Stroke, Ischemic

SOURCE

Source: Fagan SC, Hess DC. Stroke. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic Approach. 10th ed. New York, NY: McGraw-Hill; 2017. http://accesspharmacy.mhmedical.com/content.aspx?bookid=1861&sectionid=132515962. Accessed May 8, 2017.

CONDITION/DISORDER SYNONYMS

• Apoplexy.

• Cerebrovascular accident (CVA)

DEFINITION

• Interruption of blood flow to area of brain, causing death of brain cells in area.

ETIOLOGY

• Local thrombus formation (eg, cerebral atherosclerosis)

• Emboli from intra- or extracranial arteries that occlude cerebral artery.

• Unknown causes.

PATHOPHYSIOLOGY

• Carotid atherosclerosis: Ruptured plaques lead to thrombus formation that may cause local occlusion or dislodge and travel distally, eventually occluding cerebral vessel.

• Cardiogenic embolism: Stasis of blood flow in atria or ventricles leads to formation of clots that dislodge and travel through aorta to cerebral circulation.

• Resulting arterial occlusion decreases cerebral blood flow and causes ischemia and infarction distal to occlusion.

EPIDEMIOLOGY

• Stroke (including ischemic and hemorrhagic types) leading cause of adult disability in United States.

• African Americans have stroke rates twice those of whites.

• Some states in southeastern United States have stroke mortality rates 40% higher than the national average.

PREVENTION AND SCREENING

• Preventive measures directed toward reducing or eliminating modifiable risk factors for stroke.

RISK FACTORS

• Nonmodifiable risk factors:

  • Age.

  • Race.

  • Low birth weight.

  • Genetics.

• Modifiable, well documented:

  • Cigarette smoking.

  • Hypertension.

  • Diabetes.

  • Asymptomatic carotid stenosis.

  • Dyslipidemia.

  • Atrial fibrillation.

  • Sickle cell disease.

  • Poor diet.

  • Obesity.

  • Physical inactivity.

  • Other cardiac diseases (coronary heart disease, heart failure, PAD)

• Potentially modifiable, less well documented:

  • Migraine.

  • Metabolic syndrome.

  • Drug and alcohol abuse.

  • Inflammation and infection.

  • Elevated Lp(a)

  • Homocysteinemia.

  • Sleep-disordered breathing.

CLINICAL PRESENTATION

• May need to obtain medical history from family members or others because cognitive or language deficits may preclude patient from giving reliable history.

SIGNS AND SYMPTOMS

• Symptoms:

  • Weakness on one side of body.

  • Inability to speak.

  • Loss of vision.

  • Vertigo.

  • Falling.

  • Headache.

• Signs of neurologic dysfunction depend on brain area involved.

  • Hemi- or monoparesis and hemisensory deficits common.

  • Posterior circulation involvement may present with vertigo and diplopia.

  • Anterior circulation strokes result in aphasia.

  • Other potential signs:

    • Dysarthria.

    • Visual field defects.

    • Altered levels of consciousness may be present.

DIAGNOSIS

LABORATORY TESTS

• Obtain tests for hypercoagulable states (protein C, protein S, antithrombin III) only when cause cannot be determined based on review of risk factors.

• Obtain antiphospholipid antibodies in patients younger than age 50 and those who have had multiple thrombotic events or livedo reticularis.

IMAGING

• Computed tomography (CT) head scan.

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