Stroke Pathophysiology Etiology Risk factors Authors Dr Loreto

Stroke Pathophysiology, Etiology & Risk factors Authors: Dr. Loreto P. Talabucon and A/Prof. Deidre A. De Silva Level: Basic Academic Affiliation: National Neuroscience Institute Department of Neurology Singapore General Hospital Campus Version No: 1. 2 Submitted: March 2012 Editors’ Review: March 2013

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4 Learning Objectives • To define stroke • To describe its underlying pathophysiology • To understand the different etiological subtypes • To learn the epidemiology and common modifiable risk factors for stroke

5 Definition of Stroke “A sudden neurological deficit of vascular etiology lasting more than 24 hours” OR “imaging of an acute clinically relevant brain lesion in patients with rapidly vanishing symptoms”

6 Spectrum of Stroke 2 main types Ischemic stroke Vessel obstruction limits blood flow to part of the brain causing infarction arterial venous Hemorrhagic stroke Rupture of blood vessel causing hemorrhage Stroke affects blood vessels in the brain and spinal cord Image from FCIT Link here

7 Etiology of Ischemic Stroke • Large artery atherosclerosis Intracranial Extracranial • Small artery atherosclerosis • Cardioembolism Eg. Middle cerebral artery occlusion Eg. Atheroma in the carotid artery bifurcation Eg. Basal ganglia infarction due to occlusion of small penetrating artery Eg. From a thrombus in the left atrium secondary to atrial fibrillation • Others Images from Wikipedia Commons and FCIT Link here

8 Etiology of Hemorrhagic Stroke • Primary hypertensive hemorrhage • Secondary to ruptured AVM or aneurysm • Amyloid angiopathy Right basal ganglia hemorrhage on cranial CT Aneurysm as seen on angiography Histological appearance of cerebral amyloid angiopathy Images from Wikipedia Commons

9 Epidemiology • Average of first stroke is 73 years in developed countries • Males have higher stroke incidence • Ethnic differences in stroke subtypes distribution • Positive family history of stroke is associated with increased risk of stroke Image from FCIT Link here

10 Modifiable Risk Factors for Ischemic Stroke • Hypertension • Diabetes mellitus • Dyslipidemia • Atrial fibrillation • Ischemic heart disease eg recent AMI with LV thrombus • Cigarette smoking • Heavy alcohol drinking • Obesity • Physical inactivity • Drug use (cocaine and methamphetamine)

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