Chapter 9: Cerebrovascular Accident (Stroke)

A cerebrovascular accident, commonly known as a stroke, occurs when blood flow to the brain is suddenly interrupted or bleeding develops within the cranial cavity, resulting in acute neurological dysfunction. Strokes represent a major health burden in the United States, ranking among the leading causes of mortality and long-term disability in adults. Ischemic strokes, accounting for approximately eighty percent of all cases, develop when arterial occlusion reduces cerebral perfusion and oxygen delivery to neural tissue. These ischemic events occur through three primary mechanisms: thrombotic occlusion from local atherosclerotic plaque formation, embolic obstruction from circulating debris typically originating from cardiac sources or upstream arterial lesions, and hypoperfusive injury resulting from globally diminished cerebral blood flow. Hemorrhagic strokes comprise the remaining twenty percent and involve bleeding either within brain parenchyma from hypertensive rupture or amyloid angiopathy, or in the subarachnoid space from ruptured aneurysms. Transient ischemic attacks represent temporary ischemic episodes that resolve without permanent injury but signal substantially elevated future stroke risk. Risk stratification requires identification of both nonmodifiable factors such as advancing age and genetic predisposition, and modifiable factors including hypertension, atrial fibrillation, diabetes, hypercholesterolemia, and smoking. Clinical presentation depends on the vascular territory affected, with anterior circulation involvement producing contralateral motor and sensory deficits plus language disturbances, while posterior circulation compromise causes cranial nerve abnormalities, ataxia, and vertigo. Diagnosis relies on neuroimaging to differentiate ischemic from hemorrhagic pathology, with computed tomography serving as the initial screening modality and magnetic resonance imaging providing superior sensitivity for acute ischemic lesions. Acute management of ischemic strokes includes intravenous thrombolytic therapy with tissue plasminogen activator when treatment occurs within the appropriate time window, and mechanical thrombectomy for large vessel occlusions. Hemorrhagic strokes require aggressive blood pressure management and reversal of anticoagulation. Secondary prevention through antiplatelet or anticoagulant therapy, statin use, surgical revascularization procedures, and comprehensive lifestyle modification substantially reduces recurrence risk.