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Patricia Davis, MD
University of Iowa Hospitals and Clinics
First Published: September 2000
Last Revised: September 2000
Peer
Review Status: Internally Peer Reviewed
Stroke is the third leading cause of death in the United States and a leading
cause of disability. There are 600,000 new strokes every year in the United States or one
every 53 seconds. When a stroke occurs a blood vessel in the brain is blocked by
a blood clot or a blood vessel bursts causing bleeding. The area of the brain
supplied by that blood vessel is deprived of oxygen and nutrients. This causes
damage to that area of the brain. Unless blood flow is restored quickly this
damage may be irreversible. Fortunately we have treatment for acute stroke, but
this has to be administered rapidly. It is important that patients experiencing
the symptoms of stroke call 911 and get to the nearest hospital immediately so
they can receive this treatment.
What are some medical conditions that increase one's risk of stroke?
The most important risk factor for stroke is high blood pressure. That
increases your risk of stroke by about three to five times. High blood pressure is
defined as systolic blood pressure over 140 mm of mercury, a diastolic blood
pressure of over 90 mm of mercury. Even if only the systolic blood pressure is
increased, the risk of stroke still increases by about two to four times. About
20 to 25 percent of Americans have high blood pressure. Treatment of high blood
pressure reduces your risk of having a stroke by about 40 percent over two years.
Treatment can include medications, losing weight, limiting alcohol and salt
intake, and physical exercise. High blood pressure is a silent condition so it is
important to have your blood pressure checked every two years to make sure that
it is normal. Cigarette smoking increases your risk of stroke by about one and a half to two
times and is related to the number of cigarettes smoked. If you stop smoking,
your risk drops back to baseline within two to five years after quitting. Heart
disease also increases your risk of having a stroke, in particular, atrial
fibrillation or an irregular heartbeat. This increases the risk of stroke by
about three to five times and affects about two percent of the population. If you have
this condition, treatment with a blood thinner, Warfarin, can reduce your risk of
having a stroke by about 70 percent. Elevated cholesterol, while not as important
a risk factor as for coronary artery disease, is also associated with stroke--an
elevated LDL cholesterol over 160 mg/dl or low HDL cholesterol less than 35
mg/dl. We know that in patients with heart disease, lowering cholesterol with
medications called statins reduces the risk of stroke by about 30 percent.
Diabetes increases your risk of stroke by about two to three times. The presence of a
bruit or a sound over the carotid artery, which your doctor may hear, can
indicate a blockage of the artery. In some patients, surgery called carotid
endarterectomy can be performed to reduce the risk of stroke. Obesity also
doubles your risk of having a stroke. There are good data that suggest that
moderate physical exercise can reduce your risk of having a stroke. The risk of
stroke is decreased by moderate alcohol intake, which is defined as between one
drink per week to two drinks per day. Greater intake of alcohol than this will
increase the risk of stroke, however. There is also some data that suggest
consumption of fruits/vegetables of at least six servings per day can reduce your
risk of having a stroke. Some patients who have elevated homocystine, a protein
in the blood, may have an increased risk of stroke and the level of this protein
may be decreased by taking a vitamin called folate. In young patients, use of
illicit drugs, in particular, cocaine and amphetamines increases the risk of
stroke. Finally, patients who have multiple risk factors are at particularly high
risk. If you are interested in assessing your risk of stroke, the website of the
American Heart Association is www.americanheart.org.
At that website, there is
actually a calculator that will tell you your risk of having a stroke based
on your risk factors and what you can do about it. The most important point is
that stroke is a preventable disease. If you pay attention to checking your blood
pressure, stopping smoking, lowering your cholesterol, maintaining an ideal
weight, and exercising regularly, it can have a big impact in preventing a stroke.
What are the warning signs of a possible stroke? If you suspect you are
having a stroke what should you do, and also if it is detected early, can it be
stopped or maintained?
The important warning symptoms of a stroke include:
- sudden weakness
or numbness on one side of the body including the face, arm and leg;
- sudden
confusion or trouble speaking or understanding;
- sudden trouble walking,
dizziness, or loss of balance or coordination;
- sudden trouble seeing out of
one or both eyes, or
sudden severe headache with no known cause.
If you
experience any of these symptoms, the best action to take is to call 911 and get
to the nearest hospital immediately. I would not advise taking any medication,
including an aspirin, before you do that. When you arrive at the hospital, there
are some important tests that need be done. First, there will be some blood tests
and an electrocardiogram to make sure you are not at risk for bleeding, that you
have not suffered a heart attack, or have a cardiac problem, or some other
metabolic or toxic cause for your symptoms. Most importantly, they will do a CT
scan of your brain. This will tell your physician whether there has been bleeding
into the brain or whether the stroke is due to a blockage of a blood vessel. If
there is a blockage of the blood vessel, there is an effective treatment for
stroke using thrombolytic therapy. The drug is called tissue plasminogin
activator or t-PA. This is a clot-busting drug, which must be administered within
three hours after the onset of the symptoms of stroke. For this reason, it is
important that you get to the hospital quickly so that the drug will be able to
be given within this time window. The drug increases the chance of returning to
normal, or having very mild disability by about 30 percent when compared to no
treatment. Another way of putting it is that for every six patients treated with
the drug, one more person will go back to normal. Unfortunately, the drug has some
risks associated with it. About one in 16 patients treated with the drug may suffer
a brain hemorrhage as a result of the therapy. At present, only about two percent
of stroke victims receive this therapy, usually because it is too late when they
arrive at the Emergency Department. This is why it is critical that patients
recognize the symptoms and act quickly to receive medical care. We sometimes use
the term 'brain attack' instead of stroke emphasizing its similarity to heart
attack so that patients know it is an emergency. The other important reason for
seeking medical help quickly is that death and complications due to stroke can be
reduced by about 30 percent if patients are closely monitored in a stroke unit.
That is a unit staffed by a dedicated team of physicians, nurses, speech,
physical and occupational therapists and social workers who are knowledgeable
about stroke care.
What kind of rehabilitation is needed after a stroke?
Rehabilitation is important to prevent the complications of immobility
and to help the patient learn to adapt using alternate strategies to overcome
their disability. It is important to start therapy at about 24 hours after the
stroke. Physical therapy helps patients learn to walk or use a wheelchair.
Occupational therapists work with the upper limbs to improve motor skills. Speech
therapists work to improve language and communication skills. Since about half of
the survivors of a stroke have some form of paralysis, about 1/4 cannot walk and
about 1/6 have difficulty speaking, these therapies are very important. Once the
patient leaves the acute hospital, they may be transferred to a rehabilitation
unit where they can get more intensive therapy. Recent studies suggest some
interesting new positive effects of physical therapy that work oddly enough by
limiting use of the un-affected side. This causes the brain to re-wire to help
the side affected by the stroke. More research is being done in this area, but it
shows that there is still lots to be learned.
Is it possible to have more than one stroke at a time?
The risk of having a second stroke after the first is about 30 percent
over the next five years. There are some important preventive measures that can be
done to avoid a recurrent stroke. The first preventive measure that we try is
to lower risk factors as I referred to before. The second measure is to use an
antiplatelet drug to prevent further clots from forming. The most common
antiplatelet therapy that we use is aspirin, which reduces your risk of having
another stroke by about 20 to 25 percent. In patients who cannot take aspirin or
who continue to have recurrent symptoms despite aspirin, there are other antiplatelet
drugs including a drug called Clopidogrel or Ticlopidine, which thin the blood
by a different mechanism and are slightly more effective than aspirin. Another
option is the combination of aspirin added to another drug called Dipyridamole.
This may also reduce the risk of stroke more effectively than aspirin alone. In
patients who have atrial fibrillation or an irregular heartbeat, the risk of
having a second stroke can be reduced by about 70 percent using treatment with an
anticoagulant, or blood thinner, called Warfarin. In patients who have at least
50 percent blockage of their carotid artery, and symptoms in the territory of
that artery, the risk of stroke can be reduced by an operation called carotid
endarterectomy. In this surgery, the artery is opened and the fatty deposit is
removed. There are some ongoing studies looking at whether a procedure called
angioplasty and stenting, which does not require an operation, will be as
effective as carotid endarterectomy in preventing the risk of recurrent stroke.
In patients who have had bleeding into the brain or around the brain, called a
subarachnoid hemorrhage, treatment of an aneurysm or outpouching of the artery includes
putting a clip across the neck or placing a coil inside the aneurysm to make it
clot and prevent recurrent bleeding. In patients who have abnormal blood
vessels, which have bled, or an arteriovenous malformation, surgical resection of
the lesion, treatment with coils or occlusion with balloons or treatment with
focused radiation can prevent a recurrent stroke.
If you are a frequent sufferer of migraines, does that mean you are
at a higher risk of stroke?
Migraine headaches do increase the risk of stroke, particularly in
women under the age of 45 years. However, the absolute risk of having a stroke
due to migraine headaches is low at about three cases per 100,000 people with
migraines. Your risk of having a stroke with migraine headaches is increased,
particularly if you also smoke, if you use oral contraceptives, or if you have
migraine associated with an aura.
What treatments are available for strokes other than medication?
Another promising treatment that is developing is doing an angiogram
or a picture of the blood vessel in the acute setting of stroke to see if there
is a blood clot in the artery. If there is, thrombolytic therapy can be injected
into the clot or the clot can be mechanically broken up to restore blood flow to
the brain. This is called intraarterial thrombolytic therapy. There has been a
trial of using this therapy, which has to be given within six hours after the onset
of the symptoms. This showed about a 15 percent greater chance of patients going
back to normal as compared to not receiving this therapy. Unfortunately, this
therapy can only be given at specialized centers where angiography can be
performed rapidly. This is a promising therapy because the time window is longer
and one of our major hopes for the future of stroke treatment is we will have
therapies that we can use beyond three hours that are effective so that we can treat
more patients. Another important ongoing research effort is looking at drugs
called neuroprotective agents, which block some of the secondary effects due to
the lack of blood supply to the brain. Unfortunately, so far none of these drugs
have been proven to be effective but hopefully in the future, we will find a drug
that we can give in the ambulance on the way to the hospital so we can give
thrombolytic therapy beyond the three-hour window. In the future, there may be a
cocktail of drugs that we can use for stroke patients.
Does smoking increase your risk of stroke? If so, why?
Cigarette smoking increases the risk by about 1.5 to 2.5 times. There
is a strong relationship between hardening of the arteries, or atherosclerosis in
the carotid arteries, and the amount smoked. One of the ways smoking increases
your risk of smoke is by accelerating the atherosclerotic process. It may also
increase blood viscosity by causing an increased red blood cell count or
polycythemia. The increased risk is related to the number of cigarettes smoked
and it seems to be more important at a younger age than at an older age. The risk
of stroke is reduced by two years and at baseline by five years after quitting, unlike
lung cancer, where it takes about seven years before you go back to baseline, so the
effect is quite rapid.
I got sick one day at work, and I thought I was having a stroke. I have
been to a neurologist and was diagnosed with MS, but I still feel like I had a
stroke.
Multiple sclerosis can also cause focal neurologic symptoms. The onset
of symptoms is usually not as abrupt in patients with multiple sclerosis as it is
with stroke. MS usually affects younger patients between 15 and 45 years. The
risk of stroke is directly related to age. After the age of 55, the risk of
stroke doubles for each decade. The brain imaging studies , in particula\r an MRI scan, may be very helpful in
determining whether someone has MS or has suffered a stroke. There are also other studies that are helpful to diagnose multiple
sclerosis including tests on the cerebrospinal fluid and evoked potentials.
Hopefully by doing these tests, a correct diagnosis can be made because the
treatment for stroke and multiple sclerosis are very different.
Can changes in diet help one recover from a stroke?
We do not have any data suggesting that it improves the recovery after
you have already suffered a stroke, but you can certainly reduce your risk of
having a second stroke by eating a low-fat diet, limiting your salt intake, and
eating at least six servings of fruits/vegetables a day.
Can a stroke itself kill you?
The answer to that is yes, a stroke can kill you. In fact, it kills
about 160,000 people a year in the United States. The risk of dying from a stroke
is higher if you have bleeding into the brain, or a hemorrhagic stroke, than an
ischemic stroke, or blockage of a blood vessel to the brain. There is about a 50
to 60 percent risk of dying in the first month after a hemorrhagic stroke. For an
ischemic stroke, this is more like 15 percent risk at one month. In the first
week, the usual reason that you die from a stroke is due to the stroke itself, or
because of swelling around the area of the damage in the brain. After this,
complications due to the stroke such as pneumonia, pulmonary embolism, or
infections are more common causes of death.
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