Ischemic Stroke

Practice Essentials
Ischemic stroke 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.
Essential update: Study indicates intra-arterial treatment improves functional recovery in acute ischemic stroke
A randomized clinical trial from the Netherlands indicates that endovascular intervention benefits functional outcomes in patients with acute ischemic stroke resulting from a proximal intracranial arterial occlusion. In the study, by Berkhemer et al, 500 patients were randomized to receive intra-arterial treatment (within 6 hours of symptom onset) or usual treatment alone. Although 89% of the patients were treated with tissue-type plasminogen activator (t-PA) prior to randomization, only those who were found on computed tomography (CT) angiography to still have a proximal arterial occlusion were entered into the study. In most of the patients who received intra-arterial treatment, the procedure was performed with latest-generation stent retrievers.
The investigators found that at 90 days, the rate of functional independence (modified Rankin scale score of 0-2) in the intra-arterial treatment group was 32.6%, compared with 19.1% in the usual-treatment-only group, while after 5-7 days, the National Institutes of Health Stroke Scale (NIHSS) score was an average of 2.9 points lower in the intra-arterial treatment patients than it was in the other group. The two groups did not differ significaIschemic Strokently with regard to the rate of morality or symptomatic intracerebral hemorrhage.
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 patients 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:
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
  • 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:

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