Ischemic Stroke

1. Risk Factors
   1. See Cerebrovascular Accident Risk Factors
2. Epidemiology: Incidence (from most to least common)
   1. Overall Incidence: More than 795,000 cases in U.S. per year
      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. Intracerebral Hemorrhagic Stroke: 9%
   4. Subarachnoid Hemorrhage: 3%
3. 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
   5. Recent illness (e.g. Pneumonia or urinary tract symptoms)
   6. Diabetes Mellitus
4. 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
5. 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
      2. Nor (2005) Lancet Neurol 4(11):727-34
6. Signs
   1. Anterior Circulation CVA
      1. See Anterior Cerebral Artery CVA
      2. See Middle Cerebral Artery CVA
   2. Posterior Circulation CVA
      1. See Posterior Inferior Cerebellar Artery CVA
      2. See Vertebro-Basilar CVA
      3. See Posterior Cerebral Artery CVA
7. Differential Diagnosis: Most Common
   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)
8. Differential Diagnosis: Less Common
   1. Head Trauma (Closed Head Injury)
      1. Subdural Hematoma
      2. Epidural Hematoma
   2. CNS Infection
      1. Meningitis
      2. Encephalitis
   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
      2. Hypotension, shock state or Syncope
      3. Intracranial Mass (e.g. Intracranial tumor)
9. 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
10. Diagnosis
    1. Stroke is overdiagnosed in as many as a third of patients
       1. See differential diagnosis above for stroke mimics
       2. Predictors of misdiagnosis
          1. Known history of cognitive deficit
          2. Non-neurologic abnormal physical findings
          3. Decreased Level of Consciousness
          4. Hand (2006) Stroke 37(3): 769-75
    2. Dizziness is poorly corelated with Cerebrovascular Accident
       1. Exception: Associated imbalance, Nystagmus or other cerebellar signs
       2. Kerber (2006) Stroke 37(10): 2484-7
11. Associated Conditions (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)
12. Evaluation
    1. See CVA Evaluation
    2. Bedside Glucose is an initial vital sign in CVA
13. Imaging
    1. 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
    2. MRI Head appears to be better imaging for initial CVA Evaluation
       1. However too slow for current stroke protocols
       2. Higher sensitivity for Ischemic CVA
       3. Similar efficacy to CT Head for identifying Hemorrhagic CVA
       4. Chalela (2007) Lancet 369:293-8
14. Management
    1. See CVA Management
15. Prevention: After Ischemic Stroke or TIA
    1. See Prevention of Ischemic Stroke
    2. Evaluate for Carotid Stenosis
       1. See Transient Ischemic Attack
16. Prognosis: Outcomes (based on U.S. 2011 data)
    1. Total strokes: 795,000 per year in U.S.
    2. Recovery to baseline: 15% (119,000 in U.S/year)
    3. Persistent Aphasia (at 6 months): 15% (119,000 in U.S/year)
    4. Persistent Hemiparesis (at 6 months): 50% (398,000 in U.S/year)
    5. 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)
17. Resources
    1. CDC Stroke
       1. http://www.cdc.gov/stroke/facts.htm
18. References
    1. (2000) Circulation 102(suppl I):I-204 to I-216
    2. Adams (2007) Stroke 38(5): 1655-711
    3. Bath (2000) West J Med 173:209
    4. Yew (2009) Am Fam Physician 80(1):33-40