Presentation on theme: "Stroke: An Overview 台北榮民總醫院 神經醫學中心 神經血管科 許立奇 醫師. What Is Stroke ? A stroke occurs when blood flow to the brain is interrupted by a blocked or burst blood."— Presentation transcript:
What Is Stroke ? A stroke occurs when blood flow to the brain is interrupted by a blocked or burst blood vessel.
Definition of Stroke Stroke (Cerebrovascular accident, CVA): rapidly developing clinical signs of focal or global disturbance of cerebral function, with symptoms lasting 24 hours or longer, or leading to death, with no apparent cause other than a vascular origin WHO, 1976 Stroke definition by time course: Transient ischemia attack (TIA): ischemic events < 24 hours without apparent permanent neurological deficits Stoke in evolution: progressive neurological deficits over time suggesting a widening of the area of ischemia Completed stroke: ischemic event with persisted deficit
Stroke Subtypes Ischemic Stroke (83%) Hemorrhagic Stroke (17%) Atherothrombotic Cerebrovascular Disease (20%) Embolism (20%) Lacunar (25%) Small vessel disease Cryptogenic and Other Known Cause (30%) Intracerebral Hemorrhage (59%) Subarachnoid Hemorrhage (41%) Albers GW, et al. Chest. 1998;114:683S-698S. Rosamond WD, et al. Stroke. 1999;30:736-743.
Epidemiology ( I ): Global Burden 15 million nonfatal stroke each year in the world Second leading cause of death: 5 million each year Major cause of permanent disability: another 5 million each year Risk of stroke: age- and sex-dependent Incidence: varies with geography 388/100,000 in Russia, 247/100,000 in China to 61/100,000 in Fruili, Italy
Epidemiology ( II ): Taiwan The second leading cause of death Incidence: average annual incidence of first-ever stroke in Taiwan aged 36 years old or over is 300/100,000 (CI: 71%, ICH: 22%, SAH: 1%,others: 6%) Prevalence: 1,642/100,000 (>36 years old)
Pathophysiology of Ischemic Brain Injury Brain: 2% of human body’s mass 20% of cardiac output Inadequate perfusion: tissue death and functional deficit Ischemic brain injury: A series of interlocking thresholds – the “ ischemic thresholds ” Decrement in regional CBF key pathologic events
Effects of Reduced CBF Normal ml/100g/mi n 50 – 55 25 20 15 8 Ischemia Edema Loss of Na/K+ electrical pump ↑lactate activity failure; ↓ ATP Penumbra Infarction Cell Death
Pathophysiology of Ischemic Brain Injury Topography of focal ischemia Flow gradient: heterogeneous regional CBF reduction after focal ischemia Densely ischemia region surrounded by areas of less severe CBF reduction Ischemic penumbra: an area of reduced perfusion sufficient to cause potentially reversible clinical deficits but insufficient to cause disrupted ionic homeostasis
Pathogenesis of Ischaemic Stroke Penumbra Infarction
What Is the Cause of Ischemic Stroke? Atherothrombosis Embolus: Material: Red (fibrin rich) or White (platelet rich) Source: Cardiac? Aortic? Carotid Artery? Small artery disease Hypoperfusion: Hemodynamic Others: arterial dissection, arteritis, etc.
Ischemic Stroke Subtypes: Data from Taiwan Stroke Registry (2010) Subtypes Total Large artery atherosclerosis Small vessel disease Cardioembolism Other specific etiologies Undetermined etiologies 27.7% 37.7% 10.9% 1.5% 22.3% Total 100%
Stroke Warning Signs Sudden weakness or numbness of the face, arm or leg, especially on one side of the body Sudden confusion, trouble speaking or understanding Sudden trouble seeing in one or both eyes Sudden trouble walking, dizziness/vertigo, loss of balance or coordination Sudden, severe headaches with no known cause (for hemorrhagic stroke)
Localization Carotid territory Amaurosis fugax Dysphasia Hemiparesis Hemi-sensory loss Vertebrobasilar Hemianopia Quadraparesis Cranial N dysfunction Cerebellar syndrome Crossed deficit Loss of consciousness
Laboratory Examinations Hb, Hcr, thromb, leuc glu, CRP, SR, CK, CK-MB, creat APTT, TT-SPA/INR Electrolytes, osmolarity Urine analysis CSF (if needed for differential diagnosis and only after CT scan, if available) Others, e.g., coagulation survey, homocysteine for young stroke, rheumotology/immunology screening Cardiac evaluation: ECG, echocardiography
Evaluation of the Vascular System Reprinted with permission from Albers GW, et al. Chest. 2001;119:300S-320S. Penetrating artery disease Flow-reducing carotid stenosis Atrial fibrillation Valve disease Left ventricular thrombi Cardiogeni c emboli Aortic arch plaque Carotid plaque with arteriogenic emboli Intracranial atherosclerosis
Distinguishes reliably between haemorrhagic and ischemic stroke Detects signs of ischemia as early as 2 h after stroke onset Identifies haemorrhage immediately Detects acute SAH in 95% of cases Helps to identify other neurological diseases (e.g. neoplasms) Diagnosis: CT Scan
Multimodal CT Imaging Perfusion Status CTPCT CTA CT, computed tomography; PCT, positron computed tomography; CTA, computed tomography angiography. Images courtesy of UCLA Stroke Center. Tissue Status Vessel Status
Ischemic stroke Hemorrhage stroke Craniocerebral / cervical trauma Meningitis/encephalitis Intracranial mass Tumor Subdural hematoma Seizure with persistent neurological signs Migraine with persistent neurological signs Metabolic Hyperglycemia (nonketotic hyperosmolar coma) Hypoglycemia Post-cardiac arrest ischemia Drug/narcotic overdose Differential Diagnosis of Stroke
Diagnosis: MRI (DWI and PWI) Acute Ischemic Stroke Diffusion-weighted imaging (DWI) : Detects areas of restricted diffusion of water Bright-up in acute ischemic stroke Differentiation between new and old lesions Perfusion-weighted imaging (PWI): Detects abnormal tissue perfusion Diffusion-perfusion mismatch: Area of penumbra? Target of thrombolysis
Multimodal MRI Imaging Tissue Status Perfusion Status Vessel Status DWIPWIMRA DWI, diffusion-weighted imaging; PWI, perfusion-weighted imaging; MRA, magnetic resonance angiography. Images courtesy of UCLA Stroke Center.
Management of Cerebrovascular Disease: Current Strategies Treatment of risk factors in large populations Treatment of highest risk persons Management of acute stroke Prevention and treatment of medical and neurological complications Rehabilitation Prevention of recurrent stroke
Strategies for Preventing Stroke and Reducing Stroke Disability First stroke blood pressure glucose smoking lipids mass popl. strategy hypertension TIA Atrial fibrillation other vascular disease high risk strategy stroke mortality acute treatment Secondary prevention recurrent stroke Stroke related disability Rehabilitation