Definition of Ischemic Stroke
Ischemic stroke is a neurological emergency caused by an obstruction or narrowing of cerebral arteries, leading to reduced blood flow and oxygen delivery to brain tissue. The resulting ischemia causes rapid neuronal injury, potentially resulting in acute neurological deficits, motor and sensory loss, speech disturbances, and, in severe cases, death.
In short, ischemic stroke occurs when a blockage or significant reduction of cerebral blood flow leads to sudden neurological dysfunction, carrying high morbidity and mortality risks.
Epidemiology
Ischemic strokes account for approximately 85% of all stroke cases.
Older adults are most commonly affected, but young patients may also experience ischemic strokes due to cardiac emboli or inherited thrombophilia.
Men and individuals with metabolic conditions such as hypertension, diabetes, and hyperlipidemia have higher risk.
Risk Factors
The development of ischemic stroke is influenced by several factors:
Cardiovascular risk factors: Hypertension, atrial fibrillation, coronary artery disease, diabetes mellitus, hyperlipidemia.
Lifestyle factors: Smoking, alcohol use, obesity, sedentary lifestyle.
Hematologic and genetic factors: Coagulation disorders, thrombophilia, prolonged anticoagulant or oral contraceptive use.
Vascular pathologies: Atherosclerosis, carotid stenosis, cardioembolic sources.
Other causes: Endocarditis, large-vessel inflammatory disorders, rare vasculopathies.
Etiology
Ischemic strokes are typically classified into three categories:
Thrombotic Stroke: Arterial blockage due to atherosclerotic plaque formation.
Often presents gradually with prodromal symptoms.
Embolic Stroke: Emboli from the heart or large vessels occlude cerebral arteries.
Sudden onset with severe neurological deficits.
Small Vessel (Lacunar) Stroke: Occlusion of small penetrating arteries, often related to chronic hypertension or diabetes.
Frequently manifests with motor, sensory, or combined deficits.
Clinical Presentation
Symptoms depend on the stroke type and affected region:
General symptoms: Sudden dizziness, altered consciousness, severe headache.
Focal neurological deficits:
Hemiparesis or hemiplegia
Sensory loss
Speech disorders (aphasia, dysarthria)
Visual field deficits (hemianopia, diplopia)
Coordination and balance disturbances (cerebellar strokes)
Diagnostic Methods
Rapid and accurate diagnosis is critical to guide ischemic stroke management.
Neurological Assessment: NIHSS (National Institutes of Health Stroke Scale) to assess severity.
Vital signs monitoring.
Radiological Imaging
Computed Tomography Scan (CT): First-line to exclude hemorrhage; acute ischemic changes may be subtle initially.
Magnetic Resonance Imaging (MRI/Diffusion-Weighted Imaging DWI: More sensitive for small or posterior circulation strokes; detects ischemic lesions early.
CT or MR Angiography: Detects large vessel occlusions and stenoses.
Digital Subtraction Angiography (DSA): Gold standard when endovascular intervention is planned.
Additional Evaluations
Cardiac assessment: ECG and echocardiography for embolic sources.
Carotid Doppler ultrasound: To evaluate carotid stenosis or plaques.
Laboratory tests: Glucose, lipid panel, coagulation profile, thrombophilia testing (particularly in younger patients).
Treatment Approaches
1. General Principles
Immediate neurological evaluation and stabilization.
Control of blood pressure, glucose, and fluid balance.
Oxygen therapy, fever management, and electrolyte monitoring.
Rapid reperfusion therapy when indicated.
2. Acute Reperfusion Therapy
Intravenous Thrombolysis (IV r-tPA): Administered within 4.5 hours of symptom onset in eligible patients.
Dose: 0.9 mg/kg (maximum 90 mg), with 10% as a bolus and the remainder over 60 minutes.
Endovascular Thrombectomy: Indicated for large vessel occlusions (e.g., MCA, ICA, vertebrobasilar arteries) within 6–24 hours.
Techniques include mechanical aspiration or stent retrievers.
Can be performed alone or following IV thrombolysis.
3. Blood Pressure and Metabolic Management
Avoid hypotension or severe hypertension, which can worsen ischemia.
Monitor IV fluids, glucose, and electrolytes to prevent secondary brain injury.
4. Antiplatelet and Anticoagulant Therapy
Post-thrombotic stroke: Aspirin or clopidogrel within 24–48 hours.
Cardioembolic stroke: Warfarin or direct oral anticoagulants (DOACs).
Short-term dual antiplatelet therapy (up to 21 days) may be considered for high-risk recurrent strokes.
5. Surgical Interventions
Decompressive Craniectomy: For large hemispheric infarcts with significant edema.
Carotid Endarterectomy or Stenting: For selected patients with ≥70% carotid stenosis.
6. Rehabilitation
Early physical therapy and mobilization.
Speech therapy, swallowing therapy, and occupational therapy.
Long-term lifestyle modification and secondary prevention.
7. Complications and Follow-Up
Brain edema, hemorrhagic transformation, seizures.
Secondary stroke prevention through risk factor management.
Regular cardiovascular and vascular follow-up.
Prevention of Ischemic Stroke
Preventive strategies focus on modifiable risk factors:
Lifestyle changes: Quit smoking, reduce alcohol, maintain healthy weight, and exercise regularly.
Medical management: Control hypertension, diabetes, and hyperlipidemia.
Cardiovascular monitoring: Treat atrial fibrillation or other embolic sources.
Medications: Long-term antiplatelet or anticoagulant therapy as indicated.
Conclusion
Ischemic stroke is a life-threatening condition requiring urgent diagnosis and effective treatment. Key objectives in the management of ischemic stroke include restoring blood flow, preventing secondary brain injury, and reducing long-term disability.
Understanding how to treat ischemic stroke and how to prevent ischemic stroke is essential for clinicians and patients alike. Early intervention and adherence to current guidelines in ischemic stroke management can save lives and improve recovery, making rapid recognition and treatment the cornerstone of care.