Stroke
Definition
A stroke is an
interruption of the blood supply to any part of the brain. A stroke is
sometimes called a "brain attack."
See also: Arteriovenous
malformation (AVM)
Symptoms
The symptoms of
stroke depend on what part of the brain is damaged. In some cases, a
person may not even be aware that he or she has had a stroke.
Symptoms
usually develop suddenly and without warning, or they may occur on and
off for the first day or two. Symptoms are usually most severe when the
stroke first happens, but they may slowly get worse.
A headache
may occur, especially if the stroke is caused by bleeding in the brain.
The headache:
- Starts suddenly and may be severe
- Occurs
when lying flat
- Wakes you up from sleep
- Gets worse when
you change positions or when you bend, strain, or cough
Other
symptoms depend on the severity of the stroke and what part of the
brain is affected. Symptoms may include:
- Muscle weakness in
the face, arm, or leg (usually just one side)
- Numbness or
tingling on one side of the body
- Trouble speaking or
understanding others who are speaking
- Problems with eyesight,
including decreased vision, double vision, or total loss of vision
- Sensation
changes that affect touch and the ability to feel pain, pressure,
different temperatures, or other stimuli
- Changes in hearing
- Change
in alertness (including sleepiness, unconsciousness, and coma)
- Personality,
mood, or emotional changes
- Confusion or loss of memory
- Difficulty
swallowing
- Changes in taste
- Difficulty writing or
reading
- Loss of coordination
- Loss of balance
- Clumsiness
- Trouble
walking
- Dizziness or abnormal sensation of movement (vertigo)
- Lack
of control over the bladder or bowels
Causes & Risks
A
stroke happens when blood flow to a part of the brain is interrupted
because a blood vessel in the brain is blocked or bursts open.
If
blood flow is stopped for longer than a few seconds, the brain cannot
get blood and oxygen. Brain cells can die, causing permanent damage.
There
are two major types of stroke: ischemic stroke and hemorrhagic stroke.
ISCHEMIC
STROKE
Ischemic stroke occurs when a blood vessel that supplies
blood to the brain is blocked by a blood clot. This may happen in two
ways:
- A clot may form in an artery that is already very
narrow. This is called a thrombus. If it completely blocks the artery,
it is called a thrombotic stroke.
- A clot may break off
from somewhere in the body and travel up to the brain to block a smaller
artery. This is called an embolism. It causes an embolic stroke.
Ischemic
strokes may result from clogged arteries, a condition called
atherosclerosis. (See: Stroke secondary to atherosclerosis) This may
affect the arteries within the brain or the arteries in the neck that
carry blood to the brain. Fat, cholesterol, and other substances collect
on the wall of the arteries, forming a sticky substance called plaque.
Over time, the plaque builds up. This often makes it hard for blood to
flow properly, which can cause the blood to clot.
Ischemic strokes
may also be caused by blood clots that form in the heart. These clots
travel through the blood and can get stuck in the small arteries of the
brain. This is known as a cerebral embolism.
Certain drugs and
medical conditions can make your blood more likely to clot and raise
your risk for ischemic stroke. A common cause of ischemic stroke in
people under age 40 is carotid dissection, or a tear in the lining of
the carotid artery. The tear lets blood flow between the layers of the
carotid artery. This causes narrowing of the carotid artery that is not
due to plaque buildup.
HEMORRHAGIC STROKE
Hemorrhagic stroke
occurs when a blood vessel in part of the brain becomes weak and bursts
open, causing blood to leak into the brain. Some people have defects in
the blood vessels of the brain that make this more likely. The flow of
blood that occurs after the blood vessel ruptures damages brain cells.
For
more information on this type of stroke, see: Hemorrhagic stroke
STROKE
RISKS
High blood pressure is the number one risk factor for
strokes. The following also increase your risk for stroke:
- Diabetes
- Family
history of stroke
- Heart disease
- High cholesterol
- Increasing
age
Certain medications make blood clots more likely, and
therefore your chances for a stroke. Birth control pills can increase
the chances blood clots, especially in woman who smoke and who are older
than 35.
Men have more strokes than women. But, women have a risk
of stroke during pregnancy and the weeks immediately after pregnancy.
The
following can increase the risk of bleeding into the brain, which makes
you more likely to have a stroke:
- Alcohol use
- Bleeding
disorders
- Cocaine use
- Head injury
For more
information see: Stroke risk factors and prevention
Tests & Diagnostics
A
complete physical and neurological exam should be performed. Your
doctor will:
- Check for problems with vision, movement,
sensation, reflexes, understanding, and speaking. Your doctor and nurses
will repeat this exam over time to see if your stroke is getting worse
or is improving.
- Listen for an abnormal sound, called a "bruit,"
when using a stethoscope to listen to the carotid arteries in the neck.
A bruit is caused by turbulent blood flow.
- Check and assess
your blood pressure, which may be high.
Tests can help your
doctor determine the type, location, and cause of the stroke and to rule
out other disorders that may be responsible for the symptoms.
- A
CT scan of the brain is often done soon after symptoms of a stroke
begin. An MRI scan of the brain may be done instead or afterwards.
- Magnetic
resonance angiography (MRA) or CT angiography may be done to check for
abnormal blood vessels in the brain that may have caused the stroke.
- Echocardiogram
may be done if the stroke could have been caused by a blood clot from
the heart.
- Carotid duplex (a type of ultrasound exam) can show
if narrowing of the neck arteries (carotid stenosis) led to the stroke.
- An
angiogram of the head can reveal which blood vessel is blocked or
bleeding, and help your doctor decide if the artery can be reopened
using a thin tube.
- Laboratory tests will include acomplete blood
count (CBC), bleeding time, and blood clotting tests (prothrombin time
or partial thromboplastin time).
- Electrocardiogram (ECG) and
heart rhythm monitoring can help determine if an irregular heart beat
(such as atrial fibrillation) caused the stroke.
- A spinal tap
(cerebrospinal fluid exam) may also be done.
Treatments
A stroke is a
medical emergency. Immediate treatment can save lives and reduce
disability. Call 911 or your local emergency number or seek immediate
medical care at the first signs of a stroke.
It is important to
get the person to the emergency room immediately to determine if the
stroke is due to bleeding or a blood clot so appropriate treatment can
be started within 3 hours of when the stroke began.
Treatment
depends on the severity and cause of the stroke. A hospital stay is
required for most strokes.
TREATMENT IN THE HOSPITAL
Clot-busting
drugs (thrombolytic therapy) may be used if the stroke is caused by a
blood clot. Such medicine breaks up blood clots and helps restore blood
flow to the damaged area. However, not everyone can receive this type of
medicine.
- For these drugs to work, a person must be seen and
treatment must begin within 3 hours of when the symptoms first started.
A CT scan must be done to see whether the stroke is from a clot or from
bleeding.
- If the stroke is caused by bleeding rather than
clotting, clot-busting drugs (thrombolytics) can cause more bleeding.
Other
treatments depend on the cause of the stroke:
- Blood thinners
such as heparin or warfarin (Coumadin) are used to treat strokes due to
blood clots. Aspirin of clopidogrel (Plavix) may also be used.
- Other
medications may be needed to control other symptoms, including high
blood pressure. Painkillers may be given to control severe headache.
- In
some situations, a special stroke team and skilled radiologists may be
able to use angiography to highlight the clogged blood vessel and open
it up.
- For hemorrhagic stroke, surgery is often required to
remove blood from around the brain and to repair damaged blood vessels.
- Surgery
on the carotid artery may be needed. See also Carotid artery disease
and Carotid artery surgery.
Nutrients and fluids may be
necessary, especially if the person has swallowing difficulties. These
may be given through a vein (intravenously) or a feeding tube in the
stomach (gastrostomy tube). Swallowing difficulties may be temporary or
permanent.
Physical therapy, occupational therapy, speech therapy,
and swallowing therapy will all begin in the hospital.
LONG-TERM
TREATMENT
The goal of long-term treatment is to help the patient
recover as much function as possible and prevent future strokes. The
recovery time and need for long-term treatment differs from person to
person. Depending on the symptoms, rehabilitation may include:
- Occupational
therapy
- Physical therapy
- Speech therapy
Therapies
such as repositioning and range-of-motion exercises can help prevent
complications related to stroke, such as infection and bed sores. Those
who have had a stroke should try to remain as active as physically
possible.
Alternative forms of communication such as pictures,
verbal cues, and other techniques may be needed in some cases.
Sometimes,
urinary catheterization or bladder and bowel control programs may be
needed to control incontinence.
A safe environment must be
considered. Some people with stroke appear to have no awareness of their
surroundings on the affected side. Others show indifference or lack of
judgment, which increases the need for safety precautions.
Caregivers
may need to show the person pictures, repeatedly demonstrate how to
perform tasks, or use other communication strategies, depending on the
type and extent of the language problems.
In-home care, boarding
homes, adult day care, or convalescent homes may be required to provide a
safe environment, control aggressive or agitated behavior, and meet
medical needs.
Family counseling may help in coping with the
changes required for home care. Visiting nurses or aides, volunteer
services, homemakers, adult protective services, and other community
resources may be helpful.
Legal advice may be appropriate. Advance
directives, power of attorney, and other legal actions may make it
easier to make ethical decisions regarding the care of a person who has
had a stroke.
See also: Stroke recovery
Alternative Therapies
Additional
support and resources are available from the American Stroke
Association -- www.strokeassociation.org.
Complications
- Breathing
in a food into the airway (aspiration)
- Decreased life span
- Difficulty
communicating
- Permanent loss of brain functions
- Permanent
loss of movement or sensation in one or more parts of the body
- Problems
due to loss of mobility, including joint contractures and pressure
sores
- Fractures
- Malnutrition
- Muscle spasticity
- Reduced
ability to function or care for self
- Reduced social
interactions
- Side effects of medications
Prevention
To help prevent a
stroke:
- Avoid fatty foods. Follow a healthy, low-fat diet.
- Do
not drink more than 1 to 2 alcoholic drinks a day.
- Exercise
regularly: 30 minutes a day if you are not overweight; 60 - 90 minutes a
day if you are overweight.
- Get your blood pressure checked
every 1 - 2 years, especially if high blood pressure runs in your
family.
- Have your cholesterol checked. If you are at high risk
for stroke, your LDL "bad" cholesterol should be lower than 100 mg/dL.
Your doctor may recommend that you try to reduce your LDL cholesterol to
70 mg/dL.
- Follow your doctor's treatment recommendations if you
have high blood pressure, diabetes, high cholesterol, and heart
disease.
- Quit smoking.
Aspirin therapy (81mg a day
or 100mg every other day) is recommended for stroke prevention in women
under 65 as long as the benefits outweigh the risks. It should be
considered for women over age 65 only if their blood pressure is
controlled and the benefit is greater than the risk of gastrointestinal
bleeding and brain hemorrhage. Ask your doctor if aspirin is right for
you.
Your doctor may also recommend aspiring therapy or another
blood thinner if you have had a transient ischemic attach (TIA) or
stroke in the past or if you currently have:
- Congestive heart
failure
- Irregular heart beat (such as atrial fibrillation)
- Mechanical
heart valve
- Other risk factors for stroke
A type of
surgery calledcarotid endarterectomy may help prevent new strokes from
occurring in persons with large blockages in their neck arteries.