Transient Ischemic Attack (TIA) vs. Stroke

Transient Ischemic Attack (TIA)

• A TIA is a temporary blockage of blood to the brain, leading to brief neurological impairment.
• The episode lasts minutes to hours, with complete patient recovery.
• Risk factors, causes, and symptoms mirror those of a stroke.
• Untreated TIAs have a 15% chance of preceding a full stroke.
• Immediate evaluation is critical to reduce stroke risk.
• Treatment focuses on stroke prevention via diagnostic tests and minimizing patient risk factors.

Stroke

• A stroke, or cerebrovascular accident (CVA), is caused by disrupted blood flow that leads to brain cell death and often permanent disability.
• About 795,000 individuals are affected annually, with increased risk associated with age.
• Annually, 55,000 more women than men experience strokes due to increased longevity.
• Stroke is the fifth leading cause of death and a top cause of disability, with 147,810 deaths in the U.S. in 2018.
• Blacks, Hispanic Americans, and American Indian/Alaska Natives face higher stroke risks.
• Lower education and socioeconomic status, plus residence in the southeastern U.S., elevate stroke risk.

Pathophysiology

• Brain function requires consistent oxygen and glucose supply from blood.
• A stroke causes immediate brain cell death.
• The penumbra, a surrounding area of stunned brain cells, can be revived with prompt reperfusion.
• The affected brain area and symptoms depend on the vessels involved.
• Ischemia duration determines if symptoms are transient or permanent.
• Transient Ischemic Attack symptoms usually resolve within 24 hours, but can signal an impending stroke.

Etiology

• Strokes are classified as ischemic (87% of cases) or hemorrhagic (13% of cases).

Ischemic Stroke

• Ischemic stroke happens when brain blood supply is blocked or severely reduced, and main types are thrombotic and embolic.
• Thrombotic strokes occur when artery occlusion builds up until it significantly reduces or stops blood flow, often in carotid arteries.
• Embolic strokes are typically caused by blood clots formed elsewhere (commonly in the heart) which then travel to the brain.

Risk Factors

• Ischemic stroke risk factors are classified as modifiable or nonmodifiable.
• Nonmodifiable risk factors include age and gender. Modifiable risk factors, like high blood pressure, can be changed via treatment
• Women face additional risks with hormone changes during pregnancy and menopause.

Modifiable Risk Factors

• Modifiable risk factors for stroke in both men and women:
• Cigarette smoking
• High blood pressure
• Diabetes mellitus
• Cardiovascular disease
• High total cholesterol
• Low high-density lipoprotein (HDL) cholesterol
• Dyslipidemia
• Atrial fibrillation
• Asymptomatic carotid stenosis
• Sickle cell disease
• Obesity
• Excessive alcohol intake
• Poor diet (high sodium, high fat, low potassium)
• Physical inactivity
• Modifiable risk factors specific to women:
  • Pregnancy
  • Oral contraceptives
  • Hormone replacement therapy
  • High triglycerides
  • History of migraines
  • Thick waist

Hemorrhagic Stroke

• Hemorrhagic strokes result from a ruptured cerebral blood vessel
• This rupture allows blood to escape and compress surrounding brain tissue.
• Hemorrhagic strokes are classified into subarachnoid and intracerebral hemorrhage.

Subarachnoid Hemorrhage

• It occurs on the brain's surface, often from a ruptured cerebral aneurysm.
• It is usually serious, requires surgery, and can be fatal.

Intracerebral Hemorrhage

• It occurs in deeper brain tissues, often due to uncontrolled hypertension.
• They can happen with minimal deficits, but damage accumulates, leading to major deficits.
• A blood pressure goal of below 130/80 mm Hg is recommended for patients who experience one.

Warning Signs of Stroke

• Patients & family should be taught to recognize stroke signs/symptoms and activate emergency medical services (EMS).
• Treatment within 1 hour of symptom onset can minimize/avoid permanent loss of function.
• The acronym FAST (Face, Arms, Speech, Time) is used to recognize stroke.
• Immediate EMS activation is needed for:
• Sudden numbness/weakness of face, arm, or leg (especially one side)
• Sudden confusion or trouble speaking/understanding
• Sudden trouble seeing in one/both eyes
• Sudden trouble walking, dizziness, loss of balance, or coordination
• Sudden severe headache with no known cause
• Unique symptoms in women:
• Nausea
• Facial and limb pain
• Sudden behavioral changes
• Hallucinations
• General weakness
• Chest pain
• Shortness of breath
• Hiccups
• Palpitations

Acute Signs and Symptoms

• Stroke symptoms are sudden or rapidly evolving, varying with the affected brain area
• Common symptoms include:
  • Visual disturbances
  • Language disturbances
  • Weakness or paralysis on one side
  • Difficulty swallowing (dysphagia)
• Both Ischemic and Hemorrhagic strokes have similar general symptoms, including drowsiness and severe headache.

Language Disturbances

• Difficulty with language commonly occurs with TIA and stroke. -Aphasia is the absence of language. Dysphasia is difficulty with language and is not as severe as aphasia.
• Those with dysphasia struggle with:
  • Selecting correct words
  • Using incomprehensible speech
  • Understanding others' speech
  • Trouble writing or reading
• Aphasia types:
  • Expressive: Knows what to say but cannot speak or make sense.
  • Receptive: Inability to understand spoken or written words.
  • Global: Both expressive and receptive aphasia are present.
• Dysarthria: Slurred/indistinct speech due to motor problems, causes delay in treatment and emphasizes symptom observation.

Motor Disturbances

• Motor disturbances include paralysis, weakness, and numbness.
• The first sign of paralysis or weakness may be clumsiness or limb heaviness.
• The onset is typically sudden - usually involves one side of the body opposite the damaged brain area.
• Deficits can affect both body sides if there is brainstem or vertebrobasilar stroke.
• Paralysis or weakness commonly affects the arm and face.
• Some patients have complete hemiparesis (one entire side flaccid).
• Ataxia (poor balance/staggering gait) may be present due to cerebellum damage or poor coordination.
• Swallowing muscles affected: dysphagia (trouble swallowing).

Visual Disturbances

• Visual field disturbances are also common with stroke.
• Vision loss is painless, can involve losing all or part of vision in one eye.

Diagnostic Tests

• Patients should undergo a swallow (dysphagia) screening test before consuming anything to prevent possible aspiration in cases of suspected stroke.
• Facial weakness or asymmetry indicates nothing should be given by mouth. Then, have the patient swallow 30 mL of water to determine weakness.
• Perform an immediate computed tomography (CT) scan to identify hemorrhagic stroke, which determines treatment.
• Ischemic stroke changes are not visible on CT scans until several days after the event.
• After CT scan, patients may have an electrocardiogram (ECG) to determine whether atrial fibrillation is present.
• Echocardiogram may be done to determine heart disease that increases thrombus risk.
• Other tests may include complete blood count (CBC), blood glucose level, metabolic panel, blood typing, prothrombin time (PT), international normalized ratio (INR).

Interventions for Stroke

• Initial emergency care supports ABCs (Airway, Breathing, Circulation) while awaiting test results.
• Administer oxygen to maintain SpO2 at or above 94% and the patient's level of consciousness (LOC) is reduced.
• Monitor vital signs and heart rhythm, temperature >99.6°F (37.5°C) can worsen patient outcomes.
• Some hospitals have stroke teams that evaluate patients within 2 hours, assess within 15 minutes, conduct tests, and get results in 45 minutes.
• The healthcare provider (HCP) decides about thrombolytic therapy within 1 hour of arrival.
• Hyperglycemic patients should have blood glucose lowered to 140–180 mg/dL. Use IV fluids without glucose.
• Stroke patients may develop increased intracranial pressure (ICP) and are at risk for repeated strokes.
• Ischemic stroke patients may be candidates for thrombolytic therapy to lyse thrombi within 4.5 hrs.
• Thrombolytic agents can lyse thrombi by converting plasminogen to plasmin.
• Stent-retrieval devices may remove thrombus remnants after tPA use in ischemic strokes involving large brain vessels.
• Blood pressure control is vital: maintain below 185/110 mm Hg to reduce bleeding if administering tPA.

Medications

• Beta blockers or calcium channel blockers are often used for fast-acting effects (can be given via IV)
• High blood pressure may be allowed to salvage tissue, unless systolic exceeds 220 mm Hg or diastolic exceeds 120 mm Hg.

Medications Used in Cerebrovascular Disorders

• Thrombolytic Agents dissolve existing clots:
  • alteplase (tissue plasminogen activator [tPA]; Activase)
  • Administer within 3 to 4.5 hours of symptom onset
  • Monitor for bleeding
• Antiplatelet Agents Prevent formation of clots:
  • aspirin
  • clopidogrel (Plavix)
  • aspirin/dipyridamole (Aggrenox)
  • Monitor patient for bruising, change in level of consciousness, and prolonged bleeding time.
• Anticoagulant Agents Prolong time to form clots; prevent new clots:
  • warfarin (Coumadin)
  • heparin
  • Monitor patient for bruising, change in level of consciousness, and prolonged bleeding time, and INR
• Cholesterol-Lowering Agents Reduce cholesterol level:
  • simvastatin (Zocor)
  • pravastatin (Pravachol)
  • atorvastatin (Lipitor)
  • lovastatin (Mevacor)
  • Monitor for muscle pain or weakness

General Post-stroke treatments

• Medical management focuses on controlling TIA/stroke causes, diagnostic test results help determine course of treatment.
• The HCP will order physical, occupational, & speech therapy for residual deficits.
• Those with a minor stroke receive dual antiplatelet therapy: aspirin and clopidogrel (Plavix) within 24 hours.
• The patient in atrial fibrillation may also receive an anticoagulant to prevent thrombus development.
• Cholesterol-lowering medication (preferably a statin) will be ordered for patients who have a low-density lipoprotein (LDL) cholesterol level greater than 70 mg/dL. Statin helps minimize atherosclerotic plaques as well as have neuroprotective effect, and may decrease stroke risk.
• Monitor for deep vein thrombosis (DVT). Prevention involves anticoagulant medication/nondrug treatments.
• Stroke patients are at risk for respiratory complications (increased ICP, decreased LOC, impaired swallowing).

Surgery

• Carotid endarterectomy may be performed for patients with significant carotid artery occlusion.
• A carotid stent may be placed for patients at high surgical risk (catheter advances, balloon inflated, stent expands.)

Long-Term Effects of Stroke

• Often caused by lack of tx with a thrombolytic agent
• paralysis are common long-term effects of stroke.
• The side of the body opposite the cerebral infarct (contralateral side) is affected because nerve fibers cross over as they pass from the brain to the spinal cord
• Paralysis on one side of the body is termed hemiplegia (affected limbs may be weak/totally paralyzed flaccid)
• Patients are prone to contractures which cause permanent immobility.
• Adaptation/assistance with daily living activities is often required.
• Patients should be mobilized within 24 hours, and physical/occupational therapy are provided to maximize functioning.
• Motor involvement affects swallowing, urination, and bowel control.
• Sensation changes prevent awareness of pressure, temperature, injuries.
• Speech center affected when stroke affects the temporal lobe region, notably on the dominant body side (aphasia)

Pseudobulbar Affect

• It can manifest as emotional lability/instability.
• Patients rapidly shift from sadness to euphoria.
• Laughing/crying may not relate to the patient's situation.

Impaired Judgement

• Common especially in those who have a had right-sided stroke or brain injury.
• Patients have high safety risk, poor understanding of limitations.

Unilateral Neglect

• Especially in those who have right-hemisphere infarcts
• Patients may not acknowledge their environment/body side.

Long term effects

• Stroke can cause pneumonia, DVT, pulmonary embolism, pressure injuries, malnutrition, depression.

Cerebral Aneurysm, Subarachnoid Hemorrhage, and Intracranial Hemorrhage

• A cerebral aneurysm is a weakness in a cerebral artery wall which may be congenital/traumatic/disease-related. Rupture causes subarachnoid hemorrhage.
• Unruptured aneurysms are asymptomatic unless very large which causes brain tumor symptoms
• Aneurysms often occur in the circle of Willis, particularly at the bifurcation of an atery

Signs and Symptoms

• Some patients have a small hemorrhage before diagnosis of subarachnoid hemorrhage
• Rupture of an aneurysm leads to sudden onset of a severe headache.
• Sensitivity to light is common, causing reluctance to pupil examination.
• LOC varies patient may be alert/coherent, or lose conciousness, and may lead to seizures due to brain fluid disruption

Diagnostic tests

• CT or MRI scan (preferred) of the head due to symptoms
• Contrast studies may be helpful but can be frightening
• Precise diagnosis of an aneurysm requires a cerebral angiogram

Therapeutic Measures

• Patients cared for in ICU with arterial line and CVP catheter for blood pressure monitoring. High pressures increase re-rupture risk.
• Blood pressure is kept between systolic pressure maintained between 120-160mmHg
• Vasopastic drugs used to maintain blood pressure
• Surgery is done if not too dangerous and patient is healthy, surgery ends remove, reconnected to maintain blood flow

Hydrocephalus

• Blood in the ventricular system interferes with the circulation.
• Reabsorption of cerebrospinal fluid (CSF), and hydrocephalus can develop.
• Early in subarachnoid hemorrhage, an external ventricular drain may be used to treat hydrocephalus.

Vasospasm

• Vasospasm causes blood vessels to narrow and cause ischemia/infarct
• Happens in long-term complications of subarachnoid hemorrhage.

Nursing Interventions

Data Collection

• Observe these vitals associated with lack of cerebral tissue perfusion:
• Decreased LOC, instability, dizziness.
• Syncope, vision issues, and unequal pupil size/response.
• Paresthesia issues, motor function issues, and whether patient displays possible seizures.

Implementation

• Perform mobility assessments with care.
• Consult occupational therapists to assess patient deficits, then tailor specific plans to work on patient's mobility and what they can/cannot do.
• Assess patient for pressure ulcers, skin irritation, or skin-based infection.
• Regularly check patient's vitals and compare against normal values for irregularities.
• Follow any implementations as guided by the patient's plan.
• Ask for speech pathologist guidance in finding best strategies to increase patient communication.
• In cases of confusion, make an intentional effort to not cause external stimuli like loud noises or high-traffic areas.
• If patient may fall, assess and remove risks, perform checks w/ mobility, and remove restraints unless very important.

Nutrition Guidance

• Impaired motor deficits can cause insufficient nutrition and put patients at risk.
• Perform dysphagia screenings which are quick and easy methods to find if the patient is able to follow directions and swallow safely.
• A speech language pathologist can determine the best food structures to feed the patient safely and properly.
• Help patients eat slowly.
• Sit the patient upright with proper posture to lower reduce chance of choking.
• Make use of possible suction tools to prevent aspiration.

Patient Stability

• The overall goal should be to stabalize the patient to promote bloodflow and safety.
• Check circulation levels and oxygen saturation to reduce potential issues.
• Report irregularities - especially when patient begins to decline
• Report when the patient's health status is improving, has stabilized, or is free from problems.
• Prevent risks and take action if the patient gets an injury.
• In all stroke cases, act and assess fast.
• When safe, report potential areas of improvement or decline. Communicate with any external parties when helpful.