Ishemic stroke (Summary)

Ischemic strokes occur as a result of an obstruction within a blood vessel supplying blood to the brain.

A stroke is a medical emergency. There are two types - ischemic and hemorrhagic. Ischemic stroke is the most common type.

 

Ischemic stroke can be divided into two main types: thrombotic and embolic. Deprived of oxygen and other nutrients, the brain suffers damage as a result of the stroke. A thrombotic stroke occurs when diseased or damaged cerebral arteries become blocked by the formation of a blood clot within the brain.

 

About 15% of embolic strokes occur in people with atrial fibrillation (Afib). The medical word for this type of blood clot is embolus. Thrombotic Stroke. A thrombotic stroke is caused by a blood clot that forms inside one of the arteries supplying blood to the brain.

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 reperfusion options (fibrinolytic and endovascular therapies) 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 stroke symptoms (neurologic deficits)

·         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

 

 

Diagnosis

·         Emergent brain imaging is essential for evaluation of acute 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 may also be used emergently:

·         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, leukemia), provide evidence of concurrent illness, and ensure absence of thrombocytopenia when considering fibrinolytic therapy

·         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 or the use of sympathomimetics, which can cause hemorrhagic and ischemic strokes

·         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

 

Management

·         Exercise

·         Lifestyle interventions (eg, smoking cessation, alcohol moderation)

·         Secondary prevention refers to the treatment of individuals who have already had a stroke.