Section 5: Stroke - Types and Pathophysiology

NUR 433: Adult Health II; MCUSON; Mrs. Cooper

A _____ (“brain attack”) is a sudden loss of blood flow to a localized area of the brain, causing neurologic deficits

stroke

About 87% are _____ (a blocked vessel)

ischemic

about 13% are _____ (a ruptured vessel)

hemorrhagic

Stroke is the _____ leading cause of death in the U.S., a leading cause of disability, and most common after age 65

fifth

***Deficits depend on which area is affected, how large it is, and how long blood flow was reduced

_____ stroke: the process of clot formation (thrombosis) results in a narrowing of the lumen, which blocks the passage of the blood through the artery

thrombotic

_____ stroke: an embolus is a blood clot or other debris circulating in the blood. when it reaches an artery in the brain that is too narrow to pass through, it lodges there and blocks the flow of the blood

embolic

_____ stroke: a burst blood vessel may allow blood to seep into and damage brain tissues until clotting shuts off the leak

hemorrhagic

pathophysiology: why time is brain

1. Blood flow and oxygen to neurons drop; cells change within ___-___ minutes

4-5

pathophysiology: why time is brain

2. Cellular metabolism stops and the _____–_____ pump fails

sodium-potassium

pathophysiology: why time is brain

3. _____ and water enter the cells (water follows salt). Cells swell, further impeding blood flow

sodium

pathophysiology: why time is brain

4. A core of dead tissue forms, surrounded by the penumbra: hypoperfused but still viable cells. Saving the _____ is the goal of acute treatment

penumbra

pathophysiology: why time is brain

5. Deficits are _____: a left-brain stroke affects the right side of the body, and vice versa

contralateral

Cerebral circulation

The _____ ___ _____ links the major cerebral arteries and provides collateral flow if one is blocked

Circle of Willis

what artery supplies the anterior two-thirds of the hemispheres

internal carotid (ICA)

what typical stroke findings occur when the internal carotid artery is affected

• contralateral hemiparesis

• aphasia

• visual loss

what artery supplies the lateral cortex and motor/speech centers

middle cerebral (MCA) - most common

what typical stroke findings occur when the middle cerebral artery is affected

• facial droop

• arm>leg weakness

• aphasia

what artery supplies the medial and frontal lobes

anterior cerebral (ACA)

what typical stroke findings occur when the anterior cerebral artery is affected

• leg>arm weakness

• personality change

what artery supplies the brainstem, cerebellum, and posterior brain

vertebral/basilar

what typical stroke findings occur when the vertebral/basilar artery is affected

• dizziness

• ataxia

• dysphagia

• diplopia

what artery supplies the occipital lobe

posterior cerebral (PCA)

what typical stroke findings occur when the posterior cerebral (PCA) artery is affected

• visual field deficits

• cortical blindness

_____ stroke occurs when a blocked or narrowed cerebral artery causes an infarction

ischemic

a _____ _____ _____ (TIA) is the warning sign of an ischemic stroke

transient ischemic attack

a transient ischemic attack is a temporary _____ in blood flow from microemboli, vasospasm, or partial occlusion

drop

a transient ischemic attack symptoms resolve, usually within ___-___ hours and always within 24 hours: contralateral numbness or weakness, aphasia, visual changes

1-2

a transient ischemic attack has no _____ tissue change on CT or MRI

permanent

about one-third of people with a TIA will have a stroke within ___ years. Treat every TIA as an emergency.

5

what type of ischemic stroke occurs when a clot forms on atherosclerotic plaque in a cerebral artery. Often during sleep or rest, when lower BP can’t push blood past the narrowing.

thrombotic

list some causes/risks for thrombotic ischemic stroke

• atherosclerosis

• HTN

• diabetes

• hyperlipidemia

• smoking

a thrombotic ischemic stroke has a gradual or stepwise onset and is often preceded by _____

TIA (transient ischemic stroke)

what kind of ischemic stroke occurs when a clot, plaque, fat or air travels from elsewhere and lodges in a cerebral artery

embolic

list some causes/risks for an embolic ischemic stroke

• atrial fibrillation (most common)

• valve disease

• endocarditis

• post-MI mural thrombus

• prosthetic valves

embolic ischemic stroke has a sudden onset with maximum deficit at once and often occurs in _____ patients

younger

what ischemic stroke occurs when an occlusion of small penetrating arteries in deep structures (basal ganglia, pons, thalamus)

lacunar

list some causes/risks for a lacunar ischemic stroke

• chronic HTN

• diabetes

a lacunar ischemic stroke has small infarcts, pure motor or pure sensory deficit, and no _____

aphasia

what kind of stroke occurs when a ruptured vessel spills blood into brain tissue, ventricles or the subarachnoid space

hemorrhagic stroke

in a hemorrhagic stroke, _____ compresses tissue, triggers vasospasm and edema, and raises ICP, which can cause coma or death.

blood

Uncontrolled _____ is the most common cause for a hemorrhagic stroke

hypertension

an _____ hemorrhage (ICH) occurs in the brain tissue

intracerebral

list some causes/risks for an intracerebral hemorrhage

• chronic HTN (most common!)

• anticoagulants

• vascular malformation

• trauma

• tumor

list some classic findings for an intracerebral hemorrhage (ICH)

• sudden severe headache

• vomiting

• rapid neuro decline

• hemiplegia

• unequal pupils

• increased ICP

a _____ hemorrhage (SAH) occurs between the arachnoid and pia mater

subarachnoid

list some causes/risks for a subarachnoid hemorrhage

• ruptured aneurysm

• arteriovenous malformation (AVM)

• trauma

list some classic findings for a subarachnoid hemorrhage

• “worst headache of my life”

• N/V

• nuchal rigidity

• photophobia

• decreased LOC

• seizures

list some risk factors to screen for in the acute history of a hemorrhagic stroke

• hypertension (the leading risk factor)

• atrial fibrillation

• prior TIA or stroke

• diabetes

• smoking

• anticoagulant use

• cocaine or amphetamine use