Stroke

A stroke is the sudden death of brain cells due to a problem with the blood supply. When blood flow to the brain is impaired, oxygen and important nutrients cannot be delivered. The result is abnormal brain function. Blood flow to the brain can be disrupted by either a blockage or rupture of an artery to the brain. A stroke is also referred to as a cerebrovascular accident or CVA.

Signs and Symptoms

The specific abilities that will be lost or affected by the stroke depend on the extent of the cell death and where in the brain the stroke happened.
The brain is divided into four primary parts: the right hemisphere, the left hemisphere, the cerebellum and the brain stem.
The right hemisphere controls:

• left side of the body,
• analytical and perceptual tasks such as judging distance, size, speed, position,
• short-term memory

The left hemisphere controls:

• right side of the body,
• speech and language,
• memory,
  

The cerebellum controls: balance and coordination

The brain stem controls:life-support functions such as breathing, blood pressure and heartbeat,eye movements,hearing,speech,swallowing
Depending on the severity of the stroke, victims may or may not experience any or all losses of the above functions.

It's important to know the signs and symptoms of a stroke so that you or someone you know can get prompt treatment. The most common signs and symptoms include:

• Sudden numbness, weakness, or paralysis of the face, arm or leg — usually on one side of the body
  
• Loss of speech, or trouble talking or understanding speech (aphasia)
  
• Sudden blurred, double or decreased vision
  
• Dizziness, loss of balance or loss of coordination
  
• A sudden, severe "bolt out of the blue" headache or an unusual headache, which may be accompanied by a stiff neck, facial pain, pain between the eyes, vomiting or altered consciousness
  
• Confusion, or problems with memory, spatial orientation or perception
  

For most people, a stroke gives no warning. But one possible sign of an impending stroke is a transient ischemic attack (TIA). A TIA is a temporary interruption of blood flow to a part of your brain. The signs and symptoms of TIA are the same as for a stroke, but they appear for a shorter period — several minutes to 24 hours — and then disappear, without leaving apparent permanent effects. You may have more than one TIA, and the recurrent signs and symptoms may be similar or different. A TIA indicates a serious underlying risk that a full-blown stroke may follow. People who have had a TIA are nine times as likely to have a stroke as are those who haven't had a TIA.

More about Stroke

Causes

A stroke is sometimes called a brain attack. It's caused by a problem with the amount of blood in the brain. One type of stroke — ischemic stroke — is caused by too little blood in the brain. The other main type of stroke — hemorrhagic stroke — is caused by too much blood within the brain cavity.

There are two broad categories of strokes, called ischemic stroke or hemorrhagic stroke.

Ischemic stroke is caused by a blockage of a blood vessel in the brain or neck. This stroke can stem from three different conditions: thrombosis, embolism or stenosis:

• Thrombosis (cerebral thrombosis) is the formation of a clot within a blood vessel of the brain or neck and is usually caused by atherosclerotic plaque build-up.
• Embolism (cerebral embolism) is the movement of a clot from another part of body to the brain or neck. These clots can form on artificial valves in the heart, on atherosclerotic plaques in aorta or caused from a condition called atrial fibrillation. Atrial fibrillation is an irregular heartbeat whereby the upper chamber of the heart quivers rapidly rather than beats. Because this quivering motion is not forceful enough to send all the blood to the heart's lower chambers, the blood pools, thus allowing clots to develop.
• Stenosis is a severe narrowing of an artery in or leading to the brain. Roughly 2/3 of all strokes are caused by clots.
  

Hemorrhagic stroke is the bleeding into the brain or the spaces surrounding the brain which is caused by a number of disorders that affect the blood vessels (i.e., high blood pressure and cerebral aneurysm).

There are two types of hemorrhagic stroke: subarachnoid and intracerebral.

• Subarachnoid hemorrhage is caused by the rupture of a blood vessel on the surface of the brain so that blood fills the space between the brain and the skull.
• An intracerebral hemorrhage is caused by the rupture of a blood vessel within the brain itself.
  

Risk Factors

• Age -- The older a person gets, the greater the risk of stroke.
• Sex -- Men are more likely to have a stroke than women. But after menopause, a woman's risk of stroke rises significantly.
• Family history – Having a parent, grandparent, or sibling who has had a stroke, puts you at greater risk yourself.
• Race -- African Americans have a greater risk of stroke than Caucasians. This is related to an increased risk of high blood pressure, obesity, and diabetes in African Americans.
• Heart attack – If you have had a heart attack in the past, you are more likely to have a stroke than someone who has not had a heart attack.
• A history of migraine headaches -- Recent studies indicate that people who experience migraines may be at higher risk for ischemic stroke.
• A prior stroke -- If you have had a stroke, you are at increased risk for another.
• Sickle cell anemia – people with this condition are at risk for stroke at a younger age.
• Berry aneurysms -- These are small, sac-like areas within the wall of an artery in the brain with which some people are born. 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 brain.
• Use of birth control pills.
• Elevated homocysteine level.
• Diabetes.
• Cigarette smoking.
  

Diagnosis

If you've had a previous stroke or TIA or think you're at risk of stroke, talk with your doctor about screening and diagnostic tests.

Before treating a stroke, your doctor must diagnose the type of stroke and its location. Other possible causes of your symptoms, such as a tumor, also need to be excluded.

The following are most often used as screening tools to determine your risk, but they may also be used as diagnostic tools if you're having a stroke:

• Physical examination and tests. Your doctor may check for risk factors of stroke, including high blood pressure, high cholesterol levels, diabetes and elevated levels of the amino acid homocysteine. Your doctor may also use a stethoscope to listen for a whooshing sound (bruit) over your arteries that may indicate atherosclerosis.
• Carotid ultrasonography. In this procedure, a wand-like device (transducer) sends high-frequency sound waves into your neck. The sound waves pass through tissue and then return, creating on-screen images that delineate any narrowing or clotting in your carotid arteries.
• Magnetic resonance imaging (MRI). Using a strong magnetic field, an MRI can generate a three-dimensional view of your brain. This test is sensitive for detecting an area of brain tissue damaged by an ischemic stroke. Magnetic resonance angiography (MRA) uses this magnetic field and a dye injected into your veins to evaluate arteries in your neck and brain.
• Echocardiography. Your doctor can use this ultrasound technology to compose images of your heart. He or she may also use transesophageal echocardiography (TEE) to create clear and detailed ultrasound images with a better view of some things, such as blood clots, that might not be clearly visible on a traditional.

Treatment Approach

A person suffering symptoms consistent with a stroke should be taken immediately to a hospital emergency department.
The ability to quickly pinpoint the type of stroke is critically important in treatment decisions. A stroke caused by a blocked artery is treated in an entirely different way than a stroke caused by bleeding within the brain.

The key to survival and recovery is prompt medical treatment.

Surgical and other procedures. Your doctor may recommend a procedure to open up an artery that's moderately to severely narrowed by plaques. This may include:

• Carotid endarterectomy
• Angioplasty
• Other techniques

Preventive medications. If you've had an ischemic stroke, it's important to determine why the stroke occurred and to prevent another. Your doctor may recommend medications to help reduce your risk of having a TIA or stroke. These include:

• Anti-platelet drugs
• Anticoagulants

Medications

Stroke Medications

• Plavix