What is a Stroke?
A stroke is a sudden interruption in the blood supply of the brain. Most strokes are caused by an abrupt blockage of arteries leading to the brain (ischemic stroke). Other strokes are caused by bleeding into brain tissue when a blood vessel bursts (hemorrhagic stroke).
Because it occurs rapidly and requires immediate treatment, stroke is also called a brain attack. When the symptoms of a stroke last only a short time (less than an hour), this is called a transient ischemic attack (TIA) or mini-stroke.
The effects of a stroke depend on which part of the brain is injured, and how severely it is injured. Strokes may cause sudden weakness, loss of sensation, or difficulty with speaking, seeing, or walking. Since different parts of the brain control different areas and functions, it is usually the area immediately surrounding the stroke that is affected. Sometimes people with stroke have a headache, but stroke can also be completely painless. It is very important to recognize the warning signs of stroke and to get immediate medical attention if they occur.
Types of Stroke
Ischemic Stroke – ThumbnailIschemic Stroke
The most common type of stroke, accounting for almost 80 percent of all strokes, is caused by a clot or other blockage within an artery leading to the brain.
Intracerebral Hemorrhage – ThumbnailIntracerebral Hemorrhage
An intracerebral hemorrhage is a type of stroke caused by the sudden rupture of an artery within the brain. Blood is then released into the brain compressing brain structures.
Subarachnoid Hemorrhage – ThumbnailSubarachnoid Hemorrhage
A subarachnoid hemorrhage is also a type of stroke caused by the sudden rupture of an artery. A subarachnoid hemorrhage differs from intracerebral hemorrhage in that the location of the rupture leads to blood filling the space surrounding the brain rather than inside of it.
What causes a stroke?
The cause of a stroke depends on the type of stroke. The three main types of stroke are a transient ischemic attack (TIA), ischemic stroke, and hemorrhagic stroke. A TIA is caused by a temporary blockage in an artery that leads to the brain. The blockage, typically a blood clot, stops blood from flowing to certain parts of the brain. A TIA typically lasts for a few minutes up to a few hours, and then the blockage moves and blood flow is restored.
Like a TIA, an ischemic stroke is caused by a blockage in an artery that leads to the brain. This blockage may be a blood clot, or it may be caused by atherosclerosis. With this condition, plaque (a fatty substance) builds upon the walls of a blood vessel. A piece of the plaque can break off and lodge in an artery, blocking the flow of blood and causing an ischemic stroke. A hemorrhagic stroke, on the other hand, is caused by a burst or leaking blood vessel. Blood seeps into or around the tissues of the brain, causing pressure and damaging brain cells.
There are two possible causes of a hemorrhagic stroke. An aneurysm (a weakened, bulging section of a blood vessel) can be caused by high blood pressure and can lead to a burst blood vessel. Less often, a condition called an arteriovenous malformation, which is an abnormal connection between your veins and arteries, can lead to bleeding in the brain. Keep reading about the causes of different types of strokes. What causes a stroke? The cause of a stroke depends on the type of stroke. The three main types of stroke are a transient ischemic attack (TIA), ischemic stroke, and hemorrhagic stroke.
A TIA is caused by a temporary blockage in an artery that leads to the brain. The blockage, typically a blood clot, stops blood from flowing to certain parts of the brain. A TIA typically lasts for a few minutes up to a few hours, and then the blockage moves and blood flow is restored. Like a TIA, an ischemic stroke is caused by a blockage in an artery that leads to the brain. This blockage may be a blood clot, or it may be caused by atherosclerosis. With this condition, plaque (a fatty substance) builds upon the walls of a blood vessel.
A piece of the plaque can break off and lodge in an artery, blocking the flow of blood and causing an ischemic stroke. A hemorrhagic stroke, on the other hand, is caused by a burst or leaking blood vessel. Blood seeps into or around the tissues of the brain, causing pressure and damaging brain cells. There are two possible causes of a hemorrhagic stroke. An aneurysm (a weakened, bulging section of a blood vessel) can be caused by high blood pressure and can lead to a burst blood vessel. Less often, a condition called an arteriovenous malformation, which is an abnormal connection between your veins and arteries, can lead to bleeding in the brain. Keep reading about the causes of different types of strokes.
What Are the Symptoms of Stroke?
The most common symptoms of a stroke are:
- Weakness or numbness of the face, arm, or leg on one side of the body
- Loss of vision or dimming (like a curtain falling) in one or both eyes
- Loss of speech, difficulty talking or understanding what others are saying
- Sudden, severe headache with no known cause
- Loss of balance or unstable walking, usually combined with another symptom
What Should I Do If I Experience Stroke Symptoms?
Immediately call 911 if you or someone you know has symptoms of a stroke. Stroke is a medical emergency. Immediate treatment can save your life or increase your chances of a full recovery.
Is it Possible to Prevent a Stroke?
Up to 50% of all strokes are preventable. Many risk factors can be controlled before they cause problems.
Controllable Risk Factors for Stroke:
- High blood pressure
- Atrial fibrillation
- Uncontrolled diabetes
- High cholesterol
- Excessive alcohol intake
- Carotid or coronary artery disease
Uncontrollable Risk Factors for Stroke:
- Age (>65)
- Gender (Men have more strokes, but women have deadlier strokes)
- Race (African-Americans are at increased risk)
- Family history of stroke
Your doctor can evaluate your risk for stroke and help you control your risk factors. Sometimes, people experience warning signs before a stroke occurs.
These are called transient ischemic attacks (also called TIA or “mini-stroke”) and are short, brief episodes of the stroke symptoms listed above. Some people have no symptoms warning them prior to a stroke or symptoms are so mild they are not noticeable. Regular check-ups are important in catching problems before they become serious. Report any symptoms or risk factors to your doctor.
What is the NIH Stroke Scale?
Not all strokes affect the brain equally, and stroke symptoms and signs depend upon the part of the brain affected.
For example, most people’s speech center is located in the left half of the brain so a stroke affecting the left side of the brain would affect speech and comprehension. It also would be associated with weakness of the right side of the body.
A right-brain stroke would make the left side of the body weak. And depending on where in the brain the injury occurred, the weakness could be the face, arm, leg or a combination of the three.
The NIH Stroke Scale tries to score how severe a stroke might be. It also monitors whether the person’s stroke is improving or worsening as time passes as the patient is re-examined.
There are 11 categories that are scored and include whether the patient is awake; can follow commands; can see; can move the face, arms, and legs; has normal body sensations or feelings; has speech difficulties; and has coordination problems.
What is the treatment for stroke?
A stroke is a medical emergency, but prompt intervention can restore blood supply to the brain if stroke patients receive medical care early enough.
As in many emergencies, the first consideration is the CABs (Circulation, Airway, and Breathing, according to the new CPR guidelines) to make certain that the patient has blood pumping, no airway blockage and can breathe, and then has adequate blood pressure control. In severe strokes, especially those that involve the brainstem, the brain’s ability to control breathing, blood pressure, and heart rate may be lost.
Patients will have intravenous lines established, oxygen administered, appropriate blood tests, and non-contrast CT scans performed. At the same time, the health care professional performs an assessment to make the clinical diagnosis of stroke and decides whether thrombolytic therapy (tPA, a clot-busting medication) or clot retrieval (mechanically removing the clot through catheters that are threaded into the blocked artery) is an option to treat the stroke.
How stroke is treated
If the diagnosis of ischemic stroke has been made, there is a window of time when thrombolytic therapy using tPA (tissue plasminogen activator) may be an option. tPA dissolves the clot that is blocking an artery in the brain and restores blood supply. For many patients, that time window is 3 hours after the onset of symptoms. In a select group of patients, that period may be extended to 4.5 hours. During that 3-to-4½ hours, the patient or family needs to recognize the stroke symptoms, get the patient to a hospital (call 9-1-1), have the patient assessed by the health care professional, who performs a CT scan to look for other causes of stroke (including hemorrhage or tumor), consults with a neurologist, and stabilizes the patient’s blood pressure and breathing. Only then can it be time to administer the tPA or call an interventional radiologist or neurosurgeon to try to remove the clot (mechanical thrombectomy).
Hemorrhagic strokes are difficult to treat, so it’s imperative to consult a specialist (neurosurgeon) immediately to help determine whether any treatment options are available to the patient (possibly aneurysm clipping, hematoma evacuation, or other techniques). Treatment for hemorrhagic strokes, in contrast to ischemic strokes, does not use tPA or other thrombolytic agents, as these could worsen bleeding, make the symptoms of hemorrhagic stroke worse, and cause death. Consequently, it is important to distinguish between a hemorrhagic stroke and an ischemic stroke before treatment begins.
Hospital ER doctors and nurses are trained to act quickly in caring for stroke patients. The most common delay that prevents tPA from being administered is a patient delay in seeking medical attention. Health care professionals perform an urgent CT scan of the head to help distinguish an ischemic from a hemorrhagic stroke. This may also cause a delay in a few instances.
Some smaller hospitals may use telemedicine to virtually consult neurology specialists, who can help make the diagnosis of stroke, review the CT scan, and help decide whether tPA is a reasonable option. They may administer the thrombolytic drug and transfer the patient to a better-equipped hospital for further care.
How many stroke patients receive tPA?
The decision to administer tPA in the appropriate patient (there are many reasons that the drug is not indicated even if the patient arrives in time) is one that health care professionals discuss with the patient and family since there is a risk of bleeding in the brain with the use of tPA. While there is potential great benefit, because the blood vessels are fragile, there is a 6% risk that an ischemic stroke can turn into a hemorrhagic stroke with bleeding into the brain. This risk is minimized the earlier the drug is given and if the appropriate patient is selected.
In certain stroke situations, the treatment period may be extended to 4.5 hours. If tPA is given, the patient will need to be admitted to an intensive care bed for monitoring. As well, depending upon circumstances, the patient may be transferred to a stroke center.
Some stroke patients are candidates for mechanical thrombectomy, where a thin catheter is threaded into the blocked artery in the neck or brain, and the clot is sucked out. Depending upon the patient, the size of the stroke, the location of the blockage in the brain and brain function, mechanical thrombectomy may be considered up to 24 hours after onset of symptoms. Mechanical thrombectomy is not available at all hospitals and may not be appropriate for all patients. These procedures require the skill of a specially trained interventional neuroradiologist, neurologist, or neurosurgeon.
In those patients where tPA and other interventions are not possible or are not indicated, the patient is usually admitted to the hospital for observation, supportive care, and referral for rehabilitation.
What is the prognosis for a person that suffers a stroke?
Stroke remains a major killer in the United States and worldwide. In the U.S., 20% of stroke patients will die within a year. However, with the ability to intervene with thrombolytic therapy to reverse the stroke and with more aggressive rehabilitation, the goal is to increase patient survival and function after recovery.
Specialized stroke centers — hospitals that have the doctors, equipment, and resources to intervene quickly and treat strokes aggressively — have shown to increase stroke survival as well as patient function and recovery. These hospitals are certified by The Joint Commission, the American Stroke Association, and the health departments of some states. It is to your advantage to know which hospitals in your area are designated stroke centers because they will have the specialists and equipment needed to minimize diagnosis-to-treatment times.
Many complications can develop in stroke patients, some of whom may not be able to return to full-time employment because of disability. Patients are affected physically with decreased body function, mentally with decreased cognition, and emotionally with depression and anxiety.
The return to function depends upon the severity of the stroke, what parts of the brain and body have stopped working, and what complications develop. Patients who lose their ability to swallow may develop aspiration pneumonia when they inhale food or saliva into the lungs, causing infection. Patients who have difficulty moving can develop pressure sores and infection due to skin breakdown.
Seizures may be a complication in up to 10% of patients. The more severe the stroke, the more likely that seizures may develop.
Is recovery after a stroke possible?
Prompt intervention in the acute stroke and restore blood supply to brain tissue increase the likelihood that stroke patients can be rescued and brain damage minimized.
In patients who have physical, mental, and emotional deficits because of the stroke, rehabilitation offers hope of increased function and return to the level of activity that they had prior to the stroke.
Again, the best treatment for stroke is prevention and minimizing risk factors for not only stroke but for heart attack and peripheral vascular disease (PAD).
What is stroke rehabilitation?
The purpose of rehabilitation is to return the stroke patient to the life and level of function that existed before the stroke. The success of that goal depends upon the underlying health of the patient and the severity of the stroke.
Rehabilitation may take weeks or months and usually requires a team approach for success. Physical therapists, occupational therapists, and speech pathologists will coordinate care with the primary doctor and physical medicine and rehabilitation specialists.
Some of the treatments are directed to prevent life-threatening complications. For example, speech pathologists may help with swallowing to prevent aspiration pneumonia. Physical therapists may concentrate on strength and balance to prevent falls. Occupational therapists may find ways to allow the patient to perform daily activities from personal hygiene to cooking in the kitchen.
Many patients with significant stroke deficits may require admission to a rehabilitation hospital and/or longer-term nursing facility prior to returning home. Unfortunately, some patients will have had too severe a stroke to be offered that opportunity.
Can strokes be prevented?
Prevention is always the best treatment, especially when the illness can be life-threatening or life-altering. Ischemic strokes are most often caused by atherosclerosis or hardening of the arteries, and carry the same risk factors as heart attacks (myocardial infarction, coronary artery disease) and peripheral vascular disease. These include high blood pressure, high cholesterol, diabetes, and smoking. Stopping smoking and keeping the other three under lifelong control greatly minimizes the risk of ischemic stroke.
Patients who have had a transient ischemic attack (TIA) are often prescribed medications to decrease their risk of a subsequent stroke. These include medications to lower blood cholesterol levels and control blood pressure. In addition, antiplatelet medications may be prescribed to make platelets less likely to promote blood clot formation. These include aspirin, clopidogrel (Plavix), and dipyridamole/aspirin (Aggrenox).
Patients with a TIA are usually evaluated for carotid stenosis or narrowing of the carotid artery. Surgery to open critically narrowed carotid arteries (termed endarterectomy) may decrease stroke risk.
Lifelong control of high blood pressure decreases the risk of hemorrhagic stroke.
Atrial fibrillation is the most common cause of embolic stroke. Ideally, the heart rhythm can be converted to normal sinus rhythm but in those patients whose hearts are chronically in atrial fibrillation, anticoagulation or “blood thinning” minimizes the risk of blood clot formation in the heart and subsequent embolization and stroke. The drug that is prescribed depends upon the specific patient and individual situation. Patients who are prescribed apixaban (Eliquis), rivaroxaban (Xarelto), dabigatran (Pradaxa), or warfarin (Coumadin), have a decreased chance of stroke but are at risk for bleeding complications.
How to prevent a stroke
You can take steps to help prevent stroke by living a healthy lifestyle. This includes the following measures:
- Quit smoking. If you smoke, quitting now will lower your risk for stroke.
- Consume alcohol in moderation. If you drink excessively, try to reduce your intake. Alcohol consumption can raise your blood pressure.
- Keep the weight down. Keep your weight at a healthy level. Being obese or overweight increases your stroke risk. To help manage your weight:
- Eat a diet that’s full of fruits and vegetables.
- Eat foods low in cholesterol, trans fats, and saturated fats.
- Stay physically active. This will help you maintain a healthy weight and help reduce your blood pressure and cholesterol levels.
- Get checkups. Stay on top of your health. This means getting regular checkups and staying in communication with your doctor. Be sure to take the following steps to manage your health:
- Get your cholesterol and blood pressure checked.
- Talk to your doctor about modifying your lifestyle.
- Discuss your medication options with your doctor.
- Address any heart problems you may have.
- If you have diabetes, take steps to manage it.
Taking all these measures will help put you in better shape to prevent stroke.
If you suspect you’re experiencing symptoms of a stroke, it’s vital that you seek emergency medical treatment. Clot-busting medication can only be provided in the first hours after the signs of a stroke begin, and early treatment is one of the most effective ways to reduce your risk for long-term complications and disability.
Prevention is possible, whether you’re preventing a first stroke or trying to prevent a second. Medications can help reduce the risk of blood clots, which lead to strokes. Work with your doctor to find a prevention strategy that works for you, including medical intervention and lifestyle changes.
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