Transient Ischemic Attack
Alternate Names : TIA, Reversible Ischemic Neurologic Disease (RIND), Ministroke
A transient ischemic attack (TIA) is an injury to the brain caused by a
temporary interruption in its blood supply. A TIA is like a stroke, except that
it lasts only a brief time.
What is going on in the body?
During a transient ischemic attack, there is a lack of blood flow to a portion
of the brain. This causes symptoms in the body depending on the part of the
brain that is affected. A TIA can last up to 24 hours. However, typical TIAs
often last less than 30 minutes. The person remains conscious during the
episode.
What are the causes and risks of the condition?
Transient ischemic attacks are caused by a temporary interruption of the blood
flow to brain cells. Since a TIA is a short-term type of stroke, the risk
factors for stroke apply to TIAs as well.
The American Heart Association has recently issued guidelines for stroke
prevention. The guidelines discuss risk factors for stroke in 3 categories:
nonmodifiable, well-documented modifiable, and less well-documented or
potentially modifiable.
The nonmodifiable factors are ones that cannot be changed by the individual
and include:
increasing age. A person's risk of stroke doubles each year after age
55.
race. Strokes occur approximately twice as often in blacks and Hispanics as
they do in whites.
gender. Men have a 50% higher chance of stroke than women do.
family history of stroke or transient ischemic attack
Well-documented modifiable risk factors are those that can be changed by the
individual in conjunction with his or her healthcare provider. These factors
are linked to stroke by strong research findings, and there is documented proof
that changing the risk factor lowers a person's risk of stroke. These factors
include:
high blood pressure
smoking
diabetes
asymptomatic carotid stenosis, or
narrowing of one of the arteries in the neck
sickle cell anemia,
a blood
disorder that forms abnormal red blood cells
high cholesterol levels
in the
blood, including total
cholesterol and
LDL or "bad
cholesterol." Low levels
of HDL or "good
cholesterol" are also
cause for concern.
atrial fibrillation, an
abnormal
heart rhythm
Less well-documented or potentially modifiable risk factors for stroke are
those that have less proof of either a link to stroke or the impact of
modifying the risk factor. These factors include:
obesity
sedentary lifestyle
alcohol abuse
high blood levels of homocysteine, a blood component sometimes associated
with a higher risk of stroke
drug abuse
blood disorders, such as blood that clots easily or deficiencies of various
blood components
hormone replacement
therapy (HRT).
The AHA currently states that the risk of stroke associated with HRT appears
low but needs further study.
use of birth control pills, or oral
contraceptives
inflammatory processes, such as a chronic infection with chlamydia
Several recent studies have identified factors that seem to increase or
decrease the risk of stroke in particular groups of people. These studies,
which warrant further investigation, include these findings:
People who were treated for high
blood
pressure with thiazide diuretics, such as hydrochlorothiazide, had
a
significantly lower stroke risk than people on ACE inhibitors or calcium
channel blockers.
Women ages 39 to 50 who ate more fish and omega-3 polyunsaturated fatty acids had a reduced risk of stroke. This was particularly true in women who did not take aspirin regularly.
Women ages 15 to 44 who had 2 drinks of wine a day had a 40% to 60% lower
risk of stroke than women who did not drink
alcohol.
Phenylpropanolamine, a compound contained in appetite suppressants and cold
remedies, significantly increased the risk of hemorrhagic stroke in women 18 to 49
years of age. The Food and Drug Administration (FDA) has since asked
manufacturers to remove phenylpropanolamine from their products.
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