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Ischemic Stroke

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Ischemic Stroke, Cerebrovascular Accident, Cerebrovascular Disease, Cerebral Infarction, Ischemic CVA, CVA

  • Epidemiology
  • Incidence (from most to least common)
  1. Overall Incidence: More than 795,000 cases in U.S. per year (2012)
    1. First Stroke: 610,000
    2. Recurrent Stroke: 185,000
  2. Ischemic Stroke: 85-88%
    1. Thrombotic Stroke (most common)
    2. Embolic Stroke
    3. Lacunar Stroke (least common of Ischemic Strokes)
  3. Hemorrhagic Stroke
    1. Intracerebral Hemorrhage: 9%
    2. Subarachnoid Hemorrhage: 3%
  • Pathophysiology
  • Types
  1. Thrombotic CVA
    1. Typically in older patients
    2. May also occur over age 40 years old with risks (Hypertension, Hyperlipidemia, Diabetes Mellitus, Tobacco abuse, Family History)
    3. Large vessel thrombosis (carotid, Vertebral arteries or Circle of Willis) cause fluctuating or recurring deficits developing over days
    4. Small vessel thrombosis involve deeper brain tissue (e.g. Internal Capsule, Basal Ganglia, pons, Thalamus)
  2. Embolic CVA
    1. More common in patients under age 50 years old
    2. Associated with new onset Atrial Fibrillation, valvular heart disease, endocarditis
    3. Cardiac or aortic source with often multiple sites affected and maximal deficit at onset
  3. Hypoperfusion
    1. May present as focal CVA due to asymmetric atherosclosis predisposing to localized injury
    2. Chronic Hypertension predisposes to Lacunar Infarctions (small focal Ischemic Strokes)
  • History
  1. Exact time of onset (or last seen time when at baseline status)
  2. Seizure activity
    1. Before stroke-like symptoms
      1. Consider postictal paralysis (see below)
    2. After stroke-like symptoms
      1. Contraindicates Thrombolysis
  3. Migraine Headaches (recent)
  4. Trauma (esp. Head Trauma, neck injury) in preceding days
    1. High velocity injuries (e.g. MVA) may result in neck vessel injury and secondary thrombosis
  5. Recent illness (e.g. Pneumonia or urinary tract symptoms)
  6. Diabetes Mellitus
  • History
  • Mnemonic ("LoST MIND")
  1. Last well or
  2. Onset (when observed)
  3. Seizure
  4. Trauma
  5. Migraine
  6. Illness
  7. Neck injury
  8. Diabetes Mellitus
  • Findings
  • Most reliable findings suggestive of Ischemic CVA
  1. Symptoms
    1. Acute onset of focal neurologic deficit (96% of patients)
    2. Subjective arm or leg weakness (63 to 54% of patients)
    3. Subjective speech disturbance (53% of patients)
    4. Subjective facial weakness (23% of patients)
  2. Signs
    1. Arm or leg paresis (61-69% of patients)
    2. Dysphagia or Dysarthria (57% of patients)
    3. Hemiparesis or Ataxia (53% of patients)
    4. Facial paresis (45% of patients)
    5. Eye movements or visual fields abnormal (27-24% of patients)
  3. References
    1. Hand (2006) Stroke 37(3): 776-80 [PubMed]
    2. Nor (2005) Lancet Neurol 4(11):727-34 [PubMed]
  • Signs
  • Vascular Distribution
  1. Anterior Circulation CVA
    1. Anterior Cerebral Artery CVA (3% of cases)
      1. Contralateral motor weakness and sensory deficit of leg, and to lesser extent head (spares forehead) and arm
      2. May be accompanied by significant cognitive and emotional deficits
    2. Middle Cerebral Artery CVA (most common)
      1. Contralateral motor weakness and sensory deficit of head (spares forehead) and arm, and to a lesser extent leg
      2. Aphasia occurs with left MCA lesion and hemineglect occurs with a right MCA lesion
      3. May be associated with eye changes (e.g. conjugate Eye Deviation towards the Brain Lesion, contralateral homonymous hemianopsia)
    3. Lacunar CVA (lacunar syndrome)
      1. Pure motor or sensory deficits resulting from Hypertension induced small vessel infarcts in the distal MCA branches
  2. Posterior Circulation CVA
    1. Posterior Cerebral Artery CVA (PCA CVA)
      1. Contralateral homonymous hemianopsia (visual field cut) and visual Agnosia (cannot recognize objects)
      2. Dizziness
      3. Memory and language deficits
    2. Posterior Inferior Cerebellar Artery CVA (PICA CVA)
      1. Dysarthria, Dysphagia, Dysphonia, Vertigo, Nystagmus, and Ataxia
      2. May also be associated with crossed findings of Medullary CVA (Ipsilateral facial deficit, contralateral extremity deficit)
    3. Vertebro-Basilar CVA
      1. Similar Posterior Circulation findings to either PCA CVA or PICA CVA described above
      2. Ipsilateral Cranial Nerve deficit and contralateral motor and sensory deficits
      3. May be associated with Syncope, quadriplegia, Diplopia, visual field deficits, Vertigo, Nystagmus, Vomiting and Dysphagia
  • Signs
  • Anatomic Distribution
  1. Cerebral cortex CVA
    1. Motor and sensory deficits of contralateral face and extremities
  2. Cerebellar CVA
    1. Vertigo with Nystagmus
    2. Ataxia
    3. Drop attacks
    4. Severe Nausea and Vomiting
  3. Pons CVA
    1. Abnormal breathing pattern
    2. Coma
    3. Miosis and gaze paralysis
  4. Brainstem CVA
    1. Ipsilateral facial weakness
    2. Contralateral extremity weakness
  • Exam
  • Distinguishing CVA etiology
  1. Embolic stroke-related findings
    1. Most severe at onset
    2. Concurrent embolic phenomenon (e.g. sudden pale, cold extremity)
    3. Irregularly irregular heart rhythm (Atrial Fibrillation)
    4. Heart Murmur (especially mitral valve or aortic valve)
    5. Mechanical heart sounds (Heart Valve Replacement)
    6. Fever (risk of Subacute Bacterial Endocarditis)
  2. Hypoperfusion stroke-related findings
    1. Chronic Hypertension
    2. Focal, pure deficits (pure motor or sensory deficit)
  3. Thrombotic stroke-related findings (Peripheral Arterial Disease)
    1. Decreased extremity pulses
    2. Carotid Bruits
  • Evaluation
  1. See CVA Evaluation
  2. See NIH Stroke Scale
  3. Bedside Glucose is an initial Vital Sign in CVA
  • Differential Diagnosis
  • Most Common (stroke mimics)
  1. Complicated Migraine (especially younger women)
  2. Hemorrhagic Stroke (Intracerebral Hemorrhage)
  3. Hypoglycemia
  4. Hypertensive Encephalopathy
  5. Seizure (post-ictal paralysis or Todd's Paralysis)
  • Differential Diagnosis
  • Less Common (stroke mimics)
  1. Head Trauma or Spinal Trauma (Closed Head Injury)
    1. Subdural Hematoma
    2. Epidural Hematoma
    3. Spinal Epidural Hematoma
  2. CNS Infection
    1. Meningitis
    2. Encephalitis
    3. Headache and Neurologic Deficits with Cerebrospinal Fluid Lymphocytosis (HaNDL Syndrome)
  3. Metabolic abnormality
    1. Nonketotic hyperosmolar coma (Hyperglycemia)
    2. Postcardiac Arrest Ischemia
    3. Toxin Ingestion
    4. Myxedema
    5. Uremia
  4. Systemic Infection
    1. Respiratory infection
    2. Urosepsis
  5. Miscellaneous
    1. Psychiatric symptoms (e.g. Somatoform Disorder, Conversion Disorder)
    2. Hypotension, shock state or Syncope
    3. Intracranial Mass (e.g. Intracranial tumor)
    4. Acute confusional state
  • Precautions
  1. Acute stroke presentation requires rapid assessment and management ("time is brain")
    1. Thrombolytics are only indicated within first 3 hours from CVA onset
  2. ABC Management is critical
    1. Especially important in Hemorrhagic Stroke, where patients typically present obtunded
  • Diagnosis
  1. Stroke is overdiagnosed in as many as a third of patients
    1. See differential diagnosis above for stroke mimics
    2. Stroke mimics represent up to 16% of cases in which Thrombolytics were given
    3. Predictors of misdiagnosis (stroke mimic)
      1. Known history of cognitive deficit (underlying Dementia)
      2. Non-neurologic abnormal physical findings
      3. Decreased Level of Consciousness
      4. Younger age
      5. Lower baseline NIHSS Score
      6. Global Aphasia without Hemiparesis
    4. References
      1. Guillan (2012) Cerebrovasc Dis 34(2): 115-20 [PubMed]
      2. Hand (2006) Stroke 37(3): 769-75 [PubMed]
      3. Mehta (2014) J Stroke Cerebrovasc Dis 23(5): 844-9 [PubMed]
  2. Dizziness is poorly corelated with Cerebrovascular Accident
    1. Isolated Dizziness is caused by Cerebrovascular Accident in only 0.7% of cases
      1. However stroke presenting as Dizziness is missed by the examiner in almost half of cases
    2. Factors predictive of Dizziness due to stroke
      1. See Central Causes of Vertigo
      2. Acute vestribular syndrome (Posterior Circulation in 25% of cases)
        1. Rapid onset (<1 hour) of acute, persistent, continuous Vertigo or Dizziness
        2. Associated with Nystagmus, Nausea or Vomiting, head motion intolerance, gait unsteadiness
    3. References
      1. Kerber (2006) Stroke 37(10): 2484-7 [PubMed]
      2. Tarnutzer (2011) CMAJ 183(9): E571-92 [PubMed]
  • Associated Conditions
  • Disorders that may present concurrently or as causative factor
  1. Acute Coronary Syndrome
  2. Congestive Heart Failure
  3. Atrial Fibrillation
  4. Atrial Flutter
  5. Carotid Dissection
  6. Vertebrobasilar Dissection
  7. Thoracic Aortic Dissection (less common)
  • Labs
  1. See CVA Evaluation
  2. Obtain bedside Serum Glucose (fingerstick Blood Sugar)
    1. Hypoglycemia (<63 mg/dl): Administer D50W (do not over-correct)
    2. Hyperglycemia (>300 mg/dl): Administer Insulin
  3. Labs to obtain in all patients
    1. Complete Blood Count (CBC) with Platelet Count
    2. Basic metabolic profile (e.g. Chem8)
    3. INR/ProTime (PT)
    4. Partial Thromboplastin Time (PTT)
    5. Serum Troponin I (or other Serum Cardiac Marker)
    6. Electrocardiogram
    7. Oxygen Saturation
  4. Labs and other diagnostics to obtain in selected patients
    1. Liver Function Tests
    2. Urine toxicology screen
    3. Blood Alcohol level
    4. Pregnancy Test
    5. Arterial Blood Gas or Venous Blood Gas
    6. Chest XRay
    7. Thrombin Time (or Ecarin clotting time) Indications
      1. Direct Thrombin Inhibitor use
      2. Direct Factor Xa Inhibitor use
    8. Lumbar Puncture indications
      1. Subarachnoid Hemorrhage is suspected despite negative Head CT
      2. Meningitis or Encephalitis suspected
    9. Electroencephalogram (EEG) indications
      1. Seizure suspected
  • Imaging
  1. See CVA Evaluation
  2. CT Head
    1. Performed immediately in the code stroke algorithm (followed by CTA if negative)
    2. Single most important imaging test that in combination with history drives emergent management
    3. Adequate sensitivity to exclude CNS mass lesions as well as acute Hemorrhage (with caveats)
    4. Negative Head CT does not exclude CVA (especially in first few hours and in posterior CVA)
      1. More than one third of strokes are missed on initial Head CT
  3. MRI Head
    1. Appears to be better imaging for initial CVA Evaluation
      1. However too slow for current stroke protocols
      2. Similar efficacy to CT Head for identifying Hemorrhagic CVA
      3. Chalela (2007) Lancet 369:293-8 [PubMed]
    2. Higher sensitivity for Ischemic CVA (especially posterior CVA)
      1. Consider in patients with higher risk of stroke mimic (e.g. age <55 years old)
      2. Ferro (2010) Lancet Neurol 9(11): 1085-96 [PubMed]
      3. Bhattacharya (2013) J Neurol Sci 324(1):62-4 [PubMed]
    3. Preferred imaging to define CNS Injury after CVA
      1. After initial stabilization, MRI should be considered as part of CVA Evaluation
      2. Consider repeating MRI at 3-7 days if posterior CVA is suspected but negative on initial MRI
        1. Initial MRI in first 48 hours misses 15% of posterior strokes
  • Management
  • Prevention
  1. See Prevention of Ischemic Stroke
  2. See Cerebrovascular Accident Risk Factors
  3. Evaluate for Carotid Stenosis after Ischemic Stroke or TIA
    1. See Transient Ischemic Attack
  4. Educate patients and their families
    1. Urgent evaluation for possible CVA (face drooping, arm weakness, speech difficulty)
    2. American Stroke Association (F.A.S.T campaign)
      1. http://www.strokeassociation.org/STROKEORG/WarningSigns/Stroke-Warning-Signs-and-Symptoms_UCM_308528_SubHomePage.jsp
  • Prognosis
  • Outcomes (based on U.S. 2011-2012 data)
  1. Total strokes: 795,000 per year in U.S.
  2. Recurrent CVA (highest risk in the next week)
  3. Recovery to baseline: 15% (119,000 in U.S/year)
  4. Persistent Aphasia (at 6 months): 15% (119,000 in U.S/year)
  5. Persistent Hemiparesis (at 6 months): 50% (398,000 in U.S/year)
  6. Mortality: 16% (130,000 in U.S./year)
    1. Fourth leading cause of death in the United States (accounts for 5% of U.S. deaths)