Transcript Stroke Syndromes - doc meg's hideout

Stroke Syndromes
Dr. Meg-angela Christi M. Amores
Cerebrovascular Disease
• ischemic stroke
• hemorrhagic stroke
• cerebrovascular anomalies such as intracranial
aneurysms and arteriovenous malformations
(AVMs)
• Incidence increases with age
Stroke
• Most strokes manifest by the abrupt onset of
a focal neurologic deficit
• Like patients were “struck by the hand of God”
• Definition:
• abrupt onset of a neurologic deficit that is
attributable to a focal vascular cause
Definition of terms
• Thrombosis: inappropriate clotting
• Embolism: migration of clots
• Ischemia: loss of blood supply in a tissue due
to impeded arterial flow or reduced venous
drainage
• Infarction: cell death
Definition of Terms
• Cerebral ischemia is caused by a reduction in
blood flow that lasts longer than several
seconds
• infarction - death of brain tissue
• transient ischemic attack (TIA) - all neurologic
signs and symptoms resolve within 24 h
regardless of whether there is imaging
evidence of new permanent brain injury
Hemorrhagic Stroke
• Bleeding into subdural and epidural spaces is
principally produced by trauma
• SAHs are produced by trauma and rupture of
intracranial aneurysms
• Hemorrhage are classified by location
• Often identified by CT scan
Ischemic Stroke
• Acute occlusion of an intracranial vessel
causing reduction in blood flow to the brain
region
• INFARCTION results when:
– Cerebral blood flow of 0 (zero) in 4 – 10 mins
– CBF <16-18 ml/ 100g tissue per min in 1 hour
• CBF <20ml/100g tissue per min = ischemia
Causes of Ischemic Stroke
Causes of Ischemic Stroke
• 30% of strokes remain unexplained despite
extensive evaluation
• establishing a cause is essential in reducing
the risk of recurrence
• Focus on: atrial fibrillation and carotid
atherosclerosis
• 20% of all ischemic strokes is CARDIOEMBOLIC
Causes of Ischemic Stroke
Cardioembolic Stroke
• 20% of all ischemic strokes
• embolism of thrombotic material forming on
the atrial or ventricular wall or the left heart
valves
• thrombi then detach and embolize into the
arterial circulation
• Embolic strokes tend to be sudden in onset,
with maximum neurologic deficit at once
Cardioembolic Stroke causes:
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nonrheumatic atrial fibrillation
MI
prosthetic valves
rheumatic heart disease
ischemic cardiomyopathy
Carotid Atherosclerosis
• 10% of all ischemic strokes
• frequently within the common carotid
bifurcation and proximal internal carotid
artery
• RISK FACTORS:
– Male gender, older age, smoking, hypertension,
diabetes, and hypercholesterolemia
Causes of Ischemic Stroke
Other causes of stroke
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Intracranial Atherosclerosis
Dissection of Internal Carotid Artery
Hypercoagulability
Venous sinous thrombosis
Fibromuscular dysplasia
Vasculitis
Approach to patient
• Once the diagnosis of stroke is made, a brain
imaging study is necessary to determine if the
cause of stroke is ischemia or hemorrhage
• CT imaging of the brain is the standard
imaging modality to detect the presence or
absence of intracranial hemorrhage
• If bleeding is ruled out, do thrombolysis
• Medical management to reduce the risk of
complications becomes the next priority
STROKE SYNDROMES
Middle Cerebral Artery
Middle Cerebral Artery
• entire MCA is occluded at its origin :
– contralateral hemiplegia,
hemianesthesia, homonymous
hemianopia, and a day or two of gaze
preference to the ipsilateral side
– Dysarthria is common because of
facial weakness
– global aphasia
– anosognosia, constructional apraxia,
and neglect
• to be continued........