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What Causes a Stroke? - pt.1 |
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Causes of ischemic stroke
An ischemic
stroke is
caused by a blood clot that blocks blood flow to the brain. Blood
clots either develop in narrow arteries supplying blood to the
brain or travel from the heart or elsewhere in the body to an
artery
that supplies the brain.
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to see an example of an ischemic stroke
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Blood clots are usually the result of other problems in the body
affecting normal flow of blood, such as:
- Hardening of the arteries (atherosclerosis).
This is caused by high blood pressure, diabetes, and high cholesterol.
- Atrial fibrillation or other irregular heart rhythms.
- Certain heart valve problems including having an artificial
heart valve, a repaired heart valve, heart valve disease
such as mitral
valve prolapse or narrowing (stenosis) of a heart valve.
- Infection of the heart valves (endocarditis).
- A patent
foramen ovale a congenital heart defect.
- Blood-clotting disorders.
- Inflammation of blood vessels (vasculitis).
- Heart
attack.
Low blood pressure, also called hypotension, may also cause an ischemic stroke.
Though not common, low blood pressure results in reduced blood
flow to the brain and may develop as a result of narrowed or diseased
arteries, a heart attack, a large loss of blood or a severe infection.
Surgeries such as endarterectomies, or other procedures that are used to treat
narrowed carotid arteries, such
as angioplasty, may ultimately cause a blood clot to break loose
and
result
in a
stroke. |
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What Causes a Stroke? - pt.2 |
Causes of hemorrhagic stroke
A hemorrhagic
stroke is caused by bleeding inside the brain, called intracerebral
hemorrhage, or bleeding in the space around the brain, called
subarachnoid hemorrhage. Bleeding inside the brain may be a result
of long-standing
high blood pressure. Bleeding in the space around the brain may
be caused by a ruptured aneurysm or
uncontrolled high blood pressure.
Other causes of hemorrhagic stroke are less common, but include:
- Inflammation in the blood vessels, which may develop from conditions
such as syphilis or tuberculosis.
- Blood-clotting disorders such as hemophilia.
- Head or neck injuries resulting in damage to head or neck blood
vessels.
- Radiation treatment for cancer in the neck or brain.
- Cerebral amyloid angiopathy, a degenerative blood vessel disorder.
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