Description

Interruption of blood flow to a specific brain region, causing focal neurologic dysfunction that persists for more than 24 hr:

• Neurologic findings are determined by specific area affected
• Onset may be sudden and complete, or stuttering and intermittent
• 795,000 strokes every year in the US

Risk Factors

• Diabetes
• Smoking
• HTN
• Coronary artery disease
• Dysrhythmias
• Peripheral vascular disease
• Oral contraceptive use

Blood dyscrasia (Polycythemia vera, sickle cell anemia, deficiencies of antithrombin III, protein C or S)

Etiology

• May be ischemic (thrombotic, embolic, or secondary to dissection/hypoperfusion) or hemorrhagic
• Thrombotic stroke: Occlusion of blood vessels:
  • Clot formation at an ulcerated atherosclerotic plaque is most common
  • Sludging (sickle cell anemia, polycythemia vera, protein C deficiency)
• Embolic stroke: Acute blockage of a cerebral artery by foreign material from outside the brain, including:
  • Cardiac mural thrombi associated with mitral stenosis, atrial fibrillation, cardiomyopathy, CHF, or MI
  • Prosthetic or abnormal native valves
  • Atherosclerotic plaques in the aortic arch or carotid arteries
  • Atrial myxoma
  • Ventricular aneurysms with thrombi
• Arterial dissection:
  • Carotid artery dissection
  • Arteritis (giant cell, Takayasu)
  • Fibromuscular dysplasia
• Global ischemic or hypotensive stroke is caused by an overall decrease in systemic BP: Sepsis, hemorrhage, shock
• Hemorrhagic stroke:
  • Intracranial hemorrhage (ICH)
  • Non-traumatic (spontaneous): subarachoid hemorrhage