Transcript What is a Stroke?

What is a Stroke?
A stroke is an injury to the brain caused by
interruption of its blood flow, or by
bleeding into or around theventricle
brain.
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• It produces neurologic deficits that can have a
relatively sudden onset and persist for more
than 24 hours.
• It can also kill the patient.
Common Neurologic Deficits
Produced by a Stroke
• Weakness or paralysis, usually on one side only
• Loss of sensation, usually on one side only
• Problems with vision
ventricle
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• Difficulty in talking or understanding what is said
• Difficulty with organization or perception
• Clumsiness or lack of balance
STROKE FACTS
All data refer to the United States
• At least 600,000 people suffer a stroke each year
• Stroke is the third leading cause of death
• Death rate following stroke has fallen 13.9% in
ventricle
the past 10 years, but stroke deaths rose 6.6%
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(this presumably reflects an increase in the number of strokes)
• About 4,400,000 stroke survivors are alive today
• Cost of stroke-related care is over $51 billion yearly
• Risk of having a stroke and of dying from one increases
with age, yet many strokes occur in those under 65
Two Major Mechanisms
Produce Strokes
Blockage of an artery (80% of strokes)
--produces ischemia (inadequate blood flow) This
deprives the brain of oxygen and glucose,and slows
waste removal
ventricle
--affected brain tissue functions
abnormally, stops
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functioning, and will die if ischemia persists
Rupture of an artery (20% of strokes)
--causes hemorrhage within or around the brain. This
distorts, compresses, and tears surrounding tissue
Both kinds of stroke can increase intracranial pressure, a
serious complication that can lead to the patient’s death
What is a TIA?
A Transient Ischemic Attack (TIA) is a brief
episode in which neurologic deficits occur
and then disappear completely
• Most TIAs last a few minutes toventricle
an hour
However they may persist upLumen
to 24 hours
• No neurologic deficits remain once the
attack has ended, because little or no
brain tissue is permanently damaged
• A TIA is a warning sign that the stage is set
for an ischemic stroke. Treatment of patients
with TIAs can reduce their risk of stroke
TIA FACTS
• As many as 20% of patients who have a new stroke
retrospectively report on or more prior TIAs
• After a TIA, the annual risk of stroke is about 5% for
ventricle
the next five years
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• After A TIA, the risk of a stroke, myocardial infarction,
or death is about 8% annually for the next five years
• The risk of stroke is highest during the first month.
15-30% of subsequent strokes occur during the
first month, and 40-50% during the first year.
Carotid Bifurcation
artherosclerotic plaque and thrombus
Basilar Artery
artherosclerotic plaque narrows lumen (
plaque
)
Aorta - Atherosclerosis
Numerous ulcerated plaques
Atherosclerotic Plaque
Cholesterol
crystals
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Fat
Elastic Lamella
Broken
Cholesterol Embolus
Artery supplying cerebellum
ventricle
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Granule
cells
Granule
cells
gone
Cerebellar Cortex
ventricle
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Embolus Plugging Artery
fragment of thrombus originating in heart
ventricle
Lumen
ventricle
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Embolus in Basilar Artery
Embolus
ventricle
Lumen
ventricle
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Recent Ischemic Infarct
brain has begun to swell - and shift
Old Ischemic Infarct
ventricle
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Old Ischemic Infarct
Small Artery-putamen
Abnormal wall - degenerative changes
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Lacunar infarcts
putamen
Saccular Aneurysm
Anterior Communicating Artery
Subarachnoid Hemorrhage
Blood fills and outlines brain sulci
Small Artery-putamen
Abnormal wall - degenerative changes
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Intracerebral Hemorrhage
ventricle
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Clotted
blood
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Pontine Hemorrhage
Small Artery-cortex
Abnormal wall - amyloid (
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)
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Small Arteries-cortex
Histochemical stain (red) for beta-amyloid
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Lobar Hemorrhage
Normotensive patient age 84
Normal CT Scan
Lateral ventricle (CSF)
Gray matter
White matter
Pineal gland
(calcified)
Cistern
(CSF)
skull
Two Old Ischemic Infarcts
CT Scan
BIG
Infarct
Lacunar
infarct
(small)
CT Scan -Embolic Stroke
6 days after onset of left-sided weakness
CT Scan - basilar thrombus
basilar occluded where it branches
Clotted blood
appears
bright
Arteriogram - acute stroke
basilar occlusion
No
Perfusion
here
No
Perfusion
here
Flow STOPS
Thrombus
Blocking vessel
Basilar artery
Normal flow
CT Scan - Basilar Occlusion
Nothing seen 6 hours after onset of symptoms
Calcification
in choroid
plexus
CT Scan 36 hours after basilar occlusion
Areas of occipital
lobes supplied
by basilar branches
appear darker
Intracerebral Hemorrhage
CT Scan - 3 Hours after onset
ventricles
Intracerebral Hemorrhage
Rupture of small vessel in putamen
Old
infarct
Recent
hemorrhage
Blood in lateral ventricle