Stroke

A stroke is a condition in which the brain cells suddenly die because of a lack of oxygen.

A stroke can be caused by an obstruction in the blood flow, or the rupture of an artery that feeds the brain.

The patient may suddenly lose the ability to speak, there may be memory problems, or one side of the body can become paralyzed.

This Medical News Today information article provides details on the two types of stroke, who are at risk, what its causes are, its symptoms, how a stroke is treated, and how strokes can be prevented.

The two main types of stroke
The two main types of stroke include ischemic stroke and hemorrhagic stroke.

Ischemic stroke
Ischemic stroke accounts for about 87 percent of all strokes and occurs when a blood clot, or thrombus, forms that blocks blood flow to part of the brain.

If a blood clot forms somewhere in the body and breaks off to become free-floating, it is called an embolus. This wandering clot may be carried through the bloodstream to the brain where it can cause ischemic stroke.

Hemorrhagic stroke
A hemorrhagic stroke occurs when a blood vessel on the brain's surface ruptures and fills the space between the brain and skull with blood (subarachnoid hemorrhage) or when a defective artery in the brain bursts and
fills the surrounding tissue with blood (cerebral hemorrhage).

Both types of stroke result in a lack of blood flow to the brain and a buildup of blood that puts too much pressure on the brain. 

The outcome after a stroke depends on where the stroke occurs and how much of the brain is affected. Smaller strokes may result in minor problems, such as weakness in an arm or leg. Major strokes may lead to paralysis or death. Many stroke patients are left with weakness on one side of the body, difficulty speaking, incontinence, and bladder problems.

Who gets stroke?
Anyone can suffer from stroke. Although many risk factors are out of our control, several can be kept in line through proper nutrition and medical care.

Risk factors for stroke include the following:
 Age - as you get older your risk increases.
• Being male.
• A family history of stroke.
• High blood pressure
• High cholesterol
• Smoking cigarettes.
• Diabetes
• Obesity and overweight.
• A previous stroke or transient ischemic attack (TIA).
• High levels of homocysteine (an amino acid in blood).
• Divorced men have a higher risk of stroke

Heavy use of alcohol
Researchers from the University of Lille Nord de France, Lille, France, reported in the journal Neurology that heavy regular drinkers have a considerably higher risk of stroke early in life compared to others.

Depression

Middle-aged women with clinical depression have a higher risk of stroke, researchers from the University of Queensland, Australia, reported in the journal Stroke.
 
The authors gathered data on 10,547 Australian females aged from 47 to 52 years. They found that women with depression are more likely to have a stroke by a factor of 2.4, compared to women without depression.

Even after taking into account known stroke risk factors, depressed middle-aged women were still 1.9 times more likely to have a stroke.

Caroline Jackson, Ph.D., said "When treating women, doctors need to recognize the serious nature of poor mental
health and what effects it can have in the long term. Current guidelines for stroke prevention tend to overlook the potential role of  depression."

The researchers emphasized that although the risk was higher for women with depression, their total risk of stroke was still low.

What causes stroke?
Ischemic strokes are ultimately caused by a thrombus or embolus that blocks blood flow to the brain. Blood clots (thrombus clots) usually occur in areas of the arteries that have been damaged by atherosclerosis from a buildup of plaques.

Embolus type blood clots are often caused by atrial fibrillation - an irregular pattern of heart beat that leads to
blood clot formation and poor blood flow.

Hemorrhagic strokes can be caused by uncontrolled high blood pressure, a head injury, or aneurysms.  High blood pressure is the most common cause of cerebral hemorrhage, as it causes small arteries inside the brain to burst.10 This deprives brain cells of blood and dangerously increases pressure on the brain.

Aneurysms - abnormal blood-filled pouches that balloon out from weak spots in the wall of an artery - are the most common cause of subarachnoid hemorrhage. If an aneurysm ruptures, blood spills into the space between the surfaces of the brain and skull, and blood vessels in the brain may spasm. Aneurysms are often caused or made worse by high blood pressure.

A study published in the American Journal of Human Genetics found a single gene defect can lead to stroke and deadly diseases of the aorta and coronary arteries.

A less common form of hemorrhage stroke is when an arteriovenous malformation (AVM) ruptures. AVM is an abnormal tangle of thin-walled blood vessels that is present at birth.

What are the symptoms of stroke?
Within a few minutes of having a stroke brain cells begin to die and symptoms emerge. It is important to recognize the symptoms, as prompt treatment is crucial to recovery.

Common symptoms include:

• Trouble walking, loss of balance and coordination.
• Speech problems.
• Dizziness.
• Numbness, weakness, or paralysis.
• Blurred, blackened, or double vision
• Sudden severe headache
• Confusion.

Smaller strokes (or silent strokes), however, may not cause any symptoms, but can still damage brain tissue.

A transient ischemic attack (TIA) may be a sign of an impending stroke - TIA is a temporary interruption in blood flow to part of the brain. Symptoms of TIA are similar to stroke but last for a shorter period and do not leave noticeable permanent damage.