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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.
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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 • 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
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: • nonrheumaticatrial 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
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
Middle Cerebral Artery • entire MCA is occluded at its origin : • contralateralhemiplegia, 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