6.6:Neural Function Disorders — Cerebrovascular Accident

What is a cerebrovascular accident (CVA)?

A disruption of blood flow to an area of the brain

What is another name for a cerebrovascular accident?

Stroke

How can a stroke occur?

By a blocked or ruptured blood vessel

What happens to brain tissue during a stroke?

It begins to die due to lack of oxygen and nutrients

Why are strokes considered serious?

They are a leading cause of morbidity and mortality

What can happen to stroke survivors?

They may have neurologic deficits

What is key to preventing permanent brain damage in stroke?

Rapid intervention and treatment

How can stroke prevention be achieved?

Controlling modifiable risk factors

What are nonmodifiable risk factors for stroke?

Age, sex, race, prior stroke, and family history

How does age affect stroke risk?

Incidence increases with age

How does sex affect stroke risk?

Men have higher incidence younger, women have higher mortality

Which racial groups have higher stroke mortality?

African Americans and Hispanic/Latino Americans

What are modifiable risk factors for stroke?

Hypertension, hypercholesteremia, diabetes, hypercoagulopathy, cardiac disease

What are modifiable behaviors for stroke prevention?

Smoking, alcohol use, birth control pills especially with smoking, immobility, obesity, illicit drug use

What are the two mechanisms that cause strokes?

Ischemic (blocked vessel) and hemorrhagic (ruptured vessel)

What is an ischemic stroke?

A stroke caused by a blocked blood vessel

What percentage of strokes are ischemic?

About 80%

What are the two most common types of ischemic strokes?

Thrombotic and embolic

What causes a thrombotic stroke?

Atherosclerotic plaques in major brain vessels

What is an embolic stroke?

A stroke caused by a clot that travels to the brain

Where do most cerebral emboli originate?

The heart

What is another source of emboli besides the heart?

Carotid artery plaques

What cardiac conditions increase risk for embolic stroke?

Atrial fibrillation, myocardial infarction, and endocarditis

What are lacunar infarcts?

Small vessel blockages deep in the brain

What conditions are associated with lacunar infarcts?

Hypertension and diabetes

What is a transient ischemic attack (TIA)?

A temporary disruption of blood flow to the brain caused by atherosclerotic blockage in the main feeding arteries to the brain.

What are TIAs commonly called?

Mini strokes

How long do TIA symptoms typically last?

Less than 24 hours

Do TIAs cause permanent brain damage?

No

Why are TIAs important?

They are a warning sign of future stroke

What is a hemorrhagic stroke?

A stroke caused by a ruptured blood vessel

Where can hemorrhages occur in hemorrhagic stroke?

Intracerebrally or in the subarachnoid space

Why are hemorrhagic strokes dangerous?

Increased pressure causes edema and rapid tissue death

What can happen if hemorrhagic stroke is untreated?

Coma and death

What is a common cause of hemorrhagic stroke?

Uncontrolled hypertension, excessive or unmonitored use of blood thinners, weakened blood vessels or aneurysms, and less commonly arteriovenous malformations

What is an arteriovenous malformation (AVM)?

A tangle of abnormal arteries and veins that disrupt blood flow

What determines the signs and symptoms of a stroke?

Which vascular territory is compromised, brain area affected, and collateral circulation

How do stroke symptoms typically present?

Suddenly and usually unilaterally. This happens because a stroke damages one hemisphere of the brain, which controls the opposite side of the body.

What are common symptoms of a stroke?

Slurred speech, numbness or paralysis, blurred vision, difficulty walking, loss of balance, headache, vomiting, or loss of consciousness

What do neurologic impairments indicate in stroke?

That a stroke is occurring

What happens if stroke treatment is delayed?

Brain damage can become permanent

What is the most common type of deficit after a stroke?

Motor deficits

On which side of the body do motor deficits occur after a stroke?

The contralateral side

What happens to muscle tone in the first 6–8 weeks after a stroke?

Muscles are flaccid and weak

What happens to muscle tone after the initial flaccid stage?

Spasticity (abnormally increased muscle tone) develops

What type of muscle tone is seen in the upper extremities after stroke?

Increased flexor tone

What type of muscle tone is seen in the lower extremities after stroke?

Increased extensor tone

What are contractures?

Shortening and hardening of muscle tendons limiting joint motion

What can result from untreated increased muscle tone?

Contractures; Loss of mobility and skin breakdown occurs

How can spasticity be beneficial after a stroke?

It can compensate for muscle weakness

Why must spasticity be monitored?

To prevent complications like contractures

What is dysarthria?

A motor speech disorder affecting articulation, pitch, and quality

What causes dysarthria?

Weakness of speech muscles

Is language comprehension affected in dysarthria?

No

What is aphasia?

Inability to comprehend, interpret, or express language

Which artery is commonly involved in aphasia?

Middle cerebral artery

What is the main function of broca’s area?

Speech production and articulation

What is hemineglect?

Inability to perceive sensory input from one side

Which side is affected in hemineglect?

The contralateral side

How does hemineglect affect movement?

People may not use limbs on the affected side

What cognitive changes can occur after a stroke?

Memory loss, depression, and apraxia

What is apraxia?

the impaired ability to perform previously learned motor activities even though they possess normal sensory and motor function.

Are visual impairments common after a stroke?

Yes

What is required to diagnose a stroke?

A thorough patient history and neurologic exam

What are the goals of stroke evaluation?

Determine if ischemic or hemorrhagic, cause, and severity of neurologic involvement

What imaging techniques are primarily used to diagnose stroke?

CT scan, vascular imaging, and MRI

What is the purpose of CT and MRI in stroke diagnosis?

Determine stroke type and rule out other disorders

What is vascular imaging used for in stroke diagnosis?

To determine the source of arterial involvement

What are examples of vascular imaging techniques?

CTA, MRA, arteriography, and ultrasound

What are the main goals of stroke treatment?

Salvage brain tissue, prevent another stroke, and reduce disability

Where should stroke treatment ideally occur?

A hospital certified in stroke care

What medication is used for acute ischemic stroke?

Tissue plasminogen activator (tPA)

What is the function of tPA?

Breaks up the clot causing the stroke

When must tPA be administered?

Within 3–4.5 hours of symptom onset

What must be ruled out before giving tPA?

Hemorrhagic stroke

What is a major risk of tPA in hemorrhagic stroke?

Intracranial hemorrhage

What are catheter-based treatments for ischemic stroke?

Mechanical break down clot, targeted thrombolytics to the clot, or stent placement for normal blood flow

Why are catheter-based treatments used?

Although more invasieve, it provides treatment for patients outside the tPA time window

What is the focus of treatment for hemorrhagic stroke?

Control bleeding and reduce brain pressure

How can hemorrhagic stroke be treated?

Pharmacologically or surgically

What is done if a patient on blood thinners has a hemorrhagic stroke?

Given drugs to counteract their effects

What medications are used in hemorrhagic stroke?

Drugs to lower intracranial pressure, blood pressure, and seizure risk

What happens after bleeding is controlled in hemorrhagic stroke?

Patient is monitored while blood is reabsorbed

When is a craniotomy needed in hemorrhagic stroke?

When bleeding is severe

What is a craniotomy?

Surgical opening of the skull

What vascular abnormalities may require surgery in hemorrhagic stroke?

surgical clamping of an aneurysm or removal of an AVM.

What is the goal of post-stroke rehabilitation?

Prevent another stroke and regain function

What does the medical team provide during rehabilitation?

Education on reducing modifiable risk factors

When is physical rehabilitation started after stroke?

Once the patient is stabilized

When is the most functional recovery seen after stroke?

Within the first 6 months

Where are patients often sent after stroke stabilization?

Inpatient rehab facility

What is the purpose of inpatient rehab?

Regain function to return home or train caregivers to provide care

What additional therapy may patients need after discharge?

Home or outpatient therapy