Stroke Overview and Risk Factors

Stroke Overview

• A stroke, or cerebrovascular accident (CVA), is a sudden neurological deficit lasting at least 24 hours, presumed to have a vascular origin.
• Transient ischemic attacks (TIAs) are ischemic neurological deficits lasting less than 24 hours, usually less than 30 minutes.
• Strokes can be ischemic (85%) or hemorrhagic (15%).

Risk Factors

• Non-modifiable risk factors include increased age, male gender, and heredity.
• Modifiable risk factors include hypertension, cardiac disease (e.g., CAD), diabetes mellitus, dyslipidemia, and cigarette smoking.

Pathophysiology - Ischemic Stroke

• Ischemic strokes occur due to a local thrombus or emboli that block a cerebral artery, reducing cerebral blood flow and causing ischemia and infarction.

Pathophysiology - Hemorrhagic Stroke

• Hemorrhagic strokes result from bleeding within the brain (intracranial) or on its surface (subarachnoid).
• Blood in the brain damages tissue due to a mass effect and neurotoxicity of blood components.

Clinical Presentation

• Patients may present with unilateral weakness, speech difficulties, vision loss, vertigo, or falling.
• Ischemic strokes are typically not painful, but headaches can occur in hemorrhagic strokes.
• Neurologic deficits vary depending on the affected brain area, including hemiparesis, monoparesis and hemisensory deficits being common.
• Posterior circulation strokes may cause vertigo and diplopia.
• Anterior circulation strokes frequently result in aphasia, dysarthria, visual field defects, and altered levels of consciousness.

Diagnosis

• Initial diagnosis involves a CT scan or MRI of the brain.
• Further tests assess risk factors, such as blood pressure (hypertension), blood glucose (diabetes), and electrocardiogram (ECG) for arrhythmias.
• Carotid Doppler (CD), transthoracic echocardiogram (TTE), and transcranial Doppler (TCD) provide further diagnostic information.

Treatment - Ischemic Stroke

• Goals: Reduce ongoing neurologic injury, decrease mortality and disability, prevent complications from immobility, prevent stroke recurrence.
• General Approach: Ensure respiratory and cardiac support, quickly determine if lesion is ischemic or hemorrhagic. Elevated blood pressure (BP) typically not treated in the first 7 days of an ischemic stroke. BP lowered only if >220/120mmHg or there's evidence of specific conditions.
• Thrombolysis (tPA): Patients within 4.5 hours of stroke onset should receive intravenous tissue plasminogen activator (tPA) if appropriate, as it improves stroke outcomes.
• Brain Oedema Management: Elevated ICP managed by head elevation and osmotic agents like mannitol.

Treatment - Hemorrhagic Stroke

• No proven pharmacologic strategies exist yet for treating intracerebral hemorrhage. Medical guidelines focus on managing BP, intracranial pressure, and other complications.
• Patients with warfarin-related ICH receive intravenous vitamin K and replacement of clotting factors.
• Ca channel blocker Nimodipine (60mg every 4 hours for 21 days) may reduce the incidence and severity of neurologic complications from delayed ischemia.

Patients Monitoring

• Monitor for neurologic worsening (recurrence, extension), complications (infection, thromboembolism), adverse treatment effects.
• Common causes of deterioration include lesion extension, cerebral edema, hypertension, infections, venous thromboembolism, electrolyte abnormalities, and rhythm disturbances.
• Continuous monitoring is important, especially in the first few days

Complications (prevention and treatment)

• Various complications (Chest infections, Seizures, DVT/PE, Hyperglycemia, Pressure sores, Urinary infections, Constipation) can occur after a stroke.
• Prevention and management strategies include nurse care for oxygenation, treatment of diabetes, frequent turning for pressure sores, appropriate diuretics, and laxatives accordingly. Different medical treatments (antibiotics, anticonvulsants, anticoagulants, insulin) may be needed to manage specific complications.

Diagnostic Considerations - Ischemic Stroke

• Inclusion Criteria: Age ≥ 18, clinical diagnosis of ischemic stroke with measurable neurologic deficit, symptoms onset within 4.5 hours of treatment.
• Exclusion Criteria: History of previous intracranial hemorrhage, symptoms of subarachnoid hemorrhage (SAH), active internal bleeding or acute bleeding diathesis, recent heparin use (>48 hours), specific anticoagulant use, recent head trauma, arterial puncture at non-compressible site, intracranial neoplasm, significant previous stroke (<3 months), and blood glucose <50mg/dL or >400mg/dL.

This quiz covers essential information about strokes, including definitions, types of strokes, and their respective risk factors. Learn about ischemic and hemorrhagic strokes and their pathophysiology. Test your knowledge on how these medical conditions affect the brain.