Strokes are assaults upon the brain. These can occur by blocking the blood supply to the brain. A stroke is a medical emergency which requires immediate medical care.
This article from the Nccmed Knowledge Center will clarify why strokes occur and how they are handled, as well as discuss the various types and measures that a person can take to avoid a stroke.
Fast facts on stroke:
- During a stroke, the brain does not receive enough oxygen or nutrients, causing brain cells to die.
- Strokes need to be diagnosed and treated as quickly as possible to minimize brain damage.
- Treatment depends on the type of stroke.
- The most effective way to prevent strokes is through maintaining a healthy lifestyle and treating underlying conditions that could be a risk factor.
What is a stroke?
A stroke happens when blood supply to the brain is either stopped or reduced. The brain does not get enough oxygen or nutrients when this occurs and brain cells start to die.
In the U.S. about 40 percent of people who die from stroke are male, with 60 percent of female deaths.
According to the American Heart Association (AHA), African-Americans have almost double the chance of a first-time stroke and a much higher risk of stroke mortality compared with the Caucasian people.
Given the different causes of ischemic and hemorrhagic strokes, both require different forms of treatment.
It is necessary not only to diagnose the form of stroke rapidly to reduce the damage done to the brain, but also because a medication appropriate for one type of stroke can be dangerous when treating different types.
Ischemic strokes are caused by blocking or narrowing the arteries and therefore care focuses on restoring an sufficient blood flow to the brain.
Care begins with medications which break down the clots and prevent the formation of others. Aspirin may be given, as can a plasminogen activator (TPA) tissue injection. TPA is very effective in dissolving clots but must be injected within 4.5 hours of the onset of stroke symptoms.
Emergency procedures involve injecting TPA directly into a brain artery, or using a catheter to dissolve the clot physically. Work on the value of those procedures is still ongoing.
There are other treatments that may be used to reduce the risk of strokes or TIAs. A carotid endarterectomy involves the expansion of the carotid artery by a surgeon and removing any plaque that may block it.
Instead, angioplasty involves a surgeon stretching a small balloon through a catheter in a narrowed artery, and then inserting a mesh tube called a stent into the cavity. It prevents drying up of the artery again.
Blood leakage into the brain causes hemorrhagic strokes, and care focuses on minimizing bleeding and reducing the pressure on the brain.
Care can begin with drugs administered to reduce brain pressure, regulate overall blood pressure, prevent seizures and prevent sudden blood vessel constrictions.
If an individual takes blood-thinning anticoagulants or an antiplatelet such as warfarin or clopidogrel, drugs may be administered to counteract the effects of medication or blood transfusions to compensate for blood loss.
Surgery can be used to repair any blood vessel complications that have led to hemorrhagic strokes or that could lead to them. Surgeons may place small clamps at the aneurysm base, or fill them with detachable coils to stop blood flow and prevent rupture.
If arteriovenous malformations (AVMs) cause the hemorrhage, surgery may also be used to remove them if they are not too large and not too deep within the brain. AVMs are intertwined artery-vein connections, which are smaller and burst more rapidly than other normal blood vessels.
Strokes are life-changing events which can physically and emotionally impact a person. Successful rehabilitation following a stroke will also require different treatments and support, such as:
- Speech Therapy: It deals with any speech problems. Practice, relaxation and an evolving style of communication can all help.
- Physical therapy: This can benefit a person to relearn movement and coordination. Staying involved is important even if it is hard at first.
- Occupational therapy: It is used to help an person improve his or her ability to perform daily routine tasks such as washing, eating, dressing, sleeping, reading and writing..
- Support groups: They help with common problems of mental health, such as depression that may occur after a stroke. Most think sharing common experiences and exchanging information are useful.
- Friends and family care: After a stroke, people closest to a patient should be offering practical support and comfort. It’s really important to let friends and family know what can be done to help.
Rehabilitation is a significant and continuing part of treatment. Rehabilitation to a normal quality of life is possible with the right help and support from loved ones, depending on the severity of the stroke.
The best way to prevent a stroke is to address the underlying causes. This is best achieved through lifestyle changes, including:
- eating a healthy diet
- maintaining a healthy weight
- exercising regularly
- not smoking tobacco
- avoiding alcohol or drinking moderately
Eating a nutritious diet includes plenty of fruits, vegetables and healthy whole grains, nuts, seeds and legumes included. Make sure you eat little or no red or processed meat, and restrict cholesterol and saturated fat intake. Minimize the consumption of salt to help healthy blood pressure.
Other steps implemented to help reduce stroke risk include:
- keeping blood pressure under control
- managing diabetes
- treating obstructive sleep apnea
As well as these lifestyle improvements, a doctor can help by administering anticoagulant or antiplatelet medicine to reduce the risk of possible ischemic strokes.
Moreover, arterial surgery can also be used to reduce the risk of repeat strokes, as well as some other surgical options that are still under review.
There are three main types of stroke:
- Ischemic stroke: This is the most common type of stroke. A blood clot prevents blood and oxygen from reaching the brain.
- Hemorrhagic stroke: This occurs when a weakened blood vessel ruptures and normally occur as a result of aneurysms or arteriovenous malformations (AVMs).
- Transient ischemic attacks (TIAs): Also referred to as a mini-stroke, these occur after blood flow fails to reach part of the brain. Normal blood flow resumes after a short amount of time, and symptoms cease.
The different types of stroke have different causes. However, stroke is more likely to affect people if they have the following risk factors:
- being overweight
- being aged 55 years or older
- a personal or family history of stroke
- an inactive lifestyle
- a tendency to drink heavily, smoke, or use illicit drugs
This form of stroke is caused by blockages or narrowing of the arteries that supply the brain with blood, leading to ischemia. Ischemia is a serious decrease of blood flow, which kills brain cells.
Such blockages are often caused by blood clots that can form in the arteries of the brain. In other blood vessels in the body, they can also occur before being swept through the bloodstream and into smaller arteries in the brain.
Fatty deposits inside the plaque-like arteries can cause clots that cause ischemia.
Hemorrhagic strokes are caused either by leaking blood or by bursting open arteries in the brain.
Leaked blood exerts pressure on and kills brain cells. It also reduces the blood supply that can enter post-hemorrhage brain tissue. Blood vessels may burst and blood spill into the brain or near the brain surface, sending blood into the space between the brain and the skull.
Conditions including hypertension, trauma, blood-thinning medications, and aneurysms may cause the ruptures. Aneurysms are defects in blood vessel walls.
Intracerebral hemorrhage is the most common type of hemorrhagic stroke which happens after an artery in the brain bursts when the brain tissue is flooded with blood.
Hemorrhage of subarachnoid is the second type of hemorrhagic stroke, and is less common. Bleeding occurs in that form of stroke in the region between the brain and the thin tissues that cover it.
Transient ischemic attack (TIA)
TIAs vary from the above forms because blood flow to the brain is only disrupted momentarily. TIAs are similar to ischemic strokes in that blood clots or other clots also cause them.
These should be considered medical emergencies, even though artery blockage and its consequences are temporary. These act as warning signs for potential strokes and show a partially blocked source of artery or clot is in the heart.
According to the Centers for Disease Control and Prevention (CDC), if they have not undergone any treatment, about one third of people who undergo a TIA will have a major stroke within one year. Within 3 months of a TIA, between 10 and 15 per cent of people will have a major stroke.
Symptoms of a stroke often appear without warning.
The main symptoms of stroke are:
- confusion, including trouble with speaking and understanding
- a headache, possibly with altered consciousness or vomiting
- numbness or inability to move parts of the face, arm, or leg, particularly on one side of the body
- vision problems in one or both eyes
- trouble walking, including dizziness and lack of co-ordination
Strokes can lead to long-term health problems. Depending on how quickly it is diagnosed and treated, an individual can experience temporary or permanent disabilities in the aftermath of a stroke.
In addition to the persistence of the problems listed above, people may also experience the following:
- bladder or bowel control problems
- pain in the hands and feet that gets worse with movement and temperature changes
- paralysis or weakness on one or both sides of the body
- trouble controlling or expressing emotions
Symptoms vary and may range in severity.
The acronym F.A.S.T. is a way to remember the signs of stroke, and can help identify the onset of stroke:
- Face drooping: If the person tries to smile, does one side of the face droop?
- Arm weakness: If the person tries to raise both their arms, does one arm drift downward?
- Speech difficulty: If the person tries to repeat a simple phrase, is their speech slurred or strange?
- Time to call 911: If any of these signs are observed, contact the emergency services.
The faster a person with suspected stroke receives medical attention, the better their prognosis will be, and the less likely they will be to experience permanent damage or death.
Signs of a stroke require immediate medical attention.
Strokes onset rapidly and will often occur before an individual can be seen by a doctor for a proper diagnosis.
For a person experiencing a stroke to get the best diagnosis and treatment possible, they should be treated at a hospital within 3 hours of their symptoms first appearing.
There are several different types of diagnostic tests that doctors can use to determine which type of stroke has occurred:
- Physical examination: A doctor will ask about symptoms and medical history. They may check blood pressure, listen to the carotid arteries in the neck, and examine the blood vessels at the back of the eyes to check for indications of clotting.
- Blood tests: A doctor may perform blood tests to find out how quickly the clots occur, the levels of particular substances in the blood, including clotting factors and whether or not an infection is present.
- CT scan: A series of X-rays can show hemorrhages, strokes, tumors, and other conditions within the brain.
- MRI scan: Radio waves and magnets create an image of the brain to detect damaged brain tissue.
- Carotid ultrasound: An ultrasound scan to check the blood flow in the carotid arteries and to see if there is any plaque present.
- Cerebral angiogram: Dyes are injected into the brain’s blood vessels to make them visible under X-ray. This gives a detailed view of the brain and the blood vessels in the neck.
- Echocardiogram: This creates a detailed image of the heart to check for any sources of clots that could have traveled to the brain to cause a stroke.
It is only possible to confirm the type of stroke someone has had by giving them a brain scan in a hospital environment.