From: deputyfife23x@gmail.com   
      
   Ischemic Stroke   
   Author: Edward C Jauch, MD, MS, FAHA, FACEP; Chief Editor: Helmi L Lutsep, MD    
   more...   
   Updated: Jul 30, 2015   
   Overview   
   Practice Essentials   
      
      
   Ischemic stroke (see the image below) is characterized by the sudden loss of   
   blood circulation to an area of the brain, resulting in a corresponding loss   
   of neurologic function. Acute ischemic stroke is caused by thrombotic or   
   embolic occlusion of a    
   cerebral artery and is more common than hemorrhagic stroke.   
      
   Maximum intensity projection (MIP) image from a co   
   Maximum intensity projection (MIP) image from a computed tomography angiogram   
   (CTA) demonstrates a filling defect or high-grade stenosis at the branching   
   point of the right middle cerebral artery (MCA) trunk (red circle), suspicious   
   for thrombus or    
   embolus. CTA is highly accurate in detecting large- vessel stenosis and   
   occlusions, which account for approximately one third of ischemic strokes.   
   View Media Gallery   
   See Acute Stroke, a Critical Images slideshow, for more information on   
   incidence, presentation, intervention, and additional resources.   
      
   Signs and symptoms   
      
   Consider stroke in any patient presenting with acute neurologic deficit or any   
   alteration in level of consciousness. Common stroke signs and symptoms include   
   the following:   
      
   Abrupt onset of hemiparesis, monoparesis, or (rarely) quadriparesis   
   Hemisensory deficits   
   Monocular or binocular visual loss   
   Visual field deficits   
   Diplopia   
   Dysarthria   
   Facial droop   
   Ataxia   
   Vertigo (rarely in isolation)   
   Nystagmus   
   Aphasia   
   Sudden decrease in level of consciousness   
   Although such symptoms can occur alone, they are more likely to occur in   
   combination. No historical feature distinguishes ischemic from hemorrhagic   
   stroke, although nausea, vomiting, headache, and sudden change in level of   
   consciousness are more common    
   in hemorrhagic strokes. In younger patients, a history of recent trauma,   
   coagulopathies, illicit drug use (especially cocaine), migraines, or use of   
   oral contraceptives should be elicited.   
      
   With the availability of fibrinolytic therapy for acute ischemic stroke in   
   selected patients, the physician must be able to perform a brief but accurate   
   neurologic examination on patients with suspected stroke syndromes. The goals   
   of the neurologic    
   examination include the following:   
      
   Confirming the presence of a stroke syndrome   
   Distinguishing stroke from stroke mimics   
   Establishing a neurologic baseline, should the patient's condition improve or   
   deteriorate   
   Establishing stroke severity, using a structured neurologic exam and score   
   (National Institutes of Health Stroke Scale [NIHSS]) to assist in prognosis   
   and therapeutic selection   
   Essential components of the neurologic examination include the following   
   evaluations:   
      
   Cranial nerves   
   Motor function   
   Sensory function   
   Cerebellar function   
   Gait   
   Deep tendon reflexes   
   Language (expressive and receptive capabilities)   
   Mental status and level of consciousness   
   The skull and spine also should be examined, and signs of meningismus should   
   be sought.   
      
   See Clinical Presentation for more detail.   
      
   Diagnosis   
      
   Emergent brain imaging is essential for confirming the diagnosis of ischemic   
   stroke. Noncontrast computed tomography (CT) scanning is the most commonly   
   used form of neuroimaging in the acute evaluation of patients with apparent   
   acute stroke. The    
   following neuroimaging techniques are also used:   
      
   CT angiography and CT perfusion scanning   
   Magnetic resonance imaging (MRI)   
   Carotid duplex scanning   
   Digital subtraction angiography   
   Lumbar puncture   
      
   A lumbar puncture is required to rule out meningitis or subarachnoid   
   hemorrhage when the CT scan is negative but the clinical suspicion remains high   
      
   Laboratory studies   
      
   Laboratory tests performed in the diagnosis and evaluation of ischemic stroke   
   include the following:   
      
   Complete blood count (CBC): A baseline study that may reveal a cause for the   
   stroke (eg, polycythemia, thrombocytosis, thrombocytopenia, leukemia) or   
   provide evidence of concurrent illness (eg, anemia)   
   Basic chemistry panel: A baseline study that may reveal a stroke mimic (eg,   
   hypoglycemia, hyponatremia) or provide evidence of concurrent illness (eg,   
   diabetes, renal insufficiency)   
   Coagulation studies: May reveal a coagulopathy and are useful when   
   fibrinolytics or anticoagulants are to be used   
   Cardiac biomarkers: Important because of the association of cerebral vascular   
   disease and coronary artery disease   
   Toxicology screening: May assist in identifying intoxicated patients with   
   symptoms/behavior mimicking stroke syndromes   
   Pregnancy testing: A urine pregnancy test should be obtained for all women of   
   childbearing age with stroke symptoms; recombinant tissue-type plasminogen   
   activator (rt-PA) is a pregnancy class C agent   
   Arterial blood gas analysis: In selected patients with suspected hypoxemia,   
   arterial blood gas defines the severity of hypoxemia and may be used to detect   
   acid-base disturbances   
   See Workup for more detail.   
      
   Management   
      
   The goal for the emergent management of stroke is to complete the following   
   within 60 minutes of patient arrival[3] :   
      
   Assess airway, breathing, and circulation (ABCs) and stabilize the patient as   
   necessary   
   Complete the initial evaluation and assessment, including imaging and   
   laboratory studies   
   Initiate reperfusion therapy, if appropriate   
   Critical treatment decisions focus on the following:   
      
   The need for airway management   
   Optimal blood pressure control   
   Identifying potential reperfusion therapies (eg, intravenous fibrinolysis with   
   rt-PA or intra-arterial approaches)   
   Involvement of a physician with a special interest in stroke is ideal. Stroke   
   care units with specially trained personnel exist and improve outcomes.   
      
   Ischemic stroke therapies include the following:   
      
   Fibrinolytic therapy   
   Antiplatelet agents [4, 5]   
   Mechanical thrombectomy   
   Treatment of comorbid conditions may include the following:   
      
   Reduce fever   
   Correct hypotension/significant hypertension   
   Correct hypoxia   
   Correct hypoglycemia   
   Manage cardiac arrhythmias   
   Manage myocardial ischemia   
   Stroke prevention   
      
   Primary stroke prevention refers to the treatment of individuals with no   
   previous history of stroke. Measures may include use of the following:   
      
   Platelet antiaggregants   
   Statins   
   Exercise   
   Lifestyle interventions (eg, smoking cessation, alcohol moderation)   
   Secondary prevention refers to the treatment of individuals who have already   
   had a stroke. Measures may include use of the following:   
      
   Platelet antiaggregants   
   Antihypertensives   
   Statins   
   Lifestyle interventions   
   See Treatment and Medication for more detail.   
      
   Background   
      
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