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Northeast Ohio’s First Joint Commission-Certified
Comprehensive Stroke Center
Patient Education Series
What is a stroke?
A stroke is a brain injury resulting from a blocked or leaking blood vessel that carries blood to the brain.
Ischemic Strokes
The brain needs a steady supply of blood flow carrying oxygen and nutrients
– without it, brain injury can occur within minutes. Ischemic strokes, which
account for 85 percent of all strokes, result from a lack of blood flow to the
brain due to blockage of a brain artery. The most common causes are:
• Atherosclerosis (hardening of the arteries) is the most common cause of
damaged arteries and causes 45 percent of all ischemic strokes. High blood
pressure and cholesterol, diabetes and smoking cause injury to the lining of
the artery and the wall thickens with plaque. Stroke risk is greatest when
more than 70 percent of the artery is blocked or when an artery plaque
becomes unstable and ruptures. A thrombus is a blockage of an artery with
plaque and blood clot. Atherosclerosis can affect the large carotid arteries
in the neck, the medium-sized intracranial arteries at the base of the brain,
or the small arteries deep inside the brain. (Picture A shows a plaque and
thrombus in the carotid artery. Picture B shows a small lacunar stroke in blue
caused by a thrombus in one of the small arteries deep in the brain.)
A
• Cardiac embolism causes 20 percent of all ischemic strokes. An embolus
occurs when a clot forms in the heart and a piece breaks loose to block
an artery within the brain. (Picture C shows a large ischemic stroke in blue
caused by an embolus blocking the middle cerebral artery.) Heart conditions
such as atrial fibrillation, heart failure, heart valve disorders and a recent
heart attack can cause such a stroke.
• Cryptogenic (unknown cause) strokes are responsible for 30 percent of all
strokes, but some are later found to be due to cardiac embolism.
• The remaining 5 percent of ischemic strokes are caused by dissection,
clotting disorders and inflammatory disorders of blood vessels.
CT angiogram Digital angiogram
Carotid plaque
(as in picture A)
MRI brain scan of
small lacunar infarct
(as in picture B)
MRI brain scan of
large embolic infarct
(as in picture C)
C
B
Hemorrhagic Strokes
Hemorrhagic strokes, which account for 15 percent of all strokes, occur when a
blood vessel in the brain ruptures – causing bleeding in or around the brain. The two
main types are:
• Intracerebral hemorrhage occurs when a fragile brain artery ruptures – causing
bleeding into the brain tissue. The rupture is sudden and can be severe, causing
brain damage and swelling. The most common cause is damage to small arteries
from high blood pressure and diabetes. Blood-thinning medications can also
increase the risk of bleeding into the brain. (Picture D shows an intracerebral
hemorrhage due to rupture of small arteries within the brain.)
D
E
• Subarachnoid hemorrhage results from bleeding around the brain which causes
a severe “worst in my life” headache. Although this type of stroke causes only
5 percent of all strokes, it is the most severe. Most are due to a brain aneurysm
which forms from a weakness in the wall of the artery. (Picture E shows an
aneurysm of the carotid artery.)
MRI brain scan of large intracerebral
hemorrhage
(as in picture D)
Digital angiogram of basilar artery
aneurysm
(as in picture E)
Cerebral angiogram of
carotid aneurysm
(as in picture E)
What are the warning signs of a stroke?
• Sudden weakness or numbness of the face, arm or leg, especially on one side of the body
• Sudden confusion, trouble speaking or understanding
• Sudden trouble seeing in one or both eyes
• Sudden trouble walking, dizziness, loss of balance or coordination
• Sudden, severe headaches with no known cause
A stroke is a medical emergency that must be treated right away. Even if the symptoms go away
at first, some patients will go on to have a stroke, usually within hours or even days.
If you think someone is having a stroke, the best way to get
treatment quickly is to call 9-1-1.
To Schedule an Appointment: 1-866-UH4-CARE (1-866-844-2273)
To Learn More: UHhospitals.org/Stroke
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