Cerebrovascular Accident (CVA) / Stroke and Transient Ischemic Attack (TIA) Study Notes

Understanding Cerebrovascular Accident (CVA) / Stroke

Stroke, also known as a Cerebrovascular Accident (CVA) or "brain attack," occurs due to either bleeding in the brain (hemorrhagic stroke) or a clot in the brain (ischemic stroke), leading to insufficient blood flow and tissue damage.

Epidemiology and Statistics

  • Stroke is the most common disease of the nervous system.

  • Approximately 795,000 people in the U.S. suffer from a stroke annually.

  • It is the fourth leading cause of death in the United States, accounting for 140,000 deaths per year.

  • It primarily affects individuals between 75 and 85 years of age.

  • Racial Disparities:

    • Thrombotic strokes are twice as common among African Americans.

    • Hemorrhagic strokes are three times more common among African Americans.

    • Hispanics, Native Americans, and Asian Americans exhibit a higher stroke incidence compared to White individuals.

Long-Term Disabilities from Stroke

Common long-term disabilities include:

  • Hemiparesis: Weakness on one side of the body.

  • Hemiplegia: Paralysis on one side of the body. (Note the critical distinction between hemiparesis and hemiplegia).

  • Inability to walk.

  • Complete or partial dependence in Activities of Daily Living (ADLs).

  • Aphasia: Difficulty with language.

  • Depression.

Risk Factors for Stroke

Risk factors are categorized as modifiable (changeable) or non-modifiable (unchangeable).

  • Modifiable Risk Factors:

    • Obesity

    • Stress

    • Smoking

    • Atherosclerosis

    • Atrial fibrillation (accounts for 15 to 20 percent of strokes)

    • Heart disease

    • Hypertension (single most important modifiable risk factor; appropriate treatment can reduce stroke risk by up to 42\%)

    • Kidney disease

    • Peripheral vascular disease

    • Diabetes (increases stroke risk 4 to 5 times)

    • Carotid artery stenosis (responsible for approximately 80\% of Transient Ischemic Attacks - TIAs)

    • High serum cholesterol

    • Use of cocaine

    • Sedentary lifestyle

    • Smoking while taking oral contraceptives

  • Non-Modifiable Risk Factors:

    • Family history of stroke

    • Age

    • Sex

    • Ethnicity

Types of Strokes

Ischemic Stroke

This type occurs due to insufficient blood flow to the brain from a partial or complete occlusion of an artery. Ischemic strokes, including thrombotic and embolic types, represent 85 to 90 percent of all strokes.

Thrombotic Stroke

  • Definition: A thrombus (a clot that forms in the artery, usually around a fatty deposit called plaque) gets lodged in the plaque, obstructing blood flow. In 95\% of cases, it remains stationary.

  • Most common cause of stroke.

  • Often preceded by a Transient Ischemic Attack (TIA).

  • Most frequently observed in the 60 to 90-year-old age group.

  • Symptoms typically occur during sleep or soon after waking, when resting blood pressure is lower, leading to brain ischemia.

Embolic Stroke

  • Definition: An embolus (a blood clot or other circulating matter that detaches) travels through the bloodstream and becomes lodged in a vessel, obstructing blood flow.

  • Second most common cause of stroke.

  • Usually affects younger individuals.

  • Common origins of emboli:

    • Heart conditions: Rheumatic heart disease, mitral stenosis, myocardial infarction, infective endocarditis, valve replacements, atrial septal defects.

    • Other sources: Air embolus, fat from long bone fractures, amniotic fluid after childbirth, tumors.

  • The embolus travels upward into the cerebral circulation and lodges where a vessel narrows or bifurcates (branches into a V-shape).

Hemorrhagic Stroke

  • Definition: A blood vessel in the brain bursts and leaks blood into the brain tissue.

  • Accounts for approximately 15\% of all strokes.

  • Often caused by the rupture of an aneurysm (a localized dilation or bulge in the wall of a vessel, typically due to atherosclerosis and hypertension).

  • More commonly affects women than men.

  • Usually occurs in people aged 35 to 60 years.

  • Mechanism: The aneurysm ruptures, and the bleeding spreads rapidly, causing damage and irritation to cerebral vessels. The bleeding eventually stops when fibrin forms a plug, and the hemorrhage is typically absorbed within three weeks.

  • Prognosis: High risk of recurrent rupture 7 to 10 days after the initial event. No warning signs; symptoms are sudden, severe, and rapid in onset. There is usually a poor prognosis for recovery, with approximately 50\% of individuals dying soon after the aneurysm ruptures.

  • Characteristic Symptom: Sudden, explosive, excruciating headache.

  • Aneurysms can occur in any blood vessel in the body.

Patient Assessment for Stroke

Subjective Assessment

  • Onset Description: Gather details about when symptoms started and what they consisted of.

  • Headache: Inquire about a sudden or explosive headache, indicative of hemorrhagic stroke.

  • Sensory Deficits: Ask about numbness, tingling, or changes in sensation.

  • Cognitive Issues: Assess for inability to think clearly.

  • Visual Problems: Look for sudden loss of vision, double vision, or blurred vision.

Objective Assessment

  • Motor Function: Assess for hemiparesis (weakness) or hemiplegia (paralysis) on one side of the body. Check for arm/leg symmetry and facial drooping.

  • Level of Consciousness (LOC): Monitor for changes.

  • Increased Intracranial Pressure (ICP): Watch for signs.

  • Respiratory Status: Assess breathing patterns and effectiveness.

BE FAST Acronym (Stroke Symptoms)

  • Balance: Has the person lost their balance? (Also H for Headache or dizziness)

  • Eyes: Is there a loss of vision in one or both eyes?

  • Face: Does the person's face look uneven? Is there mouth or eye drooping on one side?

  • Arm: Is there weakness? Ask the person to hold both arms out; an "arm drift" (inability to hold one arm up) is a sign.

  • Speech: Is the person having trouble speaking or forming words?

  • Time: Time is of the essence; call 911 immediately.

Aphasia and Dysarthria

  • Aphasia: Total loss of comprehension and use of language.

    • Expressive Aphasia: Difficulty articulating words; associated with stroke affecting Broca's area (frontal lobe).

    • Receptive Aphasia: Difficulty comprehending spoken and written communication; associated with stroke affecting Wernicke's area (temporal lobe).

  • Dysarthria: Difficulty with speech articulation.

Contralateral Effects

A lesion on one side of the brain produces signs and symptoms on the opposite side of the body due to the crossing of nerve fibers at the base of the brain.

  • Right Brain Damage (Stroke on the right side): Presents with symptoms on the left side of the body.

    • Left hemiplegia or hemiparesis.

    • Left-sided neglect.

    • Spatial-perceptual defects, including hemianopia (loss of vision in the left visual field).

    • Tendency to deny or minimize problems.

    • Short attention span.

    • Impulsivity and lack of safety awareness.

    • Impaired judgment.

    • Impaired time concepts.

  • Left Brain Damage (Stroke on the left side): Presents with symptoms on the right side of the body.

    • Right hemiplegia or hemiparesis.

    • Aphasia (left side is dominant for speech).

    • Impaired right-left discrimination.

    • Slow performance with ADLs and walking.

    • Depression or anxiety.

    • Impaired comprehension related to language or math.

Diagnostic Tests

  • CT Scan: Crucial for rapid diagnosis, especially to differentiate between ischemic and hemorrhagic stroke. Usually shows up on CT; if not, MRI is typically performed.

  • MRI Scan: Provides detailed images if CT is inconclusive.

  • PET Scan: Shows the extent of tissue damage.

  • Cerebral Angiogram: Allows for detailed evaluation of brain vasculature, particularly important after a TIA.

Medical Management of Stroke

Stroke is a medical emergency requiring rapid triage, transport, and treatment. Knowing the exact time of symptom onset is critically important.

Management for Hemorrhagic Stroke

  • Surgery: May be performed to prevent re-bleeding of an aneurysm, including craniotomy, tying or clipping the aneurysm, and removing the clot.

  • Nimodipine: A calcium channel blocker used to prevent vasospasms, must be started within 96 hours of stroke onset. Blood is an irritant, causing vasospasm and reducing blood flow.

Management for Ischemic Stroke

  • Thrombolytics (e.g., tissue plasminogen activator - TPA or alteplase):

    • Can only be given within 3 hours of symptom onset.

    • 30\% more likely to recover with little to no disability if given within the timeframe.

    • Many patients do not receive TPA due to being outside the time window or having contraindications (e.g., history of GI bleed, hemorrhagic stroke, or bleeding problems).

    • TPA works by dissolving the clot, but carries a high risk of death from bleeding. Patients must weigh the risk against permanent disability.

  • Anticoagulants: Heparin, oxaparin, warfarin.

  • Anti-platelets: Aspirin, Plavix.

  • Endovascular Embolectomy:

    • Surgical removal of a blood clot from inside the brain.

    • Can be performed up to 8 hours after stroke onset.

    • Procedure: Catheter inserted through the femoral artery, clot entrapped, balloon inflated to temporarily stop blood flow, clot removed, balloon deflated, blood flow restored.

    • Effective for larger clots unresponsive to TPA.

    • Key Principle: "Time is brain" – emphasizing the importance of rapid intervention.

General Supportive Treatments

  • Dexamethasone: Used to reduce intracranial pressure.

  • Suppositories: To prevent straining with bowel movements.

  • Fluid Restriction: To prevent cerebral edema.

  • Energy or Gastrostomy Tube: May be placed to prevent aspiration during feeding.

  • Bed Rest: Essential for recovery.

  • Rehabilitative Therapies: Physical therapy (PT), occupational therapy (OT), and speech therapy are crucial disciplines.

Nursing Diagnoses and Interventions

  • Monitor Neurological Status:

    • Utilize the Glasgow Coma Scale for rapid determination of LOC.

    • Use the NIH Stroke Scale to evaluate extremity weakness, facial drooping, aphasia, and spatial-perceptual deficits.

    • Assess pupillary responses, vital signs, and extremity movement/strength.

  • Address Impaired Swallowing (Dysphagia):

    • Perform dysphagia screening before initiating feedings.

    • Position the patient with the head elevated and turned to the unaffected side during feeding.

    • Provide soft foods and thickened liquids; avoid milk products (thicken mucus).

    • Do not allow straw use.

    • Inspect the mouth for "pocketing" of food after meals.

    • Ensure oral hygiene, especially on the affected side.

    • Educate family members on dysphagia techniques.

  • Assist with Self-Care Deficits:

    • Encourage self-care as much as possible.

    • Teach one-handed dressing and feeding techniques.

  • Manage Incontinence:

    • Remove Foley catheters as soon as possible if inserted in the ED.

    • Implement bladder training programs.

  • High Risk for Injury:

    • Patients have lost proprioception, increasing injury risk.

    • Repeat directions and demonstrate care.

    • For hemianopia, approach the patient from the non-paralyzed side and teach them to scan past the midline.

    • Watch for unilateral neglect (failure to recognize a paralyzed side); inspect and protect the affected side from injury.

    • Implement safety precautions due to poor judgment and impulsivity.

  • Address Emotional Responses: Patients may exhibit exaggerated or unpredictable emotional responses.

  • Compromised Verbal Communication:

    • A speech pathologist will evaluate and treat.

    • Use yes/no questions, speak slowly and distinctly, and approach in an unhurried manner.

    • Provide communication boards or computers.

    • Wait for the patient to finish sentences; do not interrupt.

    • Ensure the call light is within reach.

    • Teach family members strategies to enhance communication.

Patient and Family Teaching

  • Rehabilitation begins at admission.

  • Educate on medication side effects, follow-up plans, safety techniques, and appropriate communication.

  • Recognize stroke as a family issue; refer to stroke support groups.

Transient Ischemic Attack (TIA) - "Mini Stroke"

A TIA is a transient ischemic attack, characterized by cerebral vascular insufficiency with temporary episodes of neurologic dysfunction. These episodes typically last less than 24 hours, most often less than 15 minutes, and usually resolve within a 3-hour period.

Significance

  • TIAs are a crucial precursor to a full stroke; a patient experiencing TIAs has a significantly higher risk of a future stroke (approximately 40\% of patients with TIAs will have a stroke in 2 to 5 years).

  • Underlying pathological conditions must be identified and addressed.

Causes

  • Microemboli.

  • Narrowing of small vessels in the brain.

  • Common in patients with carotid artery stenosis, leading to decreased blood flow to and within the brain.

Common Deficits and Symptoms

Symptoms are similar to a stroke but are temporary and resolve completely between attacks.

  • Contralateral weakness of the lower face, hands, and arms.

  • Transient dysphagia (difficulty swallowing that comes and goes).

  • Temporary loss of vision in one eye.

  • Sudden inability to speak.

  • Numbness or loss of sensation.

  • Tinnitus.

  • Vertigo.

  • Blurred vision.

  • Diplopia (double vision).

  • Eyelid ptosis (drooping eyelid).

  • Ataxia (impaired coordination).

Diagnostic Tests for TIAs

  • CT Scan of the brain without contrast: The most important initial diagnostic study.

  • Lab work.

  • X-rays.

  • Ultrasounds of the carotid arteries.

  • Cardiac testing.

Treatment for TIAs

  • Medications:

    • Anti-platelets: Aspirin or Plavix.

    • Anticoagulants: Typically Coumadin for patients with atrial fibrillation who have experienced a TIA.

  • Surgical Interventions:

    • Carotid Endarterectomy: Surgical removal of a lesion from the carotid artery to improve blood flow. Reserved for patients with carotid artery blood flow occlusions of 70\% to 99\%.

    • Percutaneous Transluminal Angioplasty: A balloon is inserted to open stenosed arteries and increase blood flow. The biggest risk with this procedure is the dislodgement of an embolus, which can lead to a stroke.