Stroke (Cerebrovascular Infarction)

Stroke, sometimes called a brain attack, is a general name for a variety of disorders that occur within seconds or minutes when the blood supply to the brain is interrupted. Approximately 700,000 Americans suffer strokes every year. Stroke is the third leading cause of death in the United States, killing approximately 163,000 people each year.

Anyone can have a stroke no matter what age, race or gender. There are some risk factors that you can control by selecting a healthy lifestyle. However, even that is not a guarantee. It is important to be able to recognize the signs of stroke and react immediately to get help. The following will guide you through what you need to know about stroke.

• What are the warning signs of stroke?
• What are the different kinds of strokes?
• Ischemic Stroke and Hemorrhagic Stroke Defined
• Who gets strokes, and how can I reduce my risk?
• Ways to Diagnose Strokes
• What is the treatment for strokes, and what is the prognosis?

^ Top What are the warning signs of stroke?

Warning signs are indications that the brain isn't getting enough oxygen. Call for help immediately if you or someone around you experiences one or more of these signs. 

• Sudden weakness, paralysis or numbness of the face, arm or leg, especially on one side of the body
• Sudden onset of double vision, dimness or loss of vision
• Sudden difficulty speaking or understanding language
• Sudden severe headache without apparent cause
• Unexplained dizziness, unsteadiness or loss of balance, especially in combination with other signs

Sometimes, people will experience stroke symptoms that disappear within a few minutes. These "mini-strokes" - transient ischemic attacks (TIAs) - are caused by temporary interruptions to the blood supply of the brain. TIAs are a risk factor for stroke and shouldn't be ignored. About one-third of people who have a TIA will eventually have a stroke, one-third will continue to experience occasional TIAs, and the final third won't have further symptoms. Your doctor will perform tests to determine the cause of TIAs and treat the problem through surgery or medication, if possible.

^ Top What are the different kinds of strokes?

There are four major types of strokes - two are caused by clots, and two by hemorrhage. The two caused by clots, cerebral thrombosis and cerebral embolism, account for 70 to 80 percent of all strokes. The remaining two, cerebral and subarachnoid hemorrhages, are caused by ruptured blood vessels and have a much higher fatality rate than strokes caused by clots.

• Cerebral thrombosis: Cerebral thrombosis, the most common kind of stroke, occurs when a blood clot forms in an artery, blocking the flow of blood to the brain. A TIA often proceed these types of strokes.
• Cerebral embolism: This type of stroke occurs when a blood clot forms in a distant body part, often the heart, and is carried to one of the major arteries in the brain, where it blocks blood flow. A heart disorder called atrial fibrillation is a risk factor for this kind of stroke.
• Subarachnoid hemorrhage: This type of stroke is caused when a blood vessel on the surface of the brain ruptures, bleeding into the space between the brain and the skull.
• Cerebral hemorrhage: About 10 percent of strokes are cerebral hemorrhages, which occur when an artery in the brain bursts because of a head injury or an aneurysm. An aneurysm is a weak blood vessel that swells out like a balloon - though they're not always dangerous, the artery wall can weaken and burst.

Damage can result from cerebral hemorrhages in two ways - loss of blood supply to the brain and pressure from the accumulated blood. Although this type of stroke has a fairly high fatality rate, those who survive have an especially good chance of full recovery.

^ Top Ischemic Stroke and Hemorrhagic Stroke Defined

Ischemic Stroke—An ischemic stroke, the most common stroke, happens when an artery bringing blood to your brain is completely blocked. Brain tissues die and parts of one side of your body become weak or numb for days or weeks or even permanently.

• Causes of Ischemic Strokes
  • Most are caused by atherosclerosis, the buildup of fatty deposits inside artery walls. Blood clots can form along walls damaged or narrowed by these deposits.
  • Clots also can flow from other areas and get stuck in a narrowed artery.
  • Pieces of plaque can break free and travel to the brain.
• Treatment. Treatment usually begins in the emergency room so doctors can diagnose the type of stroke you are having. You may be given drugs to dissolve a possible clot. If your brain swells (edema) from blood leaking from damaged vessels, you may receive medications to reduce this swelling. Once a patient becomes stable, doctors may prescribe medications to improve blood flow to the brain over the long-term.
  • Aspirin
  • Other medications
  • Anticoagulants (blood thinners)

Hemorrhagic Stroke—Hemorrhagic Stroke is a stroke that results from an artery rupturing in the brain, causing tissues in that area to die. While less common than ischemic strokes, this stroke usually is more severe.

• Types of Hemorrhagic Strokes
  • Aneurysms. A weakened part of a blood vessel ruptures.
  • Subarachnoid hemorrhage. Blood leaks between the brain and the skull wall.
  • Intracerebral hemorrhage. Bleeding occurs deep within the brain
• Hemorrhagic Stroke Symptoms
  • A sudden, extremely severe headache is main symptom
  • Weakness
  • Dizziness
  • Confusion
  • Extreme sensitivity to light
  • Stiff neck
  • Paralysis or unconsciousness in severe cases
• Diagnosis—Doctors use symptoms, CT scans and a test called a lumbar puncture (tests to find blood in the spinal cord fluid) to determine if it is a hemorrhagic stroke.
• Treatment—Limiting brain damage is the primary treatment goal for hemorrhagic stroke. Monitoring blood pressure and draining blood from the brain to reduce swelling and prevent damage are two priorities. A subarachnoid hemorrhage requires immediate surgery to repair the ruptured vessel.
• Results—The effects of a stroke vary among individuals, depending on the area of the brain affected and severity of the stroke. Common effects include the following.
  • Vision difficulties
  • Speech difficulties
  • Paralysis in parts of the body
  • Loss of consciousness
• Recovery—Most people can resume many of their usual activities once they go home from the hospital. About 20 percent of people who have strokes continue to need help with some tasks; another 15 percent become dependent on others. Stroke patients can benefit from
  • Physical therapy. Keep joints of paralyzed limbs flexible.
  • Occupational therapy. Teaches ways to adapt to new tasks.
  • Speech therapy. Helps with speaking and understanding of language, including learning new ways to communicate.
  • Support groups. Can help with recovery, learning new behaviors, and countering depression.

UT Medical Center’s Rehabilitation Services offers each of these recovery methods/tools.

^ Top Who gets strokes, and how can I reduce my risk?

Anyone, no matter what age, race or sex, can experience a stroke. However, stroke is much more likely to occur with age. After age 35, your risk of having a stroke doubles every 10 years. Five percent of the population older than 65 has had some form of stroke.

The death rate from stroke among African-Americans is almost twice that of white Americans. There is no clear explanation for this, but researchers are evaluating risk factors in minority groups to discover why. You can reduce your risk of stroke by doing the following.

• Control high blood pressure. It is estimated that 70 percent of all strokes occur in people with high blood pressure. Ways to decrease your blood pressure include cutting back on salt, exercising regularly and losing weight. Your doctor may prescribe medications to reduce blood pressure—if so, it is important to take them as directed.
• Stop smoking. Reduced stroke risk is among the many health benefits of quitting smoking. Cigarette smoking has been linked to the build-up of fatty substances in the carotid artery, which supplies blood to the brain—blockage of this artery is the leading cause of stroke among Americans. Plus, substances in cigarette smoke such as nicotine and carbon monoxide increase blood pressure, make blood more likely to clot and reduce the amount of oxygen the blood can carry to the brain.
• Control diabetes. Diabetes is a disorder affecting the body’s ability to process sugar. It also can cause blood vessel damage throughout the body, including the brain, and if blood sugar levels are high at the time of a stroke, then brain damage often is more severe. Keeping diabetes under control can help delay or prevent complications that increase stroke risk.
• Treat heart disease. Many common heart disorders, including valvular heart disease, recent heart attack, irregular heartbeat and atherosclerosis, can contribute to your stroke risk. Your doctor will treat the heart disease and may prescribe medicine, often aspirin, to help prevent blood clot formation.
• Seek immediate treatment for transient ischemic attacks. Transient ischemic attacks (TIAs) are caused by temporary interruptions to the blood supply of the brain. TIA symptoms are similar to stroke symptoms, but last only a few minutes before disappearing completely. TIAs are a risk factor for stroke, so they should not be ignored.

Some patients may be treated with medication alone. Others may undergo a type of test called cerebral arteriography, which maps the blood supply to the brain so that doctors can see where the blockage is occurring. The test can provide important information on whether to treat TIAs or stroke with surgery to remove the blockage. One type of surgery for TIAs is called carotid endarterectomy in which doctors remove plaque from the carotid artery to improve blood supply to the brain.

^ Top Ways to Diagnose Strokes

• Computed tomography or CT scan is the best way to determine if a stroke was caused by a ruptured artery. A CT scan also can show the location and size of a damaged area. Magnetic resonance imaging (MRI) is similar to a CT scan, but instead of using X-rays, it uses a magnetic field to create a signal that a computer can translate into a message. MRIs can diagnose strokes caused by blockages or ruptures.
• Carotid ultrasound uses sound waves to find the location and extent of blockages in the carotid arteries in your neck. These arteries supply blood to your brain, so a clot in one of them can cause a stroke.
• Cerebral angiography. If an ultrasound finds a blocked carotid artery, cerebral angiography is used to get more information. This procedure produces an image of the arteries in your brain and your neck so your doctor knows the location and extent of blockages in these areas. Doctors can also diagnose blood vessel abnormalities.
• Carotid endarterectomy. Removes plaque from the artery.

^ Top What is the treatment for strokes, and what is the prognosis?

Acute care for people who have just suffered a stroke often includes life-support equipment to supply oxygen, nutrients and medications. Unfortunately, there is no way to “cure” brain damage caused by a stroke. The main goal of acute care is to help the patient survive by preventing another stroke and taking care of any other medical problems. The doctor may prescribe drugs (anticoagulants) that decrease the blood’s clotting ability.

Most patients begin to spontaneously recover from their strokes, slowly regaining lost abilities. This process usually is fastest during the first few weeks, but patients may continue to improve for a long time.

The prognosis for every stroke patient is different, depending on where in the brain the stroke occurs, how much damage is sustained and the patient’s overall health. Some patients will make a complete or nearly complete recovery. Others are disabled through the loss or partial loss of speaking ability or memory, while others suffer permanent paralysis or weakness.

After a stroke, rehabilitation is vital to help the patient recover as quickly and completely as possible. Many decisions about which kind of rehabilitation program is necessary are made by the physician, family and patient before the patient is released from acute care. Rehabilitation programs and services commonly include physical, occupational and recreational therapy customized to each individual patient.

Treatments for stroke vary depending on the type of stroke, health of the patient and rehabilitation needs, etc. UT Medical Center’s Brain and Spine Institute offers many services and procedures to help stroke patients fully or partially recover from stroke damage.