help to inform stroke prevention strategies around the world and to reduce the global burden of stroke."


Do You Know Your Stroke Risk?

Some of the most important risk factors for stroke can be determined during a physical exam at your doctor's office. If you are over 55 years old, the worksheet below can help you estimate your risk of stroke and show the benefit of risk-factor control.

The worksheet was developed from NINDS-supported work in the well-known Framingham Study. Working with your doctor, you can develop a strategy to lower your risk to average or even below average for your age.

Score your stroke risk for the next 10 years-MEN

Key: SBP = systolic blood pressure (score one line only, untreated or treated); ; Diabetes = history of diabetes; Cigarettes = smokes cigarettes; CVD (cardiovascular disease) = history of heart disease; AF = history of atrial fibrillation; LVH = diagnosis of left ventricular hypertrophy

Points	0	+1	+2	+3	+4	+5	+6	+7	+8	+9	+10
Age	55-56	57-59	60-62	63-65	66-68	69-72	73-75	76-78	79-81	83-84	85
SBP-untrd	97-105	106-115	116-125	126-135	136-145	146-155	156-165	166-175	176-185	186-195	196-205
or SBP-trtd	97-105	106-112	113-117	118-123	124-129	130-135	136-142	143-150	151-161	162-176	177-205
Diabetes	No		Yes
Cigarettes	No			Yes
CVD	No				Yes
AF	No				Yes
LVH	No					Yes

Your Points	10-Year Probability
1	3%
2	3%
3	4%
4	4%
5	5%
6	5%
7	6%
8	7%
9	8%
10	10%
11	11%
12	13%
13	15%
14	17%
15	20%
16	22%
17	26%
18	29%
19	33%
20	37%
21	42%
22	47%
23	52%
24	57%
25	63%
26	68%
27	74%
28	79%
29	84%
30	88%

Compare with Your Age Group	Average 10-Year Probability of Stroke
55-59	5.9%
60-64	7.8%
65-69	11.0%
70-74	13.7%
75-79	18.0%
80-84	22.3%

Score your stroke risk for the next 10 years-WOMEN

Key: SBP = systolic blood pressure (score one line only, untreated or treated); ; Diabetes = history of diabetes; Cigarettes = smokes cigarettes; CVD (cardiovascular disease) = history of heart disease; AF = history of atrial fibrillation; LVH = diagnosis of left ventricular hypertrophy

Points	0	+1	+2	+3	+4	+5	+6	+7	+8	+9	+10
Age	55-56	57-59	60-62	63-64	65-67	68-70	71-73	74-76	77-78	79-81	82-84
SBP-untrd		95-106	107-118	119-130	131-143	144-155	156-167	168-180	181-192	193-204	205-216
or SBP-trtd		95-106	107-113	114-119	120-125	126-131	132-139	140-148	149-160	161-204	205-216
Diabetes	No			Yes
Cigarettes	No			Yes
CVD	No		Yes
AF	No						Yes
LVH	No				Yes

Your Points	10-Year Probability
1	1%
2	1%
3	2%
4	2%
5	2%
6	3%
7	4%
8	4%
9	5%
10	6%
11	8%
12	9%
13	11%
14	13%
15	16%
16	19%
17	23%
18	27%
19	32%
20	37%
21	43%
22	50%
23	57%
24	64%
25	71%
26	78%
27	84%

Compare with Your Age Group	Average 10-Year Probability of Stroke
55-59	3.0%
60-64	4.7%
65-69	7.2%
70-74	10.9%
75-79	15.5%
80-84	23.9%

Many risk factors for stroke can be managed, some very successfully. Although risk is never zero at any age, by starting early and controlling your risk factors you can lower your risk of death or disability from stroke. With good control, the risk of stroke in most age groups can be kept below that for accidental injury or death.

Americans have shown that stroke is preventable and treatable. In recent years, a better understanding of the causes of stroke has helped Americans make lifestyle changes that have cut the stroke death rate nearly in half.

Scientists at the NINDS predict that, with continued attention to reducing the risks of stroke and by using currently available therapies and developing new ones, Americans should be able to prevent 80 percent of all strokes.

CT scan slice of the brain showing a right-hemispheric ischemic stroke (left side of image).



CT scan showing an intracerebral hemorrhage with associated intraventricular hemorrhage.



A slice of brain from the autopsy of a person who suffered an acute middle cerebral artery (MCA) stroke



Head CT showing deep intracerebral hemorrhage due to bleeding within the cerebellum, approximately 30 hours old.


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May God Saves you all and keeps you away from harm's way.Amen