Strokes are brain attacks. They occur when the
blood supply to the brain becomes blocked. A stroke is a medical emergency that
needs immediate medical attention.
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 occurs when the supply of blood to the
brain is either interrupted or reduced. When this happens, the brain does not
get enough oxygen or nutrients, and brain cells start to die.
Treatment
As ischemic and hemorrhagic strokes have different
causes, both require different forms of treatment.
It is not only important that the type of stroke
is diagnosed quickly to reduce the damage done to the brain, but also because a
treatment suitable for one type of stroke may be harmful when treating
different type.
Ischemic strokes are caused by arteries being
blocked or narrowed, and so treatment focuses on restoring an adequate flow of
blood to the brain.
Treatment starts with drugs that break down clots
and prevent others from forming. Aspirin can be given, as can an injection of tissue
plasminogen activator (TPA). TPA is very effective at dissolving clots but
needs to be injected within 4.5 hours of stroke symptoms starting.
Emergency procedures include administering TPA
directly into an artery in the brain or using a catheter to physically remove
the clot. Research is still ongoing as to the benefit of these procedures.
There are other procedures that can be carried out
to decrease the risk of strokes or TIAs. A carotid endarterectomy involves a
surgeon opening the carotid artery and removing any plaque that might be
blocking it.
Alternatively, an angioplasty involves a surgeon
inflating a small balloon in a narrowed artery via catheter and then inserting
a mesh tube called a stent into the opening. This prevents the artery from
narrowing again.
Hemorrhagic strokes are caused by blood leaking
into the brain, so treatment focuses on controlling the bleeding and reducing
the pressure on the brain.
Treatment can begin with drugs given to reduce the
pressure in the brain, control overall blood pressure, prevent seizures and
prevent sudden constrictions of blood vessels.
If an individual is taking blood-thinning
anticoagulants or an antiplatelet medication like warfarin or clopidogrel, they
can be given drugs to counter the effects of the medication or blood
transfusions to make up for blood loss.
Surgery can be used to repair any problems with
blood vessels that have led or could lead to hemorrhagic strokes. Surgeons can
place small clamps at the base of aneurysms or fill them with detachable coils
to stop blood flow and prevent rupture.
If the hemorrhage is caused by arteriovenous
malformations (AVMs), surgery can also be used to remove them if they are not
too big and not too deep in the brain. AVMs are tangled connections between
arteries and veins that are weaker and burst more easily than other normal
blood vessels.
Rehabilitation
Strokes are life-changing events that can affect a
person both physically and emotionally. After a stroke, successful recovery
will often involve specific therapies and support, such as:
Speech therapy: This helps with any problems
producing or understanding speech. Practice, relaxation, and changing
communication style can all help.
Physical therapy: This can help a person relearn
movement and co-ordination. It is important to stay active, even if it is
difficult at first.
Occupational therapy: This is used to help a
person to improve their ability to carry out routine daily activities, such as
bathing, cooking, dressing, eating, reading, and writing.
Support groups: These help with common mental
health problems such as depression that can occur after a stroke. Many find it
useful to share common experiences and exchange information.
Support from friends and family: The people
closest to a person should offer practical support and comfort after a stroke.
Letting friends and family know what can be done to help is very important.
Rehabilitation is an important and ongoing part of
treatment. With the right assistance and the support of loved ones,
rehabilitation to a normal quality of life is possible, depending on the
severity of the stroke.
Prevention
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 means including plenty of
fruits, vegetables, and healthy whole grains, nuts, seeds, and legumes. Be sure
to eat little or no red or processed meat and limit intake of cholesterol and
saturated fats. Minimize salt intake to support healthy blood pressure.
Other measures taken to help reduce the risk of
stroke include:
keeping blood pressure under control
managing diabetes
treating obstructive sleep apnea
As well as these lifestyle changes, a doctor can
help to reduce the risk of future ischemic strokes through prescribing
anticoagulant or antiplatelet medication.
In addition, arterial surgery can also be used to
lower the risk of repeat strokes, as well as some other surgical options still
being studied.
Types
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.
Causes
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
Ischemic stroke
This type of stroke is caused by blockages or
narrowing of the arteries that provide blood to the brain, resulting in
ischemia. Ischemia is severely reduced blood flow that damages brain cells.
These blockages are often caused by blood clots,
which can form in the brain arteries. They can also occur in other blood
vessels in the body before being swept through the bloodstream and into
narrower arteries in the brain.
Fatty deposits within the arteries called plaque
can cause clots that result in ischemia.
Hemorrhagic stroke
Hemorrhagic strokes are caused by arteries in the
brain either leaking blood or bursting open.
Leaked blood puts pressure on brain cells and
damages them. It also reduces the blood supply that can reach the brain tissue
after the hemorrhage. Blood vessels can burst and spill blood into the brain or
near the surface of the brain, sending blood into the space between the brain
and the skull.
The ruptures can be caused by conditions including
hypertension, trauma, blood-thinning medications, and aneurysms. Aneurysms are
weaknesses in the walls of blood vessels.
Intracerebral hemorrhage is the most common type
of hemorrhagic stroke and occurs when brain tissue becomes flooded with blood
after an artery in the brain bursts.
Subarachnoid hemorrhage is the second type of
hemorrhagic stroke and is less common. In this type of stroke, bleeding occurs
in the area between the brain and the thin tissues that cover it.
Transient ischemic attack (TIA)
TIAs are different from the types above because
the flow of blood to the brain is only briefly interrupted. TIAs are similar to
ischemic strokes in that they are often caused by blood clots or other clots.
They should be regarded as medical emergencies,
even if the blockage of the artery and its symptoms are temporary. They serve
as warning signs for future strokes and indicate that there is a partially
blocked artery or clot source in the heart.
According to the Centers for Disease Control and
Prevention (CDC), over a third of people who experience a TIA have a major
stroke within a year if they have not received any treatment. Between 10 and 15
percent of people will have a major stroke within 3 months of a TIA.
Symptoms
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
depression
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.
Diagnosis
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.
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