NURS 4581: Strokes

Cerebrovascular Disorder Overview

  • Definition: A cerebrovascular disorder indicates a functional abnormality of the central nervous system (CNS) due to disrupted blood supply to the brain.

  • Stroke in the U.S.: Leading cerebrovascular disorder and a major cause of serious long-term disability.

  • Statistics: Stroke has decreased to the 5th leading cause of death.

Types of Stroke

  • Categories:

    • Ischemic Stroke: 87% of strokes, caused by blockage of blood vessels leading to significant hypoperfusion.

    • Types of Ischemic Stroke:

      • Large artery thrombotic strokes (20%)

      • Small penetrating artery thrombotic strokes (25%)

      • Cardiogenic embolic strokes (20%)

      • Cryptogenic strokes (30%)

      • Others (5%)

    • Hemorrhagic Stroke: 13% of strokes, involves blood extravasation into brain tissue or subarachnoid space.

Ischemic Stroke

  • Definition: Sudden loss of brain function due to disruption of blood supply, also called a "brain attack."

  • Treatment Window: The FDA-approved thrombolytic therapy (t-PA) must be administered within 3 hours after stroke onset; can be extended to 4.5 hours.

  • Ischemic Cascade:

    • Initiation: Decreased cerebral blood flow leads neurons to switch from aerobic to anaerobic respiration, causing a lactic acid buildup, diminished ATP production, and cellular dysfunction.

    • Penumbra Region: Surrounding area of low cerebral blood flow which may be salvaged if treated quickly.

    • Pathophysiological Events: Increase in intracellular calcium, release of glutamate, vasoconstriction, production of free radicals leading to cellular destruction.

Clinical Manifestations of Ischemic Stroke

  • General Symptoms:

    • Numbness/weakness on one side of the body (face, arm, leg)

    • Confusion, changes in mental status

    • Speech issues (dysarthria, dysphasia, aphasia)

    • Visual disturbances

    • Loss of balance or coordination

    • Severe headache

  • Motor Function: Loss of voluntary control; common dysfunction includes hemiplegia and hemiparesis.

Communication and Cognitive Function Impact

  • Language:

    • Aphasia (expressive, receptive, global), apraxia (difficulty in performing tasks), and dysarthria (difficulty speaking).

  • Perceptual Disturbances:

    • Visual-perceptual dysfunction affecting the ability to interpret sensations leading to conditions like agnosia.

  • Cognitive Function: Damage to the frontal lobe may lead to impaired learning and memory.

Assessment and Diagnostics

  • Initial Assessment: Focus on airway, cardiovascular status, functional deficits. Rapid history-taking is crucial.

  • Transient Ischemic Attack (TIA): Symptoms resolving within 24 hours but indicates risk for stroke.

  • Diagnostic Tools:

    • Non-contrast CT scans are preferred at presentation.

    • Further evaluations may include MRI, CT angiography, and ECGs.

Prevention of Stroke

  • Primary Prevention: Managing modifiable risk factors is key, including:

    • Controlling hypertension and diabetes

    • Healthy diet (DASH and Mediterranean diets recommended)

    • Regular physical activity, maintaining healthy weight, avoiding smoking.

  • Medication: Low-dose aspirin may reduce the risk of first stroke for those at risk.

Medical Management of Post-Stroke

  • Medications:

    • Anticoagulants for TIA or stroke patients.

    • Platelet inhibitors and dual antiplatelet therapy (aspirin + clopidogrel).

    • Statins recommended for long-term stroke prevention.

Thrombolytic Therapy (t-PA) Protocol

  • Administration:

    • Dosage: 0.9 mg/kg maximum 90 mg; 10% as IV bolus, remaining as infusion over 1 hour.

    • Intensive monitoring is crucial.

  • Goals: Rapid diagnosis and treatment can significantly improve outcomes.

Hemorrhagic Stroke

  • Definition: Caused mainly by intracerebral hemorrhage; high mortality rate (up to 50%).

  • Causes: Include hypertension, cerebral aneurysms, arteriovenous malformations (AVMs).

  • Clinical Presentation: Symptoms similar to ischemic stroke with severe headaches, nausea, decreased consciousness.

  • Management: Focus on controlling blood pressure, surgical interventions may be required.

Complications of Stroke Management

  • Increased Intracranial Pressure (ICP): Monitor for deterioration in neurological status.

  • Preventative Measures: Bed rest, medication for blood pressure management, seizure precautions, monitoring for signs of hydrocephalus and cerebral vasospasm.

  • Surgery: Carotid endarterectomy (CEA) and stenting procedures are essential for certain patients.

Conclusion

  • Holistic Approach: Comprehensive assessment and timely intervention are vital for effective stroke management and rehabilitation.