Stroke / Brain Attack
Stroke, also called brain attack, occurs when blood flow to the brain is disrupted. Disruption in blood flow is caused when either a blood clot blocks one of the vital blood vessels in the brain (ischemic stroke), or when a blood vessel in the brain bursts, spilling blood into surrounding tissues (hemorrhagic stroke).
The brain needs a constant supply of oxygen and nutrients in order to function. Even a brief interruption in blood supply can cause problems. Brain cells begin to die after just a few minutes without blood or oxygen. The area of dead cells in tissues is called an infarct. Due to both the physical and chemical changes that occur in the brain with stroke, damage can continue to occur for several days. This is called a stroke-in-evolution.
A loss of brain function occurs with brain cell death. This may include impaired ability with movement, speech, thinking and memory, bowel and bladder, eating, emotional control, and other vital body functions. Recovery from stroke and the specific ability affected depends on the size and location of the stroke. A small stroke may result in problems such as weakness in an arm or leg. Larger strokes may cause paralysis (inability to move part of the body), loss of speech, or even death.
According to the National Stroke Association (NSA), it is important to learn the three R's of stroke:
- Reduce the risk
- Recognize the symptoms
- Respond by calling 911 (or your local ambulance service)
Stroke is an emergency and should be treated as such. The greatest chance for recovery from stroke occurs when emergency treatment is started immediately.
Stroke is the third largest cause of death, ranking behind diseases of the heart and all forms of cancer. Strokes kill more than 144,000 Americans each year. Almost 80 percent of strokes are preventable.
The following are the most common symptoms of stroke. However, each individual may experience symptoms differently. If any of these symptoms are present, call 911 (or your local ambulance service) immediately. Treatment is most effective when started immediately.
Symptoms may be sudden and include:
- Weakness or numbness of the face, arm, or leg, especially on one side of the body
- Confusion or difficulty speaking or understanding
- Problems with vision such as dimness or loss of vision in one or both eyes
- Dizziness or problems with balance or coordination
- Problems with movement or walking
- Severe headaches with no other known cause
All of the above warning signs may not occur with each stroke. Do not ignore any of the warning signs, even if they go away - take action immediately. The symptoms of stroke may resemble other medical conditions or problems. Always consult your physician for a diagnosis.
Other, less common, symptoms of stroke may include the following:
- Sudden nausea, vomiting, or fever not caused by a viral illness
- Brief loss or change of consciousness such as fainting, confusion, seizures, or coma
- Transient ischemic attack (TIA), or "mini-stroke"
A TIA can cause many of the same symptoms as a stroke, but TIA symptoms are transient and last for a few minutes or up to 24 hours. Call for medical help immediately if you suspect a person is having a TIA, as it may be a warning sign that a stroke is about to occur. Not all strokes, however, are preceded by TIAs.
Evaluating the risk for stroke is based on heredity, natural processes, and lifestyle. Many risk factors for stroke can be changed or managed, while others that relate to hereditary or natural processes cannot be changed.
|Risk factors for stroke that can be changed, treated, or medically managed:
- High blood pressure
The most important controllable risk factor for stroke (brain attack) is controlling high blood pressure (140/90 or higher). High blood pressure can damage blood vessels called arteries that supply blood to the brain. According to the Centers for Disease Control and Prevention (CDC), reducing the systolic (or top number) blood pressure by 12 to 13 points can decrease the risk for a stroke by 37 percent.
- Heart disease
Heart disease is the second most important risk factor for stroke, and the major cause of death among survivors of stroke. Heart disease and stroke have many of the same risk factors.
- Diabetes mellitus
Diabetes is controllable, but having it increases the risk for stroke. People with diabetes have two to four times the risk of having a stroke than someone without diabetes. Blood pressure for people with diabetes should be 130/80 or less to reduce the risk of stroke. Talk with your healthcare provider on specific ways to manage your overall health and diabetes care.
- Cigarette smoking
Apart from other risk factors, smoking almost doubles the risk for ischemic stroke (blockage of a blood vessel supplying blood to the brain). The use of oral contraceptives, especially when combined with cigarette smoking, greatly increases stroke risk.
- History of transient ischemic attacks (TIAs)
A person who has had one (or more) TIA is almost 10 times more likely to have a stroke than someone of the same age and sex who has not had a TIA.
- High red blood cell count
A significant increase in the number of red blood cells thickens the blood and makes clots more likely, thus increasing the risk for stroke.
- High blood cholesterol and lipids
High blood cholesterol and lipids increase the risk for stroke. High cholesterol levels can contribute to atherosclerosis (thickening or hardening of the arteries) caused by a build-up of plaque (deposits of fatty substances, cholesterol, calcium). Plaque build-up on the inside of the walls of arteries can decrease the amount of blood flow to the brain. A stroke occurs if the blood supply is cut off to the brain. Atherosclerosis is a slow, progressive disease that may start as early as childhood.
- Lack of exercise, physical inactivity
Lack of exercise and physical inactivity increases the risk for stroke.
Excess weight increases the risk for stroke.
- Excessive alcohol use
More than two drinks per day raises blood pressure, and binge drinking can lead to stroke.
- Drug abuse (certain kinds)
Intravenous drug abuse carries a high risk of stroke from cerebral embolisms (blood clots). Cocaine use has been closely related to strokes, heart attacks, and a variety of other cardiovascular complications. Some of them, even among first-time cocaine users, have been fatal.
- Abnormal heart rhythm
Various heart diseases have been shown to increase the risk of stroke. Atrial fibrillation (an irregular heartbeat) is the most powerful and treatable heart risk factor of stroke. About 15 percent of strokes occur in people with atrial fibrillation.
- Cardiac structural abnormalities
Damaged heart valves can cause chronic heart damage, which can ultimately increase the risk of developing stroke. This is known as valvular heart disease. New evidence shows that heart structure abnormalities including patent foramen ovale and atrial septal defect may possibly increase risk for embolic stroke.
|Risk factors for stroke that cannot be changed:
For each decade of life after age 55, the chance of having a stroke more than doubles.
Men have about a 19 percent greater chance of stroke than women.
African-Americans have a much higher risk of death and disability from a stroke than Caucasians, in part because the African-American population has a greater incidence of high blood pressure.
- History of prior stroke
The risk of stroke for someone who has already had one is many times that of a person who has not had a stroke.
The chance of stroke is greater in people who have a family history of stroke.
|Other risk factors of stroke to consider:
- Where a person lives
Strokes are more common among people living in the southeastern United States than in other areas. This may be due to regional differences in lifestyle, race, cigarette smoking, and diet.
- Temperature, season, and climate
Stroke deaths occur more often during periods of extreme temperatures.
- Socioeconomic factors
There is some evidence that strokes are more common among low-income people than among more affluent people.
Strokes can be classified into two main categories:
- 87 percent are ischemic strokes - strokes caused by blockage of an artery
- 13 percent are hemorrhagic strokes - strokes caused by bleeding
An ischemic stroke occurs when a blood vessel that supplies the brain becomes blocked or "clogged" and impairs blood flow to part of the brain. The brain cells and tissues begin to die within minutes from lack of oxygen and nutrients. The area of tissue death is called an infarct. About 87 percent of strokes fall into this category. Ischemic strokes are further divided into two groups, including the following:
- Thrombotic strokes - caused by a blood clot that develops in the blood vessels inside the brain
- Embolic strokes - caused by a blood clot or plaque debris that develops elsewhere in the body and then travels to one of the blood vessels in the brain via the bloodstream
Thrombotic strokes are strokes caused by a thrombus (blood clot) that develops in the arteries supplying blood to the brain. This type of stroke is usually seen in older persons, especially those with high-cholesterol levels and atherosclerosis (a build-up of fat and lipids inside the walls of blood vessels).
Sometimes, symptoms of a thrombotic stroke can occur suddenly and often during sleep or in the early morning. At other times, it may occur gradually over a period of hours or even days. This is called a stroke-in-evolution.
Thrombotic strokes may be preceded by one or more "mini-strokes," called transient ischemic attacks, or TIAs. TIAs may last from a few minutes to a few days and are often a warning sign that a stroke may occur. Although usually mild and transient, the symptoms caused by a TIA are similar to those caused by a stroke.
Another type of stroke that occurs in the small blood vessels in the brain is called a lacunar infarct. The word lacunar comes from the Latin word meaning "hole" or "cavity." Lacunar infarctions are often found in people who have diabetes or hypertension (high blood pressure).
Embolic strokes are usually caused by an embolus (a blood clot that forms elsewhere in the body and travels through the bloodstream to the brain). Embolic strokes often result from heart disease or heart surgery and occur rapidly and without any warning signs. About 15 percent of embolic strokes occur in people with atrial fibrillation, a type of abnormal heart rhythm in which the upper chambers of the heart do not beat effectively.
Hemorrhagic strokes occur when a blood vessel that supplies the brain ruptures and bleeds. When an artery bleeds into the brain, brain cells and tissues do not receive oxygen and nutrients. In addition, pressure builds up in surrounding tissues and irritation and swelling occur. About 13 percent of strokes are caused by hemorrhage (10 percent are intracerebral hemorrhage and 3 percent are subarachnoid hemorrhage strokes). Hemorrhagic strokes are divided into two main categories, including the following:
- Intracerebral hemorrhage - bleeding from the blood vessels within the brain
- Subarachnoid hemorrhage - bleeding in the subarachnoid space (the space between the brain and the membranes that cover the brain)
Intracerebral hemorrhage is usually caused by hypertension (high blood pressure), and bleeding occurs suddenly and rapidly. There are usually no warning signs and bleeding can be severe enough to cause coma or death.
Subarachnoid hemorrhage results when bleeding occurs between the brain and the meninges (the membrane that covers the brain) in the subarachnoid space. This type of hemorrhage is often due to an aneurysm or an arteriovenous malformation (AVM).
- An aneurysm is a weakened, ballooned area on an artery wall and has a risk for rupturing. Aneurysms may be congenital (present at birth), or may develop later in life due to such factors as hypertension or atherosclerosis.
- An AVM is a congenital disorder that consists of a disorderly tangled web of arteries and veins. The cause of AVM is unknown.
Recurrent strokes occur in about 25 percent of stroke victims within five years after a first stroke. The risk is greatest right after a stroke and decreases over time. The likelihood of severe disability and death increases with each recurrent stroke. About 3 percent of stroke patients have a second stroke within 30 days of their first stroke, and about one-third have a second stroke within two years.
Treatment is most effective when started immediately. Emergency treatment following a stroke may include the following:
- Medications used to the dissolve blood clot(s) that cause an ischemic stroke
Medications that dissolve clots are called thrombolytic agents and are commonly known as "clot busters." These drugs have the ability to help reduce the damage to brain cells caused by the stroke. In order to be most effective, these agents must be given within several hours of a stroke's onset.
- Medications and therapy to reduce or control brain swelling
Corticosteroids and special types of intravenous (IV) fluids are often used to help reduce or control brain swelling, especially after a hemorrhagic stroke (a stroke caused by bleeding into the brain).
- Medications that help protect the brain from damage and ischemia (lack of oxygen)
Medications of this type are called neuroprotective agents, with some still under investigation in clinical trials.
- Life support measures including such treatments as ventilators (machines to assist with breathing), IV fluids, adequate nutrition, blood pressure control, and prevention of complications
Other medications that may help with recovery following a stroke, or may help to prevent a stroke from occurring, include the following:
- Medications to help prevent more blood clots from forming
Medications that help to prevent additional blood clots from forming are called anticoagulants, as they prevent the coagulation of the blood. Medications of this type include, for example, heparin and warfarin (Coumadin®).
- Medications that reduce the chance of blood clots by preventing platelets (a type of blood cell) from sticking together
Examples of this type of medication include aspirin and dipyridamole (Persantine®).
- Medications to treat existing medical conditions such as diabetes, heart, or blood pressure problems
Several types of surgery may be performed to help treat a stroke, or help to prevent a stroke from occurring, including the following:
- Carotid endarterectomy
Carotid endarterectomy is a procedure used to remove plaque and clots from the carotid arteries, located in the neck. These arteries supply the brain with blood from the heart. Endarterectomy may help prevent a stroke from occurring.
A craniotomy is a type of surgery in the brain itself to remove blood clots or repair bleeding in the brain.
- Surgery to repair aneurysms and arteriovenous malformations (AVMs)
An aneurysm is a weakened, ballooned area on an artery wall that has a risk for rupturing and bleeding into the brain. An AVM is a congenital (present at birth) or acquired disorder that consists of a disorderly, tangled web of arteries and veins. An AVM also has a risk for rupturing and bleeding into the brain. Surgery may be helpful, in this case, to help prevent a stroke from occurring.
- Patent foramen ovale (PFO) closure
The foramen ovale is an opening that occurs in the wall between the two upper chambers of a baby's heart before birth. It functions to provide oxygen-rich blood to the baby from the mother's placenta while in the womb. This opening normally closes soon after birth. If the flap does not close, blood flows from the right atrium directly to the left atrium. It then flows out to the central circulation of the body. If this blood contains any clots or air bubbles, they can pass into the brain circulation causing a stroke or transient ischemic attack (TIA). PFO closure procedure can be performed through a percutaneous (through the skin) approach. Signs and symptoms of a PFO may not occur until early or middle adulthood and may even go undetected.
Many individuals who have a stroke are left with paralysis of the upper extremities. CIT is a treatment that encourages the use of the stroke-affected limb by constraining the non-affected limb in a mitt, sling, splint or glove. Intense exercises are done using the stroke-affected arm or hand.
- CIT restraints are worn for up to 90 percent of the waking hours.
- Restraints can be removed for activities such as bathing.
- Small steps are used to break down complex tasks such as making a phone call.
- Verbal and written feedback is used to help motivate and inform persons undergoing CIT.
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