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:

• 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

• 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........