An Introduc+on to Stroke Elizabeth Huntoon MS, MD Assistant Professor Department of Physical Medicine and Rehabilita>on Vanderbilt University School of Medicine
Defini+on Sudden focal neurologic deficit due to occlusion or rupture of blood vessels supplying the brain TIA- symptoms < 24 hours, may have mild residua Stroke- symptoms usually more sever; > 24 hours AKA: Cerebrovascular accident or CVA
Risk Factors: non- modifiable Age > 55 Male > female Family history Race : African Americans 2x > whites> Asians
Risk Factors: Modifiable 10 risk factors that account for 90% of stroke risk are: Hypertension was the leading risk factor for all types of stroke Smoking Abdominal obesity Diabetes Lack of physical ac+vity Poor diet More than 30 drinks per month or binge drinking Ra+o of blood fats known as apolipoprotein B (apo B) to apolipoprotein AI (apo AI) Heart disease Psychosocial stress/depression O'Donnell, M.J. TheLancet 2010
Risk Factors: Possibly Modifiable History of TIA/prior stroke Heart disease, chronic heart failure, coronary artery disease, valvular heart disease, atrial fibrilla+on Caro+d stenosis Cocaine use High dose estrogens (Oral contracep+ves) Hyper- coagulable states (sickle cell disease, protein S or C deficiency, Cancer, etc.) Hyperlipidemia Patent foramen ovale Migraine headaches Sleep apnea
Types of Stroke Ischemic- 85% Thrombo+c Embolic Lacunar Hemorrhagic- 15% Intra- cerebral- hypertensive hemorrhage Subarachnoid- ruptured aneurysm
Ischemic - Thrombo+c Frequency of Ischemic strokes- 35% Perfusion failure Gradual, progressive deficit 50% with preceding TIA, usually same vascular territory
Ischemic - Embolic Frequency of Ischemic strokes 30% Usually cardiac source Sudden, severe deficits, may have seizure Preceding TIA- 11%
Ischemic - Lacunar Frequency of Ischemic strokes 20% < 15mm in diameter Due to occlusion of a single deep penetra+ng artery; occur most frequently in the basal ganglia and internal capsule, thalamus, corona radiata and brain stem May be asymptoma+c Abrupt or gradual onset Preceding TIA 23% lacunar infarct implies hypertensive small- vessel disease MRI more sensi+ve, acute lacunar infarcts are ofen undetectable on CT (Prac>cal Differen>al Diagnosis for CT and MRI edited by E. Lin, E. Escog, K. Garg 2008)
Hemorrhagic Stroke Hypertension Aneurysm Arterio- venous malforma+on Bleeding disorders An+coagula+on Tumors Angiopathies
Hemorrhagic Stroke Hypertensive Intracerebral Hemorrhage Linked to chronic hypertension Headache Nausea and Vomi+ng Nuchal rigidity
Hemorrhagic Stroke Subarachnoid Hemorrhage The main symptom is a severe headache that starts suddenly and is ofen worse near the back of the head. Pa+ents ofen describe it as the "worst headache ever Aneurysmal rupture
Imaging Non- contrast CT of the brain remains the mainstay of imaging in the sekng of an acute stroke CT is used to differen+ate ischemia from hemorrhage. Evidence of hemorrhage will be a contraindica+on to the use of thromboly+c or an+coagulant agents.
Advantages/Disadvantages of CT Advantages: Widespread access, noninvasiveness, speed of acquisi+on. Disadvantages: provides limited informa+on about the nature and age of an ischemic stroke during the crucial first three hours Limited capacity to show vascular lesions in the brain stem and cerebellum and small ischemic infarc+ons deep within the cerebral hemispheres. h-p://www.meddean.luc.edu/lumen/meded/radio/curriculum/neurology
Advantages of MRI MRI can also help define intra- cerebral hemorrhages, old and new. MRI is more sensi+ve than CT for the early diagnosis of brain infarc+on. With MRI, you can determine the precise loca+on and size of the infarc+on and follow the lesion over +me. h-p://www.meddean.luc.edu/lumen/meded/radio/curriculum/neurology
Advantages of MRI Lacunar infarcts and small cor+cal strokes are seen with higher sensi+vity. MRI scanners with the ability to perform FLAIR images (fluid- agenuated inversion recovery) and DWI (diffusion- weighted images) are very useful in showing infarcts early afer onset of symptoms. DWI images are useful in dis+nguishing acute from chronic ischemic changes. h-p://www.meddean.luc.edu/lumen/meded/radio/curriculum/neurology
Imaging It is important to remember that in pa+ents with ischemia who do not yet have infarc+on, both CT and MRI may be normal. Repea+ng the CT in 48 hours will most likely demonstrate the stroke lesion. h-p://www.meddean.luc.edu/lumen/meded/radio/curriculum/neurology
Treatment Immediate Management: ABC s Blood pressure management Intracranial Pressure Management Seizure management
Treatment Thromboly+c Therapy An+coagulant Therapy Caro+d endarterectomy Surgery Craniotomy and aneurysm clipping Endovascular coiling - - placing coils in the aneurysm to reduce the risk of further bleeding
Stroke Sequelae Deficits: Hemiparesis Spas+city Speech deficits Sensory abnormali+es Cogni+ve dysfunc+on
Rehabilita+on of Stroke- to be con+nued See An Introduc+on to Stroke : Part 2