What is a stroke?
A stroke occurs when the blood supply to the brain is suddenly blocked or when a blood vessel in the brain bursts. Deprived of oxygen, nerve cells in the affected area of the brain can't function and die within minutes.
A person with loss of blood flow to the heart is said to be having a heart attack; similarly, a person with loss of blood flow to the brain or sudden bleeding in the brain can be said to be having a "brain attack."
Although stroke is a disease of the brain, it can affect the entire body, including cognitive and memory deficits, speech problems, emotional difficulties, daily living problems, and pain.
Paralysis is a common outcome of stroke, often on one side of the body (hemiplegia). Paralysis may affect only the face, an arm or a leg, or it may affect one entire side of the body and face.
A person who suffers a stroke in the left hemisphere of the brain will show right-sided paralysis, or paresis. Likewise, a person with a stroke in the right hemisphere will show deficits on the left side of the body.
There are two main types of stroke:
- Ischemic strokes occur as a result of an obstruction (clot) within a blood vessel supplying blood to the brain and account for 87 percent of all stroke episodes.
- Hemorrhagic strokes result from a weakened blood vessel that ruptures and bleeds into the surrounding brain.
Stroke is the nation's fourth leading cause of death and is a leading cause of serious, long-term disability in the United States. Approximately, 4.5 million stroke survivors are alive today.
Risk factors and symptoms
The most important risks for stroke are hypertension, heart disease, diabetes, and cigarette smoking. Others include heavy alcohol consumption, high blood cholesterol levels, illicit drug use, and genetic or congenital conditions, particularly vascular abnormalities.
An increase in the red blood cell count is another risk factor for stroke – excess red blood cells thicken the blood and make clots more likely. Eighty percent of strokes are preventable.
The symptoms of a stroke include:
- Sudden numbness or weakness (especially on one side of the body)
- Confusion or trouble speaking or understanding speech
- Vision impairment in one or both eyes
- Difficulties with walking
- Dizziness or loss of balance or coordination
- Severe headache with no known cause.
Treatment and recovery
Ischemic stroke is treated by removing the obstruction and restoring blood flow to the brain. In hemorrhagic stroke, doctors attempt to prevent the rupture and bleeding of aneurysms and arteriovenous malformations.
When blood flow to the brain is interrupted, some brain cells die immediately, while others remain at risk. The damaged cells can often be saved by early intervention with a clot-dissolving drug called tissue plasminogen activator (t-PA) if administered within three hours of the onset of the stroke.
Unfortunately, only 3 to 5 percent of those who suffer a stroke reach the hospital in time to receive treatment.
The appropriate response to a stroke is emergency action. Every minute lost, from the onset of symptoms to the time of emergency room contact, cuts into the limited window of opportunity for intervention.
Meanwhile, other neuroprotective drugs are being developed to prevent the wave of damage after the initial attack.
The brain often compensates for the damage caused by stroke. Some of the brain cells that do not die may resume functioning. Sometimes, one region of the brain takes over for a region damaged by the stroke. Stroke survivors have experienced remarkable and unanticipated recoveries that can't be explained.
General recovery guidelines show:
- 10 percent of stroke survivors recover almost completely
- 25 percent recover with minor impairments
- 40 percent experience moderate to severe impairments requiring special care
- 10 percent require care in a nursing home or other long-term care
- 15 percent die shortly after the stroke
Rehabilitation starts in the hospital as soon as possible after the stroke. In patients who are stable, rehabilitation may begin within two-days after the stroke has occurred, and should be continued as necessary after release from the hospital.
Rehabilitation options may include the rehab unit of a hospital, a subacute care unit, a rehab hospital, home therapy, outpatient care, or long term care in a nursing facility.
The goal in rehabilitation is to improve function so that the stroke survivor can become as independent as possible. This must be accomplished in a way that preserves dignity while motivating the survivor to relearn basic skills the stroke may have taken away – such as eating, dressing and walking.
Activities may include the following:
- Self-care skills such as feeding, grooming, bathing, and dressing
- Mobility skills such as transferring, walking, or moving a wheelchair
- Communication skills; cognitive skills such as memory or problem-solving
- Social skills for interacting with other people.
Rehabilitation doesn't reverse the effects of a stroke but it does build strength, capability, and confidence so a person can continue daily activities despite the effects of stroke.
Although stroke is a disease of the brain, it can affect the entire body. Some of the disabilities that can result from a stroke include paralysis, cognitive deficits, speech problems, emotional difficulties, daily living problems, and pain.
Stroke may cause problems with thinking, awareness, attention, learning, judgment, and memory. A stroke patient may be unaware of his or her surroundings, or may be unaware of the mental deficits that resulted from the stroke.
Many have problems understanding or forming speech. Language problems usually result from damage to the left temporal and parietal lobes of the brain.
A stroke can lead to emotional problems. Stroke patients may have difficulty controlling their emotions or may express inappropriate emotions in certain situations. One common disability that occurs with many stroke patients is depression – more than a general sadness resulting from the stroke incident.
Some may experience pain, uncomfortable numbness, or strange sensations after a stroke. These sensations may be due to many factors including damage to the sensory regions of the brain, stiff joints, or a disabled limb.
Stroke survivors often find that once-simple tasks around the house become extremely difficult or impossible. Many adaptive devices and techniques are available to help people retain their independence and function safely and easily. The home usually can be modified so the stroke survivor can manage personal needs.
Research advances have led to new therapies and new hope for people who are at risk or who have had a stroke.
When a stroke occurs, some brain cells die immediately; others remain at risk for hours and even days due to an ongoing sequence of destruction. Some damaged cells can be saved by early intervention with drugs.
The search for so-called neuroprotective drugs, ongoing for many years, has been difficult and frustrating, as one drug after another that showed great promise in animal studies and early human trials was found ineffective in large-scale clinical studies.
Meanwhile, the only approved clot-busting treatment, t-PA, is underutilized. New delivery methods and refinements of t-PA are being developed, including intra-arterial t-PA, which is infused into a main artery in the neck or even smaller arteries in the brain for faster, safer delivery.
Here are some of the research developments for treating stroke:
- An enzyme (DSPA) found in saliva from vampire bats may help dissolve blood clots in the brains of stroke survivors.
- Erythropoietin, a hormone produced by the kidney, appears to protect some neurons from executing genetically programmed "cell suicide" missions.
- A protein called fibronectin may protect against serious brain damage from stroke.
- Trials have taken place to see if taking amphetamines for several weeks after a stroke will help kick-start the process of self-repair in the brain.
- For many years, doctors have relied on warfarin, a drug with potentially dangerous side effects (it is also used as rat poison), to reduce the risk of stroke in people at risk for clotting in the heart.
- Cell transplantation has shown some early-trial success in humans who have had a stroke. To be sure, there is great excitement for stem cells as a stroke treatment.
- ReNeuronis recruiting participants to test the safety of a manufactured neural stem cell line delivered by injection into the damaged brains of male patients 60 years of age and older following an ischemic stroke.
- Researchers have reported that transplanted adult stem cells (from bone marrow) restored function in laboratory animals with stroke. Human trials have begun.
Human umbilical cord blood cells have been effective in animal models; trials are underway to test these cells in children with strokes. For information on clinical trials see www.clinicaltrials.gov.
Clinical trial information
Clinical trials have tested the safety and effectiveness of a protein called E-selectin, administered by way of a nasal spray, to prevent the formation of blood clots that could cause stroke.
The National Institute of Neurological Disorders and Stroke (NINDS) has initiated a program called Specialized Programs of Translational Research in Acute Stroke (SPOTRIAS). This is a national network of centers that perform early phase clinical projects, share data, and promote new approaches to therapy for acute stroke.
The network currently includes eight stroke research centers. The goal is to reduce the disability and mortality of stroke survivors by promoting rapid diagnosis and effective interventions.
In the area of stroke rehabilitation, an approach called constraint-induced movement-based therapy (CIT) has improved recovery in people who have lost some function in a single limb. The therapy entails immobilizing a patient's good limb to force use of the weakened limb. CIT is thought to promote a remodeling of nerve pathways, or plasticity.
Resources and support for managing strokes
If you are looking for more information on strokes or have a specific question, our information specialists are available business weekdays, Monday through Friday, toll-free at 800-539-7309 from 9am to 5pm ET.
Additionally, the Reeve Foundation maintains a fact sheet on how to support individuals living with a stroke with additional resources from trusted Reeve Foundation sources. Check out our repository of fact sheets on hundreds of topics ranging from state resources to secondary complications of paralysis. We encourage you to reach out to stroke support groups and organizations, including:
- American Stroke Association (ASA), affiliated with the National Heart Association, features the Stroke Family Support Network, which provides information and support to stroke families at any stage of recovery.
- National Stroke Association (NSA) offers information and support, including publications.
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